Embed Size (px)
Citation preview
9/28/2016
1
A Multiple Deficit Model of DyslexiaWhat is it and what does it mean for assessment and intervention?
RiteCare 2016 National ConferenceDenver, CO
October 14, 2016
Jeremiah RingLuke Waites Center for Dyslexia and Learning Disorders
Texas Scottish Rite Hospital for Children
Financial DisclosureEmployed at Texas Scottish Rite Hospital for Children
Texas Scottish Rite Hospital for Children funded this research and travel
Learning Objectives
• Understand the multiple deficit model of developmental disorders
• Describe (some) profiles of cognitive deficits associated with reading disability
• Discuss practical implications of a multiple deficit model for intervention
Consensus Definition of Dyslexia
Lyon, Shaywitz, & Shaywitz (2003). Annals of Dyslexia, 53, 1‐14.
2. These difficulties typically result from a deficit
in the phonological component of language that
is often unexpected in relation to other
cognitive abilities and the provision of effective
classroom instruction.
1. “Dyslexia is characterized by difficulties with
accurate and/or fluent word recognition and by
poor spelling and decoding abilities.
3. Secondary consequences may include problems
in reading comprehension and reduced reading
experience that can impede growth of
vocabulary and background knowledge.”
9/28/2016
2
Phonological Processes and Reading
• Alphabetic Principal depends on ‘awareness of internal phonological structure of words’ (Liberman et al., 1989)
• Phonological awareness correlates with reading ability (Calfee et al., 1973)
• Early phonological awareness predicts later reading skill (Wagner & Torgesen, 1987)
• Children with reading disability present with compromised phonological skills (Vellutino & Scanlon, 1987)
• Poor readers respond to intervention combining phonological awareness and alphabetic instruction (Hatcher et al., 1994)
Problems with Single Deficit Model
• Some children with phonological awareness deficits do not develop reading deficits (e.g., Snowling et al., 2003)
• Some children without phonological awareness deficits present with a reading deficit (e.g., Manis et al., 1997)
• Comorbidity
• Reading disability prevalence of 7% (Petersen & Pennington, 2012)
• ADHD prevalence of 5% (Boada, Willcutt, & Pennington, 2012)
• Co‐occurrence rate 25‐40% (Willcutt & Pennington, 2000)
Multiple Deficit Model
Adapted from Pennington (2006). Cognition, 101, 385‐413. Figure 2.
Level of Analysis
Non‐Independence at each Level
G1 G2G3E1 E2Etiologic Risk and
Protective FactorsGxE Interaction& G‐E Correlation
PleiotropyNeural Systems N3N2N1
Interactive Development
Cognitive Processes C3C2C1
ComorbidityComplex Behavioral Disorders D3D2D1
KEYG= genetic risk protective factor, E = environmental risk or protective factor,N = neural system, C = cognitive process, D = disorder
9/28/2016
3
Multiple Deficits of ADHD and RD
PhonologicalAwareness
Inhibition
Verbal Working Memory
Naming Speed
Adapted from McGrath et al. (2011). Journal of Child Psychology and Psychiatry, 52, 547‐557. Figure 3.
Processing Speed
Single Word Reading
Inattention
Hyperactivity‐Impulsivity
Multiple Deficits of Reading Disability
Single Word Reading
Component Skill
Component Skill
Component Skill
Component Skill
PhonologicalAwareness
Cut‐off Deficit Definition
Deficit ≤ 80 SS
9/28/2016
4
MultipleSingle
Deficit Category
Is PA Deficit Necessary?
Yes
No
Note: PA refers to phonological awareness
Pennington et al. (2012). Journal of Abnormal Psychology, 121, 212‐224. Table 1.
I. Single phonological deficit
II. Single deficit subtype
III. Phonological core, multiple deficit
IV. Multiple deficit
Theoretical Models of Reading Deficit
Luke Waites Center Diagnostic Clinic
• Average 1200 psycho‐educational evaluations each year
• Eligibility Criteria
• Academic concerns include reading, math, and writing
• Ages 5 through 14 years
• English as primary language
• Demographics
• 45% Female
• 30% Ethnic minority
• 70% public school
Total patients with WISC‐IV, CTOPP, WIAT Reading N = 2653
School and diagnosis inclusion criteria
Excluden = 1032
Includen = 1621
Typical ReaderWord Reading > 90SS
n = 901
Reading DeficitWord Reading ≤ 80SS
n = 215
Sample Selection
9/28/2016
5
Cognitive Predictors
• Phonological Awareness (PA)1: segmentation, manipulation, and blending
• Rapid Automatic Naming (RAN)1 : serial naming colors, letters, and numbers
• Working Memory (WM)2 : digit recall forward and backward, letter‐number sequencing
• Verbal Comprehension (VCI)2 : vocabulary, analogy, and pragmatics
1 Comprehensive Test of Phonological Processing (Wagner et al., 1999). 2 Wechsler Intelligence Scale for Children IV (Wechsler, 2004).
