INTERNAL TREMOR IN PATIENTS WITH PARKINSONS-DISEASE

Although sensory symptoms were not originally described in Parkinson's disease (PD), in recent years it has been increasingly recognized tha t painful sensations and paresthesias occur in similar to 40% of patie nts. It has been our observation that PD patients often describe a sen sation of internal tremor, a feeling of tremor inside the chest, abdom en, arms, or legs that cannot be seen. We investigated the prevalence and characteristics of internal tremor by administering a questionnair e to 100 consecutive patients with PD and 50 age-matched controls seen in our movement disorders center. A sensation of internal tremor was present in 44% of this sample of PD patients and in 6% of the control population (p < 0.0001). The presence of internal tremor was unrelated to Unified Parkinson's Disease Rating Scale score, Hoehn and Yahr sta ge, duration of disease, or the presence of observable tremor. The fre quency of other sensory symptoms (aching, tingling, burning) was highe r in the PD patients with internal tremor (73%) than in those without (45%; p = 0.005). Internal tremor is associated with anxiety in 64% of patients (p < 0.0001). It was described as uncomfortable and was unre lieved by antiparkinsonian medication in three quarters of patients. A sensation of internal tremor is commonly reported by PD patients and should be recognized as a useful diagnostic factor in PD.