2-POINT DISCRIMINATION TEST OF THE SKIN AS AN INDEX OF SENSORY AGING

Although the two-point discrimination test of the skin is a simple tes t of the sensory nerve function, there have been few studies on age-re lated changes in the ability to discriminate between two points in a l arge noninstitutionalized population. In this study we attempted (1) t o determine normal values on the two-point discrimination test by age and gender in a large population with a wide age span; (2) to describe age-related changes on the two-point discrimination test; and (3) to test the independence of this index from other indices measuring physi ological aging by sensory functions, such as accommodation and hearing tests. The subjects were 2,036 men and women aged 10-87 years. The mi nimal distance at which two points could be discriminated was measured longitudinally on a line from the palmar pad to the base of the index finger of the right hand. The two points of a caliper were applied at the same time (stationary two-point discrimination test) using the we ight of the caliper alone. An age-related decline in the ability to di scriminate two points was apparent, but there were no significant diff erences in ability between men and women. The minimal distance of disc rimination on the hand increased almost linearly between 10 and 60 yea rs of age. The results of the two-point discrimination test of the ski n were independent of those of visual accommodation tests and hearing loss of high-frequency sound. From these results, the two-point discri mination test of the skin can be used as a powerful and simple index o f sensory aging.