astereognosis
Pronunciation: ay-ster-ee-og-NO-sis
Inability to identify objects by touch alone without visual input, indicating parietal lobe dysfunction.
Full Definition
Astereognosis is the inability to recognize objects through tactile sensation alone, despite intact elementary touch sensation. This neurological sign indicates dysfunction of the parietal lobe, particularly the primary and secondary somatosensory cortices. Testing involves asking patients to identify common objects placed in their hand while their eyes are closed. The condition is distinguished from simple tactile anesthesia, where basic touch sensation is impaired. Clinical documentation of astereognosis requires specific testing methodology and clear distinction from other sensory deficits. This term frequently appears in stroke evaluations and neurological assessments where cortical function is being evaluated.
Usage
Usage note: Frequently misspelled; note the double 'e' in the middle. Distinguish from apraxia (motor planning deficit) and ataxia (coordination disorder).
In Context
- "Testing revealed astereognosis of the left hand, with the patient unable to identify a coin or key by touch." — Neurological examination
- "The presence of astereognosis suggested right parietal lobe involvement in this stroke patient." — Neurology consultation note