Sleep scientists Magdy Younes, MD, PhD, and associates have revealed new insights into clinical symptoms of sleep disorders found in sleep architecture but not detected through conventional metrics. They’ve accomplished this using an EEG metric named “Odds Ratio Product (ORP),” licensed exclusively to Cerebra Health, as a measure of sleep quality.

The paper, published in Sleep, identifies 9 base ORP Sleep Architecture profiles, which provide a framework to assist in diagnosing, managing, and understanding the underlying mechanisms of sleep disorders. ORP Sleep Architecture provides physicians with a visual point of reference, while diagnosing patients and prescribing treatment based on the nine profile types with suggested interpretation and clinical implications.

“The evaluation of sleep quality and depth has been based on guidelines and technology developed in the 1960s. This paper represents a new approach to look at sleep, employing new digital technology that presents sleep architecture as a way to identify potential underlying mechanisms of sleep disorders with the potential to advance their management,” says Younes, scientific founder of Cerebra Health, in a release, 

The additional information provided by ORP is sensitive enough to show variations in sleep quality that traditional sleep stages are unable to detect. (This aspect of ORP is further supported by the paper, A novel EEG marker predicts perceived sleepiness and poor sleep quality, which observes how high ORP wake is predictive of perceived sleepiness and poor sleep quality in two large population cohorts and shows promise as a biomarker of hyperarousal and insomnia.)

New Insights Into Sleep Architecture

According to the paper: 

  1. Clearly abnormal ORP patterns are uncommon in individuals with mild/moderate obstructive sleep apnea (OSA), but those with severe OSA demonstrated more drowsy wakefulness and transitional sleep and less deep sleep;
  2. Contrary to individuals with insomnia-short sleep duration, those with insomnia-normal sleep duration have significantly reduced amounts of full wakefulness; 
  3. There are two types of architecture in participants with insomnia-short sleep duration, one associated with poor sleep quality and quality of life, and the other with no such associations; 
  4. Architecture types that are associated with OSA, insomnia-short sleep duration, and reduced quality of life exist in subjects with neither OSA nor insomnia. 

Odds Ratio Product is a patented EEG metric invented by Magdy Younes. ORP micro analyzes the EEG signal, moving beyond conventional scoring methods to dig deeper into brain activity during sleep. ORP is a continuous metric of sleep depth ranging from 0 (very deep sleep) to 2.5 (full wakefulness). It has been validated as an accurate measure of sleep depth and strongly correlates to both clinical and self-reported symptoms of sleep disorders.

When presented as an architecture, ORP is broken down into 10 deciles ranging from 0-2.5. The deciles reflect the amount of time spent in different sleep depths across the night, creating a pattern of the patient’s sleep profile. The shape of the sleep profile describes a patient’s sleep quality; represented by the deep sleep deciles on the left, balanced by the wake deciles on the right.  

ORP is available through the Cerebra Sleep System, a home sleep test that is available for clinical use in Canada and pending US Food and Drug Administration clearance.

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