This article was downloaded by: [b-on: Biblioteca do conhecimento online UC]On: 15 November 2013, At: 09:19Publisher: RoutledgeInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Journal of Clinical Child & Adolescent PsychologyPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/hcap20

Cogmed Working Memory Training for Youth with ADHD:A Closer Examination of Efficacy Utilizing Evidence-Based CriteriaAnil Chacko a b c d , Nicole Feirsen b , Anne-Claude Bedard c , David Marks e , Jodi Z.Uderman c & Alyssa Chimiklis ca Department of Psychology, Queens College , City University of New Yorkb Department of Psychology , The Graduate School and University Center, CUNYc Department of Psychiatry , The Mount Sinai School of Medicined Department of Child and Adolescent Psychiatry , New York University School of Medicinee New York University Langone Medical Center Child Study CenterPublished online: 13 May 2013.

To cite this article: Anil Chacko , Nicole Feirsen , Anne-Claude Bedard , David Marks , Jodi Z. Uderman & Alyssa Chimiklis(2013) Cogmed Working Memory Training for Youth with ADHD: A Closer Examination of Efficacy Utilizing Evidence-BasedCriteria, Journal of Clinical Child & Adolescent Psychology, 42:6, 769-783, DOI: 10.1080/15374416.2013.787622

To link to this article: http://dx.doi.org/10.1080/15374416.2013.787622

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Cogmed Working Memory Training for Youthwith ADHD: A Closer Examination of Efficacy

Utilizing Evidence-Based Criteria

Anil Chacko

Department of Psychology, Queens College, City University of New York;Department of Psychology, The Graduate School and University Center, CUNY;

Department of Psychiatry, The Mount Sinai School of Medicine; andDepartment of Child and Adolescent Psychiatry, New York University School of Medicine

Nicole Feirsen

Department of Psychology, The Graduate School and University Center, CUNY

Anne-Claude Bedard

Department of Psychiatry, The Mount Sinai School of Medicine

David Marks

New York University Langone Medical Center Child Study Center

Jodi Z. Uderman and Alyssa Chimiklis

Department of Psychology, The Graduate School and University Center, CUNY

The current review applied the evidence-based treatment criteria espoused by the Societyfor Clinical Child and Adolescent Psychology (Silverman & Hinshaw, 2008) to specifi-cally evaluate the short-term and longer term efficacy of Cogmed Working MemoryTraining (CWMT) as a treatment for youth with Attention-Deficit=Hyperactivity Dis-order (ADHD). Utilizing a systematic literature search, 7 studies that employed theschool-age version of CWMT were identified for this review. The data reviewed hereinsuggest mixed findings regarding the benefit of CWMT for youth with ADHD. Tworandomized controlled studies have demonstrated that CWMT led to improvements inneuropsychological outcomes and parent-rated ADHD symptoms relative to wait-listcontrol and placebo treatment conditions. Another study demonstrated effects ofCWMT relative to a placebo condition on an analog observation of behavior duringan academic task, although this study did not find an effect of CWMT on parent-ratedADHD. Finally, an additional study utilizing an active comparison control condition didnot find incremental benefits of CWMT on parent- or teacher-rated ADHD. Criticalissues in interpreting existing studies include lack of alignment between demonstratedoutcomes and the hypothesized model of therapeutic benefit of CWMT, issues withequivalence of control conditions, and individual differences that may moderate

Support during the preparation of this manuscript was provided through Award Number R34MH088845 from the National Institute of Mental

Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Mental

Health or the National Institutes of Health. We acknowledge Dr. Torkel Klingberg for his helpful assistance in reviewing this manuscript.Correspondence should be addressed to Anil Chacko, Department of Psychology, Queens College, 65-30 Kissena Boulevard, Flushing, NY

11367. E-mail: anil.chacko@qc.cuny.edu

Journal of Clinical Child & Adolescent Psychology, 42(6), 769–783, 2013

Copyright # Taylor & Francis Group, LLC

ISSN: 1537-4416 print=1537-4424 online

DOI: 10.1080/15374416.2013.787622

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

treatment response. Collectively, the strengths and limitations of the studies reviewedsuggest that CWMT is best defined as a Possibly Efficacious Treatment for youth withADHD.We suggest future directions for research and conclude with clinical implicationsof our findings for the treatment of youth with ADHD.

Behavioral interventions (i.e., contingency managementin the classroom and behavioral parent training) as wellas pharmacological interventions, most prominentlystimulant medication, are considered the best-supportedtreatments for Attention-Deficit=Hyperactivity Disorder(ADHD) (American Academy of Pediatrics, 2011;Pelham & Fabiano, 2008). These interventions resultin significant benefits for youth with ADHD across mul-tiple domains of functioning (Pelham & Fabiano, 2008).Important to note, these treatment modalities are notwithout limitations. Although stimulant medication isrelatively easy to implement, and for many providesrapid therapeutic benefit, a significant minority of youthwith ADHD do not respond to stimulant medication(10–30%; Goldman, Genel, Bezman, & Slanetz, 1998)or experience significant side effects that prohibit contin-ued use (<10%; Graham & Coghill, 2008). Parentalperceptions of the impact of stimulant medication onoverall health, as well as parental preference for alterna-tive treatments, influence the acceptance of and adher-ence to stimulant medication (see Chacko, Newcorn,Feirsen, & Uderman, 2010, for a review).

Behavioral interventions, in contrast, are often moredifficult to sustain over long periods, are generally morecostly, and arguably may be less effective than stimulantmedications—particularly for the core symptoms ofADHD (MTA Cooperative Group, 1999). The avail-ability of providers who utilize behavioral interventionshas also been noted as a limiting factor in providingeffective treatment for ADHD (American Academy ofPediatrics, 2011). In addition, there are several limita-tions that both stimulant medication and behavioralinterventions share. First, although efficacious, theseinterventions do not normalize the behavior of a signifi-cant number of youth with ADHD (J. M. Swanson et al.,2001), nor do treatment effects persist past the point ofactive dosing=implementation (Chronis, et al., 2001;Chronis, Pelham, Gnagy, Roberts, & Aronoff, 2003).Last, there appears to be very little data supporting theeffects of either intervention on key areas of functioning,such as academic achievement (Raggi & Chronis, 2006).

Given these limitations there has been a continuedinterest in developing alternative interventions forADHD. In particular, development of interventions thatmore directly address the pathophysiology of the dis-order, underlying compensatorymechanisms or identifieddeficiencies may yield benefits that persist after formaltreatment discontinuation. This treatment approachmay more likely impact the negative trajectories

experienced by youth with ADHD (Halperin & Healey,2011). There has been a growing recognition of theneuropsychological deficits underlying ADHD (Makris,Biederman, Monuteaux, & Seidman, 2009), which overthe past decade have focused substantially on the roleof executive function deficiencies. As such, there has beenincreasing efforts to target these deficits in youth withADHD (e.g., Sonuga-Barke, Thompson, Abikoff, Klein,& Brotman, 2006).

Working memory has received particular attention asan important factor in understanding ADHD in youth.First, although youth with ADHD have an array ofexecutive functioning deficits, working memory has beenobserved as one of the most significantly impaired(Willcutt, Doyle, Nigg, Faraone, & Pennington, 2005).Working memory has also been posited to serve a basicfundamental function that underlies more complexexecutive functions and core behavioral symptoma-tology characteristic of ADHD (Rapport, Chung,Shore, & Isaacs, 2001). There is also increasing recog-nition that youth diagnosed with ADHD and executivefunctioning deficits (including working memory deficits)may represent a distinct subgroup of ADHD (Lambeket al., 2010). Working memory is also an essentialcognitive ability that is related to reading and mathachievement (e.g., H. L. Swanson & Jerman, 2007;H. L. Swanson, Jerman & Zheng, 2008).

Given the role of working memory deficits in indivi-duals with ADHD, targeted interventions focused onimproving working memory appear to be an importantline of empirical inquiry. Notably, if working memorycan be improved in youth with ADHD, not only shouldADHD symptoms and other key impairments associa-ted with ADHD and working memory (e.g., academicimpairments) improve, but the underlying change inworking memory should result in more enduringtreatment-related changes that generalize across settingsand persist following treatment discontinuation.

