Shape design of an optimal comfortable pillow based on the analytic hierarchy process method

The Influence of Mattress Stiffness on Spinal Curvature and Intervertebral Disc Stress-An Experimental and Computational Study

Sleeping support systems can influence spinal curvature, and the misalignment of the spinal curvature can lead to musculoskeletal problems. Previous sleep studies on craniocervical support focused on pillow variants, but the mattress supporting the pillow has rarely been considered. This study used a cervical pillow and three mattresses of different stiffnesses, namely soft, medium, and hard, with an indentation load deflection of 20, 42, and 120 lbs, respectively. A novel electronic curvature measurement device was adopted to measure the spinal curvature, whereby the intervertebral disc loading was computed using the finite element method. Compared with the medium mattress, the head distance increased by 30.5 ± 15.9 mm, the cervical lordosis distance increased by 26.7 ± 14.9 mm, and intervertebral disc peak loading increased by 49% in the soft mattress environment. Considering that the pillow support may increase when using a soft mattress, a softer or thinner pillow is recommended. The head distance and cervical lordosis distance in the hard mattress environment were close to the medium mattress, but the lumbar lordosis distance reduced by 10.6 ± 6.8 mm. However, no significant increase in intervertebral disc loading was observed, but contact pressure increased significantly, which could cause discomfort and health problems.

Memory Foam Pillow as an Intervention in Obstructive Sleep Apnea Syndrome: A Preliminary Randomized Study

Specific pillow use is a seldom studied or controlled factor in the setting of sleep disordered breathing. The aim of this study was to investigate the effect of different pillows [own pillow (OP), memory foam pillow (MFP), generic laboratory pillow (LP)] on polysomnography (PSG)-derived parameters in patients with Obstructive Sleep Apnea Syndrome (OSAS). Thirty-two consecutive patients with OSAS were randomly allocated into two groups with randomized pillow usage [Group A: 3 h with LP and 3 h with OP (Age: 53.8 ± 12.5 years, BMI: 32.1 ± 4.6 kg/m²); Group B: 3 h with LP and 3 h with MFP (Age: 52.0 ± 6.3 years, BMI: 30.6 ± 2.2 kg/m²)]. Statistically significant differences between pillow types were detected in desaturation index and heart rate. In Group B (with MFP), a statistically significant decrease of 47.0 ± 15.9% was observed in snoring events (p < 0.05) and 10.6 ± 6.7% in their duration (p < 0.05) compared to LP. On the other hand, group A with OP recorded a decrease of 29.1 ± 32.1% in snoring events and 32.5 ± 33.1% in duration, but these values were not statistically significant (p > 0.05) compared to LP. These findings indicate that pillow type and usage, often uncontrolled in OSAS studies (contribution to the field), may impact several PSG parameters and are related to a snoring subtype of the syndrome. Secondly, they indicate that a focus on the treatment of the snoring OSAS subtype warrants further dedicated investigation.

Ergonomic Consideration in Pillow Height Determinants and Evaluation

(1) Background: Sleep problems have become one of the current serious public health issues. Pillow height affects the alignment of the cervical spine and is closely related to the mechanical environment of the cervical spine. An appropriate pillow height can provide adequate support for the head and neck to reduce the stress in the cervical spine and relax the muscles of the neck and shoulder, thereby relieving pain and improving sleep quality. (2) Methods: We reviewed the current trends, research methodologies, and determinants of pillow height evaluation, summarizing the evidences published since 1997. In particular, we scrutinized articles dealing with the physiological and mechanical characteristics of the head-neck-shoulder complex. (3) Results: Through the investigation and analysis of these articles, we presented several quantitative and objective determinants for pillow height evaluation, including cervical spine alignment, body dimension, contact pressure, and muscle activity. The measurement methods and selection criteria for these parameters are described in detail. However, the suggested range for achieving optimal cervical spine alignment, appropriate pressure distribution, and minimal muscle activity during sleep cannot yet be identified considering the lack of sufficient evidence. Moreover, there remain no firm conclusions about the optimal pillow height for the supine and lateral positions. (4) Conclusions: A comprehensive evaluation combining the above determinants provides a unique solution for ergonomic pillow design and proper pillow height selection, which can effectively promote the public sleep health. Therefore, it is necessary to develop a reasonable algorithm to weigh multiple determinants.

