Comfort and its measurement--a literature review

The factors affecting the performance of the tunnel wall drilling task and their priority

Clarifying the relationship between the man-machine environment and its impact on the tunnel wall drilling task performance (TWDTP) is crucial for enhancing the task performance. Based on a questionnaire survey, indicators of the man-machine environment that affect the TWDTP were proposed in this study, and exploratory factor analysis and a structural equation model were employed to examine the potential factors influencing the task performance and their degrees of influence. By comparing the discrepancy between the perceived performance and importance, the satisfaction of potential factors was evaluated, and the priority order for optimizing these factors was determined by considering the degree of influence and dissatisfaction. The results of survey data analysis based on actual tunnel drilling operation scenarios indicated that tools had the greatest impact on the TWDTP, followed by the quality of the physical environment, while human factors had the least influence on the task performance. Convenient functional maintenance is the key to improving the TWDTP, along with enhancing the quality of the working environment. Once these main aspects are optimized, it is important to consider additional factors such as availability of spare tools, efficient personnel organization, man-tool matching, and safety and health assurance. This research approach provides significant guidance in understanding the relationships between the man-machine environmental factors affecting the performance of complex engineering tasks and identifying key influencing factors, thus providing essential insights for optimizing the TWDTP.

Autonomic responses to pressure sensitivity of head, face and neck: Heart rate and skin conductance

Subjective scales are frequently used in the design process of head-related products to assess pressure discomfort. Nevertheless, some users lack fundamental cognitive and motor abilities (e.g., paralyzed patients). Therefore, it is vital to find non-verbal measurements of pressure discomfort and pressure pain. This study gathered the autonomic response data (heart rate and skin conductance) of 30 landmarks in head, neck and face from 31 participants experiencing pressure discomfort and pressure pain. The results indicate that pressure stimulation can change heart rate (HR) and skin conductance (SC). SC can be more useful in assessing pressure discomfort than HR for specific landmarks, and SC also possesses a faster arousal rate than HR. Moreover, HR decreased in response to pressure stimulation, while SC decreased followed by an increase. In comparisons between genders, the subjective pressure discomfort threshold (PDT) and pressure pain threshold (PPT) of women were lower than those of men, but men's autonomic responses (HR and SC) were more intense. Furthermore, there was no linear correlation between subjective pressure thresholds (PDT and PPT) and autonomic response intensity. This study has significant implications for resolving ergonomic issues (pressure discomfort and pain) associated with head-related products.

Mapping wheelchair functions and their associated functional elements for stair climbing accessibility: a systematic review

PURPOSE

Wheelchair (WC) design elements are subjected to the accessibility and assistive needs of a person with locomotor disability. In order to pursue a holistic design for a stairclimbing WC, there is a need for literature review on WC functions reported for both stair climbing and plane surface movement.

METHODS

A total of 112 Research articles are reviewed for the purpose of extracting the relationship between WC design elements and the functions associated with them. Stairclimbing technologies are reviewed for their technological assessment in terms of functional elements associated with stairclimbing. Cross-functional mapping between functional elements and their dominant function is performed. Heat map for primary user needs and associated design elements is generated from cross mapping.

CONCLUSIONS

A design gap for user's functional needs is indicated from the review of literature on prototypes and products of WC. The literature in stairclimbing technology is primarily focussed on stair climbing capability and not on the other functional needs, such as safety, ride comfort, seat comfort, manoeuvrability, etc.Implications for rehabilitationFor attaining the goal of an effective rehabilitation, it is important to design and develop an assistive technology that can provide maximum accessibility and functioning for a person with disability. In case of locomotor disability, wheelchair (WC) is the most empowering tool that can assist people in both accessibility and activities of daily living. This review of literature was conducted to draw out the functions fulfilled by a WC, such as safety, comfort, propulsion for its users and the associated WC elements like seat, wheels, backrest, etc., that are required to fulfil those functions.WC being the most important technological intervention in the life of a person who cannot walk should be designed with the highest level of empathy. Therefore, each and every aspect of the user's physical and emotional needs should be catered up to the limits of engineering design. The research on stair climbing technologies has also grown exponentially, fuelled by technological growth in engineering mechanisms, ambient awareness sensors, actuators, etc. The review attempts to envelop such technologies and consolidate them on the basis of their capabilities and efficacies.The virtue of stair climbing has been realized through some novel and innovative mechanisms reviewed in this article that can be integrated with the research in field of functional elements required to carry out primary functions of a disabled person, such as safety, comfort, intuitiveness, etc. This review can help in coupling both of them in a more rational way where a designer who is designing the technology is more empathetic towards the design for accessibility. It can also help user in becoming more confident towards adapting a new assistive technology.

