The Effect of Morphosemantic Treatment on Verb Tense Inflection in Persian-speaking Patients with Agrammatism: A Single-Subject Study

One of the relatively common symptoms in non-fluent aphasia is agrammatism. Agrammatism is characterized with low syntactic complexity and deficits in verbs inflection especially tense markers. Verbs as the main core of sentences have vital function on effective communication. In persian, verbs have two main structures of the root and the inflectional morphemes. There are two kinds of the past and the present root. (6). The inflectional structure of verbs in Persian is comprised of several patterns namely those of participle, voice, infinitive, tense, mood, aspect and person plus number. The current study aimed at evaluating the effect of morphosemantic method on verb tense inflection in Persian-speaking aphasic patients with agrammatism. The participants were two aphasic males with agrammatism and verb inflection deficits. In the current study, a comprehensive set of tools was used to evaluate different aspects of the patients problems. A researcher-made demographic questionnaire, the Persian version of the Western Aphasia Battery, Persian Aphasia Battery Test, Persian Aphasia Naming Test, picture verb naming test for patients with aphasia (a common-clinical tool), verbal apraxia test, oro-motor control assessment form (a common-clinical tool), Edinburgh handedness scale, a researcher-made verb inflection test and Elder Mini-cog cognitive screening test. The current study had a single-subject ABA design. The material were 46 black and white line-drawing pictures related to 23 verbs including 10 training, 10 expansion, and three exemplar verbs drawn in present and past tenses. During three phases, the percentage of correct verb inflection in the training and expansion verbs was measured and also the graph examination of level, trend and slope, C statistic, 2-standard deviation band, effect size (percentageof non-overlapping data) and d statistic were used to analyze the data. Both participants demonstrated significant changes in training and expansion verbs during therapeutic sessions in comparison to the baseline (P<0.05). They showed an upward trend over the course of treatment for training verbs and an increase from baseline level to the treatment level. The effect of therapy was maintained for a three-week follow-up and in both participants maintenance effect yielded large effect size. Therapy for verb inflection in spontaneous speech is clinically important. The current study demonstrated that morphosemantic method can be used successfully for tense marker deficits in Persian-speaking patients with agrammatism. This therapeutic approach has high potential to generalize the improvement to the non-therapeutic targets in Persian because of the unique features of the Persian language.

Keywords:

Aphasia , Agrammatism , Treatment efficacy , Single subject design