Tremor in Parkinson's disease: 24-hr monitoring with calibrated accelerometry.

Monitoring systems enable the long-term registration of tremor in patients with Parkinson's disease This method is useful in the objective measurement of tremor during the course of treatments. Indeed, the symptoms of tremor as well as the aggravating and attenuating influences can be observed under real-life conditions. The methodology of data recording and analysis, described in previous investigations, was extended to automatically detect body position and certain movement patterns with calibrated 4-channel accelerometry. The main purpose of the present investigation was to apply this refined and extended methodology to patients in a clinical rehabilitation program, and to examine its practability with respect to the results of the treatment and the patients' compliance. The methodology was tested on 30 patients (17 male, 13 female) with Parkinson's disease. The mean age was 64.8 years (s = 8.9). The Hoehn-Yahr index ranged from 1 to 3 (m = 2.3, s = 0.7) and the overall UPDRS scale between 10 and 74 (m = 42.9, s = 18.1). The data recording included: (1) the registration of tremor under standardised conditions of rest and postural tremor test with and without distraction; (2) a standard protocol to obtain reference values for body position and movement; and (3) the 24-hr monitoring. 21 patients could be recorded a second time, on average 18 days after the first recording. Between the two registrations, patients received individually tailored drug treatment supplemented with specific activating physiotherapy, ergotherapy measures, and individual psychotherapeutic counseling. Changes between first and second recording were evident for the three tremor variables, but significant only for the 24-hr ambulatory monitoring. The between and within-subjects correlations of the tremor variables were rather low except the correlations between occurrence and amplitude (between-subjects. 87; within-subjects. 67). Conditions of rest and postural tremor test showed a correlation with corresponding segments of the ambulatory monitoring of about. 50 for the tremor occurrence. The best prediction of the day-time monitoring was made by the tremor tests with distraction, whereas the night segment was best predicted by the standard protocol.