Effective nursing interventions in ADL care affecting independence and comfort - a systematic review

Despite its frequent provision, evidence of nursing interventions in Activities of Daily Living (ADL) remains unclear. Hence, we addressed the research question: What are the effects of ADL nursing interventions on independence and comfort in adults across all care settings? We conducted a systematic review of randomized controlled trials and quasi-experimental studies described in systematic reviews. In three databases, we searched for systematic reviews that we used as a portal to select (quasi) experimental studies. After narratively summarizing the studies on characteristics, effects, and interventions, we assessed the risk of bias. Among the 31 included studies, 14 studies evaluated independence, 14 studies measured comfort, and three studies assessed both outcomes. Seven interventions significantly improved independence and seven interventions significantly improved comfort. The studies varied highly in intervention components, outcome measures, and quality. Evidence on ADL nursing interventions affecting independence and comfort remains fragmented and inconclusive, limiting guidance for nursing professionals.

A Decision Tree Model for Analysis and Judgment of Lower Limb Movement Comfort Level

To address the problem of ambiguity and one-sidedness in the evaluation of comprehensive comfort perceptions during lower limb exercise, this paper deconstructs the comfort perception into two dimensions: psychological comfort and physiological comfort. Firstly, we designed a fixed-length weightless lower limb squat exercise test to collect original psychological comfort data and physiological comfort data. The principal component analysis and physiological comfort index algorithm were used to extract the comfort index from the original data. Secondly, comfort degrees for each sample were obtained by performing K-means++ to cluster normalized comfort index. Finally, we established a decision tree model for lower limb comfort level analysis and determination. The results showed that the classification accuracy of the model reached 95.8%, among which the classification accuracy of the four comfort levels reached 95.2%, 97.3%, 92.9%, and 97.8%, respectively. In order to verify the advantages of this paper, the classification results of this paper were compared with the classification results of four supervised classification algorithms: Gaussian Parsimonious Bayes, linear SVM, cosine KNN and traditional CLS decision tree.

The effect of axillary crutch length on upper limb kinematics during swing-through gait

BACKGROUND

Axillary crutches are commonly used in rehabilitation. Inappropriately fit crutches may result in upper limb pain or injury.

OBJECTIVE

To investigate the effects of axillary crutch length on upper limb kinematics to better understand potential injury mechanisms. It was hypothesized that crutches that were longer or shorter than standard-fit crutches would alter upper limb kinematics.

DESIGN

Cross-sectional.

SETTING

Gait laboratory.

PARTICIPANTS

Fifteen healthy males with no prior crutch experience.

INTERVENTIONS

Participants were fit with axillary crutches using standardized methods, as well as with crutches that were 5 cm longer and 5 cm shorter. Participants performed swing-through gait (1.20 ± 0.07 ms^-1 ) with all crutch lengths in randomized order. Kinematics were recorded using an optical motion-tracking system and joint angles for the scapula, shoulder, elbow, and wrist were computed.

MAIN OUTCOME MEASURES

The effects of crutch length on joint range of motion (ROM) and joint angles at initial crutch contact were analyzed using multivariate analysis (Hotelling's T² ; α = .025) and simultaneous confidence intervals (CI).

RESULTS

The long-standard crutch fit comparison showed effects across all joints (ROM p = .009; initial contact p < .001). Longer crutches resulted in greater scapular upward rotation (mean difference [95% CI] ROM: 1.0 [-0.2 to 2.2]; initial contact: -2.7 [-4.4, -1.1]) and shoulder abduction (ROM: 0.8 [-0.1 to 1.8]; initial contact: -1.9 [-4.1 to 0.3]). Crutch length also had effects across all joints for the short-standard fit comparison (ROM p = .004; initial contact p = .016). Shorter crutches resulted in greater scapula downward rotation (2.2 [-0.4 to 4.8]) and greater shoulder adduction (2.5 [-0.6 to 5.6]) at initial contact. Shorter crutches also reduced shoulder flexion/extension ROM (-2.5 [-4.4 to -0.6]).

CONCLUSIONS

Altered crutch length results in scapular and shoulder kinematic deviations that may present risk factors for upper limb injury with crutch-walking. This may underline the importance of appropriate device fitting to reduce injury risk in crutch users.

Footwear comfort: a systematic search and narrative synthesis of the literature

OBJECTIVE

To provide a narrative synthesis of the research literature pertaining to footwear comfort, including definitions, measurement scales, footwear design features, and physiological and psychological factors.

METHODS

A systematic search was conducted which yielded 101 manuscripts. The most relevant manuscripts were selected based on the predetermined subheadings of the review (definitions, measurement scales, footwear design features, and physiological and psychological factors). A narrative synthesis of the findings of the included studies was undertaken.

