Acoustic analysis of essential voice tremor

Abstract

This study examined differences in selected phonatory characteristics of essential tremor (ET) patients and normal, matched controls. All patients exhibited limb tremor of 4–10 Hz and minimal to severe audible vocal tremor. Tape-recorded speech sample for 14 ET and normal speakers from our subject pool were analyzed acoustically to determine individual and group mean fundamental frequency (f0) measures. Both the female and male ET groups had a significantly lower mean f0 (20–40 Hz) than that of their matched controls during sustained vowel productions. As well, the performance patterns of the ET and control groups were markedly different across repeated trials of vowel production. In connected speech, the male ET speakers' average f0 and phonation range were significantly reduced relative to that of their matched controls. Although there was no statistical difference, female ET speakers also tended to have a reduced mean f0 and phonation range in connected speech compared to their matched controls. These preliminary findings suggest that an abnormally low f0 may be a critical factor contributing to the perception of voice tremor in ET patients. [Work supported by Center on Aging, KUMC.]