One intervention focused on improving working mem-ory in youth with ADHD which has both undergoneempirical investigation and is now commercially availablefor use is Cogmed Working Memory Training (CWMT;http://www.cogmed.com). CWMT is a computerizedtraining program designed to improve working memoryby effectively increasing working memory capacity overa five-week training period. The program is built aroundthree age-specific software applications for preschoolchildren, school-age children, and adults, and wasdeveloped to target both storage and manipulation of

770 CHACKO ET AL.

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

TABLE1

Evidence-BasedCriteria(Silverm

an&Hinshaw,2008)

Criteria1:Well-Established

Treatm

ent

Criteria2:Probably

EfficaciousTreatm

ents

Criterion3:Possibly

EfficaciousTreatm

ents

Criterion4:Experim

ental

Treatm

ents

1.1.Theremust

beatleast

twogoodgroup-design

experim

ents,conducted

inatleast

two

independentresearchsettingsandby

independentinvestigatory

teams,dem

onstrating

efficacy

byshowingthetreatm

entto

be:

(a)statistically

significantly

superiorto

pillor

psychologicalplacebo

orto

another

treat-

ment

OR

(b)equivalent(ornotsignificantlydifferent)to

an

alreadyestablished

treatm

entin

experim

ents

withstatisticalpower

beingsufficientto

detect

moderate

differences

2.1.Theremust

beatleast

twogood

experim

ents

showingthetreatm

entis

superior(statisticallysignificantlyso)to

a

waitlist

controlgroup

OR

Criteria2.2

2.2.Oneormore

goodexperim

ents

meeting

theWell-Established

Treatm

entCriteria

with

theoneexception

ofhavingbeen

conducted

inatleast

two

independent

research

settings

and

by

independent

investigatory

teams

Atleastone‘‘good’’studyshowing

thetreatm

entto

beefficaciousin

theabsence

ofconflicting

evidence

Treatm

entnotyet

tested

intrials

meetingtask

forcecriteria

for

methodology

1.2.Treatm

entmanualsorlogicalequivalentwere

usedforthetreatm

ent

1.3.Conducted

withapopulation,treatedfor

specified

problems,forwhom

inclusioncriteria

have

beendelineatedin

areliable,validmanner

1.4.Reliable

andvalidoutcomeassessm

ent

measures,atminim

um

tappingtheproblems

targeted

forchangewereused

1.5.Appropriate

data

analyses

771

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

verbal and nonverbal working memory components.CWMT can be delivered in settings only where there isInternet access (e.g., home, school, etc.), makingwidespread dissemination more feasible relative to otherinterventions.

Although the school-age version includes 12 differentworking memory exercises, each individual completesonly eight exercises during a given session. For theschool-age version, training takes place in approxi-mately 30- to 45-min increments over 5 days per week(25 training days total), with 20 or more training ses-sions completed within 5 weeks considered complianceto CWMT. In the school-age version, exercises consistof tasks that require the user to store and=or manipulatevisual and=or auditory information. As an example, theuser may be presented digits verbally and asked to recallthese digits but in reverse order using a visual numberpad. In a given training session, the order of the eightwork memory exercises are decided by the user, but alleight exercises must be completed for the training ses-sion to be considered complete. The amount of time tocomplete an exercise is often approximately 3 to 4minbut will largely depend on how quickly responses areprovided by the user for each trial within an exercise.

For all versions of CWMT, the trials areindividualized=titrated to the capacity of the individualusing an adaptive, staircase design that adjusts the dif-ficulty of the program on a trial-by-trial basis. That is,correct trials are followed by successive trials with heigh-tened working memory demands, whereas incorrecttrials result in subsequent trials with diminished workingmemory load. Contingent reinforcement is integratedwithin the program such as earning small rewards (e.g.,toys, stickers, etc.) for successful completion of a trainingday or training week. Finally, each individual’s trainingis supervised by a training aide (typically a parent orguardian) and a certified CWMT coach, who is able toclosely track (via online access) each individual’s perfor-mance. The roles of the training aide and CWMT coachare essential, particularly for youth with ADHD wheremotivational issues and=or oppositional behavior maydetract from compliance to CWMT. During CWMT,the training aide is responsible for supporting the userthrough reinforcing on-task behavior, effort, and com-pletion of CWMT by providing praise, encouragementand contingent rewards. On a weekly basis by phone,the CWMT coach, training aide, and the user reviewtraining and problem solve struggles with adherence,ranging from motivational to logistic (e.g., scheduling)challenges.

In light of the growing importance of working mem-ory in ADHD, and the current active dissemination ofCWMT as an intervention for routine clinical practice(approximately 450 certified CWMT coaches inter-nationally; Pearson, personal communication, April 27,

2012) the current review was designed to apply theevidence-based treatment (EBT) criteria espoused bythe Society for Clinical Child and Adolescent Psychology(Silverman & Hinshaw, 2008; see Table 1) to evaluateCWMT for youth with ADHD. The most recent EBTreview for youth with ADHD (Pelham & Fabiano,2008) did not explicitly review the CWMT literature.The ultimate aim of this review is to determine, usingthe EBT criteria, the short- and longer-term efficacy ofCWMT for the treatment of ADHD in youth and toinform clinical practice for the treatment of ADHD.

METHODS

To identify studies which specifically utilized CWMT forthe treatment of youth with ADHD, we utilized thePRISMA (Preferred Reporting Items for SystematicReviews and Meta-Analyses) guidelines (http://www.prisma-statement.org). We conducted a systematicliterature search in electronic databases (i.e., PsycINFO,PubMed) as well as identified studies through CWMT’swebsite (http://www.cogmed.com). Keywords that wereutilized during the electronic search included workingmemory training, computerized intervention, CogmedWorking Memory Training, treatment, ADHD, attentiondeficit disorder, attention deficit hyperactivity disorder,inattention, hyperactivity, impulsivity, ADD, children,youth, and=or adolescents. A study was included if it(a) utilized CWMT, (b) included youth (ages 4–17) diag-nosed with ADHD or identified as displaying ADHD-type behaviors (i.e., parent- and=or teacher-ratedinattention, hyperactivity, and=or impulsivity), (c) deter-mined the short- and=or longer term treatment effectsof CWMT, and (d) was accepted=published in a peer-reviewed English language journal. Identified studieswere then coded on the following variables: authorsand year of publication, total sample size, age range ofstudy participants, inclusion criteria, comparison group,and the outcome measures used.

Similar to Pelham and Fabiano (2008), the quality ofthe study design was coded utilizing criteria developed byNathan and Gorman (2002), which include six typesof treatment studies. As detailed in Silverman andHinshaw (2008), Type 1 studies are the most rigorousand involve randomized, prospective clinical trial meth-odology. They involve comparison groups with randomassignment, blinded assessments, clear presentation ofthe study’s inclusion and exclusion criteria, state-of-the-art diagnostic methods (i.e., obtaining direct reportsfrom parents and teachers regarding ADHD symptomsand associated impairments to obtain an ADHD diag-nosis), adequate sample size to offer statistical power,and clearly described statistical methods. Type 2 studiesare clinical trials in which an intervention is tested but at

772 CHACKO ET AL.

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

least one aspect of the Type 1 study requirement is miss-ing. Type 3 studies are open trials aimed at obtainingpilot data. Type 4 studies are reviews with secondarydata analyses such as meta-analyses. Type 5 studies arereviews that do not include secondary data analyses.Type 6 studies are case studies, essays, and opinionpapers. Finally, we reported effect-size outcomes acrossvarious domains (i.e., parent and=or teacher-reports[e.g., ADHD symptoms], observed behavior, trainedcognitive tasks [tasks that closely resemble CWMT train-ing exercises], and nontrained cognitive tasks). Cohen’s deffect sizes were computed by calculating the change inimprovement in the CWMT condition minus the changein improvement in the control condition divided by thepooled standard deviation. Effect sizes were interpretedas no (d¼�.20 to .19), small (d¼ .20–.49), moderate(d¼ .50–.79), and large (d> .80) posttreatment effectsof CWMT. For studies that reported multiple outcomemeasures with a domain, an average effect size acrossmeasures was calculated.

RESULTS

The systematic literature search identified 1,091 publica-tions, and one publication was identified by contactingthe primary author listed on the CWMT website. Elevenof these studies were screened eligible for study inclusion.Of these 11, four did not meet inclusion criteria (i.e., didnot utilize CWMT as an intervention for the treatmentof ADHD in youth), leaving seven studies meetinginclusion criteria (i.e., Beck, Hanson, Puffenberger,Benninger, & Benninger, 2010; Gray et al., 2012; Greenet al., 2012; Holmes et al., 2010; Klingberg, Forssberg,& Westerberg, 2002; Klingberg et al., 2005; Mezacappa& Buckner, 2010). Three individuals coded eachcategorical criterion for each study. Cohen’s kappa forcategorical variables was j¼ 0.97 (p< .0001), and theagreement rate was 97%. Any disagreements betweenraters were resolved by consulting the respective paperand by discussion. Of the seven studies, five includedyouth diagnosed with ADHD within the context of thestudy (Beck et al., 2010; Green et al., 2012; Holmeset al., 2010; Klingberg et al., 2005; Klingberg et al.,2002) or from previous diagnosis (Gray et al., 2012),whereas the last (Mezacappa & Buckner, 2010) includedyouth whose teachers rated them as having significantissues with attention, hyperactivity, and=or impulsivity.All of these studies involved the school-age version ofCWMT (Cogmed RM) and met Nathan and Gorman(2002) criteria for a Type 1, 2, or 3 study. Next we discussthe application of the EBT criteria to these studies(please see Table 2 for description of these studiesincluding Nathan and Gorman classification for eachstudy).

