Abstracts

RATIONALE: In adults, neuropsychological functioning was correlated with spike-wave discharges (SW), but in a recent study with children this relationship was not observed (Koop et al., 2000). The lack of a correlation in children may be due to more subtle SW that were undetected. Sleep deprivation prior to an EEG increases sensitivity to SW (Liamsuwan et al., 2000). Thus, it was hypothesized that the degree of sleep attained during EEG recording would moderate the relationship between spike-wave discharges and neuropsychological performance. At the conclusion of this presentation, the participant will better understand the relationship between sleep, SW, and neuropsychological functioning.
METHODS: Memory and attention scores on standardized tests were obtained in 70 children with epilepsy (age M = 10.8, SD = 2.7; 34.3% recent onset, 65.7% chronic). Clinical reports of the most recent EEG recording were reviewed and coded for degree of sleep attained (none, drowsy, stage 2).
RESULTS: As a manipulation check, the relationship between sleep and SW was examined; although not significant in this small sample ([chi]2=2.96, p[gt].05), higher proportions of children showed SW with stage 2 sleep (73%) than did those who did not attain stage 2 sleep (53%). In a 2 x 3 (Presence of SW x Level of Sleep) ANOVA on memory, there was no main effect for sleep, F (2, 67) = 0.45, p [gt] .05, or for SW, F (1, 69) =0.55, p [gt] 0.05, nor was the interaction term significant, F (2, 69) = 0.89, p [gt] 0.05. In a 2 x 3 (Presence of SW x Level of Sleep) ANOVA on attention, there was no main effect for sleep, F (2, 67) = 0.48, p [gt] .05, or for SW, F (1, 69) =0.15, p [gt] 0.05, nor was the interaction term significant, F (2, 69) = 1.37, p [gt] 0.05. However, the pattern of means for the six groups generally followed the pattern hypothesized (worse memory and attention with presence of SW, but only when sleep was attained). This pattern was even more evident in the chronic subsample.
CONCLUSIONS: The degree of sleep attained during EEG did not moderate the relationship between SW and neuropsychological performance. However, the pattern of subgroup means supported the hypothesis, even though the differences did not reach the prescribed level of significance. Similarly, the relationship between SW detection and levels of sleep followed the predicted pattern, without reaching significance in this sample. Part of the reason for this may lie in the constitution of the sample. Though the sample size was reasonable, approximately one-third of this sample had recent onset of seizures; consequently, limited variability in SW and/or in neuropsychological functioning may have attenuated the effect sizes. Future studies should examine the potential moderating relationship in a larger sample of children with chronic epilepsy. [Supported by Epilepsy Foundation, NIH/NINDS #NS22416, and NIH/NINR #NR04836.]
[Supported by: Supported by Epilepsy Foundation, NIH/NINDS #NS22416, and NIH/NINR #NR04836.]