Quantitative measurements in spasmodic torticollis. Description of a method and results of measurement.

A method for measuring head tremor and rotation in spasmodic torticollis using specially devised instrument is described in detail. Repeated measurements in ten patients with spasmodic torticollis have revealed this method to be consistently reproducible regarding both the rotation and tremor of the head. Analysis of the tremor recordings from these patients reveals basically two types of head tremor, (a) a regular tremor varying in rate from 4 to 7 cycles per second and (b) an irregular tremor which varies in frequency as well as amplitude at different times of recording. This method provides quantitative data regarding the two outstanding features of spasmodic torticollis, viz: head rotation and head tremor, and is especially suited for comparing clinical response to various forms of treatment as well as studying the natural history of this disease.