Semantic errors are commonly found in semantic dementia (SD) and some forms of stroke aphasia and provide insights into semantic processing and speech production. Low error rates are found in standard picture naming tasks in normal controls. In order to increase error rates and thus provide an experimental model of aphasic performance, this study…

Studies of sentence comprehension deficits in Parkinson's disease (PD) patients suggest that language processing involves circuits connecting subcortical and cortical regions. Anatomically segregated neural circuits appear to support different cognitive and motor functions. To investigate which functions are implicated in PD comprehension…

In a previous study (Dronkers, 1996), stroke patients identified as having apraxia of speech (AOS), an articulatory disorder, were found to have damage to the left superior precentral gyrus of the insula (SPGI). The present study sought (1) to characterize the performance of patients with AOS on a classic motor speech evaluation, and (2) to…