Electroencephalographic correlates of near-drowning encephalopathy in children.

Findings of the serial EEGs of 9 children involved in fresh water near-drowning were correlated with neurological signs and final outcome. Our observations revealed that in young near-drowning victims there is a distinct evolution of the EEG which differs considerably from any stereotyped classification outlined for other types of encephalopathies. In patients with a poor clinical outcome, the early phase of near-drowning encephalopathy was characterized electrically by diffuse delta waves, often with alpha or beta frequencies superimposed (alpha-delta and beta-delta pattern). Additional features included poor sleep-waking differentiation and abnormal reactivity. Repetitive focal or multifocal biphasic or triphasic wave forms occurred exclusively in the group with a fatal outcome. The intermediate phase of the encephalopathy was signaled by an attenuation of all fast frequencies (alpha and beta rhythms), enhancement of delta activity, and disappearance of sleep parameters (if present in the earlier recordings). Finally, a modified burst suppression pattern occurred as a late EEG evolution in an encephalopathy of complex and protracted nature.