The modular treatment of agrammatism

Integrated training for aphasia: an application of part-whole learning to treat lexical retrieval, sentence production, and discourse-level communications in three cases of nonfluent aphasia

PURPOSE

The purpose of this study was to evaluate integrated training for aphasia (ITA), a multicomponent language-production treatment based on part-whole learning that systematically trains lexical retrieval, sentence production, and discourse-level communications. Specific research objectives were to evaluate acquisition of target structures, statistical parameters associated with learning variables, treatment generalization, and the efficacy of individual treatment components.

METHOD

ITA was administered to 3 individuals with nonfluent aphasia following a multiple-baseline, across-behaviors design. Effect size and correlational coefficients were computed to assess acquisition, generalization, and maintenance of target structures. Standardized tests and a treatment efficacy questionnaire were also completed.

RESULTS

A significant treatment effect was found in 2 of the 3 participants. In addition, as is seen in normal skill acquisition, practice time and error rate were significantly correlated. All participants demonstrated evidence of generalization on standardized language measures. Only 1 participant improved, however, on the communication measures. Results of the treatment component analysis revealed significant differences in the perceived efficacy of individual therapy tasks.

CONCLUSIONS

Findings add to the evidence supporting multicomponent aphasia treatments, provide preliminary support for ITA and the application of a part-whole learning approach, and suggest that specific treatment components may contribute differentially to outcomes and generalization effects.

The application of rules in morphology, syntax and number processing: a case of selective deficit of procedural or executive mechanisms?

Declarative memory is a long-term store for facts, concepts and words. Procedural memory subserves the learning and control of sensorimotor and cognitive skills, including the mental grammar. In this study, we report a single-case study of a mild aphasic patient who showed procedural deficits in the presence of preserved declarative memory abilities. We administered several experiments to explore rule application in morphology, syntax and number processing. Results partly support the differentiation between declarative and procedural memory. Moreover, the patient's performance varied according to the domain in which rules were to be applied, which underlines the need for more fine-grained distinctions in cognition between procedural rules.

Mapping therapy for sentence production impairments in nonfluent aphasia

This study investigated a new treatment in which sentence production abilities were trained in a small group of individuals and nonfluent aphasia. It was based upon a mapping therapy approach which holds that sentence production and comprehension impairments are due to difficulties in mapping between the meaning form (thematic roles) and the syntactic form of sentences. We trained production of both canonical and noncanonical reversible sentences. Three patients received treatment and two served as control participants. Patients who received treatment demonstrated acquisition of all trained sentence structures. They also demonstrated across-task generalisation of treated and some untreated sentence structures on two tasks of constrained sentence production, and showed some improvements on a narrative task. One control participant improved on some of these measures and the other did not. There was no noted improvement in sentence comprehension abilities following treatment. Results are discussed with reference to the heterogeneity of underlying impairments in sentence production impairments in nonfluent patients, and the possible mechanisms by which improvement in sentence production might have been achieved in treatment.

Poststroke Aphasia

Aphasia, the loss or impairment of language caused by brain damage, is one of the most devastating cognitive impairments of stroke. Aphasia is present in 21-38% of acute stroke patients and is associated with high short- and long-term morbidity, mortality and expenditure. Recovery from aphasia is possible even in severe cases. While speech-language therapy remains the mainstay treatment of aphasia, the effectiveness of conventional therapies has not been conclusively proved. This has motivated attempts to integrate knowledge from several domains in an effort to plan more rational therapies and to introduce other therapeutic strategies, including the use of intensive language therapy and pharmacological agents. Several placebo-controlled trials suggest that piracetam is effective in recovery from aphasia when started soon after the stroke, but its efficacy vanishes in patients with chronic aphasia. Drugs acting on catecholamine systems (bromocriptine, dexamfetamine) have shown varying degrees of efficacy in case series, open-label studies and placebo-controlled trials. Bromocriptine is useful in acute and chronic aphasias, but its beneficial action appears restricted to nonfluent aphasias with reduced initiation of spontaneous verbal messages. Dexamfetamine improves language function in subacute aphasia and the beneficial effect is maintained in the long term, but its use is restricted to highly selected samples. Pharmacological agents operating on the cholinergic system (e.g. donepezil) have shown promise. Data from single-case studies, case series and an open-label study suggest that donepezil may have beneficial effects on chronic poststroke aphasia. Preliminary evidence suggests that donepezil is well tolerated and its efficacy is maintained in the long term. Randomised controlled trials of donepezil and other cholinergic agents in poststroke aphasia are warranted.

Remediation of asyntactic sentence comprehension using a multimedia microworld

We report the evaluation of a new automated protocol for the treatment of asyntactic comprehension. This is a follow-up study to the "Microworld for Aphasia" work of Crerer, Ellis, and Dean (1996). An efficacy study involving three patients is reported. All three patients achieved statistically significant improvements in written sentence comprehension as a result of eight hours of treatment focusing on active, passive, and object cleft sentence structures. Treatment effects generalized both to untreated Microworld sentences and to the more naturalistic sentences of the Philadelphia Comprehension Battery (Saffran, Schwartz, Linebarger, Martin, & Bochetto, 1988), with some further evidence of generalization to spoken sentence comprehension. Treatment effects were obtained with minimal input from a clinician.

An investigation of the interaction between thematic and phrasal structure in nonfluent agrammatic subjects

Garrett (1982) developed a model of normal sentence production which has been used in the description of aphasic language (Schwartz, 1987). This study investigated the effects of the thematic representation specified at the functional level on the complexity of the phrases produced at the positional level. A group of 14 nonfluent, agrammatic subjects were compared to 20 normal controls in their production of the story of Cinderella. The agrammatic subjects produced fewer argument structures than the normal control subjects. Their phrasal realization of the arguments, however, was not qualitatively different from that of the normal subjects. In both cases, with an increase in the number of arguments, there was a concurrent increase in the mean complexity of the phrases used to realize those arguments and in the total phrasal complexity of the utterances. The complexity of noun phrases differed according to the thematic roles expressed; this seemed to be a consequence of their different locations in the sentence. Preverbal noun phrases were much less complex than postverbal noun phrases. There was no evidence to suggest that there was a trade-off between the production of thematic structure and subsequent phrasal production. Neither was there evidence to suggest that production differed according to whether the phrase was an argument of the verb or a nonargument. The complexity of a phrase was determined by the type of information it conveyed.

Patterns of sentence comprehension in aphasia: a consideration of three hypotheses

Three hypotheses concerning the functional source of aphasic patients' difficulty comprehending semantically reversible sentences were tested using declarative sentences in active and passive voice and sentences with center-embedded relative clauses. Each of the three hypotheses is predicated on relative patterns of impairment and sparing of patient performance on these (and other) sentence types, yet the three hypotheses make somewhat different predictions about performance patterns across these types. Results from 5 Broca's aphasic patients were not consistent with the predictions of the linguistically motivated Trace Deletion Hypothesis or of a hypothesis based on an impairment involving grammatical morphemes. The hypothesis that aphasic comprehension impairments reflect a general limitation of working memory capacity was given partial support by the ordinal pattern of difficulty for a mixed group of 10 patients, but failed to account for patterns obtained from individual patients. Results are interpreted as having relevance for methodological as well as theoretical aspects of research on aphasic sentence comprehension.