Cutoff‐Defined Deficit Profiles
Distribution of Reading Deficit Sample
Percent of Patients
Deficit Type
None PA RAN WM VCI PA‐Core Multiple
10
20
30
40
50
60
70
80
90
100
28
914
10
23
141
13
15Mild
Note: ‘Mild’ deficit > 80 SS and < 90 SS. Differences in reading ability by deficit type are not significant (F (6, 208) = 1.5, p=.17)
Cutoff‐Defined Deficit Profiles
Distribution of Typical Reading Sample
Percent of Patients
Deficit Type
None PA RAN WM VCI PA‐Core Multiple
10
20
30
40
50
60
70
80
90
100
76
5 8 8 2
Note: RD and Non‐RD deficit distributions are significantly different, Χ2 (6, N=1116) = 294.9, p < .0001.
<1 1
9/28/2016
6
Distribution of Deficit Types
MultipleSingle
Deficit Category
Is PA Deficit Necessary?
Yes
No
Note: Reading deficit sample. PA refers to phonological awareness
Totals
9%
25%
34%
23%
14%
36%
Totals
32%
39%
Path Analysis
PA
RAN
WM
VERBAL
READ e.79
.37
.20
.17
.26
.29
.07
.18
.16
.34
.33
R2 = .37
Note: Analysis includes total sample (n=1621). Coefficients in bold p < .05.
PA
RAN
WM
VERBAL
READ
See Pennington et al. (2012). Journal of Abnormal Psychology, 121, pp. 212‐224 for method details.
Individual Prediction of Reading Deficit
9/28/2016
7
Predictor Standard Score
Outcome Standard Score
130
120
110
100908070 130120110
100
90
80
70
small error
Individual Prediction of Reading Deficit
Single Deficit Models
Model 1: Word Reading = Phonological Awareness (PA)
Model 2: Word Reading = Rapid Automatic Naming (RAN)
Model 3: Word Reading = Working Memory (WM)
Model 4: Word Reading = Verbal Comprehension (VCI)
Phonological Core Multiple Deficit
Model 5: Word Reading = PA + RAN
Model 6: Word Reading = PA + WM
Model 7: Word Reading = PA + VIQ
Model 8: Word Reading = PA + RAN + WM
Model 9: Word Reading = PA + RAN + VIQ
Model 10: Word Reading = PA + WM + VIQ
Model 11: Word Reading = PA + RAN + WM + VIQ
9/28/2016
8
Other Multiple Deficit Models
Model 12: Word Reading = RAN + WM
Model 13: Word Reading = RAN + VIQ
Model 14: Word Reading = WM + VIQ
Model 15: Word Reading = RAN + WM + VIQ
Regression‐Defined Profiles
Distribution of RD Patients by Deficit Type
Percent of Patients
Deficit Type
None PA RAN WM VCI PA‐Core Multiple
10
20
30
40
50
60
70
80
90
100
11 9 6
37
29
9<1
Distribution of Regression‐Defined Deficits
MultipleSingle
Deficit Category
Is PA Deficit Necessary?
Yes
No
Note: PA refers to phonological awareness
Totals
11%
24%
35%
37%
29%
66%
Totals
48%
53%
9/28/2016
9
RAN as Phonological Processing
MultipleSingle
Deficit Category
Is PA Deficit Necessary?
Yes
No
Note: PA refers to phonological awareness + Rapid Automatic Naming
Totals
19%
15%
34%
52%
14%
66%
Totals
71%
29%
See Wagner, Torgesen, & Rashotte (1994) for model details.
