title: Tactile agnosia and tactile aphasia: symptomatological and anatomical differences.
abstract: Two patients with tactile naming disorders are reported. Case 1 (right hand tactile agnosia due to bilateral cerebral infarction) differentiated tactile qualities of objects normally, but could neither name nor categorize the objects. Case 2 (bilateral tactile aphasia after operation of an epidural left parietal haematoma) had as severe a tactile naming disturbance as Case 1, but could categorize objects normally, demonstrating that tactile recognition was preserved. Case 1 may be the first case of tactile agnosia clearly differentiated from tactile aphasia. CT scans of Case 1 revealed lesions in the left angular gyrus, and in the right parietal, temporal, and occipital lobes. Case 2 had lesions in the left angular gyrus and of posterior callosal radiations. Our findings suggest that tactile agnosia appears when the somatosensory association cortex is disconnected by a subcortical lesion of the angular gyrus from the semantic memory store located in the inferior temporal lobe, while tactile aphasia represents a tactual-verbal disconnection.
authors.affiliation: Department of Neuropsychology, Kakeyu Hospital Rehabilitation Center, Nagano, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Endo
authors.forename: M
authors.initials: M
authors.lastname: Miyasaka
authors.forename: H
authors.initials: H
authors.lastname: Makishita
authors.forename: N
authors.initials: N
authors.lastname: Yanagisawa
authors.forename: M
authors.initials: M
authors.lastname: Sugishita
mesh_terms: D000368:Aged; D000377:Agnosia / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D000381:Agraphia / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D000849:Anomia / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D001037:Aphasia / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001288:Attention / Q000502:physiology*; D001925:Brain Damage, Chronic / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D002544:Cerebral Infarction / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D004292:Dominance, Cerebral / Q000502:physiology*; D004411:Dyslexia, Acquired / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D007839:Functional Laterality / Q000502:physiology*; D006407:Hematoma, Epidural, Cranial / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D013236:Stereognosis / Q000502:physiology; D014057:Tomography, X-Ray Computed; D014110:Touch / Q000502:physiology*