A Nov. 27, 2019 news report in the New York Times shook up the Parkinson’s disease community. The story by journalist Denise Grady was titled, “Swimmers Beware of Deep Brain Stimulation”, an ominous warning. The article was based on a published study in the journal Neurology so the source was reliable.

The study was the work of a medical team from the University of Zurich. The researchers had identified nine cases of Parkinson’s disease (PD) patients who underwent Deep Brain Stimulation (DBS) to control their tremor and other physical PD symptoms. DBS is a type of neurosurgery that allows implantation of electrical wires in the brain’s thalamus; when the system is switched on, the electrical stimulation controls the symptoms, but when switched off, the symptoms return.

The Zurich team found that nine PD patients who had DBS indeed found it successful in their daily lives. However, each of them also happened to be good swimmers—until they went swimming with their DBS turned on. Suddenly, they were unable to perform normal swimming strokes and found themselves in danger. However, if their stimulators were switched off, the problem stopped. There was no other conclusion than the DBS itself had somehow disabled what their brains and muscles otherwise knew well.

The journal article chronicled three cases out of the nine in greater detail. Two of them were women (one age 59, the other age 61) who had been competitive swimmers. Each of them was disturbed upon finding herself unable to perform unless DBS was turned off—in which case they could immediately perform normally. The other was a 69-year old man who was a good swimmer but found himself about to drown if his wife hadn’t rescued him. As with the women, he returned to normal swimming ability when DBS was off.

One of the Zurich authors, Daniel Waldvogel, MD cautioned, “Until more research is done to determine why some people with deep brain stimulation can no longer swim, it is crucial that people be told now of the potential risk of drowning and the need for a carefully supervised assessment of their swimming skills before going into deep water.”ⁱ

This sounds like scary stuff, but the American Parkinsons Disease Association (APDA) hurried to add a note of balance to Dr. Waldvogel’s justifiable warning. The APDA site published a statement that included the following points:

• For many PD patients, DBS is successful and improves their quality of life.
• The majority of people who receive DBS are still able to swim competently.
• Anyone with PD who swims should be accompanied since symptoms can change without warning and they may find themselves in jeopardy.
• The nine patients included in the Zurich study felt that the benefits of DBS outweighed the swimming risks.ⁱⁱ

It is important to view a problem from all sides, and to gather as much information as possible before arriving at a conclusion. While there is no doubt that for a small number of PD patients who receive DBS, their swimming ability may be affected while the stimulator is on. And yes, patients should be aware before they have DBS or other intervention for tremor control that there are risks—however small—of side effects.

An alternative to DBS for tremor control is MRI-guided Focused Ultrasound, or MRgFUS. It’s relatively new but the number of cases is growing rapidly because of its advantages, including its noninvasive outpatient procedure, high success rate, durability, and extremely low risk of side effects. Currently, it is offered for cases of Essential Tremor (ET) and for PD tremors that are medication-resistant. As of this writing, there are no reports of swimming mishaps after treatment with MRgFUS.

For more information, contact Sperling Neurosurgery Associates.

ⁱhttps://eurekalert.org/pub_releases/2019-11/aaon-bos112219.php
ⁱⁱhttps://www.apdaparkinson.org/article/deep-brain-stimulation-and-swimming/