Vib-bracelet: a passive absorber for attenuating forearm tremor

Tremor is a rhythmic, involuntary, oscillatory movement of a limb produced by alternating contractions of reciprocally innervated muscles. More than 4% of the population over 40 years old suffer from tremor. There is no cure for most tremors, and while psychological therapy is sometimes helpful, tremors are usually treated with either medication or invasive surgery including thalamotomy and deep brain stimulation. Both medications and surgery may have adverse effects, and thus, there is a growing interest in developing non-invasive vibration attenuation devices. This paper presents a passive absorber device for attenuating pronation/supination tremor, dubbed Vib-bracelet. It is based on the principles of dynamic vibration absorption and is tuned to the frequency of the tremor. Prototypes were manufactured and tested on a mechanical model of the human forearm. Simulations and experiments demonstrate the efficiency of the device in attenuating vibrations in the range of 4-6 Hz, which is the range of frequency of observed tremor, with maximum amplitude attenuation of 85%.