Studies Contributing to EBT Status

Four of these studies (i.e., Beck et al., 2010; Gray et al.,2012; Green et al., 2012; Klingberg et al., 2005) contrib-ute to the evaluation of CWMT EBT criteria as deli-neated in Silverman and Hinshaw (2008). These fourstudies were (a) between-group experiments, (b) conduc-ted in independent research settings by independentinvestigatory teams, (c) utilized an operationally definedtreatment methodology, (d) were conducted with anADHD population, (e) utilized reliable and valid ADHDoutcomes (i.e., ADHD symptoms), and (f) appliedappropriate data analytic procedures. Next, we discussthese four studies that contribute to the EBT criteriaand comment on the extent to which the additionalidentified studies provide support for the efficacy ofCWMT for the treatment of youth with ADHD.

In the only Type 1 study, which was conducted by theCWMT developer, Klingberg et al. (2005) randomized 53youth with ADHD to either CWMT or to a nontitrating,low-level working memory version (i.e., placebo) ofCWMT. Of the 27 participants assigned to CWMT, threewithdrew and an additional four did not completeCWMT. Recruitment procedures were referrals from‘‘pediatricians, child psychiatrists, and special teachersat school’’ (p. 178). Inclusion criteria were (a) diagnosisof ADHD Combined Type or Predominantly InattentiveType established at study intake, (b) being between 7 to12 years of age, and (c) having access to a personal com-puter with an Internet connection. Exclusion criteriawere (a) being treated with stimulants, atomoxetine, aneuroleptic, or any other psychoactive drugs; (b) meetingcriteria for diagnoses of oppositional defiant disorder,autism spectrum disorder or major depressive disorder;(c) having a history of seizures during the past 2 years;(d) having an IQ less than 80 (based on IQ test or thephysician’s clinical impression and school history); (e)having a motor or perceptual handicap that would pre-vent using the computer program; (f) an educational leveland socioeconomic situation that made it unlikely thatthe family would be able to follow the treatment pro-cedure and study requirements; and (g) having a medicalillness requiring immediate treatment. Eighty-threepercent of participants were compliant with CWMT.

Intent-to-treat analyses demonstrated the effects ofCWMT on various aspects of trained and non-trainedcognitive tasks which were maintained at 3-monthfollow-up (see Table 3). Of most interest, this studydemonstrated improvements in most measures of parent-rated symptoms of inattention and all measures ofhyperactivity=impulsivity symptoms at posttreatment,which were maintained at 3-month follow-up. No stat-istically significant effects of CWMT were observed onteacher-rated symptoms of inattention or hyperactivity=impulsivity, or on an objective measure of motor activity.

EBT STATUS OF COGMED FOR YOUTH ADHD 773

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

TABLE2

Summary

ofCWMTStudiesReviewed

Study

ADHD

Form

ally

Diagnosed?

Sam

ple

Dem

ographics

N(AgeRange,

Years)

Gender

(%

Male)

NathanandGorm

an(2002)CriteriaforQuality

of

StudyDesignandExplanationforClassification

Klingberget

al.(2002)

Yes

%medicated:36

Subtype:

N=A

Additionaldiagnoses:N=A

Family=Youth

characteristics:N=A

14(7–15)

79

Type2(did

notassessADHD

outcomes;did

not

utilize

state-of-the-art

assessm

entproceduresfor

ADHD

diagn

osis-

diagn

osesmadebypediatricians

usingDSM

criteria

butunknownifparentandtea-

cher

reportswerecollecteddirectly)

Klingberget

al.(2005)

Yes

%medicated:0

Subtype:

38CT;15IT

Additionaldiagnoses:N=A

Family=Youth

characteristics:N=A

53(7–12)

83

Type1(utilizedstate-of-the-art

assessm

entproce-

duresforADHD

diagn

osis;assessedADHD

out-

comes;betweengroupdesignwithtreatm

ent

comparisongroup)

Becket

al.(2010)

Yes

%medicated:61

Subtype:

29%

CT,71%

IT

Additionaldiagnoses:46%

ODD=CD;39%

ANX;8%

mooddisorder

Family=Youth

characteristics:96%

Caucasian

52(7–17)

69

Type2(w

aitlist

controldesign)

Holm

eset

al.(2010)

Yes

%medicated:100

Subtype:

100%

CT

Additionaldiagnoses:N=A

Family=Youth

characteristics:N=A

25(8–11)

84

Type3(did

notincludestate-of-the-art

assessm

ent

forADHD

diagn

osis—

diagnosesmadeby

pediatriciansusingDSM

criteria

butunknownif

parentandteacher

reportswerecollecteddirectly;

did

notassessADHD

outcomes)

Mezzacappa&

Buckner

(2010)

Noofficial

diagn

osis

%medicated:0

Subtype:

noofficialdiagn

osis

Additionaldiagnoses:N=A

Family=Youth

characteristics:100%

ethnic

minority;100%

low

SES

9(8–11)

67

Type3(open

trial;did

notuse

ADHD

diagn

osisfor

inclusion)

Grayet

al.(2012)

Yes

(þLD)

%medicated:98

Subtype:

N=A

Additionaldiagnoses:N=A

Family=Youth

characteristics:N=A

60(12–17)

87

Type2(did

notutilize

state-of-the-art

assessm

ent

proceduresforADHD

diagn

osis—

diagnosismade

inthecommunitybefore

enteringstudy)

Green

etal.(2012)

Yes

%medicated:38

Subtype:

42%

CT,50%

IT,2%

H=I

Additionaldiagnoses:0%

ODD;

Family=Youth

characteristics:65%

Caucasian

26(7–14)

65

Type2(did

notutilize

state-of-the-art

assessm

ent

proceduresforADHD

diagnosis—

nodirect

teacher

ratingsfordiagnosis)

Note.ADHD¼attentiondeficit=hyperactivitydisorder;DSM

¼Diagnostic

andStatisticalManual

ofMentalDisorders;

CT¼combined

type;

IT¼inattentivetype;

ODD¼oppositional

defian

tdisorder;CD¼conduct

disorder;ANX¼anxietydisorder;SES¼socioeconomic

status;LD¼learningdisorder;H=I¼hyperactive=im

pulsivetype.

774

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

TABLE3

CogmedWorkingMemory

TrainingOutcomesbyDomain

Study

ComparisonCondition

(EffectSizea)

Trained

Cognitive

Tasks(EffectSizea)

Nontrained

Cognitive

Tasks(EffectSizea)

BehavioralObservations

(EffectSizea)

Parent-Report

(EffectSizea)

Teacher-R

eport

(EffectSizea)

Becket

al.(2010)

Waitlist

control

N=A

N=A

N=A

DSM

ADHD

Symptoms

(inattention� );CRS� ;

BRIE

F�(.85)

DSM

ADHD

Symptoms;CRS;

BRIE

F(.22)

Grayet

al.(2012)

Academ

yofMath

WISC-IV

DigitSpan

Forw

ard

and

Backward

� ;CANTABSpatial

Span� ;

CANTAB

SpatialWM

;(.06)

WMR;D2;

WRAT-PM

(.03)

N=A

SWAN;IO

WA

Conners

Scale

(�.08)

SWAN;IO

WA

Conners

Scale

(.04)

Green

etal.(2012)

Placebocomputerized

workingmem

ory

training

WISC-IV

WMI�

(.39)

N=A

RAST�b

(.84)

CRS(�

.21)

N=A

Holm

eset

al.(2010)

Within

subject-

comparedonandoff

medspre=post

AWMA

�(.57)c

WASI(.12)c

N=A

N=A

N=A

Klingberget

al.(2002)

Placebocomputerized

workingmem

ory

training

VisuospatialWM

Task

� ;Span-Board

Task

�

(5.60)

VisuospatialWM

Task

� ;Stroop

Task

� ;Raven’s� ;

CRTT

(2.38)

#ofheadmovem

ents

(infraredmotion

analysissystem

)�

(2.83)

N=A

N=A

Klingberget

al.(2005)

Placebocomputerized

workingmem

ory

training

WAIS-R

NISpan-Board

Task

� ;WISC-III

Digit

Span�(.74)

StroopTask� ;

Raven’s�(.61)

