Bilateral tactile agnosia: a case report.

This study reports a 64-year-old right-handed male who manifested bilateral tactile recognition deficits. They were diagnosed as bilateral tactile agnosia, since the patient showed difficulty in semantic association of objects despite preserved hylognosis and morphognosis. The patient had a bilateral lesion in the subcortical region of the angular gyrus. The case reported by Endo et al. (1992) had a right hand tactile agnosia due to a subcortical lesion in the left angular gyrus. Our findings support Endo's hypothesis that tactile agnosia occurs when the somatosensory association cortex is disconnected from the semantic memory store located in the inferior temporal lobe by a subcortical lesion of the angular gyrus. We suggest that the extent of the lesion in the tactual-semantic pathway is related to the severity of tactile agnosia and the types of the tactile naming errors.