Quantitation of Muscle Tone in Normals and in Parkinsonism

I. Introduction  The recent interest in the evaluation of the effectiveness of drugs and surgery in the treatment of parkinsonism has made it imperative that the muscular rigidity characteristic of this state be measured in absolute physical units, rather than given merely in terms of a subjective opinion. Muscle tone may vary from patient to patient and from time to time. Not all muscle groups in a given instance of parkinsonism are of necessity implicated in the process. Not all cases are "pure basal ganglia" disturbances. Careful neurological combing reveals pyramidal tract and other signs. All these may affect muscle tone observations in one way or another. If we are ever to learn the underlying neural mechanism in the symptom complex clinically called the parkinsonian state, objective, reliable, and, therefore, readily repeatable measurements of the phenomena must be available. These recordings later can be particulated, so that the physiologic bases