fibrillation potential
Abnormal EMG activity representing spontaneous discharge of individual denervated muscle fibers, indicating nerve or muscle pathology.
Full Definition
Fibrillation potentials are abnormal spontaneous electrical discharges of individual muscle fibers recorded during needle EMG examination. These potentials appear as biphasic spikes of 1-5 milliseconds duration with amplitudes of 20-300 microvolts. Fibrillation potentials indicate denervation and can be found in various conditions including peripheral neuropathies, radiculopathies, motor neuron diseases, and muscle disorders. They typically develop 1-3 weeks after nerve injury and may persist indefinitely without reinnervation. Clinical editors should note that fibrillation potentials are always pathological findings that must be distinguished from other spontaneous activity such as fasciculations or positive sharp waves.
Usage
Usage note: Always indicate distribution and abundance of fibrillation potentials for prognostic information.
In Context
- "Abundant fibrillation potentials were present in all muscles tested, indicating active denervation." — EMG report
- "The presence of fibrillation potentials confirmed ongoing nerve damage." — Electrodiagnostic assessment