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This Article Full Text Full Text (PDF) CME: Take the course for this article: Volume 73, Number 8, August 25, 2009 Data Supplement Correspondence: Submit a response Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Thawani, S. P. Articles by Louis, E. D. PubMed PubMed Citation Articles by Thawani, S. P. Articles by Louis, E. D. Related Collections Tremor All Cognitive Disorders/Dementia Cohort studies Prevalence studies

Essential tremor is associated with dementia

Prospective population-based study in New York

From the Department of Epidemiology, Mailman School of Public Health (S.P.T., N.S., E.D.L.), and GH Sergievsky Center (N.S., E.D.L.), Department of Psychiatry (N.S.), Taub Institute for Research on Alzheimer's Disease and the Aging Brain (N.S., E.D.L.), and Department of Neurology (E.D.L.), College of Physicians and Surgeons, Columbia University, New York, NY.

Address correspondence and reprint requests to Dr. Elan Louis, Unit 198, Neurological Institute, 710 West 168th Street, New York, NY 10032 EDL2{at}columbia.edu

Background: Mild cognitive deficits, mainly in frontal-executive function and memory, have been reported in patients with essential tremor (ET). Furthermore, an association between ET and dementia has been reported in a single population-based study in Spain. This has not been confirmed elsewhere.

Objective: To determine whether baseline ET is associated with prevalent and incident dementia in an ethnically diverse, community-based sample of elders.

Methods: Community-dwelling elders in northern Manhattan were enrolled in a prospective cohort study. Baseline ET diagnoses were assigned from handwriting samples. Dementia was diagnosed at baseline and follow-up using DSM-III-R criteria.

Results: In cross-sectional analyses, 31/124 (25.0%) ET cases had prevalent dementia vs 198/2,161 (9.2%) controls (odds ratio [OR]_unadjusted = 3.31, 95% confidence interval [CI] = 2.15–5.09, p < 0.001; OR_adjusted = 1.84, 95% CI = 1.13–2.98, p = 0.01). In prospective analyses, 17/93 (18.3%) ET cases vs 171/1,963 (8.7%) controls developed incident dementia (hazard ratio [HR]_unadjusted = 2.78, 95% CI = 1.69–4.57, p < 0.001; HR_adjusted = 1.64, 95% CI = 0.99–2.72, p = 0.055).

Conclusions: In a second population-based study of elders, essential tremor (ET) was associated with both increased odds of prevalent dementia and increased risk of incident dementia. Presence of dementia, therefore, appeared to be greater than that expected for age (i.e., a disease-associated feature). Rather than attributing cognitive complaints in patients with ET to old age, assessment and possible treatment of dementia should be routinely incorporated into the treatment plan.

Abbreviations: AD = Alzheimer disease; CES-D = Center for Epidemiologic Studies–Depression; CI = confidence interval; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders, 4th edition; ET = essential tremor; HR = hazard ratio; MCI = mild cognitive impairment; MCI+M = MCI with memory impairment; MCI-M = MCI without memory impairment; OR = odds ratio; UPDRS = Unified Parkinson's Disease Rating Scale; WHICAP = Washington/Hamilton Heights and Inwood Aging Project.

Supplemental data at www.neurology.org

Disclosure: Author disclosures are provided at the end of the article.

Received February 13, 2009. Accepted in final form May 18, 2009.