Agreement of Deficit Definitions
Regression Defined Deficit
Totals
Cut‐off Defined Deficit
None PA
RAN
WM
VCI
PA‐Core
Multiple
Multiple
PA‐Core
PA
RAN WM
VCI
Totals
61
13
9
2
16
12
9
3119 5030 321
23
19
12
20
79
62
020 00
00 000
10 20 0
00 10 0
411 7 05
0 513 09
8
10
7
3
40
26
8
10
7
3
40
26
Effect of Number of Deficits
100
90
80
70
60
50
Stan
dard Score
0 1 2 3 4
Number of Deficits
Reading Ability by Deficit Number
Total Sample
Reading Deficit Sample
r = ‐.22, p = .001
r = ‐.44, p < .0001
9/28/2016
10
Individual Prediction Summary
• Phonological awareness deficit is sufficient, but not necessary for word reading deficits
• Moderate agreement (61%) between cut‐off and regression deficit definition methods (κ = .40, p < .0001)
• Both definition methods support a multiple deficit model of reading disability, primarily a phonological‐core deficit model
• In the total sample, the data suggest an additive effect of increasing number of deficits on reading ability
Cognitive Profiles and Intervention
“Assessment of cognitive and neuropsychological
processes should be used not only for identification,
but for intervention purposes as well, and these
assessment‐intervention relationships need further
empirical investigation.” (Hale et al., 2010)
Patterns of Strengths and Weaknesses
• Aptitude‐Achievement Consistency (or Cross‐Battery Assessment; Flanagan, Ortiz, & Alfonso, 2007)
• Concordance/Discordance Method (Hale & Fiorello, 2004)
• Discrepancy/Consistency Method (Naglieri, 1999)
9/28/2016
11
Cognitive Profiles and Reading Intervention
• Pre‐intervention phonological awareness and rapid naming are most consistent predictors of response (e.g., Torgesen et al., 1999, c.f. Torgesen et al., 2001)
• Verbal intelligence is an inconsistent predictor of treatment response (e.g., Al Otaiba & Fuchs, 2002)
• Verbal working memory is associated with reading disability, but less so for treatment response (Swanson et al., 2009; but c.f. Savage et al., 2007)
Luke Waites Center Dyslexia Lab
• Clinically‐referred sample (n=92) without access to adequate reading remediation services
• Instruction from an Orton Gillingham‐based, multisensory, structured language curriculum (Avrit et al., 2006)
• Small group intervention model
• Comprehensive reading curriculum teaches phonological awareness, phonics, fluency, vocabulary, comprehension
• Intervention delivered for two academic years (5 hours per week for total of 230 hours contact time)
Cognitive Predictors
Descriptive Statistics
Measure Average SD Minimum Maximum W
PA
RAN
WM1
VCI
Note: N = 92. SD = standard deviation. W = Shapiro‐Wilks test of distribution normality. 1n = 61
88.2
100.5
91.5
84.2
10.2
10.2
10.6
12.7
64
81
56
52
112
129
120
109
.98
.98
.97
.97
9/28/2016
12
Treatment OutcomesStan
dard Score
Word Reading Comprehension
Gain
Baseline
120
110
100
90
80
70
10
82
11
84
Note: Reading measures from Wechsler Individual Achievement Test. Baseline to posttest Word Reading, t(91) = 10.1, p < .0001, and Comprehension, t(87) = 9.4, p < .0001.
Prediction of Baseline Status
Word Reading
Cognitive Predictor Β R2
Note: B = standardized regression coefficient. R2 = squared correlation. * p < .05 . 1n = 61.
PA
RAN
WM1
VCI
.26
.53
‐.09
.28
.07*
.28*
.01
.08*
Comprehension
Β R2
.26
.32
.11
.36
.07*
.10*
.01
.13*
Prediction of Post‐Treatment Status
Word Reading
Cognitive Predictor Β sr2
Note: Regression models include baseline status. B = standardized regression coefficient; sr2 = squared semi‐partial correlation; *p < .05; 1n = 61.
PA
RAN
WM1
VCI
.04
.11
.07
.06
.00
.01
.00
.00
Comprehension
Β sr2
.13
.09
.17
.36
.02
.01
.03
.11*
9/28/2016
13
Moderating Deficits with Treatment
PA
Deficit Intervention Accommodation
PA
Specific instruction in• articulatory awareness• phoneme‐grapheme correspondence
Scaffolding
RAN Repeated accurate practice Additional response time
WM
• Reduced text processing requirements
• Additional opportunity to engage summarizing, etc.
