A study of walking tremor characteristics and comparison with tremor characteristics during the resting, postural and kinetic position among tremor dominant Parkinsons disease patients by using tremor analysis device
Abstract:
Background: Tremors in PD can have various manifestations, with the most common type being classical parkinsonian resting tremor (1). However, hand tremor can also occur unilaterally while walking, but its characteristics have not been defined. Objectives: To delineate objective characteristics of walking tremor in PD patients in relation to classical parkinsonian resting tremor with inertial sensors. Methods: This study was a cross-sectional study involving 22 PD patients who exhibited classical resting tremor according to the consensus criteria and unilateral hand tremor while walking (1). The tremor characteristics were objectively quantified with the inertial sensors, composing of gyroscope (ChulaPD tremor device, www.chulapd.org) placed on the wrist (2). Standard testing protocols were applied (resting and postural positions) in all subjects. Walking paradigm was also included when subjects were instructed to walk at their comfortable speed for 30 seconds. Clinical demographics, rating scales, and tremor parameters (RMS of angular rate, RMS angle, peak magnitude, and frequency) were collected for further analysis. Results: Participants had a mean age of 68.18 (8.93) years, and a mean disease duration of 6.91 (5.5) years. Resting tremors were presenting complaints in all subjects. The analysis in the resting position revealed a mean frequency of 4.07 on the predominant axis (1.96), which was relatively unchanged in the postural position, consistent with classical resting tremor. During walking, tremors exhibited a significant lower frequency with a mean of 1.67 (1.77) on the predominant axis (p=0.001). Significant differences were also observed on other tremor parameters, including RMS angular rate, RMS angle, peak magnitude, and Q value (p<0.05, each). Conclusions: Based on our results, walking tremor in PD has different tremor characteristics from classical resting tremor, suggesting that walking tremor is probably not a manifestation of resting tremor while walking. Further studies should be conducted to identify a possible underlying mechanism for walking tremor in PD.