Caloric Vestibular Stimulation Helps With Parkinson Symptoms

David Wilkinson

Caloric vestibular stimulation (CVS) could help relieve motor and non-motor symptoms associated with Parkinson disease.

A team led by Professor David Wilkinson at the University of Kent's School of Psychology, sought to confirm a recent case study that found that CVS relieved Parkinson symptoms, with a 33-patient double-blind, placebo-controlled, randomized study.

Of the 33 participants, 16 patients completed an active treatment, while 17 were given a placebo. Each subject self-administered CVS twice a day a home through a portable, pre-programmed, solid-state ThermoNeuroModulation device, which was recently cleared for market for both the US and the European Union for Parkinson patients in a clinical trial.

Each subject was followed for a 4-week baseline period, followed by 8 weeks of treatment and 5-and-24 week of post-treatment. At each visit, investigators performed standardized clinical assessments during ON-medication states to evaluate the changes in motor and non-motor symptoms, activities of daily living and quality of life ratings.

Treatment for both groups involved lying on a 22 degree-elevated wedge pillow to orient the horizontal semi-circular canal vertically with the active group receiving the simultaneous delivery of a time-varying, warm, saw-tooth thermal (37 °C—42 °C) stimulus to one ear and a cold saw-tooth thermal (37 °C–17 °C) stimulus to the other ear for approximately 19-minutes.

Each of the daily treatment sessions were separated by at least 1 hour and the participants switched which ear received the warm and cold waveforms every 2 days to avoid a possible induction of a lasting, lateral, vestibular asymmetry.

Also, slow warming and cooling inner ear structures avoids vertigo and nausea issues that can result from chilled water irrigation.

The change scores between the baseline and the end of treatment shows that active-arm subjects saw significantly greater reductions in both motor and non-motor symptoms than the placebo group, as well as improved reports of daily living assessments.

The therapeutic gains could still be seen 5 weeks following the end of active treatment, but began to recede at the 24-week follow-up.

Because it was a blind trial, no reference to the thermal stimulus was made and the subjects were told they may or may not feel temperature changes in their ears, which was not an indicator of whether or not they were part of the active or placebo control group.

“Given the robust clinical effects, the failure of active-treatment subjects to accurately guess their treatment allocation was surprising,” the authors wrote. “The successful concealment of allocation in this study provides good reason to suggest that the clinical improvements were driven by more than just a placebo response.”

In the case study that spurred the double-blind study, investigators found that daily CVS sessions were linked with a ∼50% reduction in both motor and non-motor symptoms of Parkinson still evident 5 months after treatment concluded. The case study also builds upon another research project showing that vestibular stimulation in Parkinson can increase functional neural connectivity and improve specific aspects of motor control.

The study, “Caloric vestibular stimulation for the management of motor and non-motor symptoms in Parkinson's disease,” was published online in Parkinsonism & Related Disorders.