P047 Does applying an aggressive low-pass filter change timing of sleep onset and sleep stage scoring in adult patients undergoing MSLT?

Abstract Background Accurate sleep staging and sleep-onset timing is critical in determining an accurate mean sleep latency in a MSLT in order to accurately diagnose patients with disorders of hypersomnolence, such as narcolepsy. Determining when a patient changes from a wake to sleep (N1) stage can prove challenging, such as when there are high-frequency noises from muscle or eye-movement artefact despite application of AASM-recommended low-pass filters of 35Hz in EEG leads. To overcome this, many sleep scientists & Physicians anecdotally apply an aggressive low-pass filter of 20Hz to more accurately determine sleep onset. To date, there is no published data evaluating the impacts of applying an aggressive low-pass filter in accurately determining sleep staging and mean sleep latency in adult MSLT patients. Methods Study investigators will review de-identified paired retrospective data sets of patients who have undergone MSLT in the past 24 months with a standard and aggressive low-filter applied separately and score when sleep-onset occurs. Comparison of de-identified paired patient data sets will be used to evaluate whether there was any statistical difference in determining timing of sleep onset with using either a standard or aggressive low-pass filter. Progress to Date Ethics approval has been granted and data collection is currently underway. Intended Outcome To determine whether application of an aggressive low-pass filter changes scoring of sleep-onset and advice whether specific recommendations can be made in its usage in standard clinical practice.