No.ofheadmovem

ents

(infraredmotion

analysissystem

)(.07)

DSM

ADHD

Symptoms�;CRS�

(.54)

DSM

ADHD

Symptoms;CRS(.19)

Mezzacappa&

Buckner

(2010)d

Pre=post

no-control

group

WISC-IV

DigitSpan� ;

WRAMLFinger

Windows�

d

N=A

N=A

N=A

DSM

ADHD

Symptoms;

ADHD-R

SIV

�,d

Note.DSM

¼DiagnosticandStatisticalManual

ofMentalDisorders;ADHD¼attentiondeficit=hyperactivitydisorder;CRS¼ConnersRatingScale;BRIE

F¼BehaviorRatingInventory

of

ExecutiveFunction;WISC¼Wechsler

Intelligence

TestforChildren;CANTAB¼CambridgeNeuropsychologicalTestingAutomatedBattery;WM

¼WorkingMem

ory;WMR¼Working

Mem

ory

RatingScale;D2¼TheD2TestofAttention;WRAT-PM

¼Wide-RangeAchievem

entTest-4-ProgressMonitoringVersion;SWAN¼StrengthsandWeaknessofADHD-symptoms

andNorm

al-behaviorScale;IO

WA

¼;WISC

¼;WMI¼WorkingMem

ory

Index;RAST¼RestrictedAcadem

icSituationsTask;AWMA¼AutomatedWorkingMem

ory

Assessm

ent;

WASI¼Wechsler

AbbreviatedScale

ofIntelligence;CRTT¼ChoiceReactionTim

eTask;Raven’s¼Raven’s

ColoredProgressiveMatrices;WAIS-R

NI¼Wechsler

AdultIntelligence

Scale

–Revised

asaNeuropsychologicalInstrument;WRAML¼WideRangeAssessm

entofMem

ory

andLearning;ADHD-R

SIV

¼AttentionDeficit=HyperactivityDisorder

RatingScale,Fourth

Edition.

aCohen’sdreported

foreach

domain.Averageeffect

size

calculatedfordomainswherethereare

multiple

measures.

bEffectsize

calculatedonly

forcontinuousdata

asother

categories

werecoded

asbinary

outcomes.

c Effectsize

determined

bydifference

betweennomedicationconditionandCWMT.

dStandard

deviationswerenotreported

instudyin

order

tocalculate

effect

sizes.

� Significantdifference

betweengroupsin

favorofCogmed

WorkingMem

ory

Training.

775

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

Effect size data suggest a moderate effect of CWMT onparent-rated ADHD (d¼ .54) and a no effect onteacher-rated ADHD (d¼ .19).

In a randomized clinical trial of CWMTwith 52 youthwith ADHD, Beck and colleagues (2010) replicatedmany of the findings of Klingberg et al. (2005). Childrenand adolescents were recruited from a private school foryouth with ADHD and=or learning difficulties throughflyers sent to parents. All participants met Diagnosticand Statistical Manual of Mental Disorders (4th ed.[DSM–IV]; American Psychiatric Association, 1994)criteria for ADHD using a structured clinical interviewat study intake. No additional information was providedregarding inclusion=exclusion criteria. Informationgleaned from Beck and colleagues suggest that allparticipants completed CWMT, but no clear data werereported regarding youth compliance to CWMT.

Beck et al. (2010) determined the efficacy of CWMTcompared to a waitlist group on parent- and teacher-rated reports of working memory and ADHD symptoms(see Table 3 for details). Youth randomly assigned to thewaitlist control condition received CWMT after theposttreatment assessment. All study participants com-pleted a 4-month follow-up assessment. Results from thisstudy indicated that participants in the CWMT con-dition had improved parent-rated working memory,parent-rated inattention symptoms=problems at post-treatment, which were maintained at follow-up assess-ment. No statistically significant effect of CWMT wasobserved on parent-reported hyperactivity=impulsivitysymptoms, oppositional defiant behaviors or on anyteacher-rated outcomes. The posttreatment results weremostly replicated when the waitlist control youth partici-pated in the CWMT intervention but significant attritionin the waitlist group prohibited meaningful comparisonsof follow-up outcomes. Effect size data suggest a largeeffect of CWMT on parent-rated ADHD symptoms(d¼ .85) and a small effect on teacher-rated ADHDsymptoms (d¼ .22).

Green and colleagues (2012) conducted a randomizedclinical trial comparing CWMT to a placebo-version ofCWMT (i.e., identical to that used in Klingberg et al.,2005) in a sample of 30 youth with ADHD. Youth wererecruited from the participating medical center, as well asfrom flyers and advertisements posted around the com-munity and to a support group. Eligibility for the studyinvolved a multistep process, including (a) positive phonescreening for ADHD, (b) meeting DSM criteria forADHD based on structured clinical interview at studyintake, and (4) a t score of at least 65 on the ConnersParent Rating Scale. Families also had to have reliableInternet access and speak English fluently. Youth wereexcluded if they met criteria for mental retardation(i.e., IQ< 70) or severe mental illness (i.e., psychosis,bipolar, major depressive disorder) or autism spectrum

disorder. In addition, families were asked not to makechanges in treatment during the course of the study.

Green and colleagues (2012) found that, relative to theplacebo condition, CWMT resulted in significant bene-fits on objective working memory tasks (see Table 3).Of interest, this was the first study to determine theeffects of CWMT on observed behaviors. The RestrictedAcademic Setting Task is a 15-min task where the child,in isolation, engages in academic worksheets (e.g., math)that are one grade level below their current ability.Behaviors observed and quantified during the taskinclude off-task behavior, out-of-seat behavior, fidget-ing, vocalizing, and playing with objects. CWMT led tosignificant reductions in off-task behavior and in playingwith objects. Surprisingly, CWMT did not improve par-ent-rated ADHD symptoms. Of importance, parents inboth treatment conditions reported significant improve-ments in ADHD symptoms as a function of time. Thisstudy only analyzed data from participants who com-pleted the placebo (14 of the 15 participants) and theCWMT (12 of the 15 participants) interventions. Assuch, results reflect those who are compliant to treat-ment. Effect size data suggest a small negative effect ofCWMT on parent-rated ADHD symptoms (d ¼�.21);teacher-rated ADHD symptoms were not collected.

Most recently, in a randomized clinical trial of 60 ado-lescents with severe learning disorders (LD) and ADHD,Gray and colleagues (2012) evaluated CWMT comparedto an intensive computerized academic instruction pro-gram (Academy of Math; http://www.autoskill.com).Gray and colleagues used an unbalanced design, ran-domly assigning 36 of the 60 participants to the CWMTcondition. Of these 36, four did not complete CWMT(two participants moved from the school and two parti-cipants withdrew from CWMT resulting in a compliancerate of 88%). Both interventions occurred during theschool day. Of interest, this was the only study ofCWMT delivered within the context of a school settingby school staff. Youth were recruited from a semiresiden-tial school for adolescents with severely impairing LDand ADHD. Eligibility criteria for the school includeco-occurring LD=ADHD previously diagnosed in thecommunity plus severe problems in learning and beha-vior with poor response to the available standards of careand intervention in their home communities, whichincluded special education and pharmacological treat-ment. Students with comorbid diagnoses of conduct dis-order, severe aggression, depression, or anxiety requiringspecific and immediate treatments were considered ineli-gible for the school. Inclusion criteria for this study were(a) full-time attendance at the participating school, (b)age between 12 and 17 years, (c) IQ> 80, and (d) Englishas the primary spoken language. ADHD diagnosis wasbased on available reports obtained from previousassessment in the community. Exclusion criteria were

776 CHACKO ET AL.

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

uncorrected perceptual, motor, or language impairmentsthat would impede usage of the computer program orintelligibility of spoken responses.

Results demonstrated effects of CWMT on two of thethree trained working memory tasks. No differenceswere found on nontrained cognitive tasks. CWMT hadno differential effect on parent- or teacher-rated ADHDbehavior or oppositional behavior. There were no effectsfound on academic measures (see Table 3). Supplemen-tal analyses revealed that there was an effect of time oncognitive attention, reading, and math as well as parent-reported ADHD behavior. This suggests that the effectof the remedial educational setting combined withstimulant medication improved some key areas of func-tioning. Effect size data suggest no effect of CWMT onparent-rated ADHD symptoms (d ¼�.08) and no effecton teacher-rated ADHD symptoms (d¼ .04).

Additional Studies Focusing on CWMT

Three additional studies support the efficacy of CWMTbut were not considered to contribute to the determi-nation of EBT status because these studies did not utilizeADHD-symptom outcomes (Holmes et al., 2010;Klingberg et al., 2002) or did not include youth with aformal diagnosis of ADHD (Mezzacappa & Buckner,2010). We briefly review these next.

