Format

Send to

Choose Destination
Front Neurol. 2017 Apr 19;8:148. doi: 10.3389/fneur.2017.00148. eCollection 2017.

Action Tremor Asymmetry Profile Does Not Aggregate in Families with Essential Tremor.

Author information

1
Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.
2
Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA.
3
Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.
4
College of Physicians and Surgeons, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
5
Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA.
6
G.H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
7
Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
8
Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA.
9
Division of Epidemiology, New York State Psychiatric Institute, New York, NY, USA.

Abstract

BACKGROUND:

Action tremor is the hallmark feature of essential tremor (ET). While the tremor typically is mildly asymmetric, in some patients, it is markedly asymmetric. There are few data on factors that influence this asymmetry. ET is also a highly familial disease. Whether the tremor asymmetry profile (i.e., differential expression of tremor in each arm in a given patient) is similar across family members is not known. The alternative possibility is that this feature is not heritable. There are no published data addressing this issue. The aim of this study was to determine whether the extent of action tremor asymmetry ran in ET families.

METHODS:

ET probands and relatives were enrolled in a genetic study at Yale and Columbia Universities. An in-person evaluation included a videotaped neurological examination, including a detailed assessment of tremors. A senior movement disorders neurologist reviewed all videotaped examinations, and the severity of postural and kinetic arm tremors was rated on 12 examination items using a reliable rating scale. The tremor asymmetry index = right arm tremor score - left arm tremor score. We used a bivariate linear regression model to assess the predictors of the tremor asymmetry index in relatives; this model used the tremor asymmetry index in the proband as a primary predictor of interest. In an analysis of variance (ANOVA), we tested for heterogeneity across families in the tremor asymmetry index (i.e., to see whether there was a significant family effect).

RESULTS:

There were 187 enrollees (59 probands, 128 affected relatives). In a bivariate linear regression model, the tremor asymmetry index in the proband was not a predictor of the tremor asymmetry index in their relatives (p = 0.66). In an ANOVA, family grouping did not explain a significant proportion of the total variance in the tremor asymmetry index (p = 0.56).

CONCLUSION:

Tremor asymmetry did not aggregate in families with ET. Therefore, this does not seem to be a disease feature that is heritable. These data will provide added value to the clinical dialog, giving patients one more piece of information about the way the disease manifests within families.

KEYWORDS:

clinical; essential tremor; familial aggregation; genetics; movement disorders

Supplemental Content

Full text links

Icon for Frontiers Media SA Icon for PubMed Central
Loading ...
Support Center