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CHAPTER 18Pelagic M Beeson a nd Steven Z Rapcsak

h phasias

Aphasia is anacquired language impairment that results fromneurological damageto the language areasof thebrain, whichar etypically located in the lefthemisphere. Also referred to asdysphasia, aphasia is characterized by impaired word selection,language production, and language comprehension. Incorrectwordchoiceandsound substitution errorsarecommon featuresof aphasic speech and are referred to asparaphasic errors,orparaphasias. Language comprehension deficits are present tosome extent in allaphasias,but asubtle impairmentmay be-come apparentonlywhenthepatientistested with syntacticallycomplex sentences.Becauseaphasiais acentral language impair-ment, itaffects notonly spoken languagebutalsothe compre-hensionand production of written language (i.e., reading andwriting).Reading impairment isreferred to asalexia, an dwrit-ing disorders ar e labeled agraphia (o r acquired alexia an dagraphia todistinguish them f romdevelopmental disordersofreadinga ndwriting).Thespecificcharacteristicsofaphasia an dits accompanying deficits reflect the site an d extent of neuro-logical damage, aswell as individual differences in brain or-ganization. Various aphasia syndromes are characterized byidentifiable constellations of language symptoms and providea useful framework for the diagnostic evaluation of patientswith aphasia.436

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TheAphasias 437

Figure 18 1 Schematic drawingof the left hemisphereofth ebrain.Rolandic Fissure

Supramarginal

SylvianFis

[j J Perisylvian region

I ETIOLOGYThe most common cause of acute aphasia is ischemic stroke(embolic or thrombotic) in the distribution of the left midd lecerebral artery, which provides th e main blood supply to theperisylvian cortical language areas (Figure18.1).Other causesof acute aphasia includ e cerebral hem orrhage (hypertensive, orfol lowingthe rupture of an aneurysm or arteriovenous malfor-mation) and traum atic braininjury.In co ntrast, slow ly progres-sive aphasia typically occurs with brain tumors and corticaldegenerative disorders (e.g., aphasia associated with dem entia oftheA lzheime r's typeorprim ary progressive aphasia). Transientaphasia may be associated with transient ischemic attacks(TIAs),migraine, and seizures.Aphasia most often results from left-hemisphere lesionsbecause about 95% of right-handed individuals and about 70%of le ft-handed individualsare left-hemispheredom inant fo rlan-guage. However, aphasia can occur following right-hemispheredamage in left-handed individuals; and, in rare cases, right-hemisphere damage in a right-handed individu al results in whatiscalledcrossed aphasia.

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438 Beesonand Rapcsak

II FUNCTIONAL NEUROANATOMICCORRELATESOFAPHASIAA P erisylvian Versus Extrasylvian Lesions

Aphasiais most often caused by damage to the perisylvian lan-guage areasof the lefthemisphere (seeFigure 18.1).Theperi-sylvianlanguage zone includes Broca's area, which isinvolvedin the motor programming of speech; Wernicke's area, whichiscriticalfor theauditory comprehension ofspoken words;andthe supramarginal gyrus and the under lying arcuate fasciculus,which linksBroca'sandWernicke's areasand isthought toplayanimportantroleinrepetition.Aphasiamay also becausedbylesions that do notdirectly damagetheperisylvian languageareasbut isolatethemfrombrain regions involved in semanticprocessingand the production of volitional speech. The extra-sylvian aphasias are referred to astranscortical aphasias.B Fluency

Aphasic speech production can be classified as either fluentor nonfluent. Fluentaphasiasarecharacterizedbyplentifu lverbal out-put consistingofwell-articulated, easily produced utter-ancesofrelatively normal lengthandprosody (i.e., varia-tions of pitch, loudness, rhythm). Fluent aphasiasareassociated with posterior (post-Rolandic) lesions thatspare anterior (pre-Rolandic) cortical regions criticalformotorcontrolforspeech. Nonfluentaphasiasarecharacterizedbysparse, effort fulutterances of short phraselengthand disrupted prosody.Nonfluentaphasiasareassociated with anterior,orpre-Rolandic, lesions that compromise motor and premotorcortical regions involved in speech production.

C Auditory ComprehensionAuditory processing is defective in most aphasic patients, al-thoughthe severity of the impairment varies with aphasia type.Anterior lesions result in relatively mild auditory comprehen-sion impairments, whereas posterior lesions (especiallyiftheyinvolve Wernicke'sarea)resultinsignif icantimpairmentof au-ditory processing.

D RepetitionAphasiatypes dif fer with regard to the preservation ofrepeti-tion ability.

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The Aphasias 439

Repetition of spoken utterances requires an intact peri-sylvian region: posterior regions (Wernicke's area) forauditory processing, anterior regions (Broca's area)forspeech production, and the critical connecting fiber tract(arcuate fasciculus). Therefore, lesions anywhere in theperisylvianregion arelikelyto disrupt repetition. Extrasylvian lesionsarecharacterizedbypreserved repe-tition despite severe reduction of spontaneous speech(transcorticalmotor aphasia), severe comprehension dis-turbance (transcortical sensory aphasia), orboth(mixedtranscortical aphasia).

E NamingAl l individuals with aphasia exhibit naming impairment, oranomia, usually in combination with other language deficits.However,naming impairment canalso occurinrelative isola-tioninpatients with anomic aphasia.Becauseof itsubiquitousnature, anomia is considered the least useful localizing signin aphasia.