Analysis of neck and back muscle activity during the application of various pillow designs in patients with forward head posture

BACKGROUND

There are currently no reports of biomechanical changes in patients with forward head posture (FHP) that result in altered muscle activation throughout various functions with muscle activation response during diverse sleep postures.

OBJECTIVE

This study investigated neck and back muscle activity in individuals with and without FHP during a maintained side-sleeping position by incorporating various pillow designs.

METHODS

Thirty-four participants (i.e., 17 in each group) were enrolled. The muscle activity was investigated via surface electromyography during the use of three trial pillows: orthopedic pillow, hollow pillow, and Thai neck support pillow.

RESULTS

With the application of all three trial pillow, the FHP group demonstrated significantly greater middle-lower trapezius muscle activity than the normal head posture group (p< 0.05). Sternocleidomastoid and upper trapezius (UT) muscle activity were similar between the two groups (p> 0.05). Only UT muscle activity was affected by variations in pillow design. In the normal group, no difference was observed in the muscle activity between all three pillows (p> 0.05).

CONCLUSIONS

Feasibly, the ability to appropriately modify a pillow configuration without creating undesired muscle activation was limited to those exhibiting FHP. Therefore, specially designed pillows or mattresses should be investigated in terms of their relevance to muscle fatigue and potential musculoskeletal pain in FHP patients.

The effects of pillow designs on neck pain, waking symptoms, neck disability, sleep quality and spinal alignment in adults: A systematic review and meta-analysis

BACKGROUND

Neck pain is a prevalent condition that can adversely affect quality of life, productivity at work, and sleep quality. The aim of this systematic review and meta-analysis was to identify clinical trials assessing the effect of different types of pillows on neck pain, waking symptoms, neck disability, sleep quality, and spinal alignment.

METHODS

We systematically searched CINAHL Complete, Cochrane Library, EMBASE, Medline, Pubmed and Psychinfo databases from inception to September 2020. Two reviewers independently assessed the articles and evaluated the methodological quality using PEDro.

FINDINGS

Thirty-five articles fulfilled the inclusion criteria of the study. There were nine high-quality studies involving 555 participants. The meta-analysis revealed significant differences favouring the use of rubber pillows to reduce neck pain [standardized mean difference (SMD): -0.263; P < 0.001). Moreover, waking pain (SMD: -0.228; P < 0.001) and neck disability (SMD: -0.506; P = 0.020) were reduced while the satisfaction rate was enhanced (SMD: 1.144; P < 0.001) with pillow use. Pillow designs did not influence sleep quality (SMD = 0.047; P = 0.703) in patients with chronic neck pain.

INTERPRETATION

The use of spring and rubber pillows are effective in reducing neck pain, waking symptoms, and disability and enhancing pillow satisfaction in patients with chronic neck pain. Moreover, there may be no change in the alignment of the cervical spine in the side-lying position, regardless of the use of rubber or feather pillows. Rather, the cervical alignment may be significantly impacted by the shape and height of the pillow.

Risk factors of occupation related back pain and neck pain among patients attending tertiary care hospital, Ahmedabad, India

Introduction

Neck/back pain is one of the common health problems associated with significant impact on health resulting in sickness absenteeism. Neck/back pain is one of important causes of disability adjusted life years worldwide. The objectives of study were: To identify various occupations related risk factors and their possible role in occurrence of back pain/neck pain and visual analogue scale(VAS) assessment of their perceived pain.

Methods

The study was conducted at one of the tertiary care hospital at Ahmedabad city, India. All patients above age of 18 years attending physiotherapy department for treatment of back pain/neck pain and gave consent were taken as study participants. Information about certain body postures in their lifestyle or at workplace which can have effects on back pain/neck pain were asked. VAS for perceived pain was anchored by “no pain” (score 0) and “pain as bad as it could be” (score 100). Data were entered in MS Excel and analyzed by frequency, contingency coefficient and Goodman and Kruskal’s Gamma test.

