Dementia could three times more common among people suffering from essential tremor, a movement disorder that causes involuntary shaking, a new study suggests.

“Not only do tremors affect a person’s ability to complete daily tasks such writing and eating, our study suggests that people with essential tremor also have an increased risk of developing dementia,” said researcher Dr. Elan Louis, chair of neurology at the University of Texas Southwestern Medical Center in Dallas.

However, the dementia risk posed by essential tremor remains less than that from Parkinson’s disease, which is a less frequent but more severe movement disorder, the researchers added.

Essential tremor causes the hands, arms, legs, head, trunk, jaw or voice of a patient to shake rhythmically, according to Johns Hopkins Medicine. It’s most common among people over 65, but it can affect people at any age and is frequently mistaken for Parkinson’s.

It’s not known what causes essential tremor, but one theory holds that it happens when the cerebellum fails to communicate properly with other parts of the brain, Johns Hopkins says. The cerebellum controls muscle coordination.

For the study, researchers tracked 222 patients with essential tremor.

The patients had an average age of 79 at the start of the study, and were regularly given thinking and memory tests to track the onset of dementia.

At the beginning, 168 had normal brain function, 35 had mild cognitive impairment and 19 had dementia, researchers said. During the study, 59 developed MCI and 41 developed dementia.

About 19% of participants developed dementia during the study, and each year an average 12% of people with MCI went on to develop dementia.

Those rates were three times higher than rates of the general population, but lower than rates found in people with Parkinson’s, researchers said.

Researchers also found that 27% of participants either had or developed MCI during the study, a rate almost double that of the 14.5% found in the general population but less than the 40% found in people with Parkinson’s.

The findings will be presented at the American Academy of Neurology annual meeting in April.

Researchers could not say why essential tremor might be linked to dementia, since the study was only observational in nature. And research presented at meetings should be viewed as preliminary until published in a peer-reviewed journal.

“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,” Louis said.

More information

Johns Hopkins Medicine has more about essential tremor.

SOURCE: American Academy of Neurology, news release, March 6, 2024

Source: HealthDay