III ASSESSMENTOFAPHASIATheinitial assessmentofaphasiacan beperformed informally,as in the context of abedside evaluation.A 15- to 30-minuteinterview that includes conversational interaction, aswellassome structuredtasks,istypically adequatetodiscernthepres-enceorabsenceofaphasia, provideanestimateof the aphasiaseverity,establishaprofile,anddocumenttherelative strengthsand weaknessesof the patient (Exhibit18.1).Amore formal ,in-depth assessmentofaphasiaisnecessaryforotherpurposes,such asdesigninga treatment plan, prognosticating recovery,and answering research questions.

A Medical Chart ReviewInadditiontoobtaininginformation aboutthepatient'scurrentand past medical history, the following information should beobtained, ifpossible: handedness: to anticipate possible exceptions to left-

hemisphere dominance for language and to guide theassessment of writing in cases of hemiparesis (i.e., todetermine whether writingwillbe assessed with the dom-inant ornondominanthand);

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440 Beeson and Rapcsak

Exhibit18.1. KeyQuestionsto ConsiderWhenExaminingfor AphasiaIsitaphasia? Is the patient awakeandalert withthe intention tocommunicate?

If not, assessment willbe invalid. I sthere evidence ofword retrievaldiff iculty (anomia)?

Example:Arethere paraphasic errors?

phonemic semantic neologisticExample:

Isthere evidence ofcomprehension diff iculty?Example:

Is the language impairment present acrossallmodalities? Y Nspoken language auditory comprehensionwriting reading

Whatis theaphasiaprofile? (UsedecisiontreeinFigure 18.2.) Is theverbal output fluent ornonfluent? I sauditory comprehension significantly impaired? Y N Isrepetition significantly impaired? Y NWhatis the communicationstatus? Howsevereis thecommunication impairment?

mild moderate severe Is the patient using compensatory strategiestoachievecommunication? Y N

gesture writingdrawing other

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The Aphasias 441

education and occupation: to shape assumptionsre-garding premorbid language, reading,and writingabili-ties; and vision and hearingstatus: todetermine theneedforeyeglasses orsound amplification during testing.B BedsideEvaluation

Toassess aphasia properly,onemust ensurethatthe patientisawake,alert, and able to engage in interaction with the intenttocommunicate. If thepatient hasdiminished responsivenessor isinattentive anduncooperative, the assessmentforaphasiashould bedelayed because the performanceof an obtunded,delirious, orconfused patient willnot provideavalid basisforlanguage assessment. General measuresofmental status, suchastheMini-Mental State Examination,are not appropriateforindividuals with aphasia because of the dependence of thesetestson language comprehension and production.Bedside assessment should concentrate on fou rlanguagetasks: production of conversationalspeech, auditorycompre-hension, repetition, and naming.Abriefassessmentofreadingandwri ting should alsobeperformed. Throughout the evalua-tion, the examiner should seek to discover the patient's success-ful communication strategies,aswellas torevealdeficits.Partic-ularlywhen the impairment is obvious and severe, the examinershould discern what levelofassistance resultsinsuccessfulcom-munication and how communication breakdowns are bestrepaired.

1. ASSESSMENTOFCO NVERSATIONAL SPEECHBeginthe evaluation by conversing with thepatient.Whileestablishing rapport, listen for evidence oflanguage impair-ment.Having reviewedthemedical chartforbackgroundinfor-mation, ask biographical questions that allow observation ofthepatient'sability to communicate.Askopen-ended questionsto elicit a sample of connected speech. Picture description canalsobe used to elicit spontaneous speech. Obtain enough infor-mationtoaddress the following questions:a Is there evidence of word-retrieval difficulty?1. Are there word-finding pauses, hesitations, or self-

corrections?2. Does the patient show circumlocution, which meanstalkingaround thetopicbecause of inability to retrievespecificwords?

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(a) semantic circumlocu tion: Hand me that thing overthere,thatthingformynose,thatwiper,youknow,that . . . [facial tissue]or(b) empty circum locu tion: It's for this one and thatone,and one and two and three, andthen boom,boom, boom . . . and Iwish Icould tell you. [tar-get unknown].3. Arethere paraphasicerrors?(a) verbal or semantic paraphasia: an incorrect wordthatmay berelatedto theintended wordinmeaning(e.g., he fo r she),(b) literalorphonem ic paraphasia: errorofsound selec-tion (e.g., boap fo r boat), or(c) neologism: a novel utterancethatbearsno obviousrelationship to theintended wordinsoundormean-ing (e.g., kleeza fo r table).

b Is theoutput fluent or nonfluent?1. Fluent aphasia ischaracterizedby the following:(a) utterancelengththatis typically greater than fourwords and m ay approxim ate a norm al range of f iveto eightormore words;(b) relatively nor m al speech prosod y (i.e., pitch, loud -ness,andtim ing variations), althoughfluentutter-ancesmay beinterruptedbyoccasional hesitations,word-finding pauses,and revised utterances;(c ) articulation that is relatively facile and producedwithout struggle;and(d ) conversational speech that is lacking in informa-tional content and may sound empty becauseofa paucity of content words (e.g., nouns and actionverbs) and an excess of grammatical functors (e.g.,articles, prepositions, conjunctions) and indefinitewords (e.g., thing ).2. No nfluent aphasia is characterized by the fol lowing:(a) reduced utterance length of typically lessthan fourwords; may be primarily single words;(b ) halting speech lacking normal prosodic variationsof pitch, loudness, and timing;(c) effortful articulation, although reactive or auto-matic responses m aybe surprisingly well articulated,such as hello or fine or Idon't know ; and(d ) reduced gramm atical complexity, with utterancesconsisting mostly ofnouns and lacking function

