A Layer Jamming Soft Glove for Hand Tremor Suppression

Tremors are a common movement disorder that affects a person's life adversely. With various drawbacks of current treatment methods, there is a need for a mechanical solution. The authors present a soft orthosis based on layer jamming for the suppression of hand tremors. A vacuum supplied to the layer jamming elements which contain a stack of layers attached to the glove leads to increased stiffness in the glove, suppressing the tremor. The behavior of the tremor in a cohort of patients in Sri Lanka was studied and showed that the tremor's mean frequency was 5.05 ± 2.03 Hz. An existing analytical model was modified and verified experimentally to select the layer jamming element. An element with sandpaper (320 grade) and tracing paper was chosen based on the high stiffness provided at a lower weight (total weight of the glove = 30g). Experimental results show minimal variation in stiffness for vacuum pressures between 10-50 kPa (abs.). The performance evaluation on a test rig was used to verify the efficacy of the glove and showed optimal placement on the palmar side with a mean tremor amplitude reduction of 78.32%. Clinical trials conducted on 11 recruited tremor patients showed a mean frequency power reduction of 41.74 ± 12.11%, 41.99 ± 14.82%, and 24.71 ± 12.18% in the index and middle fingers and in grasping, respectively with a maximum power reduction of 59.15%. The soft, low weight orthosis shows a high tremor suppression in both the test rig and clinical experiments.