astereognosis
Pronunciation: ay-ster-ee-og-NO-sis
Inability to recognize objects by touch alone despite intact primary sensory functions.
Full Definition
Astereognosis is a form of tactile agnosia characterized by the inability to identify familiar objects through touch alone, despite preserved elementary sensory functions such as light touch, pressure, and position sense. This condition typically results from lesions in the somatosensory association areas of the parietal cortex, particularly the postcentral gyrus. Patients with astereognosis can feel that an object is present and may describe its basic properties like texture or temperature, but cannot integrate this information to identify what the object actually is. The assessment of stereognosis is a standard component of neuropsychological evaluations, particularly following stroke or traumatic brain injury.
Usage
Usage note: Distinguish from primary sensory deficits by confirming intact basic touch sensation.
In Context
- "The patient demonstrated clear astereognosis, unable to identify common objects like keys or coins when placed in the affected hand." — Sensory examination report
- "Astereognosis in the right hand suggested involvement of the left parietal cortex in this stroke patient." — Neuropsychological consultation