| Abstract: | Thirty-eight horses suspected of having laryngeal hemiplegia had electromyograms (EMGs) performed on the dorsal cricoarytenoid muscle (DCAM). Electromyographic abnormalities consisted of fibrillation potentials, positive sharp waves, bizarre high frequency discharges, and reduced insertional activity. Normal motor activity consisted of motor unit activity during inspiration, or less frequently motor unit activity during inspiration with subsequent tonic motor activity. In affected muscles, motor unit activity was often absent but when present there was activity consisting of motor units which did not correspond to a particular phase of respiration or it was consistent with normal motor unit activity. |
