Korea University Ansan Hospital researchers demonstrate brain stimulation therapy improves depression and apathy in Parkinson's disease

A research team led by Professor Ho Kyung Yoon of the Department of Psychiatry and Professor Do Young Kwon of the Department of Neurology at Korea University Ansan Hospital has demonstrated that transcranial direct current stimulation (tDCS) significantly improves depression and apathy in patients with Parkinson's disease.

The study is particularly noteworthy for incorporating wearable technology into clinical evaluation. By using smart bands to objectively monitor changes in patients’ physical activity in real-world settings, the researchers proposed a new approach to personalized Parkinson’s disease management that combines non-invasive brain stimulation with wearable technology.

Transcranial direct current stimulation is a non-invasive neuromodulation therapy that delivers a low-intensity electrical current through electrodes placed on the scalp to modulate activity of cells in targeted brain regions. Since the treatment requires neither surgery nor anesthesia and is associated with minimal discomfort and few adverse effects, it is a safe therapeutic option for improving emotional and cognitive symptoms.

Parkinson's disease is a progressive neurodegenerative disorder characterized not only by motor symptoms such as tremor, rigidity, and bradykinesia, but also by non-motor symptoms—including depression, anxiety, and apathy—that can substantially diminish patients' quality of life and interfere with effective disease management.

The research team enrolled 20 patients with Parkinson's disease experiencing depressive symptoms and administered 10 sessions of tDCS over several weeks, with treatments delivered three times per week to brain regions involved in emotional regulation. Throughout the study, participants wore smart bands that continuously recorded daily activities, including step counts and sleep patterns.

Following treatment, patients showed significant improvements in both emotional well-being and physical function. Depressive symptoms decreased by approximately 54%, while anxiety symptoms were reduced by about 38%. Apathy—a condition characterized by diminished motivation and loss of interest—improved by approximately 25%, and motor symptoms, including rigidity and slowed movement, improved by roughly 35%.

Importantly, these clinical improvements were reflected in patients' daily lives. Wearable device data revealed a significant increase in spontaneous daytime physical activity following treatment, indicating that patients became more active beyond the clinical setting.

The researchers further found that reductions in apathy were the strongest predictor of increased daily activity. Improvements in motivation were more closely associated with greater spontaneous physical activity than improvements in depression, and this relationship remained consistent regardless of patients' age or disease duration.

"Patients with Parkinson's disease often experience substantial declines in daily functioning and quality of life due not only to motor symptoms but also to non-motor symptoms such as depression and apathy," said Professor Yoon. "Our findings demonstrate that non-invasive brain stimulation can improve emotional symptoms while also increasing patients' real-world activity levels, suggesting that tDCS has considerable potential as a safe and effective adjunctive treatment."

Professor Kwon added, "Evaluating treatment outcomes in Parkinson's disease requires looking beyond assessments conducted in the clinic to understand how patients function in their everyday lives. By objectively measuring changes in daily activity using wearable technology, our study demonstrates the value of integrating real-world data into patient care. Wearable-based assessment may play an important role in enabling more precise monitoring and supporting personalized treatment strategies."

The study was published in Acta Neuropsychiatrica, an internationally recognized peer-reviewed journal in the field of neuropsychiatry.