Assessment of Intrinsic Hand Neuromuscular Physiology
Abstract
Alterations to the peripheral nervous system and neuromuscular physiology may impact hand function in a typical or clinical population, such as individuals with ulnar neuropathy. The mechanisms that influence these positive and negative changes are still not well understood. The three studies within my thesis aim to validate the reliability of decomposition-based quantitative electromyography (DQEMG) measurements and explore the changes in intrinsic hand neuromuscular physiology in a typical aging population and individuals recovering from a surgical intervention for severe ulnar neuropathy.
The purpose of the first study was to determine the test-retest reliability of near-fibre (NF) jiggle, a measure of motor unit stability. I found that NF jiggle had good measurement reliability with low error, especially when contrasted with traditional jiggle. The context of this reliability was specific to the intrinsic hand muscles: first dorsal interosseus (FDI), abductor digiti minimi (ADM), and fourth dorsal interosseous (4DI).
The purpose of the second study was to compare the intrinsic hand neuromuscular physiology of a typical aging population using multivariate analyses. I determined that with aging, there are decreases in motor unit number estimations (MUNE) and motor unit stability (NF jiggle) with increases to motor unit potential (MUP) area in the intrinsic hand muscles. Using a multivariate approach allowed for age-related differences and the relationship between the variables to be further elucidated.
The purpose of the third study was to describe the responses, functional outcome, and motor unit physiology of three participants following an ulnar nerve transfer surgery to treat severe ulnar neuropathy and the rehabilitation that followed. I determined that functional outcomes were associated with improvements to neuromuscular physiology and may be influenced by rehabilitation adherence. Also, factors such as comorbidities, psychosocial barriers and delay in treatment may affect functional outcomes and rehabilitation adherence.
Overall, the progression of quantitative EMG measurements and exploring mechanisms of neuromuscular changes in aging and clinical populations provide foundational knowledge that may impact rehabilitation and treatment approaches. I hope that my thesis may provide new avenues of assessment, treatment, and prognosis for persons with pathologies that influence hand function and neuromuscular physiology.