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Aphasia - Assessment

Purposes of Language Assessment

• Differential Diagnosis - It is necessary to determine whether a patient's language dysfunction is aphasia or something else.
  • Does the patient possess a speech or language impairment?
  • Is this impairment aphasia?
  • If the primary disorder is aphasia, what is its type and severity?
• Determination of Level of Functional Communication
  • Primary reason is obtaining information initially and at subsequent intervals is to provide a reasonable basis for the design and implementation of an individual treatment program. On the basis of the appraisal one determines the:
    • modalities of most efficient input and output
    • the level of response of which the patient is capable
      • at what level he succeeds
      • at what level he fails
  • Plan a program of stimulation in order to facilitate optimal input and make possible maximum response and improvement.
  • What is the prognosis for recovery?
• Localization of Brain Lesion - Detailed information about language performance may provide some hint regarding the locus of a patient's cerebral lesion. The importance of language data has significantly decreased by the development of advanced electrophysiologic and radiologic techniques.

Appraisal Battery

• Motor Speech Battery - Evaluating motor speech indicates the presence or absence of coexisting apraxia and/or dysarthria.
• Orientation and General Information - Appraisal of orientation and fund of general information assists in deciding whether what we are seeing is aphasics, confusion, or dementia.
• Measure of General Language Ability - provides an overall impression of severity, strengths, and weaknesses in each modality and suggests for further exploration with specific modality measures.

Tests of Aphasia

Most attention is given to 3 test batteries: MTDDA, PICA & Boston. These have been noted to be the most popular or widely used aphasia batteries. They differ in their orientation with respect to 3 major goals of testing stated by Goodglass & Kaplan (1972). These objectives are (1) comprehensive assessment of the assets and liabilities of patient in all language areas as a guide to therapy, (2) measurement of the level of performance over a wide range, for both initial determination and detection of change over time, and (3) diagnosis of presence and type of aphasic syndrome, leading to inferences concerning cerebral localization.

• Porch Index of Communicative Ability (PICA) - PICA is oriented toward the second goal of evaluation, which relates to providing a sensitive and reliable measurement of degree of deficit and amount of recovery.
  • Description - Measurement of change is based on a multidimensional scoring system which is intended to be a sensitive to subtle differences among aphasic behaviors. PICA consists of 18 subtests of 4 language modalities and of object manipulation, visual matching, and copying abstract forms.
  • Prognosis & Recovery - PICA has been used extensively as an objective measure of recovery. It provides a single summarizing score which can be treated statistically to represent changes in single subtest related functions, response categories, and overall language function. Mean scores are used as the basis for predicting later levels of function. Overall score is a single indicator as to the amount of recovery made by an aphasic patient.
  • Treatment Planning - Performance patterns from the PICA indicate the areas of language function which are successful but challenging for the patient. By placing the patient in tasks in which his responses are slowed but correct, or self corrected, the clinician can maximize the probability that the patient is working on tasks which are not beyond his capacity, but are at a level of difficulty which forces him to work at near capacity. Tasks which require the patient to utilize his language processing system at near capacity seem to be more effective and efficient in restoring the function of the system.
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• Minnesota Test for Differential Diagnosis of Aphasia (MTDDA) - Of the 3 goals of examination, MTDDA or Schuell is oriented most toward the comprehensive assessment of the patient's strengths and weaknesses in all language modalities as a guide to planning treatment. Additional aims include differential diagnosis and prediction of recovery. Differential diagnosis refers to whether patient has aphasia or aphasia plus perceptual disorders, apraxia, dysarthria, or some other brain damage. It does not refer to differentiating aphasia from chronic brain syndrome, for example, or to differentiation among the syndromes of aphasia.
  • Description - MTDDA is the most comprehensive of the tests for aphasia, it takes 2 to 6 hours to administer, 3 hours on the average. It consists of 46 subtests divided into 5 sections:
    • Auditory Disturbances
    • Visual and Reading Disturbances
    • Speech and language disturbances
    • Visuomotor and writing disturbances
    • Disturbances of numerical relations and arithmetic processes
  • Differential Diagnosis - Minnesota test is intended to differentiate aphasia from normal levels of language function with the aid of the normative data. Interpretation guidelines are primarily provided to differentiate among the categories of communication disorders defined by Schuell.
    • Simple Aphasia represented reduced language function in all modalities without complicating conditions.
    • Aphasia with visual involvement consisted of simple aphasia with more severely reduced reading and writing functions.
    • Aphasia with sensorimotor involvement resembled aphasia with what may have been apraxia of speech. 94 % of this group had hemiplegia or hemiparesis, which is suggestive of nonfluent aphasia or Broca's aphasia with apraxia.
    • Aphasia with scattered findings compatible with generalized brain damage usually including both visual and motor involvement. This group showed impaired mental status. This group has been questioned as being truly aphasic (Porch, 1979).
    • Irreversible aphasic syndrome was used for almost complete loss of language function in all modalities, a global aphasia.
  • Treatment Planning - because of its comprehensiveness, the Minnesota provides many circumstances for task and item comparisons so that the clinician can make inferences about the basic problems to be treated. The Minnesota provides a wide sampling of potentially adequate types of stimuli, of situations in which responses can be elicited, and of the kinds of circumstances in which a patient can use language successfully.

• Boston Diagnostic Aphasia Examination (BDAE)
  • Description - The Boston is oriented toward diagnosis of the presence and type of aphasia, leading to inferences concerning the location of brain damage (Goodglass & Kaplan, 1972). The BDAE is primarily designed for the sampling of language behaviors which have been demonstrated to be discriminative in the identification of aphasic syndromes. These behaviors include auditory comprehension, self initiated and conversational speech, word retrieval, and repetition. When a symptom pattern indicative of a syndrome is apparent from test results, the probable site of brain lesion may be inferred. As an aid to planning treatment, it is relatively comprehensive battery which contains 27 subtests.
  • Differential Diagnosis - The BDAE provides an objective basis for the identification of aphasic syndromes and for pinpointing the deviations form these syndromes in patients who do not quite fit the classification molds. They include profiles of a prototypical case and of range of performance for Broca's, Wernicke's, conduction and anomic aphasias.

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