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TheAphasias 443

words, resulting in agrammatic, or telegraphic,speech.2. ASSESSMENT OF AUDITORY COMPREHENSIONAuditorycomprehension is typically impa ired to some ex-tent in allaphasias.Apatient's ability to respond in anaturalconversational exchange should be observed, but it is also im-portant to evaluate responses to auditory-verbal informationon more structured tasks. Response modali t ies may need tobe adapted so that other impairmentsdo not cause responseinterference (e.g.,unreliable yes or no responses may requirepointing to notecards printed withyesandnoor + and -).a Sample tasks1. word recognition ( Where's the phone? Show methe chair. ),2. co m m ands of increasing complexityfor the patient tocarry out,(a) simple comm ands ( Make a fist. ),(b) multistep complex commands ( Point to the win-dow,the door,and then the pen. ), and3. yes/no questionsofincreasingcomplexity( Doyoulivein Tucson? Do you close your umbrella when it startsto rain? ).b Takenoteof the following:1. At what point does auditory comprehension breakdown: single words, short commands, complex com-mands?2. Howdoesthe patient respondto auditory comprehen-sion difficulties?Arethererequests for clarification orrepetition? Isthere a lack of awarenessof the deficit?3. If com prehension problems are mild, they may becomeevident only indifficultlistening situationsthatrequiredivided attention or under conditions offatigue.3. ASSESSMENT OF REPETITIONAlthough the abilityto repeat spoken utterancesh aslittlecom m unicative valu e, repetition tasks provide an assessmentofspeech inputandoutputprocessesandhavediagnosticvaluefo r aphasia classificationand lesion localization. If repetition

is severely impaired, and even single words are not repeated,emotionally laden words or phrases may evoke better responses(e.g., money, I love you) .

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a Sample tasks1. repetition of single words (e.g., dog, apple, baseball),2. Shor t phrase s (e.g., a cup of c o f f e e salt a nd pepper, go fora walk), and3. Sentencesofincreasing length (e.g.,T he telephone is ring-ing.He saw a very good m o v i e . I had cereal, toast,a nd juicefo r breakfast.).b Takenoteof the following:1. Is repetition better or worse than spontaneous speech?2. Does repetition breakdownat the single-word level oronlyat the sentence level?3. Do repetition attempts result in the production of pa-raphasicerrors?4 ASSESSMENT OF NAMINGAlthough word-findingdifficulties in spontaneous speechmay suggest anomia, formal testing of confrontation namingallowsdirect assessmentofthe patient's ability to retrievespecificwords.Theextentofnamingdifficultyis agood general measureofaphasia severity. Select com m on objectsin theroomf ornam-ing, and if no errorsare made, probe naming oflesscommonobjects. Individuals with aphasia typically exhibit aword f re -quencyeffect,in that morefrequent lyused co ntent w ords (e.g.,shirt) ar e retrieved more easily than less frequent words(e.g., collar).Naming can also be assessed in response to ques-tions,butthey should probe relatively com mo n knowledgeand

not bedependent onhigher educationorextensive vocabulary.Aphasia typically results in impaired confrontation naming re-gardless of the modality of presentation (visual, auditory, ortactile). Naming deficitsconfinedto asingle mod ality suggestsrecognition impairment oragnosia (see SectionV ).a Sample tasks1. nam ing com mo n o bjects: cup, watch, table, pencil;2. namingof less com mo n items: fingernail, collar, eraser;3. respondingtoquestions (Whatdo you use totell time?What color is an apple?);4. naming to definition (What do you call the African

animal withthe long neck?);and5. generative nam ing (Nam e all the animals you can thinkof in 1 minute. Nameall the wordsyou can thinkofthat begin with the letterSin 1m inute).

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The Aphasias 445

b. Takenoteof the following:1.What is the nature of the naming errors?2. Arethere paraphasic responses? What type?3. Can the patient produce the word if given the first

sound, thatis,with phonemic cuing?4. Isthere anyevidenceofmodality-specific impairment,suchas naming difficulty when shown an object, butimproved naming when allowedtohold theobject?5. Isthere awarenessof errors?Ar ethere attempts to self-correct?A rethose attempts successful?6. Is thepatient abletogenerateatleast12 to 15animalnamesin 1minute?5. ASSESSMENT OFREADINGAND WRITINGA bedside evaluation of reading and writing is brief bynecessity. Inquire whether the patient hasattempted to reado rwrite an d what difficulties were experienced. Readingan d

writ ing abilities ar egenerally impaired in aphasia. Ifreadingand writingarespared,thepatientmay not have aphasia butratheraselective impairment affecting speech inputor outputprocesses(seeSection V). Ifaphasia ismild, and the patient isno t fatigued,amore extensive explorationo freadingan dwrit-ing may be performed to assess the type and severity of alexiaand agraphia.a Sample tasks1. Readaloud single wordso r sentences.2. Carryoutwritten commands.3. Write single wordsto dictation. Include nouns, verbs,