RESULTS

The available evidence is highly fragmented and incorporates a wide range of study designs, participants, and assessment approaches, making it challenging to draw strong conclusions or implications for clinical practice. However, it can be broadly concluded that (i) simple visual analog scales may provide a reliable overall assessment of comfort, (ii) well-fitted, lightweight shoes with soft midsoles and curved rocker-soles are generally perceived to be most comfortable, and (iii) the influence of sole flexibility, shoe microclimate and insoles is less clear and likely to be more specific to the population, setting and task being performed.

CONCLUSION

Footwear comfort is a complex and multifaceted concept that is influenced not only by structural and functional aspects of shoe design, but also task requirements and anatomical and physiological differences between individuals. Further research is required to delineate the contribution of specific shoe features more clearly, and to better understand the interaction between footwear features and individual physiological attributes.

Comfort Evaluation of Wearable Functional Textiles

Wearable E-textile systems should be comfortable so that highest efficiency of their functionality can be achieved. The development of electronic textiles (functional textiles) as a wearable technology for various applications has intensified the use of flexible wearable functional textiles instead of wearable electronics. However, the wearable functional textiles still bring comfort complications during wear. The purpose of this review paper is to sightsee and recap recent developments in the field of functional textile comfort evaluation systems. For textile-based materials which have close contact to the skin, clothing comfort is a fundamental necessity. In this paper, the effects of functional finishing on the comfort of the textile material were reviewed. A brief review of clothing comfort evaluations for textile fabrics based on subjective and objective techniques was conducted. The reasons behind the necessity for sensory evaluation for smart and functional clothing have been presented. The existing works of literature on comfort evaluation techniques applied to functional fabrics have been reviewed. Statistical and soft computing/artificial intelligence presentations from selected fabric comfort studies were also reviewed. Challenges of smart textiles and its future highlighted. Some experimental results were presented to support the review. From the aforementioned reviews, it is noted that the electronics clothing comfort evaluation of smart/functional fabrics needs more focus.

Custom-Fitted In- and Around-the-Ear Sensors for Unobtrusive and On-the-Go EEG Acquisitions: Development and Validation

OBJECTIVES

This paper aims to validate the performance and physical design of a wearable, unobtrusive ear-centered electroencephalography (EEG) device, dubbed "EARtrodes", using early and late auditory evoked responses. Results would also offer a proof-of-concept for the device to be used as a concealed brain-computer interface (BCI).

DESIGN

The device is composed of a custom-fitted earpiece and an ergonomic behind-the-ear piece with embedded electrodes made of a soft and flexible combination of silicone rubber and carbon fibers. The location of the conductive silicone electrodes inside the ear canal and the optimal geometry of the behind-the-ear piece were obtained through morphological and geometrical analysis of the human ear canal and the region around-the-ear. An entirely conductive generic earpiece was also developed to assess the potential of a universal, more affordable solution.

RESULTS

Early latency results illustrate the conductive silicone electrodes' capability to record quality EEG signals, comparable to those obtained with traditional gold-plated electrodes. Additionally, late latency results demonstrate EARtrodes' capacity to reliably detect decision-making processes from the ear.

CONCLUSIONS

EEG results validate the performance of EARtrodes as a circum-aural and intra-aural EEG recording system adapted for a wide range of applications in audiology, neuroscience, clinical research, and as an unobtrusive BCI.

A method for postural critical factors checking: The case of library chairs

BACKGROUND

According to ergonomic researches regarding a good sitting posture, it is essential to ensure a natural back-curve in order to prevent musculoskeletal disorders. A brief observation among the Scientific Technology Library inside the University of Salerno showed that students used to complain about neck and lumbar pain, especially after a study day.

OBJECTIVE

On the light of this background, a sitting posture comfort analysis had been performed on chairs inside the library to check the critical factors that influence the postural comfort and, consequently, the learning.

METHODS

A prolonged sitting posture, that is common during the daily study activity, had been simulated with fifteen volunteer students performing 1-hour tests (divided into four 15-minutes tasks). Subjective perceptions had been gathered through questionnaires rating on a 5-point Comfort scale, both the expected comfort at the beginning of the experiment and the Localized Postural Comfort at the end of each task have been investigated. Then, postural angles had been gathered through photographic acquisition and Kinovea®. CaMAN software had been used to calculate the objective (dis)comfort indexes. Finally, subjective and objective data had been statistically processed and compared.

RESULTS

Lumbar area scored the lowest perceived comfort while the perceived comfort was independent of participants and tasks, but dependent on time.

