People with Parkinson's disease report that tremors worsen during stressful situations. ‘Tremors act as a sort of barometer for stress; you see this in all people with Parkinson's’, says neurologist Rick Helmich from Radboud university medical center. The commonly used drug levodopa usually helps with tremors, but it tends to be less effective during stress, when tremors are often at their worst. Helmich and his team wanted to investigate whether a medication targeting the stress system could help and how this effect of stress on tremors works in the brain.
The study
The team tested 27 people with Parkinson’s. Each person took propranolol one day and a placebo on another. Researchers measured their tremors and brain activity using special equipment and MRI scans. The participants also completed a stressful task, solving mathematical problems, while their stress levels were tracked by heart rate and pupil size.
The results showed that propranolol reduced tremors both at rest and during stress. MRI scans revealed that the medication calmed the brain circuit responsible for tremors. Neurologist Rick Helmich explains: “Stress hormones can act like an amplifier for tremors. Propranolol blocks this effect and reduces the symptoms.”
Interestingly, propranolol also reduced tremors when participants were at rest. Researcher Anouk van der Heide says: “We thought the stress system was only active during stressful moments, but it seems it also affects tremors when at rest.”
A new treatment option
Levodopa remains the first-choice treatment for Parkinson’s, as it helps with many symptoms. However, when levodopa doesn’t reduce tremors, propranolol might be an option, though doctors need to monitor for side effects like low blood pressure.
About the publication
Read more information in the Radboudumc press release. This research was published in Annals of Neurology: Propranolol reduces Parkinson’s tremor and inhibits tremor-related activity in the motor cortex: a placebo-controlled crossover trial. Anouk van der Heide, Maaike Wessel, Danae Papadopetraki, Dirk E.M. Geurts, Teije H. van Prooije, Frank Gommans, Bastiaan R. Bloem, Michiel F. Dirkx, Rick C. Helmich. DOI: 10.1002/ana.27159.
If you or a loved one experience tremors due to Parkinson's and would like to know if propranolol is an option, please contact your treating neurologist.