• Scaffolding
VCI
Specific instruction in• Vocabulary• Figurative language• Strategies
• Additional opportunities reading authentic text
• Scaffolding
Deficits that Matter for Intervention
Deficit Intervention
Phonological Awareness • articulatory awareness• phoneme‐grapheme correspondence
Decoding• phonological awareness• grapheme‐phoneme correspondence
Word Recognition
• orthographic patterns • morpho‐phonemic structure• Fry’s Instant Word lists• Print exposure
Fluency• repeated readings• print exposure
Comprehension
• vocabulary and background knowledge• figurative language• strategies• print exposure
Treatment Summary
• Good curricula will meet some component deficits with direct instruction (e.g., phonological awareness)
• Good therapists will accommodate some individual differences within therapeutic environment (e.g., working memory)
• Deficits that matter most for reading intervention content decisions involve the child’s specific reading problem(s) (e.g., Miciak et al., 2013)
9/28/2016
14
General Conclusions
• Phonological awareness deficit is sufficient for a reading deficit, but not necessary
• Phonological‐core multiple deficit model reflects most common profile of children with reading deficit (Stanovich, 1988; Morris et al., 1998; Pennington et al., 2012)
• Quality intervention may moderate effects of individual variation in component skills, but this effect needs to be formally evaluated
• Profile analysis for intervention may be promising, but has “…yet to meaningfully inform the design of targeted reading‐related interventions ...” (Elliott & Grigorenko, 2014)
Consensus Definition of Dyslexia
Lyon, Shaywitz, & Shaywitz (2003). Annals of Dyslexia, 53, 1‐14.
1. “Dyslexia is characterized by difficulties with
accurate and/or fluent word recognition and by
poor spelling and decoding abilities.
3. Secondary consequences may include problems
in reading comprehension and reduced reading
experience that can impede growth of
vocabulary and background knowledge.”
2. These difficulties typically result from a deficit
in the phonological component of language that
is often unexpected in relation to other
cognitive abilities and the provision of effective
classroom instruction.
Important Limitations
• Identification questions limited to word level outcomes
• Analyses used a small set of predictors and excluded some important components of reading (e.g, orthographic processing)
• The sample was clinically‐referred and distributions of deficits may not accurately reflect general population
• Component deficits may be a consequence of the reading deficit rather than cause (e.g., Wagner et al., 1994)
References
Al Otaiba, S. & Fuchs, D. (2002). Characteristics of children who are unresponsive to early literacy intervention. Remedial and Special Education, 23, 300-316.
Avrit, K., Allen, C., Carlsen, K., Gross, M., Pierce, D., & Rumsey, M. (2006) Take Flight: A comprehensive intervention for students with dyslexia. Dallas, TX: Texas Scottish Rite Hospital.
Boada, R., Willcutt, E.G., & Pennington, B.F. (2012). Understanding the comorbidity between dyslexia and attention-deficit/hyperactivity disorder. Topics in Language Disorders, 32, 264-284.
Calfee, R.C., Lindamood, P., & Lindamood, C. ( 1973). Acoustic-phonetic skills and reading – kinbdergarten through twelfth grade. Journal of Educational Psychology, 64, 293-298.
Elliott, J.G. & Grigorenko, E.L. (2014). The dyslexia debate. New York: Cambridge University Press.
Flanagan, D. P., Ortiz, S. O., & Alfonso, V. C. (2007). Essentials of cross-battery assessment (2nd ed.). New York: Wiley.
Hale, J., Alfonso, V., Berninger, V., Bracken, B., Christo, C., Clark, E., et al. (2010). Critical issues in Response-to-Intervention, comprehensive evaluation, and specific learning disabilities identification and intervention: An expert white paper consensus. Learning Disabilities Quarterly, 33, 223-236.
Hale, J. B., & Fiorello, C. A. (2004). School neuropsychology: A practitioner’s handbook. New York: Guilford Press.
Hatcher, P., Hulme, C. & Ellis, A.W. (1994). Ameliorating early reading failure in disabled readers with and without oral language delay. Child Development, 65, 41-57.
Liberman, I.Y., Shankweiler, D., & Liberman, A.M. (1989). The alphabetic principle and learning to read. In D. Shankweiler & I.Y. Liberman (Eds.). Phonology and reading disability: Solving the reading puzzle. Ann Arbor, MI: The University of Michigan Press.
Lyon, Shaywitz, & Shaywitz (2003). A definition of dyslexia. Annals of Dyslexia, 53, 1-14.
Manis, F.R., Seidenberg, M.S., Doi, L.M., McBride-Chang, C., & Petersen, A. (1996). On the bases of two types of development dyslexia. Cognition, 58, 157-195.
McGrath, L.M., Pennington, B.F., Shanahan, M.A., Santerre-Lemmon, L.E., Barnard, H.D., Willcutt, E.G., et al. (2011). A multiple deficit model of reading disability and attention-deficit/hyperactivity disorder: Searching for shared cognitive deficits. Journal of Child Psychology and Psychiatry, 52, 547–557.
Page 1 of 3
Miciak, J., Fletcher, J.M., Steubing, K.K., Vaughn, S., Tolar, T.D. (2013). Patterns of cognitive strengths and weaknesses: Identification rates, agreement, and validity for learning disabilities identification. School Psychology Quarterly, 29, 21-37.
