How do normal EMG findings compare with the findings seen in a denervated muscle (neurogenic disorder)?
Note that fibrillations and positive sharp waves are not seen in acutely denervated muscles until 7 to 14 days after the onset of axonal degeneration. Full reinnervation of denervated muscle, resulting in large, polyphasic MUAPs may take 3 to 4 months or more. In patients with reinnervation after nerve injury, muscles may be clinically strong and yet be very abnormal on needle EMG testing.
