Voice Handicap in Essential Tremor: A Comparison with Normal Controls and Parkinson’s Disease
Background: Although voice tremor is one of the most commonly-noted clinical features of essential tremor (ET), there are nearly no published data on the handicap associated with it.
Methods: The Voice Handicap Index (VHI) was self-administered by participants enrolled in a research study at Columbia-University Medical Center. The VHI quantifies patients' perceptions of handicap due to voice difficulties. Data from 98 ET cases were compared to data from 100 controls and 85 patients with another movement disorder (Parkinson’s disease, PD).
Results: Voice tremor was present on examination in 25 (25.5%) ET cases; 12 had mild voice tremor (ETMild VT) and 13 had marked voice tremor (ETMarked VT). VHI scores were higher in ET cases than controls (p=0.02). VHI scores among ETMarked VT were similar to those of PD cases; both were significantly higher than controls (p<0.001). The three VHI subscale scores (physical, functional, emotional) were highest in ETMarked VT, with values that were similar to those observed in PD.
Conclusions: The voice handicap associated with ET had multiple (i.e., physical, functional, and emotional) dimensions. Moreover, ET cases with marked voice tremor on examination had a level of self-reported voice handicap that was similar to that observed in patients with PD.