Insert needle in belly of muscle
Measure: insertion, at rest, and removal
Fibrillations: abnormal involuntary muscle fiber contraction not observable by naked eye, seen with reinervation of muscles
+proximal disease (anterior horn/radiculopathy)
Seen by naked eye
Positive Sharp Waves: downward wave after needle insertion (normal needle irritation felt by muscle)
Insertional activity: discharge of single muscle at needle insertion. Abnormal if no activity.
Polyphasic units (>4 phases): abnormal, neurogenic or myogenic disorders.
MUAP (motor unit action potential)
SM - EMG (single fiber EMG)
Record 1 muscle fiber action potential
Fiber density - # of fibers in a motor unit
Jitter - variability of successive discharges of muscle fibers in a motor unit