Tense/aspect category in fluent and nonfluent German aphasia: An experimental training programme for verb production

Abstract

Background: Results from previous studies on tense production in aphasia have not provided a homogeneous picture of which temporo-aspectual structures are most affected. It is postulated that the aphasic individuals have problems with encoding the [+past] feature into inflectional morphology, and then they are unable to generate the past forms of the verbs. In addition, typically agrammatic data have been analysed, with scarce information on fluent aphasia. Finally, the category of aspect has rarely been considered in verb production therapy.

Aims: We present data regarding the experimental training of aspect in fluent and nonfluent German aphasia. On the basis of the results, some linguistic theories are discussed in terms of the semantic character of aspect processing.

Methods & Procedures: Four aphasic German speakers (two fluent and two nonfluent) took part in the treatment. The participants were diagnosed as moderate Broca's or Wernicke's aphasic by means of the Aachener Aphasie Test (Huber, Poeck, Weniger, & Willmes, 1983). The training focused on the inflected verb elicitation and was carried out by means of a specially designed computer program. Altogether, 38 triplets of depictable verbs were used. The patients were exposed to three drawings depicting the prospective, ongoing, and completed action, and asked to fill in the gaps with appropriate verb forms. In addition, the comprehension task including three drawings and a distractor was also conducted to check the potential training influence on receptive skills.

Outcomes & Results: We demonstrated that the experimental training on tense/aspect production proved to be effective. The significant improvement was noted in the case of three patients, for whom the overall frequency of errors and the sum of aspect substitutions were significantly reduced. Moreover, the data collected showed that German aphasic speakers had problems not only with the past/perfective aspect, but also with the future/prospective condition. However, no influence on the receptive performance was noted.

Conclusions: The study showed that combinations of tense/aspect errors are not typical exclusively of agrammatism, but might also be observed in the verbal output of participants with fluent aphasia. The initial results from our experimental treatment showed that the reduction of tense/aspect errors is possible, regardless of aphasia type. We concluded that the complexity of verbal morphology (especially in the past tense) cannot explain the tense/aspect substitutions that were noted in the present and future conditions. Therefore a morpho-semantic deficit related to tense/aspect production in German aphasia is suggested.

Keywords:

• Aspect
• Tense
• German aphasia
• Aphasia treatment

Acknowledgments

We would like to thank the patients who kindly agreed to participate in the training. Special thanks to Julia Greuel who helped us with the study design and the organisation of therapy sessions.