andfunctors.Alsoinclude words with regular (e.g.,bake)and irregular (e.g., choir)spellings4. Write a sentence or paragraph.b. Takenoteof thefollowing:1. Is thepatient abletoread aloud? What kindsofreadingerrors(paralexias)ar eproducedinoral reading?Aretheyvisuallysimilarto the target?Is the patient soundingout the word so that some errorsare phonologicallyplausible? Arethere more errorsonwords with irregularversusregular spelling?Is the patient spelling out theword letter by letter?2. Does the patient comprehend written words?Sen-tences?3. What is the nature of the spelling errors? Are theypho-nologically plausible (e.g., kwire fo rchoir), suggesting

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reliance on a phonological spelling strategy?Aretheysemantically relatedto thetar get (e.g.,apple fo rorange)?4. Arethere m otor difficulties that interferewith writing?If paralysis precludes use of the dominant hand, canwritingbeaccomplished withthe nondominant hand?Does the patient have difficulty form ing legible letterseven when using a nonparalyzed limb (i.e., apraxicagraphia)?6. PRAGMATIC ASSESSMENTOF

COMMUNICATION ABILITYThere can be considerable variation in communicativesuccess by individuals with similar language impairments.Throug hout the exam ination process, takenoteof the comm u-nication strategies used by the patient. First,note whether thepatient isawareof the communication deficit. If so, what at-tempts are made to repair communication failures? Does thepatient supplement spoken utterances with gesture or with at-tempts towriteordraw?In the caseofunintelligible orpersev-erative utteranc es, doesthepatient convey inform ation thro ughtoneof voice and prosodic variations? What are the mo st suc-cessful communication modalities and strategies fo r thispatient?IV C L A S S IC A P H A S I A S YN DR O M E STh e performanceprofile thatemergesfrom the brief languageassessment can be used to assign patients to one of eight classicaphasia syndrom es. Classificationisachieved by a seriesof bi-nary decisions regarding fluency, auditory com prehension, andverbalrepetition as shown in Figure18.2. V ario us apha sia syn-drom es have been used for over a century to comm unicate theprofileo f apatient. However,not allpatients exem plifyaclassicaphasia type; in such cases, patients may be distinguished bytheir divergence from a given syndrome.Althoughit isimportant toassess readin gandwr iting abili-ties, performance inthosemo dalities does not pred ict aphasiatype. Oral reading performance often issimilarto spoken lan-guage,and written languagedeficitsm ay mimic the agramm aticor paragram matic elementso fspoken language. However, thereisconsiderable variability within a given aphasia type regardingreading and writing ability. Fo rthat reason, adescription ofreading and writing abilities is not included in the followingsummariesof the clinical charac teristics that co nstitute the clas-sic aphasia syndrom es.

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TheAphasias 447fta 1c M.a-2a gsis1T SS (Jc-< CS9Sli/12.S'gg> t/5 ;5^351 _, u111HM-I ^i|:H G >-i| S8 ns

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A FluentA phasiasAnomic aphasia is a f luent aphasia in which there is goodauditory comprehension and repetition. Conversationalspeech isf luent,with normal utterance

length and grammaticallywel l -formedsentences. Word-finding difficulty in spontaneous speech may be evi-denced by occasional pauses and circumlocutions. Auditorycomprehensionis goodforeveryday conversa-tion, but there may be some difficulty with complexsyntax or in difficult listening situations, such as thosethatrequire divided attention. Repetition is generally preserved even for full-lengthsentences. Namingimpairment,in theabsenceofother significantlanguagedeficits,is the hallmarkof this aphasia type. Lesion location. Lesions in acute anomic aphasia areusually located outside the perisylvian language zoneand involve the angular gyms or the inferior temporalregion. Moderate and mild aphasias of various typescaused by perisylvian lesions may evolve to chronicano-micaphasia. Generalizedeffects ofhead trauma,Alzhei-mer's disease, and increased intracranial pressure associ-ated with brain tumor can also result in anomia;therefore,except in cases of acute anomic aphasia, ano-miahas limited localizing value. Accompanying deficits. Anomic aphasia often existswithout significant concomitant neurological deficits,but when caused by lesions of the angular gyms, it maybe associated with the Gerstmann syndrome (fingerag-nosia, acalculia, agraphia,lef t-r ightconfusion) and limbapraxia. Significant impairment ofreadingand spellingmayaccompany anomia becauseofdamagetoleftposte-rior temporo-parieto-occipital regions. Prognosis.Acute anomic aphasia frequently resolvestominimal language impairmentin the formofoccasionalword-findingdifficulty.Anomic aphasiais themost com-mon evolutionary endpoint for mild-to-moderate apha-sia of all types.Conductionaphasia is af luent aphasia inwhich thereisgood comprehension but poor repetition.

