A Novel <scp>EEG</scp> Scoring System to Assess Sleep in Critically Ill Children: A Proof of Concept Study

Sleep disturbance may be a modifiable risk factor for neurocognitive decline in critically ill children. Polysomnography, the gold standard for sleep analysis, is time and cost-intensive and not commonly available in the paediatric intensive care unit (PICU). Electroencephalography (EEG) also provides measurements of sleep and is more commonly used. We devised a novel EEG-based scoring system to categorise electrographic sleep and assessed its feasibility. In this retrospective observational cohort study across two PICUs, EEGs performed in patients aged 6 months to 18 years were analysed for sleep using a four-category system: category 1-invariable background, no state cycling or reactivity; category 2-reactivity and variability present, no discernable sleep architecture; category 3-discernable sleep architecture, abnormal pattern of sleep cycle; and category 4-normal sleep architecture and pattern. We evaluated 51 subjects. Seven patients (14%) were classified as category 1, 11 patients (22%) as category 2, 24 patients (47%) as category 3, and 9 patients (18%) as category 4. For those patients in whom sleep was detected (categories 3 and 4), N2 sleep was detected in 33 (100%) of patients, N3 sleep was detected in 24 (73%), and REM sleep was identified in 13 (39%). In this small cohort study across two centres, paediatric neurologists were able to qualify sleep in critically ill children using a novel EEG-based scoring system. If clinically validated, this scoring system could facilitate exploration of modifiable risk factors leading to sleep disruption in the PICU.