ABSTRACT
Felix and Shuster (3) modified self-winding wrist watches to measure limb movements in the act of nocturnal scratching in various pruritic skin diseases. They demonstrated that nocturnal scratching correlated well with the subjective assessment of the severity of the itching. They also measured scratch movements on the bed with proximity vibration transducers attached to the bed legs, which gave qualitative and quantitative information about scratching and served as a reference for the measurement with limb meters. Summerfield and Welch (4) developed an electromagnetic movement detector as a later version of the limb meter, which increased sensitivity and could record cumulative time spent on scratching. They measured nocturnal scratching of patients with itchy and nonitchy liver diseases.