Conversationalspeech isf luent with relatively normalutterance length but is marred by paraphasias. Phonemicparaphasic errors predominate, and self-correction

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The Aphasias 449

attempts mayresultin increasingly closer phonologicalapproximationso f thedesired word,referredto ascondui td approche. Rateofspeechmay beslowedbyword-findingproblemsandattempts to self-monitor,but the overallprosodic pattern isakinto normal.Despite word-findingdifficultiesan dparaphasias, spontaneous speechi smuchmore meaningfulthanin Wernicke's aphasia. Auditory comprehension isrelatively good forcasualconversation. Single-word comprehension is well pre-served, but patients may havedifficultywith complexsyntaxormultistep commands. Repetition impairmentis the hallmark ofconductionaphasia, despite relatively good spontaneous speech.Pa-raphasias tendto beparticularly prominent during repe-titiontasks.Insevere cases,patientsmay not be able torepeat even single words. In milder cases, single-wordrepetition ispossible,but phraseor sentence repetitionis impaired. Repetition of unfamiliar or meaninglessitems is especially difficult. In some cases, attempts atsentencerepetition mayresultin semantic restatementsratherthanverbatim repetition (e.g., He's gone for Heisnot coming back ). Naming is always impaired. Paraphasic errorsare notuncommon and are typically phonemic. Lesionlocation.Conductionaphasia resultsfrom poste-riorperisylvian lesionsaffectingprimarilythesupramar-ginal gymsin theparietal lobeand theunderlying whitematter (arcuatefasciculus). Associated deficits. Conduction aphasiais not associ-ated with significant motor deficit,but cortical sensorylossaffecting the right sideof thebodymay be present.Limbandbuccofacial apraxiaare not uncommon. Prognosis. Conduction aphasia may persist or mayevolve into anomic aphasia.Transcorticalsensoryaphasia (TcSA) is a fluent aphasiawith impaired comprehension and preserved repetition. Conversationalspeech isfluent with relatively normalutterance length, but semantic paraphasias, word-find-ingdifficulties,andcircumlocutionsarecommon. Verbaloutput maysound similartothatofWernicke's aphasiain thatutterancesmay be semantically empty becauseof alacko fcontentwordsa nd overuse offunctors andimprecise words,but output isgenerallynot asvolubleasin Wernicke's aphasia.

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Auditory comprehensionissignificantly impaired,al-though usually not to the extent seen in Wernicke'saphasia. Repetitionis surprisingly preserved, sometimes even forlong complex utterances and unfamil iarwords. Patientsrepeatwordsandsentences without evidenceofcompre-hension and may spontaneously correct minor grammat-icalviolations.Attimes, repetition cannot be inhibited(echolalia). Namingis severely impaired. Lesionlocation.TcSAmost commonly resultsfromex-trasylvianlesions involving the temporo-parietal-occipi-tal region, typically located posterior and deep toWernicke's area. This posterior regionis in thewatershedzone between the posterior and middle cerebral arteryterritories. In asmaller number of cases,TcSA followslesions of the parieto-occipital convexity. Preservationof Wernicke's area and connections to anterior motorspeech regions allowforrepetitionto besparedinTcSA.Alzheimer'sdiseaseca nalso resultin aTcSA profile. Accompanyingdeficits.TcSAmay be accompanied byright hemianopia and right hemisensory loss. Prognosis. TcSA due to strokemay evolve to anomicaphasia. TcSA associated with dementing disease mayprogressto Wernicke's aphasia over time and ultimatelytoglobal aphasia.Wernicke s aphasiais a fluent aphasia with poor auditorycomprehension and repetition. Conversational speech is fluent, easily articulatedspeechofrelatively normal utterance length. Abundantsemantic and phonemic paraphasias are present, as wellassome neologisms. Speech may be completely meaning-lessto the listener, sometimesreferredto asjargon apha-sia.Utterancesmay beempty becauseof alacko fcontentwords (nouns, verbs),an excess ofgrammatical words(e.g., articles, prepositions), and overuse of imprecisewords it, thing). Word retrieval failures m ay result incircumlocutions. Utterancesmayviolatetherulesofsyn-tax and grammar, resulting in paragrammatic speech(e.g., We need the thing in the over the house ).Verbaloutput may be excessive and rapid, with an apparentlack ofinhibition of the flow of speech, referred to as pressofspeech or logorrhea. Auditory comprehension is severely impaired, ofteneven at the single-word level. Difficulty with complex

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The phasias 451

syntax or multistep commands isalways present. Poorself-monitoring oftheir ownspeech m aymake patientssurprisinglyunawareoftheir inabilitytoproduce mean-ingful speech an d result in failure to attempt self-correction. Repetition issignificantly defective; patients may notbeable torepeatevensingle words.Repetition issimilartospontaneous speechinthatitcontains phonemicandsemantic paraphasias. Namingattemptsareoften paraphasic,andsevere ano-mia is therule. Lesion localization. Wernicke's aphasia is typicallyassociated with large posterior perisylvian lesionsencompassing the posterior superior temporal gyrus(Wernicke's area) an d often extending superiorly intothe inferiorparietal region.Acommon causeisembolicocclusionof the inferiordivisiono f the leftmiddle cere-

bral artery. Accompanyingdeficits. Right visualfielddefect some-times accompanies Wernicke's aphasia. Lack ofaware-nessof the languagedeficit (i.e.,anosagnosia)iscommonin theacute stage. Prognosis. Ifauditorycomprehension improves overtime,theprofi lebecomes more consistent with conduc-tionaphasia. Othercasesmayevolvein the directionofTcSA.Aparticularly good recovery could resultinresidualanomic aphasia.B Nonfluent Aphasias

