Comparative Analysis of Brain Activity in Verbal and Spatial Thought in Healthy Subjects and Patients with Speech Disorders

Abstract

We report here an analysis of specific brain activity measured by fMRI during solution of spatial and verbal tasks in 15 healthy subjects and nine patients with dysarthria or mild sensorimotor aphasia. In healthy subjects, activation of Brodmann area (BA) 19 and Broca’s area was more characteristic of verbal thought, while greater bilateral activation of the temporal-parietal-occipital zone, along with the left insula and visual fields 17 and 18 on the left, was specific for spatial thought. In patients with speech disorders, the distribution of areas specific to one task or another underwent significant changes, with non-activation of areas of brain activation characteristic of healthy subjects. Despite the absence of clinical signs of cognitive impairments, the mean verbal task solution time was significantly longer and the proportion of correct responses was smaller in patients than in healthy subjects.