Figures & data
Figure 1. Excerpts of EEG reports, which erroneously imply that phase reversals are abnormal and indicative of epilepsy.
Figure 2. Montages are bipolar longitudinal for a, b, c, d, and transverse for e.
(a). Electrode pop artifact due to sudden change in electrode impedance; confined to a single electrode (F8). (b). Lateral eye movement to the right. Note the lateral rectus spike (bottom arrow) followed by a slower potential. The positive cornea moving to right results in positivity toward right temple and negativity on left (top arrow). (c). Small sharp spikes; a normal variant seen during light sleep in the temporal region. Note the low amplitude and short duration. (d). Wicket spikes: single or brief trains of sharply contoured waves, recorded from the temporal region during drowsiness and light sleep. Note the monomorphic morphology, absence of a following slow wave, and normal EEG activity before and after. (e). Vertex waves: sharp, central, in N1 and N2 sleep. Note the transverse montage.