Transcortical motor aphasia (TcMA) is a nonfluent aphasiacharacterized by relatively good auditory comprehension andpreserved repetition. Conversationalspeechisnonfluent,butunlikepatientswith Broca'saphasia,who try to communicate, patientswith TcMAar egenerally abulican d make little attemptto produce speech spontaneously. In the acute stage,patientsmay be mute. When utterances are produced,usually after a long delay,they tend to be of reducedlength (typically less than fourwords)andgrammaticalcomplexity. Articulationisgenerally preserved. Auditory comprehension isgood formost conversa-tional interaction, but theremay bedifficultywith com-plex syntaxormultistep commands. Accurate assessmentofauditory comprehension isproblematic insome cases

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because of prominent akinesia (i.e., thefailure to initiatevoluntary movement) and the tendency to perseverate. Repetitionispreservedinstriking contrastto thevirtualabsence of spontaneous conversational speech. Namingcan berelatively preserved. Unlike most otheraphasias,inTcMAconfrontation naming may bebetterthanspontaneousspeechproduction.Generative nam-ing, however, is aparticularlydifficult task fo r patientswith TcMA. Lesionlocation.Lesions prod ucingTcMAinvolve extra-sylvian regions of the left frontal lobe. In some cases thelesions are mesial, in the distribution of the anteriorcerebral artery, encom passing the supplementary motorarea(SMA)and the cingulate gyrus, which play an impo r-tantrolein the initiation ofspeech.TcMAhasalso beendescribed following dorsolateral frontal lesions locatedanterior or superior to Broca's area. These lesions areoften in the watershed zone between the middle an danterior cerebral artery territories. Associateddeficits. Mesialfrontal lesionsmay beassoci-ated with co ntralateral leg weakness and urin ary inconti-nence. Dorsolateralfrontallesions in the watershedterri-tory may be associated with predominantly proximalweaknessofthe right extrem ities, at times sparing theface. Prognosis.TcMAm ayessentially resolve,or it mayper-sist as relatively mild anom ic aphasia.Broca'saphasia is anonfluent aphasia in which there isrelatively good comprehension and poor repetition. Conversationalspeech isnonf luent, w ith slow, haltingspeech production. Articulatoryimpairmenti scommon.Utterances are of reduced length (typically lessthan fourwords) with simplified gramm ar, referred to asagram-matism.Nou ns predominate, with some verbsandadjec-tivesbu tveryfewfunctors.Wordsoften lackmorpholog-ical endings, such as -ing, -es, -ed. Auditorycomprehensionisrelatively goodforconver-sational speech, bu t thereisconsiderabledifficulty withcom plex syntax or multistep com m ands. E specially dif-ficulta re semantically reversible or passive sentences inwhich wo rd ord er cues alone are not sufficientfo r correctcomprehension (e.g., Thegirlwa spushedby the boy ). Repetitionislimitedtosingle word sand short phrases,typically commensurate with the length of spontane-ousutterances.

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The phasias 453

Namingisalways impairedtosome degree, especiallyforlow-frequencywords. Motor speech production deficitsmay interfere with intelligibility. Lesion location.Lesions restrictedtoBroca's area causeonly transient disruption o fspeech production an dflu-ency. Persistent Broca's aphasia resultsfrommuch largerperisylvian lesionsencompassingtheentireterritoryofthesuperior division of themiddle cerebral artery.T helesionstypically includenotonly Broca's area properbutalso both banksof the Rolandicfissure(including themotor an dsensory regionsfor the face), th einsula, ante-riorparietal lobe, andsubcortical regions deep to theseareas.Persistent Broca's aphasia characteristically evolvesfromglobal aphasia over several months. Associated deficits. Right hemiparesis iscommon, af-fecting the faceand the arm morethanthe leg. Motorprogramming deficits including buccofacial apraxia,apraxia ofspeech, and apraxiaof the nonparalyzed leftlimb ar efrequently observed. Prognosis.Variable recovery occurs inBroca's aphasia;patients in whom the cause isvascular have the bestchance of some recoveryo flanguage.Mixedtranscorticalaphasia(MTcA),also calledtheisola-tionsyndrome,is anonfluent aphasia with poor comprehen-sionbutrelatively preserved repetition. Conversationalspeechissimilarto thatfoundinglobalaphasia, inthatmeaningful verbal expression isseverelylimited or is absent altogether. Stereotyped utterancesar e common, as is echolalia, the inappropriate, andsomewhat irrepressible, repetition ofwhat others say. Auditory comprehension ismarkedly impaired, oftenevenat thesingle-word level. Repetition of phrases and complete sentences ispre-served, although repetition typically occurs withoutcomprehension. Namingissignificantly impaired. Lesionlocation.MTcAisseeninassociation with diffuseo rmultifocal lesions that resultinanatomic isolationo ftheperisylvian language zonefrom surrounding corticalareas.MTcAm ayfollowcarotid artery occlusion, produc-ing aconfluentarc ofinfarctionin thewatershed regionalongth eperipheryo f themiddle cerebral artery vascularterritory.MTcAhas alsobeendescribed incorticalde-mentia and following carbon monoxide poisoning.