Results and Conclusion

Total of 512 participants were included in study, among which(10.3%)and 392 (76.6%) participants had neck pain and back pain alone, respectively, while 67 (13.1%) participants had both neck and back pain. Age, marital status, socioeconomic class, body mass index and type of occupation revealed statistically significant association with severity of pain. Among participants with prolonged computer usage, back rest fitting to natural back curve and adjustable height of chair were significant factors for occurrence of neck pain. Various body postures like prolonged sitting/ standing, frequent bending at waist/knee, pulling/pushing heavy objects, frequent weight lifting > 10 kg and repetitive movements of back/neck revealed as statistically significant risk factors for back/neck pain.

A Survey of Koreans on Sleep Habits and Sleeping Symptoms Relating to Pillow Comfort and Support

The number of people who complain of sleep disturbances is steadily increasing. An understanding of sleep-related factors is required to address sleep problems. This survey study investigated the sleep habits and sleeping symptoms relating to the comfort and support characteristics of pillows and the relationship between sleep quality and pillow design factors. The study utilized data from 332 participating Korean adults aged 20–76 years (mean age ± SD: males, 40.4 ± 15.2; females, 42.9 ± 15.4). We developed a questionnaire that evaluated sleep habits (sleep duration, bedtime, wake-up time and sleeping position); sleeping symptoms (snoring or coughing, breathing and sleepiness during waking hours) based on the Korean version of the Pittsburgh Sleep Quality Index (PSQI-K) questionnaire; and pillow-related factors (support, comfort, fatigue, height and shape) from existing pillow studies. The average sleep duration was 6.8 h, with more than half (52%) of participants sleeping in the supine position. The overall score for sleep quality was considered poor (4.84 points on a seven-point Likert scale), with some degree of sleepiness during waking hours (4.4 points on a seven-point Likert scale). Females went to bed earlier than males and were more likely to sleep in the lateral position compared to males. The number of toss and turn or waking events during sleep increased with age, and older individuals went to sleep earlier and woke up earlier. Among the symptoms of fatigue, pain, discomfort with changing position, snoring, coughing and breathing discomfort, participants reported their highest levels of discomfort due to sleepiness after waking, and they experienced the least head pain. Participants who used a regular-type pillow had poorer satisfaction on multiple comfort and support factors (support, comfort, height suitability, shape suitability) compared with those who used a functional-type pillow. Less head fatigue, less neck fatigue and less shoulder pain had significant effects on sleep quality. To reduce neck fatigue and shoulder pain, designers should consider the height for neck support in the lateral position. To reduce neck fatigue, it is desirable to use materials like latex or memory foam that provide neck support, which can improve sleep quality. The findings of this study contribute to a better understanding of sleep habits and characteristics of pillow comfort and provide practical guidelines for better pillow designs.

Effectiveness of a "Spring Pillow" Versus Education in Chronic Nonspecific Neck Pain: A Randomized Controlled Trial

BACKGROUND

Different types of pillows have been proposed for neck pain, but no previous randomized controlled trial has investigated the effectiveness of a "spring pillow" for adults with chronic nonspecific neck pain.

OBJECTIVE

We evaluated the effectiveness of using a pillow made from viscoelastic polyurethane and 60 independent springs compared with an educational intervention in individuals with chronic nonspecific neck pain.

DESIGN

This was a randomized controlled trial with crossover study design.

SETTING

The setting was the Occupational Medicine Unit, University Hospital, Bologna (Italy).

PARTICIPANTS

We recruited 70 adults with chronic nonspecific neck pain, of whom 64 completed the trial.

INTERVENTION

Participants were randomly assigned to 2 groups. One group used the spring pillow for 4 weeks, and the other group followed educational advice for 4 weeks while continuing to use their own pillows. After 4 weeks of treatment and 4 weeks of washout, groups were crossed over. Pain perceived in the neck, thoracic, and shoulder areas and headache were the primary outcome measures. In addition, disability, sleep quality, subjective improvement, and pillow comfort were assessed. Measures were captured at pretreatment, after 4 weeks, after the 4-week washout period, and 4 weeks after crossover. The mean differences (MD) in outcomes between groups were assessed.

