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Researchers found that people with essential tremor may be three times as likely to develop dementia than the general population. Westend61/Getty Images
  • People with essential tremor are at an increased risk for several conditions, including Parkinson’s disease, cardiovascular disease, and hearing impairments.
  • Researchers from the University of Texas Southwestern Medical Center have found that people with essential tremor may be three times as likely to develop dementia than the general population.
  • More studies on the link between essential tremor and dementia risk are needed to establish causation.

In 2020, almost 25 million people worldwide lived with essential tremor — a neurological disorder causing parts of the body to move or shake involuntarily.

There is currently no cure for essential tremor. As the condition advances, it can be hard for a person to conduct everyday activities such as handwriting, eating, and bathing.

Previous research shows that people with essential tremor are also at an increased risk for several conditions, including:

Now, researchers from the University of Texas Southwestern Medical Center have found that people with essential tremor could be three times as likely to develop dementia than the general population.

The findings were published April 24 in Annals of Neurology and recently presented at the American Academy of Neurology’s 76th Annual Meeting.

For this study, researchers recruited 222 study participants with essential tremor with an average age of 79 at the start of the study.

All participants were asked to take thinking and memory tests to determine whether or not they had healthy cognition, mild cognitive impairment, or dementia.

At the start of the study, 168 participants had healthy cognitive skills, 35 had mild cognitive impairment, and 19 had dementia.

During the study time period, participants had follow-up exams every 1.5 years for an average of 5 years.

At the conclusion of the study, researchers found nearly 19% of the study participants had or developed dementia during the study. According to the researchers, these rates were three times higher than those in the general population.

Additionally, every year, an average of 12% of participants diagnosed with mild cognitive impairment at the start of the study went on to develop dementia.

The scientists also discovered that 27% of study participants had or developed mild cognitive impairment during the study — a rate almost twice that of the rate of 14.5% for the general population, according to a press release.

“While many people living with essential tremor experience mild tremor, in some individuals, the tremor can be quite severe,” lead study author Dr. Elan D. Louis, professor and chair of the Department of Neurology at the University of Texas Southwestern Medical Center in Dallas, told Medical News Today.

“Not only do tremors affect a person’s ability to complete daily tasks such as writing and eating, our study suggests that people with essential tremor also have an increased risk of developing dementia.”

This is not the first study to find a link between essential tremor and cognition issues.

Previous research shows essential tremor is associated with a 60% increased risk of developing dementia.

A study published in September 2021 found people with dementia and essential tremor had a two to three times higher mortality risk. Research published in April 2017 found cognitive dysfunction in people with essential tremor is linked to a greater number of falls and lower balance issues.

Dr. Louis told MNT he and his team were not surprised by the study’s findings.

“While the majority of people with essential tremor will not develop dementia, our findings provide the basis for physicians to educate people with essential tremor and their families about the heightened risk and any potential life changes likely to accompany this diagnosis,” Dr. Louis said.

“Data on the rates of development of cognitive impairment in essential tremor are essential for prognosis, planning, and potential treatment of cognitive impairment in patients with essential tremor. [We will] continue to follow this cohort of patients to further refine our understanding of the underlying issue.”

— Dr. Elan D. Louis, lead study author

The new study reports the cumulative prevalence of dementia in patients with essential tremor is three times higher than in the general population.

However, the study does not provide an explanation for the increased dementia risk, said Dr. Jean-Philippe Langevin, a board certified neurosurgeon and director of the Restorative Neurosurgery and Deep Brain Stimulation Program at the Pacific Neuroscience Institute in Santa Monica, CA.

“One potential explanation would be that the circuits affected in essential tremor are also involved in higher-order cognition,” Dr. Langevin told MNT. “Over time, a deficit is seen once normal aging reduces the overall cognitive capacity.”

“Another possible explanation would be that the tremor can affect the way the patient interacts socially and with the environment in a way that leads to cognitive impairment over time,” he added.

Dr. Langevin said that patients with essential tremor often ask how their condition will progress over time so the risk of cognitive impairment should also be taken into consideration.

“It would be interesting to see if the treatment of essential tremor can reverse this risk factor,” he continued. “For example, are patients undergoing essential tremor treatment with deep brain stimulation or with focus ultrasound following the general population in terms of dementia prevalence? Are the risks for dementia linked to the severity of the tremor?”

— Dr. Jean-Philippe Langevin, neurosurgeon

MNT also spoke with Dr. Rocco DiPaola, a neurologist and movement disorder specialist at Hackensack Meridian Neuroscience Institute at Jersey Shore University Medical Center in New Jersey, about this study.

Dr. DiPaola said the findings provide further evidence that essential tremor is not a “pure” motor disorder and that cognitive impairment is a potential risk associated with the disease process.

“The mechanism [for] increased risk of cognitive impairment is unclear,” Dr. DiPaola said. “How we classify essential tremor may be a factor in that age of onset seems to play a role in the development of cognitive impairment, and there may be a link to other degenerative disorders that affect cognition.”

“Further research [could study] the age of onset, medications, and lifestyle — alcohol use, etc. — as factors in the development of cognitive impairment,” Dr. DiPaola noted.