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Accompanying deficits. Right-sided weaknessor sen-sory loss may be present in cases of MTcA caused bystroke. Prognosis. Variablerecovery occurs in MTcA; patientsin whom the causeisvascular have the best chanceofsome recovery oflanguage.Global aphasia is a severe nonfluent aphasia with poorauditory comprehension and poor repetition. Conversationalspeech isnonfluent with slow, haltingspeech production. Utterances maybe restrictedtosinglewordsorphrasesthatareperseverative, suchas /canseeArticulatoryimpairmentiscommon.Some meaningmaybeconveyedbyinflectional variations imposedonother-wisemeaningless utterances (e.g., nokeydoe, nokeydoe). Auditorycomprehensionisreducedto theextent thateven single-word comprehension is significantly com-promised. Comprehension ismarkedly impaired at thephraseorsentence level. Repetitionisdefective,andeven single wordsmay notbe repeated accurately. Namingisseverely impaired. Lesionlocalization.Lesionsinglobal aphasiaareexten-siveandtypically involvetheentire leftperisylvian lan-guage zone.Acommon causeisembolic occlusion of themain stemof themiddle cerebral artery. Accompanyingdeficits include right hemiparesis, righthemisensory loss,andright homonymous hemianopia. Prognosis.Global aphasiamayevolvetoBroca's aphasiaor maypersistasglobal aphasia.

V OTHER PH SI SYNDROMESA Subcortical Aphasias

Many cortical lesions extendtosubcortical regions,but aphasiacanalso resultfromdeep lesionsthatappeartosparethecerebralcortex. Subcortical aphasias include thalamic aphasiaandapha-sia associated with damageto thebasal gangliaandsurroundingwhite matter pathways (i.e., nonthalamic subcortical aphasia).Although not fully understood, it appears that subcorticallesions resultin cortical dysfunction causedby the disruptionof normal white matterconnections.1. Thalamicaphasiareflectsapattern oflanguageperfor-mance distinct from the cortical aphasias.In general,it ischaracterizedby fluent utterances (but may have

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The phasias 455

reduced spontaneous output), anomia, verbal parapha-sias,mild-to-moderate impairmento fauditory compre-hension, an dpreserved repetition. Prognosis fo rthala-m icaphasiaistypically good, with resolution tomildanomic aphasia.2. Nonthalamic subcortical aphasia is the term some-times used to refer toaphasia associated with damageto thebasal gangliaorwhite matter pathways withpres-ervationof the thalamusandlanguage cortex.The re-sulting aphasia profile can bequite variable. In somecases, spoken output is nonfluent an d agrammatic,whereas others produce fluent paraphasic utterances.Speech production problems have also been noted,in-cluding reduced articulatory precision, prosodic distur-bance, and even hypophonia. Thevariation in symp-toms isthoughttorelateto lesion location within thestriato-capsular region and the extent of involvement

of surrounding white matter.B AphasiaA ssociatedWithCorticalDegenerative Disease

Languageimpairment is one of the symptoms ofgeneralizedcognitive decline associated with dementia. In the caseo fAlz-heimer's disease, language deterioration typicallyfol lowsapro-gressive course that begins with anomic aphasia, proceeds totranscortical sensory aphasia andthenWernicke's aphasia,andultimately becomes global aphasia.Insome patients, progressivelanguage deterioration occurs without significant dementiaandis referred to asprimaryprogressiveaphasia (PPA).Therela-tively selective impairment oflanguage seen in PPAreflects asubtype ofasymmetrical cortical degeneration, orfocalcorticalatrophy.T heresultant behavioralprofileisvariable (presumablyreflecting the region o fcortical atrophy) and can manifest asany of thecortical aphasia syndromes.Tw ogeneral patternso fprogressiveaphasia have been characterized.1. Semanticdementiareflectsaprogressive lossofseman-ticknowledgethatresultsin fluent, anomic language.Grammatical competence remains strong, and repeti-tionispreserved. However, auditory comprehension be-comes degradedas thedisease progresses. Semanticde-mentiahasbeen associated with corticalatrophyin theleft anterior an d inferior temporal lobes.2. Progressive nonfluent aphasia is characterized bynonfluent, agrammatic language with word-finding

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difficulties andphonemic paraphasias. Repetitionis im-paired,a ndauditory comprehensionmay beaffected aswell. Apraxia ofspeech also may be noted.This syn-drome isassociated with brain atrophy in the left infe-riorfrontal lobe.VI DISTINGUISHING PH SI FROMOTHER DISORDERSAphasia needs to bedistinguished from other disorders thatimpair communication. Th efollowing disorders ar e distinctfrom aphasia.