Klingberg and colleagues (2002) randomly assigned14 youth diagnosed with ADHD at study intake to eitherCWMT or a placebo version of CWMT. No data regard-ing recruitment strategies or compliance to CWMT werereported. Several outcomes were assessed (see Table 3).This study found that CWMT resulted in significantlygreater improvements in trained and nontrainedcognitive tasks as well as observed behaviors (i.e., headmovements).

Holmes and colleagues (2010) recruited 25 childrenthrough pediatric psychiatrists and community pediatri-cians to participate in a within-subject study evaluatingthe effects of medication and CWMT on working mem-ory and IQ. Children were included in the study if theymet criteria for ADHD Combined type at study intakeand were prescribed stimulant medication. No data oncompliance to CWMT were reported. Across a four-time-point assessment schedule, the effects of no medi-cation (Time 1), medication (Time 2), CWMT (Time 3post-CWMT), and 6-month follow-up (Time 4) revealeddifferences between treatments. More specifically, therewas no effect of medication on IQ scores but improvedseveral aspects of working memory relative to no medi-cation. Relative to medication, CWMT demonstratedimprovements across working memory outcomesimmediately after CWMT (Time 3) and were maintainedat 6-month follow-up (Time 4). No effect of CWMT wasfound on IQ (see Table 3). Of importance, a limitation of

this study was that treatments were confounded withtime, making interpretation of these results challenging.

Finally, Mezzacappa and Buckner (2010) evaluatedCWMT in nine children who were attending an inner-city elementary school. All children were identified forthis study based on teacher-reports of ADHD symp-toms on rating scales. No child received previous assess-ment or treatment for any psychiatric difficulties in thepast or during the study. Administered by a researchassistant, CWMT was implemented individually duringthe school-day for 5 weeks. Eight of the nine parti-cipants completed CWMT. Of interest, results from thisstudy demonstrated improvements in teacher-rated totalADHD symptoms and measures of working memory(see Table 3). However, the role of teacher expectancybias for improvement could not be ruled out as apossible explanation for these findings; parents did notcomplete measures of treatment efficacy in this study.

DISCUSSION

Overview of Results From Key Studies

Although only recently developed, CWMT has under-gone empirical evaluation over the past decade as a treat-ment for ADHD. The utilization of randomized clinicaltrials by multiple, independent investigators, assessingmultiple outcomes by various reporters, are notablestrengths of these evaluations. Moreover, studies havebeen conducted with school-age youth and=or adoles-cents in both home and in school settings. The resultsof the four randomized clinical trials and the additionalstudies reviewed suggest more consistent effects ofCWMT on working memory outcomes (see Table 3).The results of the four studies that contribute to theEBT status of CWMT suggest mixed findings for ADHDsymptom outcomes. Two studies generally supportCWMT for school-age children and adolescents withADHD (Beck et al., 2010; Klingberg et al., 2005). Thesetwo studies utilized a waitlist control condition (Becket al., 2010) or a placebo condition (Klingberg et al.,2005) with a well-diagnosed ADHD population and gen-erally found significant short- and longer-term effects ofCWMT on ADHD symptoms as reported by parents.Green and colleagues (2012) found effects of CWMTrelative to a placebo condition on two of five observedbehavioral categories during an analog academic taskbut found no effect of CWMT on parent-rated ADHD.Data from Gray and colleagues (2012) do not supportCWMT as an intervention for ADHD. In a randomizedclinical trial of adolescents with ADHD and severe LD,they reported no effects of CWMT on parent- andteacher-rated ADHD symptoms. The unique strengthof the Gray and colleagues study was the rigor of the

EBT STATUS OF COGMED FOR YOUTH ADHD 777

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

comparison condition—this was the only randomizedclinical trial of CWMT to date with an active treatmentcomparison condition. Moreover, data document a widerange of effect sizes on parent and teacher reports ofADHD symptoms, which is often related to the type ofcontrol condition utilized (Fabiano et al., 2009). Forinstance, the largest effect size was found in Beck andcolleagues study (d¼ .85), which utilized a waitlist con-trol condition while considerably smaller effects werefound in the other three studies, all of which included atreatment control condition. Critical issues in these stu-dies, as discussed next, which mitigate the clarity of thefindings, include lack of alignment between outcomesof CWMT studies and the hypothesized model of thera-peutic benefit of CWMT, the equivalence of the placebocondition used in several studies, and individual responseto CWMT.

Critical Issues for Interpreting CWMT Studies

Alignment between CWMT outcomes and hypothe-sized model of therapeutic benefit of CWMT. As wehave reviewed herein and detailed in Table 3, there aresignificant inconsistencies in outcomes within as well asacross CWMT studies. For example, Klingberg andcolleagues (2005) found parent-rated improvements inhyperactivity but no effect of CWMT on head move-ments (an objective indicator of hyperactivity). Headmovements were, however, improved following CWMTin an earlier study (Klingberg et al., 2002). Moreover,although Klingberg and colleagues (2005) found signifi-cant effects of CWMT on some parent-rated inattentionoutcomes and all hyperactivity=impulsivity outcomes,Beck and colleagues (2010) found benefits only on par-ent-rated inattention symptoms, and Gray et al. reportedno effects of CWMT on either ADHD symptom domain.Although Green and colleagues (2012) found a benefit ofCWMT on ADHD-type behaviors observed during ananalog academic task, no effect of CWMT was reportedon parent-rated ADHD symptoms. No study has foundan effect of CWMT on teacher-rated ADHD symptoms.Multiple reasons are likely related to these variousdiscrepancies, including differences in study designs,measurement issues, and individual differences (a pointwe discuss next). However, a more fundamental issuethat should guide interpretation of this data is the extentto which findings from CWMT studies align with thehypothesized model of therapeutic benefit of CWMT.

For CWMT, it is hypothesized that the interventionhas a proximal effect on working memory capacity,which then impacts ADHD symptoms, notably inatten-tive symptoms. This model supposes that proximaleffects of CWMT on working memory should have distaleffects on inattention symptoms in various settings. Thisshould likely be most evident in settings where working

memory is taxed (e.g., classroom settings where youthmust follow complex multistep directions, read and com-prehend text, plan and organize class materials, etc.).This model of therapeutic benefit is akin to stimulantmedication—underlying neuropsychological-biologicalprocesses are proximally improved and improvementsin these factors have distal effects on ADHD symptoms.Importantly, improvement in ADHD symptoms shouldbe apparent regardless of setting, given the hypothesizedmodel. The finding that no randomized clinical trial ofCWMT, including those with a waitlist comparison con-dition (i.e., Beck et al., 2010), has found an effect ofCWMT on teacher-reports of ADHD is not in line withthe hypothesized model of therapeutic benefit ofCWMT. Moreover, findings that both parent-reportedand objectively-rated hyperactivity are improved withCWMT are at odds with the purported therapeuticmodel. These are fundamental issues that go well beyondthe discrepancies and inconsistencies found in theCWMT studies done to date and call into question thetrue impact of this intervention.

Placebo condition equivalence. The study byKlingberg and colleagues (2005) provides the most sup-portive evidence in favor of CWMT as a treatment forADHD in youth. The placebo condition used in thisstudy was designed to control for parent involvementas the training aide and child exposure to computertraining. Importantly although the placebo conditionconsisted of the same number of working memory train-ing trials as the active condition (i.e., 90 trials), overalltraining time was not matched between the two con-ditions (Pearson, personal communication, November22, 2011). Because the placebo condition was easier (non-adaptive), it required considerably less time to completethan the active CWMT condition. These two factors mayhave significantly impacted the experience that parentshad during the study, which has direct implicationsfor interpreting parent-rated improvements in ADHD.First, an easier and quicker intervention reduces theamount and quality of interactions the training aide(i.e., parent) has with their child during training. Giventhat part of the training experience is to support the childthrough positive reinforcement and encouragement,reduced training time likely also means reduced opportu-nities for supportive interactions between the parent andchild, a noted important aspect of CWMT (Holmes et al.,2010). This difference should not be minimized, as small,daily, positive interactions in which the parent providespraise and encouragement can be very helpful in improv-ing parent–child relationships and child behaviors(Harwood & Eyberg, 2006).

In addition, participating in a briefer and easier inter-vention may also influence the type of support thatthe CWMT coach provides to a family in the control

778 CHACKO ET AL.

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

condition. Much of the responsibilities of the CWMTcoach are to work closely with the family to encourageadherence, enhance motivation, and to problem solveissues that may arise in implementing CWMT. TheCWMT coach’s ability to work in a close, supportivepartnership with the training aide is likely essential formaximizing adherence and engagement to CWMT. Thebenefits of providing support and collaborative problemsolving should not be underestimated—treatment out-comes studies in youth with ADHD have demonstratedthat such support can improve parent reports of ADHDsymptoms (Sonuga-Barke, Thompson, Daley, Laver-Bradbury, & Weeks, 2001). It is unlikely that familiesin the placebo condition received the same level of sup-port and problem-solving opportunities given the nona-daptive and brief nature of the placebo intervention.

