Modality- and Task-Specific Impairments in Speaking and Reading: A Case Report From Persian

The question of whether specific patterns of impairment across different language modalities are isolated, associated, or doubly dissociated has been a major theoretical issue in aphasiology. In this paper, we describe modality- and task-specific language impairments in a Persian-speaking patient (AG) with ischemic stroke. AG’s overall language impairments were evaluated using the bedside version of Persian Western Aphasia Battery (P-WAB-1), which indicated an Aphasia Quotient (AQ) index of 86. Moreover, his performance on the Reading subtests of the Persian Diagnostic Aphasia Battery (P-DAB-3) indicated a Language Quotient (LQ) index of 60. We also evaluated his word reading, sentence reading, and sentence repetition using the subtests of the Persian version of the Bilingual Aphasia Test (BAT). Based on his performance on these assessment tools during the chronic post-onset time, AG was diagnosed with transcortical motor aphasia. Notably, he exhibited two striking characteristics, namely, (a) a modality-specific dissociation, with severely impaired reading comprehension in the face of relatively spared auditory comprehension; and (b) a set of task-specific agrammatic symptoms in verbal expression and out-loud sentence reading in the context of relatively well-preserved sentence repetition. The general characteristics of our patient’s grammatical violations also highlight certain universal and language-specific agrammatic impairments. The present clinical linguistic data argue against the existence of monolithic speech-related regions in the brain.