Weight appreciation in the hand in normal subjects and in patients with leprous neuropathy.

The Weber fraction was used as an index of the sensitivity with which subjects appreciated weights ranging from 20 to 500 g suspended from the middle finger. Normal subjects were able to appreciate weight when it caused cutaneous compression alone. The sensitivity increased when subjects lifted weights by flexing the metacarpophalangeal joint. This increase was more marked for weights ranging from 20 to 100 g than for weights ranging from 200 to 500 g. When subjects lifted weights by flexing the elbow joint, the sensitivity with which they appreciated weight was comparable to that from cutaneous compression alone. Leprous subjects having glove anaesthesia were unable to appreciate any weight up to 500 g when it caused cutaneous compression alone. However, they were able to appreciate weights above 200 g when they lifted weights by flexing the metacarpophalangeal or elbow joints.