Randomized crossover trial of cool-temperature immersion treatment to improve hand function in patients with essential tremor

Abstract

Abstract: The purpose of this study was to identify the duration of therapeutic effect of cooling on hand function in patients with essential tremor. Forty-one patients with essential tremor (20 men and 21 women; aged 34–86 years) completed this study between August 2002 and December 2003. Inclusion criteria were diagnosis of essential tremor with at least a one-year history of at least a +2 action or kinetic tremor of one or both upper limbs, and a positive family history of essential tremor. Exclusion criteria were pregnancy, sensory loss in the upper extremities, dermatologic lesions in the upper extremities, or sensitivity to cold. Each individual's dominant upper extremity function was tested by the same one rater using the WHIGET Tremor Rating Scale; the Purdue Pegboard; subtests 2, 4, and 5 of the Jebsen Test of Hand Function; and handwriting. Each subject was randomly assigned to have their dominant upper extremity immersed in a basin of water that was either body temperature or cold (15°C) for 5 minutes. Tests were repeated every 30 minutes, for a total of 120 minutes. The second treatment period began approximately 10 minutes later, with the same arm being immersed in water of the other temperature, and the procedures described above were repeated every 30 minutes, again for a total of 120 minutes. All of the individual WHIGET score means were at least 0.5 points better after cold treatment (p < 0.001), except for the drinking score, which was 0.3 points better (p < 0.04). The mean handwriting score was also substantially better after cool immersion than after body-temperature immersion (p < 0.001). The Purdue Pegboard Test results and Jebsen results were not significant (p > 0.05). The results support earlier findings that there is a therapeutic effect of cooling on hand function in patients with essential tremor that lasts as long as 60 minutes and decreases by approximately 50% every 30 minutes.