Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the death of motor neurons, leading to loss of muscle control. Ireland has the highest incidence of ALS in Europe, with one in every 400 people at risk of developing the disease during their lifetime. An ALS diagnosis is confirmed using needle electromyography (EMG) to detect abnormal patterns in the electrical activity produced by motor units within a muscle. Recently, high-density electromyography (HD-EMG) has enabled the non-invasive detection of single motor unit activity using electrode grids. A crucial step in this process is the visual inspection of the firing trains that have been decomposed from the HD-EMG signals.
This project aims to evaluate a novel method of editing motor unit firing trains from data recorded in people with ALS, developed by the McManus lab. HD-EMG data will be recorded in both healthy controls and in people with ALS. The firing trains decomposed from the HD-EMG signals will then be edited using the new method, which is a more objective procedure that is less sensitive to the experimenter’s level of experience. This project will quantify the improvements in motor unit firing train accuracy after editing, and whether there is any difference in the firing train accuracy post-editing between ALS and control groups.
Improved methods of manually editing decomposed firing trains are essential to enhance the accuracy and yield of motor units extracted from HD-EMG signals. This is particularly vital for HD-EMG recordings in ALS patients where motor unit yield is low due to muscle wasting. Achieving a sufficient yield of motor units, with acceptable levels of accuracy, will enable us to study how ALS affects the transmission of neural signals from the brain to motor units in the muscles.