Validity of clinical and patient ratings of tremor disability among older adults

OBJECTIVE: To evaluate the validity of the clinical tremor disability interview using a performance-based measure, patient ratings of tremor disability, and bedside tremor severity ratings of upper extremity (UE) action/intention (A/I) and postural (P) tremor. METHOD: Sixteen older adult essential tremor patients (mean age=75.4 years, sd=5.7 years) took part in a study evaluating the validity of clinical and self-rating scales of tremor disability. A neurologist obtained bedside clinical ratings of UE A/I and P tremor of each limb and completed a clinical tremor disability rating. A second investigator, blind to neurological exam results obtained a clinical disability rating using the same measure, patient rated tremor disability ratings and conducted a performance-based disability assessment. RESULTS: Clinical tremor disability ratings were not significantly related to functional performance-based or patient ratings of tremor disability. Bedside clinical ratings of tremor severity also were not associated with clinical or patient-rated tremor disability. Patient ratings were significantly correlated with performance-based ratings. CONCLUSIONS: Further research is needed to validate a brief, sensitive clinical rating scale of tremor disability among older adults. Use of bedside ratings of tremor severity may be problematic and possibly estimate tremor disability. Empirical evaluation of differences in rating methods needs to be directly addressed.