, new research showed.
In a prospective, longitudinal study, incidence of dementia was nearly 20% among older adults with ET. However, the rates were lower than those in adults with Parkinson’s disease.
The study is “the most complete exposition of the longitudinal trajectory of cognitive impairment in an ET cohort,” said the authors, led by Elan D. Louis, MD, MSc, from University of Texas Southwestern Medical Center in Dallas, Texas.
The findings were released ahead of the study’s scheduled presentation at the annual meeting of the American Academy of Neurology.
Mild Cognitive Impairment Prevalence Nearly Double
For the study, 222 adults with ET with an average age of 79 years at baseline underwent detailed cognitive assessments and were followed for an average of 5 years.
At baseline, 168 people had normal cognitive skills, 35 had mild cognitive impairment (MCI), and 19 had dementia. During the follow-up, 59 individuals developed MCI and 41 developed dementia.
During the follow-up, the cumulative prevalence of dementia was 18.5%, and the average annual conversion rate of MCI to dementia was 12.2% — nearly threefold higher than rates in the general population and roughly one-half the magnitude of those reported for adults with Parkinson’s disease.
The cumulative prevalence of MCI (26.6%) was nearly double that of the general population but less than that in patients with Parkinson’s disease.
“Our data indicate that the prevalence of and conversion rates to dementia in ET fall between those associated with the natural course of aging and the more pronounced rates observed in individuals with Parkinson’s disease,” the researchers wrote in their conference abstract.
Far From Trivial
Reached for comment, Shaheen Lakhan, MD, a neurologist and researcher based in Miami, Florida, said, “The days of viewing ET as just a ‘nuisance tremor’ are over. This study shatters the notion that essential tremor is a trivial condition.”
“Moving forward, the research agenda must further elucidate the link between ET and dementia and develop neuroprotective strategies. But this study represents a seismic shift in how we understand essential tremor,” Dr. Lakhan said.
“The benign label no longer applies given the cognitive risks ET patients face. Our clinical practice and communication with patients must adapt accordingly,” he added.
The study was supported by the National Institutes of Health. Drs. Louis and Lakhan had no relevant disclosures.
A version of this article appeared on Medscape.com.