P109 Paediatric Limited Channel Sleep Monitoring Alternate Sleep Scoring Compared with Type 1 PSG

INTRODUCTION: Obstructive sleep apnoea (OSA) has deleterious effects on children’s cognition, behaviour and cardiovascular system. Early diagnosis and treatment may improve long-term outcomes. Attended polysomnography (PSG) is the gold standard for OSA diagnosis, however access is limited with prolonged wait times. Home based limited channel sleep monitoring (LCSM) offers a more accessible alternative but may result in inaccurate sleep staging. We aimed to evaluate sleep scoring using a single channel combined EEG/EOG compared with full PSG. METHODS: Sample size calculations indicated 1000 epochs would be sufficient to demonstrate a kappa statistic of at least 0.7 for sleep stage comparison. Four patients undergoing in-laboratory PSG for suspected OSA gave consent for placement of an additional combined EEG/EOG simulating our LCSM montage. A single senior scientist scored sleep using full PSG montage, and after a minimum of 2 weeks, using the abbreviated montage. RESULTS: Epoch-by-epoch comparisons were made for 3,930 epochs. When comparing awake, N1, N2, N3 and REM, kappa=0.77 (p<0.001). Using the abbreviated montage, N1 was mostly misclassified as awake (28% of epochs) or REM (32% of epochs). When comparing awake, NREM and REM, kappa = 0.79 (p<0.001). When comparing awake and sleep, kappa = 0.82 (p<0.001). DISCUSSION: Accurate total sleep time is important for accurate respiratory index calculation. The abbreviated montage was reliable compared with PSG for scoring sleep versus awake (kappa >0.8). The addition of an EMG signal may correct misclassification of N1 as wake or REM and improve intra-rater agreement. EMG will be included in future studies.