Sleep Posture Affects Sleep Parameters Differently in Young and Senior Japanese as Assessed by Actigraphy

Akiko Nojiri,Yushi Ito,Chikako Okumura

doi:10.4236/health.2014.621332

Akiko Nojiri, Yushi Ito + Show 1 more

Open Access

https://doi.org/10.4236/health.2014.621332

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Journal: Health	Publication Date: Jan 1, 2014
Citations: 17	License type: CC BY 4.0

Affiliation: Kumamoto Health Science University, Kurume University

Abstract

In an attempt to study the relationship between sleep postures and sleep parameters assessed by actigraphy, we applied the newly developed Activity Monitoring and Evaluation System (A-MES) and actigraphy at the same time to younger and senior Japanese volunteer groups. It was found that sleep postures and diurnal activity determines, to some extent, sleep parameters including activity mean score (AMS), activity index (ACTX), waking episodes (WEP) and sleep fragmentation index (SFX). It was also found that sleep properties are different in younger and senior Japanese. For example, increase in the proportion of time in the supine position resulted in enhancement and deterioration of the sleep in the younger and senior groups, respectively. Furthermore, there were correlations between supine posture and AMS, ACTX, SFX, total minutes scored as awake (TMSA) and WEP obtained by actigraphy in the younger group, but only AMS and ACTX in senior group. In addition, we also assessed sleep parameters by use of questionnaires, and found that objective sleep quality was rather poor but subjective sleep quality was better in the senior group. In the younger group, in contrast, objective sleep quality was better but subjective sleep quality was poor. On the other hand, there was no correlation between sleep parameters assessed by actigraphy and self-report at all. The present study with A-MES and actigraphy provides the first evidence that sleep posture affects sleep quality and is a convenient, inexpensive and home-based method for studying sleep.

Highlights

Sleep evaluation in humans has been performed with polysomnography (PSG), a technique considered the “gold standard” for sleep studies
Postures and Posture Shifts in Sleep We applied A-MES and actigraphy at the same time, to enable us to study the postures in sleep (Figure 2(a))
Diurnal Activity and Sleep Parameters We found negative correlations between the activity mean score (AMS) or proportion of time walking during the day and Activity index (ACTX) in the senior group (Figure 5), indicating that daytime activities enhanced the sleep in the senior group

Summary

Introduction

Sleep evaluation in humans has been performed with polysomnography (PSG), a technique considered the “gold standard” for sleep studies. It is not feasible to assess sleep postures per se by use of actigraphy, and till little study has been carried out on the relation between sleep postures and sleep parameters assessed by actigraphy. By use of a newly developed Activity Monitoring and Evaluation System (hereafter referred as A-MES) [5] [6], we observed postures, posture shifts, duration of postural immobility and frequency of body movements during the time in bed of four Japanese age groups [7]. The subjects slept two or three consecutive nights at home wearing night clothes with two A-MES attached to trunk and left thigh This method allows natural and undisturbed sleep in the subject’s own bed and gives reliable data through one to two nights recording. To assess the subjective sleep quality, we used Pittsburg Sleep Quality index [9] and Oguri-Shirakawa-Azumi Sleep Inventory MA version [10] (hereafter referred as PSQI and OSA-SI-MA, respectively)

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Discussion

Conclusion