Effect of hyperbaric oxygen therapy combined with repetitive transcranial magnetic stimulation on vascular cognitive impairment: a randomised controlled trial protocol

Introduction Vascular cognitive impairment ( VCI) has an increasing prevalence worldwide, accounting for at least 20%-40% of all diagnoses of dementia. The decline in cognitive function seriously impairs patients' activities of daily living and social participation and reduces their quality of life. However, there is still a lack of advanced, definitive rehabilitation programmes for VCI. Hyperbaric oxygen therapy (HBOT) and repetitive transcranial magnetic stimulation (rTMS) are recognised treatments for improving cognitive impairment. The former can restore oxygen supply in the brain by increasing oxygen partial pressure in brain tissue, while the latter can enhance neuronal excitability and promote synaptic plasticity. However, no studies have explored the effect of HBO combined with rTMS on VCI. Methods and analysis This study is designed as a single- centre, assessor-blind, randomised controlled clinical trial with four parallel arms. A total of 72 participants will be recruited and randomly assigned to the control group, HBOT group, rTMS group and HBOT combined with rTMS group at a ratio of 1:1:1:1. All enrolled participants will receive conventional treatment. The entire intervention period is 4 weeks, with a 3-week follow-up. Outcomes will be measured at baseline (T0), after a 4-week intervention (T1) and after an additional 3-week follow-up period (T2). The primary endpoint is the Montreal Cognitive Assessment score. The secondary endpoints are Mini- Mental State Examination score, Modified Barthel Index score, latency and amplitude of P300, cerebral cortical oxygenated haemoglobin (HbO(2)) and deoxygenated haemoglobin (HbR) concentrations as measured by task- state functional near- infrared spectroscopy. Ethics and dissemination Ethics approval was obtained from the West China Hospital Clinical Trials and Biomedical Ethics Committee of Sichuan University (ethics reference: 2022 (1972)). The findings will be published in peer-reviewed journals and disseminated through scientific conferences and seminars.