Automatic sleep staging based on 24/7 EEG SubQ (UNEEG medical) data displays strong agreement with polysomnography in healthy adults

GOAL AND AIMS: Performance evaluation of automatic sleep staging on two-channel subcutaneous electroencephalography.

FOCUS TECHNOLOGY: UNEEG medical's 24/7 electroencephalography SubQ (the SubQ device) with deep learning model U-SleepSQ.

REFERENCE METHOD/TECHNOLOGY: Manually scored hypnograms from polysomnographic recordings.

SAMPLE: Twenty-two healthy adults with 1-6 recordings per participant. The clinical study was registered at ClinicalTrials.gov with the identifier NCT04513743.

DESIGN: Fine-tuning of U-Sleep in 11-fold cross-participant validation on 22 healthy adults. The resultant model was called U-SleepSQ.

CORE ANALYTICS: Bland-Altman analysis of sleep parameters. Advanced multiclass model performance metrics: stage-specific accuracy, specificity, sensitivity, kappa (κ), and F1 score. Additionally, Cohen's κ coefficient and macro F1 score. Longitudinal and participant-level performance evaluation.

ADDITIONAL ANALYTICS AND EXPLORATORY ANALYSES: Exploration of model confidence quantification. Performance vs. age, sex, body mass index, SubQ implantation hemisphere, normalized entropy, transition index, and scores from the following three questionnaires: Morningness-Eveningness Questionnaire, World Health Organization's 5-item Well-being Index, and Major Depression Inventory.

CORE OUTCOMES: There was a strong agreement between the focus and reference method/technology.

IMPORTANT SUPPLEMENTAL OUTCOMES: The confidence score was a promising metric for estimating the reliability of each hypnogram classified by the system.

CORE CONCLUSION: The U-SleepSQ model classified hypnograms for healthy participants soon after implantation and longitudinally with a strong agreement with the gold standard of manually scored polysomnographics, exhibiting negligible temporal variation.