3 October 2024
Stroke is a leading cause of long-term disability worldwide, significantly affecting the quality of life for survivors. Many stroke patients experience lower extremity motor impairments, which hinder their ability to walk independently—a crucial aspect of post-stroke rehabilitation. Despite its importance, the neuromotor control mechanisms underlying post-stroke walking are not well understood.
In a recent study, Medical School faculty, Prof Avgis Hadjipapas, and Dr Charalambos C. Charalambous, a former postdoctoral fellow at UNIC and now a faculty member at Duke University School of Medicine, have made progress in this area. Their research, published in Experimental Brain Research, investigates the role of supraspinal inputs via pyramidal and extrapyramidal tracts in the function of calf muscles during walking in chronic stroke patients.
The study involved fourteen chronic stroke patients and used techniques to assess walking kinetics and electromyography (EMG). By calculating the mechanical output, or propulsive impulse, of the calf muscles during the stance phase of walking, the researchers quantified muscle function. They also analysed intermuscular coherences (IMCs) between motor-related oscillations in different frequency bands, which serve as proxies for supraspinal input to the muscles.
The findings revealed that IMCs were differentially modulated across frequency bands and between the paretic and non-paretic sides. Notably, only the alpha IMCs on the paretic limb showed a specific correlation with propulsive impulse, highlighting a complex pattern of neuromechanical interactions.
These insights support the presence of frequency-specific descending drives to walking-specific muscles in chronic stroke patients, influencing muscle function. The study’s results pave the way for future research into neural control mechanisms and the development of new rehabilitation strategies. Techniques such as transcranial alternate current stimulation (tACS), which can target specific brain frequencies, hold promise for enhancing walking recovery.
This research was conducted in collaboration with colleagues from the University of Nevada in Las Vegas, Brooks Rehabilitation, and the Medical University of South Carolina.