Special electromyographic features in a child with paramyotonia congenita: A case report and review of literature

Figure 2 Right rectus femoris (horizontal bar 20 ms/D, vertical bar 2 mV/D; horizontal bar 100 ms/D, vertical bar 1 mV/D). A: Right rectus femoris (horizontal bar 20 ms/D, vertical bar 2 mV/D). a: Train of giant-amplitude of myotonic discharge displaying waxing-waning patterns in frequency (100-150 Hz) and amplitude (3-15 mV); b: Train of positive waves within myotonic discharge, with frequency (100-150 Hz) and amplitude (0.5-3 mV); c: Train of irregular waves within myotonic discharge, characterized by irregular frequency and waveform, with amplitude (0.2-2 mV), and challenging frequency estimation; B: Right rectus femoris (horizontal bar 100 ms/D, vertical bar 1 mV/D). Sequence of giant-amplitude myotonic discharge with sudden initiation and cessation.