More Time with Tremor: The Experience of Essential Tremor Versus Parkinson's Disease Patients

Abstract

Background: A broad range of tremors occur in patients with essential tremor and Parkinson's disease; despite this, there are virtually no published data that focus on the patient perspective. The aims were to (1) assess the subjective experience of tremor, comparing essential tremor and Parkinson's disease patients, and (2) assess the clinical correlates of that experience (i.e., what specific clinical characteristics were associated with more experienced tremor)?

Methods: 121 essential tremor and 100 Parkinson's disease cases enrolled in a cross-sectional, clinical-epidemiological study underwent a detailed clinical assessment, which included a series of standardized questionnaires and neurological examination. The question, "On a typical day, how many waking hours do you have tremor in any body part?", was also administered.

Results: Essential tremor cases reported more than three times the median number of waking hours experiencing tremor than Parkinson's disease cases: 10.1 ± 7.8 (median 10.0) vs. 5.5 ± 6.3 (median 3.0) hours (p<0.001). A small number of cases (esp., essential tremor) reported spending ≥16 hours/day shaking. Greater number of hours experiencing tremor was associated with female gender, higher Center for Epidemiological Studies Depression Scale scores, greater perceived disability and, in essential tremor, higher Essential Tremor Embarrassment Assessment scores.

Conclusions: Essential tremor patients reported more than three times the median number of waking hours experiencing tremor than Parkinson's disease patients. Certain clinical characteristics tracked with more reported tremor, and the number of such hours had clear clinical ramifications - greater number of hours was associated with both psycho-social and functional consequences.

Keywords: Parkinson's disease; clinical; essential tremor; tremor.

Figure 1

Hours experiencing tremor in a typical day: ET versus PD. On a typical day, ET patients (black bars) reported spending more than 3 times the median number of waking hours experiencing tremor than PD patients (stripped bars). Medians, shown by vertical lines, were 10.0 (ET) versus 3.0 (PD) hours (Mann‐Whitney's test = 4.48; P < 0.001).