Stereognosis

Abstract

A dissertation read before the Royal Medical Society on Friday, February 2nd, 1968.

Stereognosis may be defined as the ability to recognise objects using only tactile (somatic) sensation. The ability is best developed in blind people and depends on memory and on an intact somatic sensory system.

Loss of this ability, astereognosis, is usually considered as a defect in somatic sensation. A native of New Guinea, although he might be unable to recognise the objects commonly used to test for stereognosis, would not deserve to be given the diagnosis of a cortical lesion. His failure is a failure of learning. Patients suffering from dementia may show astereognosis as a consequence of a general deterioration in mental function. Learning and memory therefore play an important part in stereognosis, but in clinical practice and in physiology, more interest is taken in the function of the somatic sensory system.