While the majority of
tremor-afflicted Parkinso-
nian (PD) patients suffer from
rest tremors, which is not considered highly disabling, a portion of these PD patients also demonstrate
action tremors that interfere with their daily lives. Two main considerations in designing an
orthosis that aims at suppressing the
tremor, are the frequency bands of the
tremor and the joints
tremor affects. Nine subjects, which included six healthy people, two PD patients with typical
tremor afflictions, and a PD patient with severe
tremor of not only in her fingers and wrist, but also in her elbow, participated in this study. The highly afflicted patient displayed the need for
tremor suppression in action as well as when in rest. The study focuses on uncommon elbow
tremors and demonstrates that, for typically afflicted patients,
tremor amplitudes are comparable to healthy subjects, but the frequency distribution of the
tremors are different at high levels of elbow torque. For the highly afflicted patient, both
tremor amplitude and its frequency distribution are different at all levels of elbow torque. The study further investigates the
tremors in two bands of frequency on both hands of the highly troubled patient before, and after medication. The two bands are those of classical Parkinsonian
tremor (4-6 Hz) and physiological (or enhanced physiological)
tremor (8-12 Hz). Power spectrum and
tremor amplitude comparisons reveal that, for part of tremulous PD patients, both
tremors coexist and, depending on the level of affliction, the designed
orthosis needs to suppress
tremors in both bands, even at more proximal joints, such as the elbow.