Collectively, these differences in interactions as afunction of treatment condition may partially explainsome of the benefit of participation in CWMT for parti-cipants in the Klingberg et al. (2005) study. This may beeven more of a significant and confounding issue if theskills learned by parents (i.e., problem-solving issues withmotivation, using praise and encouragement) extendedwell beyond CWMT to other contexts (e.g., homeworktime) where these skills could affect ADHD-relatedsymptoms and difficulties. It is unclear the extent towhich specific components of CWMT (i.e., adaptiveworking memory training) versus other factors (e.g., par-ents learning methods to support their child’s behavior)contribute to the results found in studies that havecompared CWMT to the CWMT placebo condition.

Individual differences and response toCWMT. The four between-group studies of CWMThave recruited strikingly different participants, whichposes a significant issue in interpreting the results of thesestudies. For example, Klingberg and colleagues (2005)excluded youth with oppositional defiant disorder andthose who were taking psychoactive medication. Thisstudy found improvements in parent-reports of ADHDsymptoms as well as other trained and nontrained cogni-tive tasks. Gray and colleagues (2012) included youthwith severe learning problems and ADHD such thatavailable standards of care and intervention in theirhome communities were not beneficial. In addition,almost the entire sample was receiving medication. Aspreviously reviewed, this study largely did not finddifferential treatment effects, particularly on parentand teacher-rated ADHD symptoms. One interpretationof these discrepant findings is that individual differences,such as severity of psychopathology, may moderatetreatment response. This is not surprising given thatthese types of individual differences can be related totreatment outcomes (Owens et al., 2003). This issue isparticularly challenging in the context of interpreting

the CWMT literature given that there are few studiesfocused on youth with ADHD. As we discuss in theFuture Directions section, more representative samplesof youth are needed to better gauge the effects ofCWMT.

EBT Status of CWMT

Collectively, when accounting for the strengths and lim-itations of the four CWMT studies that contribute to theclassification of EBT status (i.e., Beck et al., 2010; Grayet al., 2012; Green et al., 2012; Klingberg et al., 2005) andnoting the fundamental issues with alignment betweenoutcomes of CWMT and hypothesized model of thera-peutic benefit purported by CWMT, CWMT best meetscriteria as a Possibly Efficacious treatment for youthwith ADHD (see Table 1 for EBT criteria). AlthoughBeck et al. (2010) and Klingberg et al. (2005) offered sup-portive results for CWMT, findings are mitigated bycritical issues in these studies. Green and colleagues(2012) provided evidence for the benefits of CWMTon observed behavior; however, the extent to which theanalog context of the observation is representative ofacademic tasks in typical classroom settings is question-able. More specifically, assessing behavior during ananalogue situation where a child completes academicwork that is at least one grade level below their ability,in isolation, for 15min is not representative of typicalacademic contexts. Moreover, no normative data wereprovided on the Restricted Academic Setting Task, mak-ing it difficult to interpret the clinical utility of theobserved improvements in behavior following CWMT.In addition, the lack of effects of CWMT on parent-ratedADHD found in the study by Green and colleagues isnot clearly interpretable. Collectively, the data for themost supportive studies of CWMT (Beck et al., 2010;Green et al., 2012; Klingberg et al., 2005) are inconsistentwith the therapeutic model of CWMT and warrant cau-tion in placing high levels of confidence in CWMT. Grayand colleagues’ (2012) recent study suggests further cau-tion when considering the EBT status for CWMT,although it is likely that the severity of the sample mayhave moderated response to treatment. Next we discussfuture directions for CWMT for the treatment of youthwith ADHD and consider clinical implications of thefindings of this review.

Future Directions

Increasing the heterogeneity of participants toobtain more clinically-useful data. Each of the fourstudies that contributed to the classification of the EBTstatus of CWMT had significant restrictions regardingthe inclusion criteria and=or the population recruitedwhich likely impacted study results and implications.

EBT STATUS OF COGMED FOR YOUTH ADHD 779

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

For instance, Klingberg and colleagues (2005) empha-sized internal validity of CWMT by maximizing thelikelihood that youth and families would adhere toCWMT by excluding youth with ODD and families fromlower socioeconomic status. Although doing so is impor-tant and logical in the early stage development of anintervention, it did limit understanding of the extent towhich these findings generalize to more comorbid anddiverse samples.

Green and colleagues (2012) conducted the smallestrandomized clinical trial reviewed herein and limitedinformation regarding the sample was presented. More-over, the sample represented a pure ADHD group in thatno child met criteria for ODD (J. Schweitzer, personalcommunication, October 12, 2012). Beck and colleagues(2010) included youth without utilizing significantexclusionary criteria. Despite these improvements,participants were exclusively recruited from one privateschool setting, suggesting that these youth and their fam-ilies were more homogenous in terms of socioeconomicstatus. Given that both clearly supportive studies ofCWMT (Beck et al., 2010; Klingberg et al., 2005) focusedon youth from higher socioeconomic status, and thatsocioeconomic status and its correlates are often associa-ted with adherence to psychosocial and pharmacologicalintervention (Chacko et al., 2010), it will be important todetermine if the high rates of adherence, feasibility, andpalatability seen thus far with CWMT generalize tofamilies with greater psychosocial challenges. Thesetypes of data have direct implications for the potentialbroader dissemination of CWMT.

Gray and colleagues recruited participants from oneschool that served adolescents who were most impairedin their community school settings. Importantly, it mayhave been difficult to observe incremental benefits ofCWMT (or any other additional intervention) in thisstudy given that all adolescents were involved in inten-sive academic interventions and stimulant medicationas part of their specialized school placement. These lim-itations and qualifications of the Gray study do notnegate the findings of the lack of effects of CWMT. How-ever, it may qualify these findings; that is, CWMT maybe unable to provide incremental benefits beyond inten-sive academic and pharmacological interventions foryouth with more severe psychopathology but may bebeneficial for more representative youth with ADHD.

Collectively, it appears that studies of CWMT thatrepresent the diversity of socioeconomic backgrounds,psychiatric comorbidities, and functioning of youthwith ADHD and their families are needed. Given thatCWMT is no longer in a treatment development phase,but being actively disseminated for clinical use, datafrom more representative studies of youth with ADHDare essential to providers in order to make informeddecisions about utilizing CWMT.

Utilizing equivalent placebo control conditions oractive treatment comparison conditions. There isclearly a need for studies to be conducted that utilizewell-designed control conditions that balance time ontask and interactions between the training aide (parent)and the child as well as the CWMT coach and the family.The only study meeting Nathan and Gorman criteria fora Type 1 study (Klingberg et al., 2005) utilized a placebocondition that arguably did not control for these criticalfactors and therefore may not have provided an equiva-lent experience for youth and their families in the placebocontrol condition. Even more important are studies thatutilize active treatment comparison conditions, such aswhat was employed in Gray and colleagues (2012). Suchinterventions have to be chosen thoughtfully as to beviable and matched on multiple parameters (scaffoldingfrequency, difficulty level, etc.).

Potential benefits of CWMT for subgroups of youthwith ADHD. There is the potential for CWMT to be akey intervention for distinct subgroups rather than forthe general population of youth with ADHD. Forexample, theoretically, CWMT may be more effectivefor youth with ADHD Inattentive subtype, althoughKlingberg and colleagues (2005) found no differentialeffects of CWMT by ADHD subtype. Further empiricalinvestigation with larger samples will be required to morefully evaluate this issue.

CWMT may be differentially effective as a function ofdevelopmental age. The four randomized clinical trials ofCWMT do not provide direct information regarding thepotential impact of CWMT as a function of age. Kling-berg and colleagues (2005) found benefit of CWMT forschool-age youth, whereas Gray and colleagues (2012)reported no benefit in a group of adolescents. Greenet al. (2012) found benefit of CWMT on some observedbehaviors for school-age youth with ADHD but no effecton parent-rated behavior. Finally, Beck and colleaguesdemonstrated a positive impact of CWMT in a wide rangeof youth with ADHD (7- to 17-year-olds), with no signifi-cant differences as a function of age. However, becausethese studies varied greatly in the type and quality of com-parison conditions and participant populations, definitiveconclusions about age effects of CWMT are premature.

