Dissociated active and passive tactile shape recognition: a case study of pure tactile apraxia.
Brain
; 124(Pt 11): 2287-98, 2001 Nov.
Article
en En
| MEDLINE
| ID: mdl-11673329
Disorders of tactile object recognition (TOR) may result from primary motor or sensory deficits or higher cognitive impairment of tactile shape representations or semantic memory. Studies with healthy participants suggest the existence of exploratory motor procedures directly linked to the extraction of specific properties of objects. A pure deficit of these procedures without concomitant gnostic disorders has never been described in a brain-damaged patient. Here, we present a patient with a right hemispheric infarction who, in spite of intact sensorimotor functions, had impaired TOR with the left hand. Recognition of 2D shapes and objects was severely deficient under the condition of spontaneous exploration. Tactile exploration of shapes was disorganized and exploratory procedures, such as the contour-following strategy, which is necessary to identify the precise shape of an object, were severely disturbed. However, recognition of 2D shapes under manually or verbally guided exploration and the recognition of shapes traced on the skin were intact, indicating a dissociation in shape recognition between active and passive touch. Functional MRI during sensory stimulation of the left hand showed preserved activation of the spared primary sensory cortex in the right hemisphere. We interpret the deficit of our patient as a pure tactile apraxia without tactile agnosia, i.e. a specific inability to use tactile feedback to generate the exploratory procedures necessary for tactile shape recognition.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Apraxias
/
Tacto
/
Reconocimiento en Psicología
/
Agnosia
/
Lateralidad Funcional
Tipo de estudio:
Prognostic_studies
Límite:
Adult
/
Female
/
Humans
Idioma:
En
Revista:
Brain
Año:
2001
Tipo del documento:
Article
País de afiliación:
Suiza
Pais de publicación:
Reino Unido