A Input Problems1 Pure word deafness refers to aselective impairmentof speech input processing. Patients with pure word

deafness cannot comprehend or repeat spoken lan-guage, but their spontaneous speech production andnamingareintact,andtheycanreadandwrite withoutdifficulty. Insome cases, recognition ofenvironmentalsounds isalso preserved. Pure word deafness is araresyndromethatusually resultsfrombilateral damaget otheauditory cortexof the temporal lobes. Aunilateraldeep left temporal lobe lesion m ayalso result inpureword deafness bydisconnecting Wernicke's area fromauditory input.2 Pure alexia or alexia without agraphia, refers to anacquired reading impairment that occursin theabsenceof significant aphasia. Language production andaudi-tory comprehension are preserved. Patients can alsowrite,although theyarefrequently unabletoread whatthey have written. In cases ofpure alexia, readingisaccomplished by serial identificationof the lettersof aword, sothatit isreferredto asletter-by-letter reading.Thesyndromeistypically seen following damageto theleft inferior-occipital region within the territory of theposteriorcerebral artery. Such lesions often result indense right hemianopia. However, pure alexia alsoo c-curswithout avisualfield cut whendamageto whitematter tracts disconnectsth e flowofvisual informationto the cortical regions responsible fo rprocessing writ-tenwords.3 Agnosia refers to recognition failure affecting asinglesensory modality (i.e., visual, tactile, auditory). Patientswith agnosiam ay beunabletoname objects presented

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Western AphasiaBattery (Kertesz, 1982) Aphasia DiagnosticProfiles (Helm-Estabrooks, 1992)2. Naming Boston Naming Test (Kaplan, Goodglass, &Wein-traub, 2001)3. Auditory comprehension Token Testof theMultilingual Aphasia Examination(Benton,deHamsher,&Siven, 1994)B Determining the Status ofCognitive Processes

A clear understanding of the nature of the aphasic languageimpairment isgainedby careful examination ofcognitive pro-cessesnecessaryf orlanguage. Some tests and informalassess-ment measuresaredesignedtoallowforisolationof the specificcomponentprocesses involved inspokeno rwritten language. Psycholinguistic AssessmentofLanguage ProcessinginAphasia (PALPA;Kay,Lesser, &Coltheart, 1992)C Assessing the Impact of Aphasia

Th e tests referenced above primarilyassesslanguage impair-ment. Other assessment tools were designed to examine thedisabilitythatresultsfromtheaphasia, thatis, theconsequencesofthe impairment at amore functional level. Examplesofsuchmeasuresincludethefollowing: ASHAFunctional AssessmentofCommunication Skillsfor Adults (Frattali, Thompson, Holland, Wohl, &Ferketic, 1995) and Communication ActivitiesofDaily Living, Second Edi-tion(Holland, Fromm,&Fr attali, 1999).

VIM CONCLUSIONThischapter providesanintroduction to differentialdiagnosisof aphasia.Wereviewed the assessmenta nd interpretation ofbehavioral characteristics, with anemphasison the inpatientbedside examination. Th esocial consequences ofaphasia canbe tremendous, affecting employment, economic status, socialroles, andoverall sense ofwell-being.It isdifficult toquantifysuch variables (and their change over time), particularly whenthelanguage impairments limit information exchange regard-ing the impact of the deficit. Appropriate measures fo r thesesocialconsequences, orhandicaps, arelimited; however, clini-ciansshouldnotoverlook such critical issues.

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B I B L I O G R A P H YR eferences for Standardized Tests

Benton,A. L.,deHamsher, K. S., &Siven,A. B.(1994).Mu lt i lin-gual Aphasia Examination. Iowa City, IA: AJAAssoc iates.Fratalli, C. M.,Thompson, C. K.,Holland, A. L.,Wohl, C. B .,&Ferketic,M. M.(1995).ASHA Funct ional Assessment of C o m -mun ica t i onSkills fo r Adults .B ethesda,MD :American Speech-Language-Hearing Association.Goo dglass, H. (2001).Boston Diagnostic Aphasia Examination (3rded.). Philadelphia: Lippincott Williams & Wilkins.Helm-Estabrooks, N . (1992). Aphasia Diagnost ic Profiles. Chi-cago: Riverside.Holland,A . L.,F rom m ,D., &Frattali,C.(1999). C ommunica t ionactivit ies o f daily l iv ing(2nd ed.). Austin,TX :PRO-ED.Kaplan, E., Goodglass, H., & Weintraub, S.(2001). Th e BostonN aming Test.Philadelphia: Lippincott Williams &Wilkins.Kay,].,Lesser,R., &Co ltheart, M.(1992). PsycholinguisticAssess-ment o f Language Processing in Aphasia. East Sussex, En-gland: Erlbaum.Kertesz, A. (1982). Western Aphasia Battery.S an Antonio, TX :Psychological Corporation.

Sources of A dditional InformationBenson,D. F., &Ardila,A.(1996).Aphasia: Acl inical perspective.N ew York: Oxford University Press.Chapey, R.(Ed .). (2001). Language intervention strategies in adu l taphasia (4th ed.). Baltimore: Lippincott Williams &Wilkins.Duffy, J. R.(1995). Motor speech disorders: Substrates, differentialdiagnosis, an d management .S t.Louis,M O: Mosby.Goodglass, H. (1993). Understanding aph as ia . San Diego, CA :Academic Press.Hei lman,K . M., &Valenstein,E . (Eds.).(1993). Clinical neuropsy-chology (3rd ed.). New York: Oxford University Press.Hillis, A. E.(E d.). (2002). H andbook on adu l t language disorders:Integrating cognitive neuropsychology, neurology, and rehabi l i ta-t ion.Philadelphia: Psychology Press.Kertesz,A.(E d.). (1994). Localizat ion and neuroimaging in neuro-psychology. SanDiego, CA :Academic Press.Rothi,L . J. G ., Crosson, B., &Nadeau ,S.(Eds.).(2000).Aphasia

and language: Theory and p r ac t i ce .N ew York: Guilford Press.

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