astereognosis
Pronunciation: a-STER-ee-og-NO-sis
The inability to recognize objects through touch alone despite intact basic tactile sensation.
Full Definition
Astereognosis is a form of tactile agnosia where patients cannot identify familiar objects placed in their hands when vision is excluded, despite having normal primary tactile sensations such as light touch, pressure, and temperature. This condition results from lesions in the parietal cortex, particularly the postcentral gyrus and superior parietal lobule. It is distinct from simple sensory loss and represents a higher-order processing deficit. Testing involves placing common objects in the patient's hand while their eyes are closed and asking them to identify the object.
Usage
Usage note: Distinguish from simple sensory loss by emphasizing preserved basic touch sensation.
In Context
- "The patient demonstrated astereognosis in the left hand following right parietal stroke." — Neurological examination note
- "Astereognosis testing revealed impaired cortical sensory processing despite normal vibration sense." — Clinical assessment