fasciculation
Pronunciation: /fəˌsɪkjʊˈleɪʃən/
Involuntary muscle twitching caused by spontaneous activation of motor units, often indicating lower motor neuron disease.
Full Definition
Fasciculation refers to visible, involuntary contractions of muscle fiber bundles (fascicles) that occur when motor units fire spontaneously. These twitches are typically benign when occasional but can be pathological when persistent and widespread. Fasciculations are commonly observed in motor neuron diseases such as amyotrophic lateral sclerosis (ALS), where they result from dying motor neurons becoming hyperexcitable. The phenomenon can also occur in healthy individuals due to fatigue, caffeine intake, or stress, making clinical interpretation context-dependent.
Usage
Usage note: Distinguish from fibrillation (invisible contractions) and myoclonus (sudden jerky movements).
In Context
- "The neurologist noted widespread fasciculations in the patient's arms and legs during examination." — Clinical examination notes
- "Fasciculation potentials were recorded during electromyography, supporting the diagnosis of motor neuron disease." — EMG report