In a recent prospective cohort study conducted by Elan Louis, MD, and his team at the University of Texas Southwestern Medical Center in Dallas, it was found that the prevalence of dementia in individuals with essential tremor was significantly higher than that of the general population. Over a 5-year period, the cumulative prevalence of dementia was reported to be 18.5%, with an average annual conversion rate of mild cognitive impairment to dementia standing at 12.2%. These rates were three times higher than the general population and approximately one-half of those observed in individuals with Parkinson’s disease.
The study emphasized that while the majority of individuals with essential tremor may not develop dementia, the heightened risk highlighted in the findings should not be overlooked. Essential tremor is a common movement disorder characterized by a kinetic tremor of the arms, although other parts of the body, such as the head or lower limbs, can also be affected. The tremor associated with essential tremor can impact daily activities, such as eating, and in some cases, can be quite severe.
Recent estimates suggest that approximately 6.4 million adults in the U.S. have essential tremor. The prevalence of essential tremor increases with age, ranging from 0.8% in individuals aged 18-30 to 8.2% in those aged 85 and older. While previous research has indicated that cognitive impairment can occur in individuals with essential tremor, the evidence linking essential tremor to a higher risk of dementia has been inconclusive.
The study evaluated 222 patients with essential tremor at baseline, with a mean age of around 79 years. Of these patients, 177 participated in follow-up evaluations at various time points over a 5.1-year observation period. Detailed cognitive assessments were conducted, and patients were classified as having normal cognition, mild cognitive impairment, or dementia at baseline and during follow-up. The results were compared with data from historical controls and individuals with Parkinson’s disease.
The findings of this study shed light on the potential link between essential tremor and an increased risk of dementia. Individuals with essential tremor and their families should be educated about this heightened risk, along with any potential lifestyle changes that may accompany a dementia diagnosis. Given the impact of dementia on functional ability and mortality rates, early detection and intervention for cognitive impairment in individuals with essential tremor are crucial.
The study by Elan Louis and colleagues provides valuable insights into the longitudinal trajectory of cognitive impairment in individuals with essential tremor. Further research is needed to better understand the underlying mechanisms linking essential tremor to dementia and to develop effective strategies for early diagnosis and management.