Significance of positive temporal sharp waves in the neonatal electroencephalogram

We reviewed our computerized neonatal EEG database for records judged to display excessive positive temporal sharp waves (PTS) to determine their electroclinical associations and significance. Typical infants with excessive PTS were: (1) mature, with a mean conceptional age of 41.2 weeks, and (2) neurologically ill, judged by their high rate of associated EEG background abnormality (37 of 46; 80%) and clinical signs of encephalopathy (19 of 29; 66%). In comparison, healthy age-matched control infants never had excessive PTS. We consider an excess of PTS to be pathologic since they arise out of an abnormal EEG background in children exposed to potentially serious central nervous system illnesses and are associated with a high incidence of cerebral structural abnormalities (16 of 25; 64%). PTS may be comparable to the positive rolandic or vertex sharp waves in premature infants with periventricular injury of the deep white matter.