Quantitative analysis of reduced arm swing frequency in essential tremor.

Background: Essential tremor (ET) has recently been accepted as a heterogeneous disorder which may be associated with synuclein pathology or a variety of other genetic disorders.

Methods: We observed decreased arm swing frequency in 18 of 136 definite ET patients, and recorded the associated arm movements in 18 ET patients and 33 sex- and age-matched healthy controls.

Results: The mean frequency of the right arm (p = 0.047), left arm (p = 0.025) and leg (p = 0.030), and the mean arm/leg frequency on the right side (p = 0.048) were significantly lower in ET patients. The mean frequencies for both arms and legs were significantly lower for the more affected side of the body (p = 0.034 and p = 0.036, respectively).

Conclusion: We conclude that ET may be associated with decreased arm and leg swing frequencies, especially on the more affected side of the body.