title: Computation of tactile object properties requires the integrity of praxic skills.
abstract: We describe a series of experiments to examine the tactile identification of objects over the course of neurological recovery in a patient with an intracerebral haemorrhage involving the left inferior and superior parietal lobe. Tactile agnosia in this case involved the ipsilesional as well as the contralesional hand, allowing us to observe the effects of dominant parietal lobe damage without the confounding effects of hemiparesis. The findings demonstrate that both apraxia and tactile apperceptive agnosia may result from a unilateral lesion involving the left parietal lobe. The findings further suggest that the computation of macro-geometrical and micro-geometrical tactile object properties is dissociable. Macro-geometrical tactile analysis depends on intact programming of exploratory hand movements, while the role of such movements in micro-geometrical analysis is less clear.
authors.affiliation: Dementia Research Centre, Department of Neurodegeneration, Institute of Neurology, University College, Box 16, National Hospital for Neurology and Neurosurgery, 8-11 Queen Square, London WC1N 3BG, UK. s.crutch@dementia.ucl.ac.uk
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Crutch
authors.forename: Jason D
authors.initials: JD
authors.lastname: Warren
authors.forename: Louise
authors.initials: L
authors.lastname: Harding
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Warrington
mesh_terms: D000328:Adult; D000377:Agnosia / Q000209:etiology / Q000503:physiopathology*; D001072:Apraxias / Q000503:physiopathology*; D002543:Cerebral Hemorrhage / Q000150:complications; D003071:Cognition / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000503:physiopathology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology*; D015898:Tomography Scanners, X-Ray Computed; D014110:Touch / Q000502:physiology*