Accelerometer measurements of muscle tremor yielded significant findings for both Huntington's disease (HD) patients and their genetically at risk offspring. Although affected individuals are usually characterized by gross involuntary muscle movements, alterations in minute muscle tremor were also found in sample of ten HD patients. Irregularities in tremor patterns were intensified with increased time since onset of the disorder and in addition reflected the effects of drug therapy for those on medication. The use of accelerometer measurements of muscle tremor may therefore, prove to be useful in evaluating new medications for affected individuals. For high risk immediate family members currently there is no safe and reliable method to identify, prior to clinical onset, any among them who will develop HD. Aberrant muscle tremor patterns resembling that shown by HD patients were found in one-thrid of a sample of 15 genetically at risk offspring. In the event an effective method of treatment is developed, early recognition of HD gene carriers by accelerometer tremor measurement could result in control of the disorder prior to substantial neurological damage.