CONCLUSIONS

After this comfort-driven analysis, critical factors of the chair-design were checked, and a proposal for a future re-design was hypothesized.

Technology for monitoring everyday prosthesis use: a systematic review

BACKGROUND

Understanding how prostheses are used in everyday life is central to the design, provision and evaluation of prosthetic devices and associated services. This paper reviews the scientific literature on methodologies and technologies that have been used to assess the daily use of both upper- and lower-limb prostheses. It discusses the types of studies that have been undertaken, the technologies used to monitor physical activity, the benefits of monitoring daily living and the barriers to long-term monitoring, with particular focus on low-resource settings.

METHODS

A systematic literature search was conducted in PubMed, Web of Science, Scopus, CINAHL and EMBASE of studies that monitored the activity of prosthesis users during daily-living.

RESULTS

Sixty lower-limb studies and 9 upper-limb studies were identified for inclusion in the review. The first studies in the lower-limb field date from the 1990s and the number has increased steadily since the early 2000s. In contrast, the studies in the upper-limb field have only begun to emerge over the past few years. The early lower-limb studies focused on the development or validation of actimeters, algorithms and/or scores for activity classification. However, most of the recent lower-limb studies used activity monitoring to compare prosthetic components. The lower-limb studies mainly used step-counts as their only measure of activity, focusing on the amount of activity, not the type and quality of movements. In comparison, the small number of upper-limb studies were fairly evenly spread between development of algorithms, comparison of everyday activity to clinical scores, and comparison of different prosthesis user populations. Most upper-limb papers reported the degree of symmetry in activity levels between the arm with the prosthesis and the intact arm.

CONCLUSIONS

Activity monitoring technology used in conjunction with clinical scores and user feedback, offers significant insights into how prostheses are used and whether they meet the user's requirements. However, the cost, limited battery-life and lack of availability in many countries mean that using sensors to understand the daily use of prostheses and the types of activity being performed has not yet become a feasible standard clinical practice. This review provides recommendations for the research and clinical communities to advance this area for the benefit of prosthesis users.

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.

Comfort assessment of running footwear: Does assessment type affect inter-session reliability?

Assessing comfort of running footwear reliably is challenging. The purpose of this study was to compare the intra-rater reliability between different assessment types, to calculate intra-individual reliability scores and to evaluate the effect of rater selection based on individual reliability scores on group level reliability. Three assessment types: ranking, Visual Analogue Scale (VAS), and Likert Scale (LS) were provided twice in six separate sessions among 30 participants, who assessed comfort of five shoes after treadmill running. Spearman's rho provided an evaluation of inter-session relative reliability and typical error as a measure of absolute reliability for each assessment type. Ranking (r = 0.70, 95% confidence interval [CI] 0.61-0.78) yielded the highest relative reliability for overall comfort, followed by VAS (r = 0.67, 95% CI 0.56-0.75) and LS (r = 0.63, 95% CI 0.52-0.72), with large-scale overlaps of CIs between assessment types. The same order of assessment types was found for the percentage of reliable raters (r ≥ 0.7) with 60% in ranking scale, 47% in VAS and 37% in LS. Forming subgroups corresponding to the intra-individual reliability substantially increased group level reliabilities. Based on measures of relative reliability, an extreme reduction in resolution as provided by the ranking from pairwise comparisons seems to be a valuable tool in footwear comfort assessments if assessment time is of minor importance. No preference can be provided for the two investigated rating scales. Besides the assessment type, a selection of the best raters in additional reliability checks seems to be a prerequisite for further comfort-related studies.

Evaluation of Chewing and Swallowing Sensors for Monitoring Ingestive Behavior

Monitoring Ingestive Behavior (MIB) of individuals is of special importance to identify and treat eating patterns associated with obesity and eating disorders. Current methods for MIB require subjects reporting every meal consumed, which is burdensome and tend to increase the reporting bias over time. This study presents an evaluation of the burden imposed by two wearable sensors for MIB during unrestricted food intake: a strain sensor to detect chewing events and a throat microphone to detect swallowing sounds. A total of 30 healthy subjects with various levels of adiposity participated in experiments involving the consumption of four meals in four different visits. A questionnaire was handled to subjects at the end of the last visit to evaluate the sensors burden in terms of the comfort levels experienced. Results showed that sensors presented high comfort levels as subjects indicated that the way they ate their meal was not considerably affected by the presence of the sensors. A statistical analysis showed that chewing sensor presented significantly higher comfort levels than the swallowing sensor. The outcomes of this study confirmed the suitability of the chewing and swallowing sensors for MIB and highlighted important aspects of comfort that should be addressed to obtain acceptable and less burdensome wearable sensors for MIB.