“…The recordings were further studied regarding the frequency of tremor, irregularity of tremor pattern, duration of bursts (100-500 ms), and synchronization of the agonist and antagonist muscle activity, and served in these patients also as a tool in the characterization of the type of dystonic head tremor. In all 20 patients polymyographic characteristics of head tremor fulfilled the published criteria for dystonic tremor, 22,23,[26][27][28] that is, the presence of co-contractions, irregular tremor pattern, and duration of bursts. The recordings excluded the possibility that the essential head tremor might be mistakenly diagnosed as a tremulous form of torticollis in our patients.…”