Morris, R. D., Shaywitz, S. E., Shankweiler, D. P., Katz, L., Stuebing, K. K., Fletcher, J. M., Lyon, G. R., Francis, D. J., & Shaywitz, B. A. (1998). Subtypes of reading disability: Variability around a phonological core. Journal of Educational Psychology, 90, 347-373.
Naglieri, J. A. (1999). Essentials of CAS assessment. New York: Wiley.
Pennington, B.F., Santerre-Lemmon, L., Rosenberg, J., MacDonald, B., Boada, R., Friend, A. et al. (2012). Individual prediction of dyslexia by single vs. multiple deficit models. Journal of Abnormal Psychology, 121, 212-224.
Pennington, B.F. (2006). From single to multiple deficit models of developmental disorders. Cognition, 101, 385-413.
Peterson, R.L. & Pennington, B.F. (2012). Developmental dyslexia. Lancet, 379, 1997-2007.
Savage, R., Lavers, N., & Pillay, V. (2007). Working memory and reading difficulties: What we know and what we don’t know about the relationship. Educational Psychology Review, 19, 185-221.
Stanovich, K.E. (1988). Explaining the differences between the dyslexic and garden-variety poor reader: The phonological-core variable difference model. Journal of Learning Disabilities, 21, 590-604, 612.
Swanson, H.L., Zheng, X., & Jerman, O. (2009). Working memory, short term memory and reading disabilities: A selective meta-analysis of the literature. Journal of Learning Disabilities, 42, 260-287.
Snowling, M.J., Gallagher, A., & Frith, U. (2003). Family risk of dyslexia is continuous: Individual differences in the precursors of reading skill. Child Development, 74, 358-373.
Torgesen, J.K., Alexander, A.W., Wagner, R.K., Rashotte, C.A., Voeller, K., & Conway, T. (2001). Intensive remedial instruction for children with severe reading disabilities: Immediate and long-term outcomes from two instructional approaches. Journal of Learning Disabilities, 34, 33–58.
Torgesen, J., Wagner, R., Rashotte, C., Lindamood, P., Rose, E., Conway, T., & Garvan, C. (1999). Preventing reading failure in young children with phonological processing disabilities: Group and individual responses to instruction. Journal of Educational Psychology, 91, 579-593.
Vellutino, F.R. & Scanlon, D.M. (1987). Phonological coding, phonological awareness, and reading ability: Evidence from a longitudinal and experimental study. Merrill-Palmer Quarterly, 33, 321-363.
Page 2 of 3
Wagner, R.K. & Torgesen, J.K. (1987). The nature of phonological processing and its causal role in the acquisition of reading skills. Psychological Bulletin, 101, 192-212.
Wagner, R. K., Torgesen, J. K., & Rashotte, C. A. (1999). The comprehensive test of phonological processing. Austin, TX: Pro-Ed.
Wagner, R., Torgesen, J., Rashotte, C. (1994). Development of young reader's phonological processing abilities: New evidence in bi-directional causality from a latent variable longitudinal study. Developmental Psychology, 30, 73-87.
Wechsler, D. (2004). The Wechsler intelligence scale for children—fourth edition. London: Pearson Assessment.
Willcutt, E.G, & Pennington, B.F. (2000).Psychiatric comorbidity in children and adolescents with reading disability. Journal of Child Psychology and Psychiatry, 41, 1039-1048, 2000.
Page 3 of 3
Mu
ltip
le D
efic
it M
od
el
Ad
apte
d f
rom
Pe
nn
ingt
on
(2
00
6).
Co
gn
itio
n, 1
01
, 38
5-4
13
. F
igu
re 2
.
Leve
l of
An
alys
is
No
n-
Ind
epen
den
ce a
t ea
ch L
evel
G1
G2
G
3
E 1
E 2
Etio
logi
c R
isk
and
P
rote
ctiv
e Fa
cto
rs
GxE
Inte
ract
ion
&
G-E
Co
rrel
atio
n
Ple
iotr
op
y N
eura
l Sys
tem
s N
3
N2
N1
Inte
ract
ive
Dev
elo
pm
ent
Co
gnit
ive
Pro
cess
es
C3
C2
C1
Co
mo
rbid
ity
Co
mp
lex
Beh
avio
ral
Dis
ord
ers
D3
D2
D1
KEY
G
= ge
net
ic r
isk
pro
tect
ive
fact
or,
E =
en
viro
nm
enta
l ris
k o
r p
rote
ctiv
e fa
cto
r,
N =
neu
ral s
yste
m, C
= c
ogn
itiv
e p
roce
ss, D
= d
iso
rder
