Neural correlates of differential finger gesture imitation deficits in left hemisphere stroke.

Behavioural studies in apraxic patients revealed dissociations between the processing of meaningful (MF) and meaningless (ML) gestures. Consequently, the existence of two differential neural mechanisms for the imitation of either gesture type has been postulated. While the indirect (semantic) route exclusively enables the imitation of MF gestures, the direct route can be used for the imitation of any gesture type, irrespective of meaning, and thus especially for ML gestures.

Reduced awareness for apraxic deficits in left hemisphere stroke.

Objective: Reduced awareness for motor or cognitive impairments has mainly been studied in relation to right-hemispheric deficits such as left-sided hemiparesis. However, recent studies suggest that also left hemisphere (LH) stroke can lead to reduced awareness for neurological/neuropsychological deficits, for example, aphasia. The aim of the current study was to characterize reduced awareness for apraxic as well as aphasic deficits in patients suffering from LH stroke.