[Reflex responses in the trapezius muscle after percussion of various parts of the body].

In a Group of 20 healthy subjects and 16 patients with different central motor disorders a reflexological investigation was made in the upper part of the trapezius muscle. The reflex responses were produced by percussion with a reflex hammer on several sites on the head, trunk and upper extremities and identified as excitatory and inhibitory modulations of recorded EMG activity resulting from the stimulus, after averaging of 50 responses. In the group of healthy subjects after percussion of the chin, upper lip, cheek, mastoid process, back of the skull, the processus spinosus of vertebras C7 and Th12 and both sides of the volar area of the wrist, reflex responses with a short and long latency were recorded. In the group of patients with central motor disorders the reflexological finding was different, depending on the type of central disorder. On the side of spastic hemiparesis after a hemispheric ischaemic cerebrovascular lesion only responses with a short latency were recorded. In patients with parkinsonism mostly only reflex responses with a long latency were elicited. In patients with the dystonic form of torticollis spastica a side asymmetry was found. The results of the investigation provided evidence of reflex connections of remote parts of the body with trapezius muscle in healthy subjects and of the incidence of specific deviations of reflex responses in this muscle in patients with various central lesions. This is important in the differential diagnosis of central motor disorders.