Theoretically, CWMT may be most effective as anearly intervention for ADHD given the increasedplasticity and sensitivity of the brain of young children(Halperin & Healey, 2011). Of interest, CWMT has beenevaluated in typically developing preschool childrenwith promising results (Thorell, Lindqvist, Nutley,Bohlin, & Klingberg, 2009), but data do not yet existon its efficacy in preschool children at risk for or withADHD. This appears to be a promising line of empiricalinvestigation.

780 CHACKO ET AL.

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

In addition, CWMT may be effective for youth withLD. Although Gray and colleagues (2012) found nobenefit of CWMT in a group of adolescents with ADHDand LD, the severity of LD in this population along withthe receipt of intensive academic interventions during thecourse of the year may have been limiting factors in re-alizing the benefits of CWMT on academic achievement.Given the role of working memory on reading and mathachievement (H. L. Swanson & Jerman, 2007; H. L.Swanson et al., 2008), there is reason to predict thatCWMT, which is designed to improve working memory,may beneficially impact academic outcomes. Forinstance, Dahlin (2011) found that CWMT had a signifi-cant impact of academic outcomes in a sample of chil-dren, many of whom had significant learning difficulties.

Given that CWMT is purported to have effects onADHD symptoms via improvement in working memory,an interesting hypothesis is that youth with ADHD andworking memory deficits should benefit the most fromthis intervention. It is important to note that, althoughworking memory deficits are associated with ADHD,not all youth with ADHD have working memory deficits(Willicutt et al., 2005). As such, this distinct subgroup ofyouth with ADHD may be most responsive to CWMT.In fact, Gray and colleagues (2012) found a significantpositive correlation between improvements in workingmemory, measured by the CWMT Index score, andparent-rated improvements in ADHD symptoms. Thisremains a beneficial area of investigation.

Broadening focus of outcomes to include functionalimpairment. Outcomes of interest in studies of CWMThave focused primarily on neuropsychological outcomesand collateral reports of ADHD symptoms. In addition,Gray and colleagues (2012) reported on the impact ofCWMT on functional impairment in daily activities(academic achievement). Green and colleagues alsoassessed the effects of CWMT on behaviors during aca-demic tasks. Importantly, there are clear limitations tothe representativeness and potential generalizability ofthe analog academic task utilized in the Green study.This is not to say that analog=laboratory tasks are notuseful as outcomes in treatment studies. Relative toparent=teacher reports, laboratory measures=tasks maybe more objective and may be more sensitive to treat-ment effects (Sonuga-Barke, Coghill, DeBacker, &Swanson, 2009). Parent=teacher reports may be influ-enced by expectations and biases, and are likely moreresistant to change—greater effects of treatment maybe necessary for parents=teachers to report change inbehavior. We argue that the more closely laboratory=analog tasks resemble=align with the day-to-day contextsthat youth with ADHD experience, the more relevantpositive outcomes on these laboratory=analog tasks willbe for understanding treatment effects.

Functional impairments experienced by youth withADHD (e.g., parent–child relationships, academicfunctioning) should be evaluated in addition to neuropsy-chological deficits and ADHD symptoms for several rea-sons. First, functional impairments experienced by youthwith ADHD are socially valid outcomes in that these arethe reasons why parents seek out treatment for their chil-dren and are key predictors of long-term outcomes inyouth (see Pelham & Fabiano, 2008). Moreover, ADHDsymptoms and impairment are related but distinct con-structs, suggesting that improving ADHD symptomsmay not necessarily lead to substantial reductions inimpairment. For instance, Gordon and colleagues(2006) found that the intensity and severity of ADHDsymptoms only accounted for approximately 10% of thevariance in impairment, suggesting that ADHD symp-toms alone do not provide a full conceptualization ofan individual’s functioning. Given these findings, studiesshould focus not only on the extent to which an inter-vention improves ADHD symptoms alone but, perhapsmore important, the extent to which an interventionimproves a child’s impairment across multiple domains.

Clinical Implications

Behavioral and pharmacological treatments are con-sidered to be the gold standard of interventions forADHD. These interventions have been tested in numer-ous short- and long-term randomized clinical trials, utiliz-ing a wide range of youth with ADHD and their families,assessing multiple and various outcomes and have beenshown to be acutely effective in improving not onlyADHD symptoms but also functional impairment(Pelham& Fabiano, 2008). Effects sizes reported of beha-vioral interventions in between-group studies of ADHDhave demonstrated an average small-to-moderate effecton parent-rated ADHD symptoms (d¼ .39) and an aver-age moderate-to-large effect on teacher-rated ADHDsymptoms (d¼ .79; Fabiano et al., 2009). It is importantto note that behavioral interventions are theorized toaffect impairment associated with ADHD rather thancore symptoms—data support this view with effects sizesfor between-group studies of ADHD ranging frommoderate-to-large effects (d¼ .55–.84; Fabiano et al.,2009). Comparatively, effects sizes reported for stimulantmedication treatment for ADHD symptoms are large(i.e., d> 1.00; Faraone, 2009).

In comparison, the evidence-base for CWMT consistsof a handful of studies conducted with more restrictedpopulations, evaluating specific key behavioral and neu-rocognitive outcomes. In general effect sizes for ADHDsymptoms suggest a small negative effect to a large effect(d ¼�.21 to .85) of CWMT and appear to vary signifi-cantly as a function of quality of control condition,respondent (parent or teacher), and severity of the study

EBT STATUS OF COGMED FOR YOUTH ADHD 781

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

participants. As such, at the present time, confidence inthe efficacy of behavioral interventions and specific med-ications for the treatment of ADHD in youth is greaterthan that for CWMT. Clearly, behavioral interventionsand specific pharmacological interventions should beconsidered first-line interventions for the treatment ofADHD. Given the state of the literature on CWMT,further investigation is needed before CWMT can beconsidered a clearly viable treatment for youth withADHD. In particular, data from CWMT studies arenot well aligned with the hypothesized model of thera-peutic benefits of CWMT, which suggests further cautionin providing clinical recommendations for CWMT as anintervention for youth with ADHD. Utilizing the EBTcriteria delineated by Silverman and Hinshaw (2008),our interpretation of the strengths and limitations ofthe data across several studies suggest that CWMT iscurrently a Possibly Efficacious treatment for youth withADHD. Future studies should represent the diversity ofyouth with ADHD and their families and include diverseoutcomes, including observed objective outcomes (cf.Green et al., 2012) and functional impairment outcomes.Closer attention must be paid to conducting studies tospecifically evaluate the hypothesized model of thera-peutic benefit of CWMT for the treatment of ADHD.Given that multiple clinical trials using CWMT forADHD in youth are now ongoing, the literature in thisarea is rapidly progressing and will likely answer manyof the questions posed herein and provide greater clarifi-cation on several issues regarding CWMT and furthercontribute to determining the EBT status of CWMTfor youth with ADHD.

REFERENCES

American Academy of Pediatrics. (2011). ADHD: Clinical practice

guidelines for the diagnosis, evaluation and treatment of attention-

deficit=hyperactivity disorder in children and adolescents. Pediatrics,

128, 1007–1022. doi:10.1542/peds.2011-2654

American Psychiatric Association. (1994). Diagnostic and statistical

manual of mental disorders (4th ed.). Washington, DC: Author.

Beck, S. J., Hanson, C. A., Puffenberger, S. S., Benninger, K. L., &

Benninger, W. B. (2010). A controlled trial of working memory

training for children and adolescents with ADHD. Journal of

Clinical Child and Adolescent Psychology 39, 825–836. doi:10.1080/

15374416.2010.517162

Chacko, A., Newcorn, J. H., Feirsen, N., & Uderman, J. Z. (2010).

Improving medication adherence in chronic pediatric health con-

ditions: A focus on ADHD in youth.Current Pharmaceutical Design,

16, 2416–2423.

Chronis, A., Fabiano, G. A., Gnagy, E. M., Wymbs, B. T.,

Burrows-Maclean, L., & Pelham, W. E., Jr. (2001). Comprehensive,

sustained behavioral and pharmacological treatment for attention-

deficit=hyperactivity disorder: A case study. Cognitive and

Behavioral Practice, 8, 346–359. doi:10.1016/s1077-7229(01)80008-0

Chronis, A., Pelham, W. E., Gnagy, E., Roberts, J., & Aronoff, H. R.

(2003). The impact of late-afternoon stimulant dosing for children

with ADHD on parent and parent–child domains. Journal of

Clinical Child and Adolescent Psychology, 32, 118–126.

Dahlin, K. I. E. (2011). Effects of working memory training on reading

in children with special needs. Reading and Writing, 24, 479–491.

doi:10.1007/s11145-010-9238-y

Fabiano, G. A., Pelham, W. E., Jr., Coles, E. K., Gnagy, E. M.,

Chronis-Tuscano, A., & O’Connor, B. C. (2009). A meta-analysis of

behavioral treatments for attention-deficit=hyperactivity disorder.

