Electronic Thesis and Dissertation Repository


Master of Science




Dr Tim Doherty


The aim of the current study was to assess the test – retest reliability of motor unit firing rates with the use of decomposition based quantitative electromyography, and to quantify motor unit firing rates in the first dorsal interosseous of patients with ulnar neuropathy. 8 healthy subjects (mean age 35 ± 10 years) and 8 patients (mean age 48 ± 10 years) with ulnar neuropathy participated in the study. Following the acquisition of a maximum M wave, needle and surface detected EMGs were collected simultaneously during 30-second contractions performed at threshold (1-2% maximum voluntary contraction (MVC)) and 10% MVC- RMS ( maximum voluntary contraction root mean square) to obtain motor unit potential (MUP) trains. From the data collected, motor unit amplitude, duration, area, firing rate, and motor unit number estimates (MUNE) were calculated. Test-retest reliability of MU firing rates in controls was high (ICC =0.85). Motor unit firing rates were found to be moderately correlated with recruitment as rated by experienced clinicians and the MU firing rates were increased in patients with ulnar neuropathy.