Stereognosis

Stereognosis is the ability to perceive the form of an object by using the sense of touch. This sense, along with tactile spatial acuity, vibration perception, texture discrimination and proprioception, are mediated by the posterior column-medial lemniscus pathway of the central nervous system. Stereognosis is a higher cerebral associative cortical function.

The lack of this ability is called astereognosis. It may be caused by disease of the sensory cortex or posterior columns. People suffering from Alzheimer's Disease show a reduction in stereognosis. For other types of dementia, stereognosis does not appear to decline.