# Daytime sleepiness estimated using the Karolinska Sleepiness Scale during mandibular advancement device therapy for snoring and sleep apnea: a secondary analysis of a randomized controlled trial

## TL;DR

This study shows that using a mandibular advancement device for snoring and sleep apnea reduces daytime sleepiness, especially in the morning and before lunch.

## Contribution

The study provides new evidence on the specific time-based effects of mandibular advancement devices on daytime sleepiness using the Karolinska Sleepiness Scale.

## Key findings

- Mandibular advancement devices reduced sleepiness scores at wake-up and before lunch.
- Positive effects were observed before dinner at the highest quartile of sleepiness.
- The benefits were most consistent during weekdays and the middle quartile of sleepiness.

## Abstract

The effect of mandibular advancement device therapy on daytime sleepiness remains unclear. Here, we evaluate the effect of a mandibular advancement device on daytime sleepiness using the Karolinska Sleepiness Scale.

We randomized 88 snoring patients with an apnea-hypopnea index < 30 and daytime sleepiness to a mandibular advancement device or a sham device for four months. The Karolinska Sleepiness Scale, which measures grades of sleepiness from 1 (very alert) to 9 (very sleepy), was used for seven consecutive days, four times each day. The results were analyzed with quantile regression at quartiles controlling for baseline, age, body mass index (kg/m2), sex, apnea-hypopnea index, and full-time work.

The Karolinska Sleepiness Scale score was lower with the mandibular advancement device than with the sham device at specific time intervals. The positive effect of mandibular advancement device therapy occurred at wake up and before lunch during the whole week and before lunch on weekdays at the middle quartile. The adjusted differences between the interventions favored mandibular advancement device therapy by almost one unit and normalized the Karolinska Sleepiness Scale scores at wake up and before lunch. In addition, there were positive effects of mandibular advancement device therapy before dinner at the highest quartile during the whole week, on weekdays, and on the weekend.

Mandibular advancement devices used for snoring and sleep apnea reduce daytime sleepiness, particularly at wake up and before lunch, but provide some benefit before dinner.

The online version contains supplementary material available at 10.1007/s11325-025-03264-9.