RESULTS

Treatment with the spring pillow appeared to reduce neck pain (MD = -8.7; 95% confidence interval [CI] = -14.7 to -2.6), thoracic pain (MD = -8.4; 95% CI = -15.2 to -1.5), and headache (MD = -16.0; 95% CI = -23.2 to -8.7). Reductions in shoulder pain were not statistically significant between groups (MD = -6.9; 95% CI = -14.1-0.3). Neither the crossover sequence nor the period (first vs second intervention administration) significantly affected the results.

LIMITATIONS

Education may not have been the best comparator for the spring pillow; drug consumption, actual pillow use, and the implementation of the educational suggestions as prescribed were not controlled.

CONCLUSIONS

Use of the spring pillow in this study was more effective than an educational intervention for improving cervical, thoracic, and head pain. Whether a spring pillow is more effective than other ergonomic pillows remains to be tested.

Sleeping mattress determinants and evaluation: a biomechanical review and critique

Background

Sleeping mattress parameters significantly influence sleeping comfort and health, as reflected by the extensive investigations of sleeping support biomechanics to prevent sleep-related musculoskeletal problems.

Methodology

Herein, we review the current trends, research methodologies, and determinants of mattress biomechanics research, summarizing evidence published since 2008. In particular, we scrutinize 18 articles dealing with the development of new designs, recommendation criteria, instruments/methods of spine alignment evaluation, and comparative evaluation of different designs.

Results

The review demonstrated that mattress designs have strived for customization, regional features, and real-time active control to adapt to the biomechanical features of different body builds and postures. However, the suggested threshold or target values for desirable spine alignment and body pressure distribution during sleep cannot yet be justified in view of the lack of sufficient evidence.

Conclusions

It is necessary to formulate standard objectives and protocols for carrying out mattress evaluation.

Sleep Environment and Insomnia in Elderly Persons Living at Home

The aim of this study was to draw a portrait of the sleep environment of elderly persons living in private households and to determine its relationship with the presence of insomnia. A sample of 599 individuals aged 70 years and older responded to questions about the comfort of their pillow and mattress and the noise level and brightness of their bedroom at night and in the morning. They were also asked whether or not they shared their bed or bedroom with a sleep partner. The Insomnia Severity Index was used to assess insomnia severity. Over 40% of the study participants were using a pillow that was not very comfortable, and almost 30% said that their bedroom was not completely quiet. Binomial logistic regression results revealed that two variables were significantly associated with insomnia symptoms: a pillow rated as moderately comfortable to very uncomfortable and a bedroom that was not completely quiet. No other sleep environment characteristics considered in this study were associated with the risk of insomnia. These results indicate that a nonnegligible proportion of the elderly population endures a suboptimal sleep environment. Although it is difficult to predict the real impact of changes to the sleep environment, this study supports the proposal that simple, minor changes to the bedroom can promote sleep in the elderly.

A preliminary study: The effect of ergonomic latex pillow on pain and disability in patients with cervical spondylosis

Background: Cervical pillows are considered to be part of the therapeutic strategy in cervical spondylosis, but there is little or no convincing scientific evidence on the effectiveness of these pillows in relieving pain and disability in these patients. Hence, this study investigated the effects of ergonomic latex pillow in conjunction with routine physiotherapy versus routine physiotherapy alone on disability and pain intensity in patients with cervical spondylosis.

Methods: 22 patients with cervical spondylosis in a single-blinded pilot study with a pre/post-test design were randomly assigned to experimental and control groups. Both groups received 12 sessions of physiotherapy for four weeks. In the experimental group, participants were given an ergonomic latex pillow to sleep it for four weeks. Participants in the control group slept on their own usual pillow. All the participants filled out the Neck Disability Index questionnaire, and scored their neck pain intensity on the Numerical Pain Rating Scale before and after the intervention. Changes of variables (pain and disability) within and between groups were compared by Paired T-test and the Independent Sample T-test, respectively via SPSS v.20 (p<0.05).

Results: Numerical Pain Rating Scale and Neck Disability Index scores were decreased statistically significant within groups. In the experimental group, neck disability scores were significantly lower than those in the control group (p=0.038). However, pain intensity scores were not significantly different between groups.

