1. Transient Unilateral Attenuation of Background Activity During Sleep
Transient Unilateral Attenuation of Background Activity During Sleep. A 41-week CA newborn with recurrent apneic episodes associated with cyanosis. The neurologic examination was normal. Head CT was unremarkable. A routine EEG during slow sleep shows intermittent attenuation of background activity over the left hemisphere lasting for 1–2 min. Transient unilateral attenuation of background activity during quiet sleep is seen in 3–4% of newborns and consists of a sudden flattening of the EEG activity occurring in one hemisphere. The asymmetry is transient, lasting from 1 to 5 min (less than 1.5 min in 75% of cases). It occurs at the beginning of quiet sleep. The EEG activity before and after the asymmetry is almost always normal. This EEG pattern may reflect the unusual functioning of mechanisms underlying the normal process of change from the low-voltage continuous EEG in REM sleep to the higher voltage discontinuous pattern of quiet sleep. This EEG phenomenon is of uncertain significance and must be differentiated from asymmetric background activity associated with structural abnormalities. The latter is usually shorter in duration, occurs in all states, and is associated with other EEG abnormalities such as sharp waves or delta slowing.5,20–22
Source: Newborn, Atlas of Pediatric EEG
Citation: Laoprasert P. Atlas of Pediatric EEG; 2011 Available at: Accessed: October 11, 2017
Copyright © 2017 McGraw-Hill Education. All rights reserved