Abstract
The power spectrum technique was used to quantitatively anaylyze tremor in healthy subjects. The spectrum of physiological tremor was recorded from the outstretched index finger of three hundreds and forty healthy subjects between 3 and 86 years old. The power spectrum patterns of the tremor frequency were divided into seven groups. Among the healthy subjects, 46.1% had a peak frequency of tremor. A high percentage of children had no peak frequency, a high percentage of the 80 year old group had a peak frequency. The mean peak frequency of tremor was 9, 469Hz. Correlation between age and peak tremor frequency was siginificant. (r=0.616, p<0.001, Y=11, 3198-0.042X, Y=peak frequency X=age) The mean peak tremor frequency of healthy subjects below the age of 40 was about 10 Hz with no evidence of decline in frequency. However, there was a steady decline in mean tremor peak frequency in healthy subjects over 50 years old (9.032 Hz at 50 years, 8.184 Hz at 60, 7.502 Hz at 70, 6.847 Hz at 80) . This indicates that the frequency of physiological tremor decreases with age. Serial tremor analysis every hour during the day for six days revealed no changes in power spectrum patterns of tremor frequency.