Conclusion: Ergonomic latex pillows can significantly decrease disability related to neck pain in patients with cervical spondylosis after four weeks.

Effect of sleep posture on neck muscle activity

[Purpose] This study investigated the effect of sleep posture on neck muscle activity. [Subjects and Methods] The study recruited 20 healthy subjects, who were positioned in three supine sleeping positions: both hands at sides, both hands on the chest, and dominant hand on the forehead. The activities of the scalene and upper trapezius muscles bilaterally were measured by surface electromyography. [Results] The upper trapezius and scalene muscle activity on the right side was significantly greater in the supine with dominant hand on the forehead position than in the other positions. [Conclusion] Sleep posture is important and prevent neck and shoulder musculoskeletal pain.

Effect of pillow height on the biomechanics of the head-neck complex: investigation of the cranio-cervical pressure and cervical spine alignment

BACKGROUND

While appropriate pillow height is crucial to maintaining the quality of sleep and overall health, there are no universal, evidence-based guidelines for pillow design or selection. We aimed to evaluate the effect of pillow height on cranio-cervical pressure and cervical spine alignment.

METHODS

Ten healthy subjects (five males) aged 26 ± 3.6 years were recruited. The average height, weight, and neck length were 167 ± 9.3 cm, 59.6 ± 11.9 kg, and 12.9 ± 1.2 cm respectively. The subjects lay on pillows of four different heights (H0, 110 mm; H1, 130 mm; H2, 150 mm; and H3, 170 mm). The cranio-cervical pressure distribution over the pillow was recorded; the peak and average pressures for each pillow height were compared by one-way ANOVA with repeated measures. Cervical spine alignment was studied using a finite element model constructed based on data from the Visible Human Project. The coordinate of the center of each cervical vertebra were predicted for each pillow height. Three spine alignment parameters (cervical angle, lordosis distance and kyphosis distance) were identified.

RESULTS

The average cranial pressure at pillow height H3 was approximately 30% higher than that at H0, and significantly different from those at H1 and H2 (p < 0.05). The average cervical pressure at pillow height H0 was 65% lower than that at H3, and significantly different from those at H1 and H2 (p < 0.05). The peak cervical pressures at pillow heights H2 and H3 were significantly different from that at H0 (p < 0.05). With respect to cervical spine alignment, raising pillow height from H0 to H3 caused an increase of 66.4% and 25.1% in cervical angle and lordosis distance, respectively, and a reduction of 43.4% in kyphosis distance.

DISCUSSION

Pillow height elevation significantly increased the average and peak pressures of the cranial and cervical regions, and increased the extension and lordosis of the cervical spine. The cranio-cervical pressures and cervical spine alignment were height-specific, and they were believed to reflect quality of sleep. Our results provide a quantitative and objective evaluation of the effect of pillow height on the biomechanics of the head-neck complex, and have application in pillow design and selection.

Development and comparative evaluation of new shapes of pillows

The purpose of this study was to determine pillow designs suitable for supine and side-lying positions. [Subjects] Twenty female and twenty male subjects with a mean age of 22.7 years (SD = 1.3) participated in the study. [Methods] First, a three-dimensional motion analysis system was used to analyze the movements of the head and the shoulder joints during changes from supine positions to side-lying positions. Second, the height from the face to the shoulder and the height from the floor to the middle of the neck in a side-lying position were measured. Third, the weight distribution ratios of the head and the trunk were compared using general pillows (polyester sponge), memory foam, and prototype pillows. [Results] During position changes from supine positions to side-lying positions, the head moved in a fan shape, and the shoulder joint moved an average of 4.4 cm upward. The height from the face to the shoulder was 9 cm on average. The height from the floor to the middle of the neck was 11 cm on average. The weight distribution ratios between the head and the trunk were compared among general pillows (polyester sponge), memory foam, and prototype pillows. The results showed significant differences in the side-lying position. [Conclusion] Pillows with uniform heights are not suitable for a supine or side-lying position. In the case of both positions, users should be allowed to select pillows in shapes that can support the neck.