Electrical stimulation: a potential alternative to positively impact cerebral health?

An increasing body of evidence confirms the effectiveness of physical exercise (PE) in promoting brain health by preventing age-related cognitive decline and reducing the risk of neurodegenerative diseases. The benefits of PE are attributed to neuroplasticity processes which have been reported to enhance cerebral health. However, moderate to high-intensity PE is necessary to induce these responses and these intensities cannot always be achieved especially by people with physical limitations. As a countermeasure, electrical stimulation (ES) offers several benefits, particularly for improving physical functions, for various neurological diseases. This review aims to provide an overview of key mechanisms that could contribute to the enhancement in brain health in response to ES-induced exercise, including increases in cerebral blood flow, neuronal activity, and humoral pathways. This narrative review also focuses on the effects of ES protocols, applied to both humans and animals, on cognition. Despite a certain paucity of research when compared to the more classical aerobic exercise, it seems that ES could be of interest for improving cerebral health, particularly in people who have difficulty engaging in voluntary exercise.

Effect of electrical muscle stimulation on cerebrovascular function and cognitive performance.

It is known that electrical muscle stimulation (EMS) can enhance physical function, but its impact on cognition and cerebral hemodynamics is not well understood. Thus, the purpose of this study was to investigate the effects of one EMS session on cerebrovascular function and cognitive performance. The 17 recruited young healthy participants undertook a 25-min session of EMS and a resting control session (Ctrl group) in a random order. Cerebral blood flow velocity (CBFv) in the middle and posterior cerebral arteries (right MCAv and left PCAv, respectively), cerebral oxygenation, cardiac output, and heart rate were measured throughout the sessions, whereas cognitive function was assessed before and after each experimental condition. MCAv, cardiac output, heart rate, and cerebral oxygenation were increased throughout the EMS session, whereas PCAv remained unchanged. In addition, EMS led to improved scores at the Rey auditory verbal learning test-part B and congruent Stroop task versus Ctrl. The present study demonstrates that a single session of EMS may improve cognitive performance and concomitantly increase CBFv and cerebral oxygenation. Therefore, EMS appears to be a valuable surrogate for voluntary exercise and could therefore be advantageously used in populations with severe physical limitations who would not be able to perform physical exercise otherwise.NEW & NOTEWORTHY This study is the first to demonstrate that one session of EMS applied to the quadriceps increases cerebral blood flow velocity and cerebral oxygenation, which are pivotal factors for brain health. Thus, EMS has the potential to be used as an interesting option in rehabilitation to increase cerebral perfusion and defend if not improve cognitive function sustainably for people with severe physical limitations who would not be able to perform physical exercise voluntarily.

FES-rowing: a well-tolerated and highly beneficial exercise for a patient with Brown-Sequard syndrome.

CONTEXT: Brown-Séquard Syndrome (BSS) is a rare neurological condition associated with Spinal Cord Injury (SCI). Hemisection of the spinal cord causes paralysis of the homolateral side, and thermoalgesic dysfunction on the opposite side. Cardiopulmonary and metabolic alterations have been reported. For all these patients, regular physical activity is highly recommended and functional electrical stimulation (FES) may be a good option, especially for those with paraplegia. However, to our knowledge, the effects of FES have primarily been studied in those with complete SCI and data regarding application and effects in patients with incomplete lesions (with sensory feedback) is lacking. The present case report therefore evaluated the feasibility and effectiveness of a 3-month FES-rowing program in a patient with BSS. METHODS: Knee extensor muscle strength and thickness, walking and rowing capacities as well as quality of life were evaluated before and after 3 months of FES-rowing (two sessions per week) in a 54 year old patient with BSS. RESULTS: The individual had excellent tolerance and adherence to the training protocol. All measured parameters were greatly improved after 3 months: on average, + 30% rowing capacity, + 26% walking capacity, + 24.5% isometric strength, + 21.9% quadriceps muscle thickness, + 34.5% quality of life. CONCLUSION: FES-rowing appears to be well tolerated and highly beneficial for a patient with incomplete SCI and could therefore be considered as an appealing exercise option for these patients.