Improving Gait in Parkinson’s Disease Patients by Non-invasive Electrical Stimulation of the Cerebellum

Study Rationale:
People with Parkinson’s disease (PD) can experience difficulties walking (e.g., freezing), which can lead to falls and negatively impact quality of life. These symptoms are difficult to treat. Until recently, scientists thought that gait deficits are caused by dysfunction in part of the brain called the basal ganglia. However, an emerging insight is that the cerebellum may be involved in gait problems seen in PD, as the cerebellum is hyperactive in PD patients during gait. Whether cerebellar hyperactivity is part of the disease or a reaction to help gait remains an open question.

Hypothesis:
We hypothesize that if cerebellar hyperactivity in PD patients is a reaction to help gait, increasing cerebellar activity should improve gait, whereas suppressing it will make gait worse. In contrast, if cerebellar hyperactivity is part of the disease, decreasing cerebellar activity will improve gait and suppressing it will worsen gait.

Study Design:
Fifteen PD patients will complete six experimental sessions. Cerebellar activity will be up and down regulated with non-invasive transcranial direct current stimulation. Patients will be assessed both ON and OFF their medication. We will assess different tests of gait, such as the Timed-Up-and-Go test. Patients will also walk on a treadmill for five minutes. 

Impact on Treatment of Parkinson’s Disease:
Successful testing of our idea will show that modulating cerebellar excitability improves gait deficits in PD patients. This will advance our understanding of the brain changes associated with gait problems in PD. It will also indicate that cerebellar transcranial stimulation could be used to treat gait deficits in Parkinson’s.

Next Steps for Development:
After successful testing of our idea, a logical next step will be to do dose-effect studies to determine the optimal stimulation settings and sites. Then a clinical trial is needed to prove the efficacy for the improvement of gait deficits in PD patients and to compare with current treatment such as physical therapy.