Background: The ability of the Essential Tremor (ET) Rating Assessment Scale (TETRAS) to detect changes in tremor severity is unknown.
Methods: Fifteen adult ET patients received a single oral ethanol dose calculated to reach 0.05 g/dL breath alcohol content (brAC). Effects were investigated independently with accelerometry and TETRAS.
Results: Accelerometry data were log-transformed and a cumulative score logACC(R+L) was calculated. Correlation between logACC(R+L) and TETRAS was significant. TETRAS and accelerometry showed a significant effect of time point using repeated-measures analysis of variance. The difference between baseline and each of the following six time points as well as the correlation of TETRAS with brAC were significant. The calculated minimum detectable change of TETRAS was 8.9% and the effect size was d = 4.75 (95% confidence interval: 3.60-5.90).
Conclusion: We demonstrated sensitivity to change of the TETRAS performance scale after a therapeutic intervention, which further establishes its potential for use in both clinical and research settings.
Keywords: alcohol challenge; assessment scale; clinical rating; essential tremor; validation study.
© 2013 International Parkinson and Movement Disorder Society.