Abstract
Background: The burden of mild (i.e., subclinical) tremor within essential tremor (ET) families is not fully understood. We assessed the burden of mild tremor in a cohort of 287 adults, none of whom reported tremor or were diagnosed with ET. Methods: We recruited adults in 2 groups based on the familial risk for ET: 244 high-risk individuals (i.e., reporting one or more first-degree relative with ET) and 43 low-risk individuals (i.e., reporting no relatives with ET). Tremor was objectively assessed on 4 hand-drawn spirals (total spiral score = 0-12). Mild tremor was defined using 3 different cut points. Results: The prevalence rates of mild tremor among high-risk individuals ranged from 41.4 to 98.4% and were highly dependent on the cut point. Above a certain threshold (i.e., a total spiral score ≥5), 1-in-5 (i.e., 19.7%) high-risk individuals exhibited mild tremor, whereas no low-risk individuals did. High-risk individuals were 3.09-4.50 times more likely than low-risk individuals to exhibit mild tremor. Conclusion: The burden of ET extends beyond the boundaries of the clinically defined disease, and partially expressed forms of ET are abundant in ET families. This fact greatly complicates gene-finding studies and epidemiological studies whose goal is to detect disease-linked associations.
Original language | English (US) |
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Pages (from-to) | 41-46 |
Number of pages | 6 |
Journal | Neuroepidemiology |
Volume | 50 |
Issue number | 1-2 |
DOIs | |
State | Published - Mar 1 2018 |
Externally published | Yes |
Keywords
- Epidemiology
- Essential tremor
- Genetics
- Penetrance
- Risk
- Subclinical
ASJC Scopus subject areas
- Epidemiology
- Clinical Neurology