Transcranial direct current stimulation (tDCS) can increase the benefits of aerobic exercise and improve the gait of people with Parkinson’s disease immediately after a session. Step time variability decreases, reaction time is shortened and executive gait control is improved.
These were the key findings of a randomized, double-blind, sham-controlled crossover study on 20 volunteers by researchers at the Institute of Life Sciences at São Paulo State University (IB-UNESP) in Rio Claro, Brazil. An article about the study was published in Neurorehabilitation & Neural Repair.
Participants took part in two 30-minute aerobic exercises (cycling at medium intensity) one week apart, combined with various tDCS conditions, active or “sham” (placebo).
Cognitive functions and prefrontal cortical activity while walking were assessed before and immediately after each session. Spatio-temporal parameters were also included in the analysis in order to assess gait variability, step length and processing speed.
“Compared to the preliminary study, participants decreased step time variability, shortened simple and optional reaction times, and increased prefrontal cortex activity in the stimulated hemisphere while only walking after aerobic exercise and active tDCS,” the article concludes. The authors were supported by FAPESP.
According to Rodrigo Vitório, professor at IB-UNESP and the last author of the article, an unbiased comparison was ensured by administering active interventions and placebo or sham treatment on different days. Half of the participants received 20 minutes of actual tDCS followed by simulated tDCS for 10 seconds. The other half went through the procedures in reverse order (sham followed by real treatment).
With the tDCS, two small rectangular electrodes are attached to specific points on the head. The device is portable and battery operated. The current is very weak (2 milliamps) but is enough to penetrate the scalp and stimulate neurons in the region of interest.
Despite the limitations of such a small sample size, we found that transcranial stimulation activates the prefrontal cortex, a region of the brain that Parkinson’s patients use more for gait control than healthy individuals. A single session associated with exercise improved cognitive function and resulted in other improvements. “
Rodrigo Vitório, professor at IB-UNESP, research fellow in the Faculty of Health and Life Sciences, University of Northumbria
In an interview with Agência FAPESP, Vitório stated that one of the study’s goals was to look deeper into the effects of tDCS than previous studies of groups he belonged to that had previously shown that aerobic exercise improved motor activity in Parkinson’s disease. Patient. “Transcranial stimulation is safe and has shown promise in increasing the effects of interventions and treatments. It is often prescribed for depression, for example,” he said.
According to the World Health Organization (WHO), around 1% of the world population over 65 suffered from Parkinson’s in 2019. The number of people affected is estimated at 250,000 in Brazil, where there is no compulsory registration.
About Parkinson’s Disease
Parkinson’s disease is a chronic and progressive degenerative disease of the central nervous system in which damage to nerve cells in the brain leads to a drop in levels of dopamine, a neurotransmitter that plays a key role in sending messages to the part of the brain that does movement controls and coordination.
When dopamine-producing neurons die, symptoms such as tremors, slowness, stiffness, and balance problems appear. Medications are usually prescribed to maintain dopamine or to replace missing dopamine in the brain, but can only control symptoms as the disease is incurable.
Parkinson’s patients have specific degenerations in brain areas that are involved in automatic movement control and use attention resources to compensate for this deficit. In the study, aerobic exercise in conjunction with tDSC improved the volunteers’ ability to compensate.
The main symptoms of the disease are bradykinesia (slow movement), stiffness in the wrists, elbows, shoulders, thighs and ankles, and resting tremors in the hands with loss of balance in severe cases. An improvement in the gait pattern can lead to a better quality of life and, for example, avoid falls.
Another research group at UNESP’s Bauru campus recently found that stride length synergy when crossing obstacles is 53% less in Parkinson’s patients than in healthy people of the same age and weight.
Stride length synergy refers to the ability of the musculoskeletal system to adjust movement by combining factors such as speed and foot position while paving the curb on a sidewalk, for example.
Research Foundation São Paulo (FAPESP)
Conceição, NR, et al. (2021) Aerobic Training Combined with Transcranial Direct Current Stimulation via the Prefrontal Cortex in Parkinson’s Disease: Effects on Cortical Activity, Gait, and Cognition. Neurorehabilitation and neural repair. doi.org/10.1177/15459683211019344.