Clinical Psychology Review, 29, 129–140. doi:10.1016/j.cpr.2008.11.001

Faraone, S. (2009). Using meta-analysis to compare the efficacy of

medications for attention-deficit=hyperactivity disorder in youths.

Pharmacy and Therapeutics, 34, 678–683.

Goldman, L. S., Genel, M., Bezman, R., & Slanetz, P. J. (1998).

Diagnosis and treatment of attention-deficit=hyperactivity disorder

in children and adolescents. Journal of the American Medical

Association, 279, 1100–1107.

Gordon, M., Antshel, A., Faraone, S., Barkley, R., Lewandowski, L.,

Hudziak, J. J., . . . Cunningham, C. (2006). Symptoms versus impair-

ment: The case for respecting DSM–IV’s criterion D. Journal of

Attention Disorders, 9, 465–475. doi:10.1177/1087054705 283881

Graham, J., & Coghill, D. (2008). Adverse effects of pharmacothera-

pies for attention-deficit=hyperactivity disorder: epidemiology, pre-

vention, and management. CNS Drugs, 22, 213–237.

Gray, S. A., Chaban, R., Martinussen, R., Goldberg, H., Gotlieb, R.,

Kronitz, R., . . . Tannock, R. (2012). Effects of a computerized

working memory training program on working memory, attention,

and academics in adolescents with severe LD and comorbid ADHD:

A randomized clinical trial. Journal of Child Psychology and

Psychiatry, 53, 1277–1284.

Green, C. T., Long, D. L., Green, D., Iosif, A., Dixon, F., Miller, M.

R., . . . Schweitzer, J. (2012). Will working memory training general-

ize to improve off-task behavior in children with attention-deficit=

hyperactivity disorder? Neurotherapeutics, 9, 639–648. doi:10.1007/

s13311-012-0124-y

Halperin, J. M., & Healey, D. M. (2011). The influences of environ-

mental enrichment, cognitive enhancement, and physical exercise

on brain development: Can we alter the developmental trajectory

of ADHD? Neuroscience and Biobehavioral Reviews, 35, 621–634.

doi:10.1016/j.neubiorev.2010.07.006

Harwood, M. D., & Eyberg, S. M. (2006). Child-directed interaction:

Prediction of change in impaired mother–child functioning. Journal

of Abnormal Child Psychology, 34, 335–347. doi:10.1007/

s10802-006-9025-z

Holmes, J., Gathercole, S. E., Place, M., Dunning, D. L., Hilton, K.

A., & Elliott, J. G. (2010). Working memory deficits can be over-

come: Impacts of training and medication on working memory in

children with ADHD. Applied Cognitive Psychology, 24, 827–836.

doi:10.1002/acp.1589

Klingberg, T., Fernell, E., Olesen, P. J., Johnson, M., Gustafsson, P.,

Dahlstrom, K., . . . Westerberg, H. (2005). Computerized training of

working memory in children with ADHD––A randomized,

controlled trial. Journal of the American Academy of Child and

Adolescent Psychiatry, 44, 177–186. doi:10.1097/00004583-

200502000-00010

Klingberg, T., Forssberg, H., & Westerberg, H. (2002). Training of

working memory in children with ADHD. Journal of Clinical and

Experimental Neuropsychology, 24, 781–791.

Lambek, R., Tannock, R., Dalsgaard, S., Trillingsgaard, A., Damm,

D., & Thomsen, P. H. (2010). Validating neuropsychological sub-

types of ADHD: How do children with and without an executive

function deficit differ? Journal of Child Psychology and Psychiatry,

and Allied Disciplines, 51, 895–904. doi:10.1111/j.1469-7610.

2010.02248.x

Makris, N., Biederman, J., Monuteaux, M. C., & Seidman, L. J.

(2009). Towards conceptualizing a neural systems-based anatomy

782 CHACKO ET AL.

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13

of attention-deficit=hyperactivity disorder. Developmental Neu-

roscience, 31, 36–49.

Mezzacappa, E., & Buckner, J. C. (2010). Working memory training

for children with attention problems or hyperactivity: A school-

based pilot study. School Mental Health, 2, 202–208. doi:10.1007/

s12310-010-9030-9

MTACooperative Group. (1999). A 14-month randomized clinical trial

of treatment strategies for attention-deficit=hyperactivity disorder.

TheMTACooperativeGroup.Multimodal Treatment Study of Chil-

dren with ADHD. Archives of General Psychiatry, 56, 1073–1086.

Nathan, P., E., & Gorman, J. M. (2002). A guide to treatments that

work (2nd ed.). New York, NY: Oxford University Press.

Owens, E. B., Hinshaw, S. P., Kraemer, H., Arnold, E. L., Abikoff, H.,

Cantwell, D. P., . . . Wigal, T. (2003). Which treament for whom for

ADHD? Moderators of treatment response in the MTA. Journal of

Consulting and Clinical Psychology, 71, 540–552. doi:10.1037/

0022-006x.71.3.540.

Pelham, W., & Fabiano, G. (2008). Evidence-based psychosocial

treatments for attention-deficit=hyperactivity disorder. Journal of

Clinical Child and Adolescent Psychology, 37, 184–214.

doi:10.1080/15374410701818681

Raggi, V. L., & Chronis, A. M. (2006). Interventions to address the

academic impairment of children and adolescents with ADHD.

Clinical Child & Family Psychology Review, 9, 85–111.

Rapport, M. D., Chung, K. M., Shore, G., & Isaacs, P. (2001). A

conceptual model of child psychopathology: Implications for

understanding attention–deficit=hyperactivity disorder (ADHD) and

treatment efficacy. Journal of Clinical Child Psychology, 30, 48–58.

Silverman, W., & Hinshaw, S. P. (2008). The second special issue on

evidence-based psychosocial treatments for children and adoles-

cents: A 10-year update. Journal of Clinical Child and Adolescent

Psychology, 37, 1–7. doi:10.1080/15374410701817725

Sonuga-Barke, E. S., Coghill, D., DeBacker, M., & Swanson, J. (2009).

Measuring methylphenidate response in attention-deficit=

hyperactivity disorder: How are laboratory classroom-based

measures related to parent ratings? Journal of Child and Adolescent

Psychopharmacology, 19, 691–698. doi:10.1089/cap.2009.002

Sonuga-Barke, E., Thompson, M., Abikoff, H., Klein, R., & Brotman,

L. M. (2006). Nonpharmaceutical interventions for preschool chil-

dren with ADHD: The case for specialized parent training. Infants

& Young Children, 19, 142–153.

Sonuga-Barke, E. J. S., Thompson, M., Daley, D., Laver-Bradbury,

C., & Weeks, A. (2001). Parent-based therapies for preschool

attention-deficit=hyperactivity disorder: a randomized, controlled

trial with a community sample. Journal of the American Academy

of Child & Adolescent Psychiatry, 40, 402–408. doi:10.1097/

00004583-200104000-00008

Swanson, H. L., & Jerman, O. (2007). The influence of working

memory on reading growth in subgroups of children with reading

disabilities. Journal of Experimental Child Psychology, 96, 249–283.

Swanson, H. L., Jerman, O., & Zheng, X. (2008). Growth in working

memory and mathematical problem solving in children at risk

and not at risk for serious math difficulties. Journal of Educational

Psychology, 100, 343–379.

Swanson, J. M., Kraemer, H. C., Hinshaw, S. P., Arnold, L. E.,

Conners, C. K., Abikoff, H. B., . . . Wu, M. (2001). Clinical rel-

evance of the primary findings of the MTA: Success rates based

on severity of ADHD and ODD symptoms at the end of treatment.

Journal of the American Academy of Child and Adolescent Psy-

chiatry, 40, 168–179. doi:10.1097/00004583-200102000-00011

Thorell, L. B., Lindqvist, S., Nutley, S. B., Bohlin, G., & Klingberg, T.

(2009). Training and transfer effects of executive functions in pre-

school children. Developmental Science, 12, 106–113. doi:10.1111/

j.1467-7687.2008.00745.x

Willcutt, E. G., Doyle, A. E., Nigg, J. T., Faraone, S. V., &

Pennington, B. F. (2005). Validity of the executive function theory

of attention-deficit=hyperactivity disorder: A meta-anlytic review.

Biological Psychiatry, 57, 1336–1346.

EBT STATUS OF COGMED FOR YOUTH ADHD 783

Dow

nloa

ded

by [

b-on

: Bib

liote

ca d

o co

nhec

imen

to o

nlin

e U

C]

at 0

9:19

15

Nov

embe

r 20

13