Focal positive spikes in electroencephalography.

Focal positive spikes and sharp waves in clinical EEG are uncommon (about 1.3 per 1,000 EEGs in this series) and encountered chiefly in early life. All of out seven patients suffered from a convulsive disorder. These discharges must be differentiated from 14 and 6 c/sec positive bursts. Atifactual electrical transients with apparent focal positivity must always be ruled out. Whenever focal positive spikes and sharp waves are identified, it is advisable to search for simultaneous focal negative discharges. The literature indicates that focal positive spikes and sharp waves could be classified according to the presumed pathophysiological mechanisms and illustrative patients were described.