Anne N. Haendiges

Grammatical class and imageability in aphasic word production: their effects are independent

Abstract This paper addresses the recent claim that grammatical class differences found among aphasic patients may reflect semantic factors such as ease of imageability rather than lexical/syntactic class. Nouns and verbs equated for rated imageability, frequency and length were elicited as completions for spoken sentences. Five aphasic patients with significantly better production of nouns than verbs in picture naming continued to show a significant grammatical class effect in the completion task. Two patients with significant imageability effects in oral reading continued to show imageability effects in sentence completion, but only one of these patients showed any difficulty producing verbs. Inspection of the individual patient data indicated that either grammatical class, or imageability, or both variables may affect patient performance, but that their effects are independent of one another.

Assessing the Elements Contributing to a "Mapping" Deficit: A Targeted Treatment Study

Aphasic patients with excellent comprehension of word meanings frequently fail to understand simple declarative sentences in which either of two nouns could reasonably serve as agent of a transitive action. This study employed targeted treatment of this comprehension problem in a chronic aphasic patient (E.A.) in an attempt to isolate the source or sources of his comprehension failure. Treatment exercises that relied on error feedback in sentence-picture matching or verification initially were not effective. Comprehension of active and passive sentences improved only after both structures were explicitly compared and linked to a picture. Subsequently E.A. maintained consistently accurate interpretation of both sentence types in the treatment exercises as long as the full sentence was available to him. E.A. learned to assign thematic roles using a limited set of cues in the surface structure. Although improvement was reported in untreated sentences, the degree of generalization and the level of performance differed across tasks and appeared to be attributable to cognitive impairments that were not addressed by the treatment. Results are interpreted as evidence suggesting that multiple impairments contribute to failure of sentence comprehension tasks.

Model-guided treatment to improve written sentence production: A case study

Abstract Impaired production of both spoken and written sentences was studied in a case of chronic aphasia. Assessment of the production impairment, guided by reference to a model of the processes normally involved in the production of spoken sentences, revealed two specific points of disturbance: (1) poor retrieval of lexical main verbs and (2) poor production of the morphological elements linked to verbs. Two interventions were targeted at the early stages of sentence construction and limited to practice in the written modality. Generalization of treatment-induced processing changes in spoken sentence production is discussed in support of the hypothesis that the intervention tasks isolated pre-phonetic and pre-articulatory aspects of sentence production. Expansion of the model of normal, spoken sentence production is proposed in order to accommodate details regarding the nature of processing requirements in written sentence production.

Verb Retrieval and Sentence Processing: Dissociation of an Established Symptom Association

A patient is described with severe anomia who produces verbs significantly better than nouns in action/object naming tasks, but who also has difficulty comprehending and producing semantically reversible sentences. This pattern differs from the frequently-reported association of symptoms involving relative verb/noun retrieval and sentence processing: impaired verb retrieval is typically associated with poor sentence processing, and preserved verb retrieval with spared sentence processing. Brain imaging reveals areas of cerebral ischemia in portions of the, territories supplied by the anterior, middle and posterior cerebral arteries. An earlier ischemic episode and extensive cortical collateral circulation are hypothesized to have contributed to this unusual pattern of left cerebral hemisphere damage. The previously-reported association of symptoms that dissociated in this patient was interpreted as reflecting a hemodynamically-influenced probability of joint involvement of neuroanatomical regions subserving functionally distinct aspects of language processing.

Production of nouns and verbs in aphasia: Effects of elicitation context

This study investigated the ability of 10 aphasic speakers and 9 normal controls to produce unambiguous, frequency-matched nouns and verbs in four elicitation conditions. Two auditory conditions included naming to definition and sentence completion; two picture conditions preceded the presentation of the picture with an auditory cue consisting of a question (what is the action shown here?) or a sentence completion (this is a picture of the action to...). Patients were grouped in terms of whether they demonstrated only word retrieval problems (anomia), or also showed difficulty with sentence comprehension and production. Contrary to expectations, there were no reliable effects of elicitation condition on performance. Although both groups of aphasic speakers found verbs more difficult than nouns to retrieve across conditions, the sentence production-impaired group showed a more severe impairment of verb production that was reliable for individual subjects. Results reinforce the importance of grammatical class as a factor in the word retrieval impairments found in aphasia.

Comprehension of reversible sentences in aphasia: the effects of verb meaning

Abstract Comprehension of semantically reversible active and passive voice sentences was tested in a timed sentence/picture verification task. Three sets of six verbs were identified that incorporated different features of meaning relevant to the assignment of nouns to the thematic role of agent. Normal control subjects showed an effect of verb set on their response times, with significant effects between sets in the predicted direction. A group of aphasic patients without sentence comprehension disorder also showed a significant effect of verb set despite long and variable response times. A group of patients with reversible comprehension disorder in screening tasks showed weaker effects, primarily because of the use of consistent response biases that ignored the sentence verb. An experimental treatment of active/passive comprehension was conducted with two of these latter patients; one patient reached ceiling in post-testing, and the other showed significant improvement but demonstrated residual comprehension problems that indicated differences across verb sets. Results support the critical importance of verb meaning to normal and aphasic sentence comprehension.