Capability of a neck worn device to measure sleep/wake, airway position, and differentiate benign snoring from obstructive sleep apnea

Abstract

To evaluate the accuracy of a neck-worn device in measuring sleep/wake, detecting supine airway position, and using loud snoring to screen for obstructive sleep apnea. Study A included 20 subjects who wore the neck-device during polysomnography (PSG), with 31 records obtained from diagnostic and split-night studies. Study B included 24 community-based snorers studied in-home for up to three-nights with obstructive sleep apnea (OSA) severity measured with a validated Level III recorder. The accuracy of neck actigraphy-based sleep/wake was measured by assessing sleep efficiency (SE). Differences in sleep position measured at the chest and neck during PSG were compared to video-editing. Loud snoring acquired with an acoustic microphone was compared to the apnea-hypopnea index (AHI) by- and acrosspositions. Over-reported SE by neck actigraphy was inversely related to OSA severity. Measurement of neck and chest supine position were highly correlated with video-edits (r = 0.93, 0.78). Chest was bias toward over-estimating supine time while the majority of neck-device supine position errors occurred during CPAP titrations. Snoring was highly correlated with the overall, supine, and non-supine PSG-AHI (r = 0.79, 0.74, 0.83) and was both sensitive and specific in detecting overall, supine, and non-supine PSGAHI >10 (sensitivity = 81, 88, 82 %; specificity = 87, 79, 100 %). At home sleep testing-AHI > 10, the sensitivity and specificity of loud snoring was superior when users were predominantly non-supine as compared to baseline (sensitivity = 100, 92 %; specificity = 88, 77 %). Neck actigraphy appears capable of estimating sleep/wake. The accuracy of supine airway detection with the neck-device warrants further investigation. Measurement of loud snoring appears to provide a screening tool for differentiating positional apneic and benign snorers.

User Compliance and Behavioral Adaptation Associated With Supine Avoidance Therapy

“…The previously described device (Levendowski et al, 2014;Levendowski et al, 2015) was affixed to the back of the neck with an adjustable nonlatex silicone rubber strap secured by a magnetic clasp (Figure 1). The instructions provided with the device explained how to adjust the strap to the neck size, when and how to charge the device, the expected feedback patterns, and where instruction videos and user reports could be accessed.…”

“…This pattern was repeated across the seven intensity levels, and engaged both haptic motors starting at the fifth intensity level. The algorithm applied to the neck-based 3-D accelerometer measures the supine position superior to the chest and sleep-wake superior to wrist actigraphy (Levendowski et al, 2014;Levendowski et al, 2015). An acoustic microphone allowed measurement of the percentage of time with loud snoring based on the number of sleep epochs with at least one snore > 50 dB divided by the total number of sleep epochs.…”

“…The sleep efficiency measured by neck actigraphy was previously shown to be negatively correlated with sleep apnea severity; only 25% of those with an apnea-hypopnea index (AHI) < 10 and 16% of those with an AHI < 15 had a sleep efficiency ≥ 80% (Levendowski et al, 2015). Evaluating sleep efficiency across the most recent 12 weeks of use, the median value for the group was 83.4% (IQR = 8.8%).…”

“…Of clinical interest was whether loud snoring (i.e., snoring > 50 dB in at least 10% of sleep time), a threshold previously associated with at least mild OSA (Levendowski et al, 2015), varied or changed substantially over time as a result of supine avoidance therapy. Evaluating the most recent 12 weeks of use across subjects, the percentage of nights with loud snoring from the most recent two weeks of therapy were compared to the two-week period that began 10 weeks earlier.…”

“…The employment of padding or foam worn around the waist that restricts the user's ability to sleep supine resulted in compliance rates at least as good as CPAP (Eijsvogel et al, 2015). More recently, vibrotactile positional therapy has been introduced to restrict supine sleep by delivering feedback, a vibratory or haptic stimulus similar to a cell phone vibration, to the neck (Levendowski et al, 2014;Levendowski, Veljkovic, Seagraves, & Westbrook, 2015;van Maanen et al, 2012) or chest (Bignold, Mercer, Antic, McEvoy, & Catcheside, 2011;van Maanen et al, 2013;van Maanen and de Vries, 2014). Vibrotactile positional therapy was found to be effective in improving sleep quality (Levendowski et al, 2014) and reducing the number of arousals per hour (Levendowski et al, 2014;van Maanen et al, 2012).…”