Cold, hard cash: Clinical assessment of stereognosis using common objects and coins in older subjects

Abstract

Stereognosis, tactile gnosis, or the ability to identify objects or discriminate between objects using touch alone, is an important hand function commonly assessed on clinical neurological examination [1]. Reduced stereognosis is associated with reduced manual dexterity in older subjects [2] and impairment of this function can be disabling, particularly in tasks requiring fine manual dexterity where vision is limited, obscured or impaired. Stereognosis is a complex neurological process, involving peripheral touch receptors such as Meissner’s corpuscles, cutaneous nerves, larger nerves particularly the median nerve, the dorsal column nuclei and neurones, medial leminisceal pathway, the thalamus and cerebral cortex and damage to any of these can impair tactile discrimination. When euro coins were released in 2002 they were designed with different diameters, weights and milled edges to allow people with visual impairment to discriminate between them using stereognosis (Fig. 1). It is known that the density of Meissner’s corpuscles reduces significantly in subjects over 50 years and that, in experimental conditions, tactile sensitivity is decreased in older subjects [3] although median nerve function and conduction velocity is