Author: Woo, Hoi Chi
Title: An investigation of the relationship between electronic device usage and upper extremity musculoskeletal disorders among university students in Hong Kong by means of self-reported questionnaire, physical examinations and ultrasound imaging
Advisors: White, Peter (HTI)
Lai, Wai Keung Christopher (HTI)
Degree: Ph.D.
Year: 2017
Subject: Musculoskeletal system -- Diseases.
Internet and youth -- China -- Hong Kong.
Computer users -- Health and hygiene.
Cell phone systems -- Health aspects.
Hong Kong Polytechnic University -- Dissertations
Department: Department of Health Technology and Informatics
Pages: xxxvi, 454 pages : illustrations
Language: English
Abstract: Background: Following current trends in the promotion of information and communication technology, the extensive use of computers and other electronic devices, such as mobile phones or handheld game consoles, hold a special fascination for young people nowadays. It is common to observe a "phubber" phenomenon involving people walking along the street with their eyes fixated on their mobile devices, with their fingers moving across the touchscreens. Despite young people being frequently engaged in mobile computing and electronic game playing in their daily lives, there is a lack of policy and guidelines on the proper ergonomic use of such technologies and little research has been conducted to date on the long-term and cumulative health effects of exposure to electronic devices. With the widespread use of such devices, adverse health effects, especially musculoskeletal disorders (MSDs), have become a subject of public concern. This study primarily aimed to explore the impact of cumulative exposure to various types of electronic devices on the musculoskeletal health of university students. The key issue addressed was that overuse of electronic devices may be. It is important to gain a deeper understanding of contributing risk factors: prolonged period of use, awkward posture, repetitive motion and forceful exertion, so as to prevent early manifestation of MSDs. These problems must be addressed at the developmental stage of emerging adulthood as it seems likely they may extend into adult life. This study evaluated these issues in great depth and proposed novel solutions for such problems. Methods: A cross-sectional research design was used that combined qualitative and quantitative methods, including: 1) A self-reported questionnaire was administered in the university in Hong Kong and students provided information about the frequency and duration of electronic device usage, including computers, mobile phones and game consoles, and reported on any musculoskeletal pain or discomfort that may relate to such activities in the immediate 12 months prior to the survey date. 2) Two physical examinations (Phalen's and Durkan's tests) were conducted on intensive and non-intensive electronic device users (.5hour/day and <5 hour/day of electronic device usage, respectively), to check whether or not they had the median nerve distribution of the hand. 3) Four ultrasound examinations (baseline resting position, finger positions, wrist positions and active hand motions) were carried out for measurements of median nerve cross-sectional area (CSA), flattening ratio (FR), swelling ratio (SR), perimeter and circularity, as well as bowing and thickness of transverse carpal ligament (TCL) within the carpal tunnel and along the hand or forearm, and compared with the ultrasound findings for intensive and non-intensive electronic device users. Firstly, baseline resting ultrasound examinations were conducted to examine the median nerve and TCL characteristics at levels of the wrist (carpal tunnel outlet, carpal tunnel inlet, proximal to carpal tunnel inlet, distal radius, and 4 cm proximal to distal wrist crease) at neutral position in both hands. Secondly, ultrasound examinations were conducted in different finger positions (neutral; flexion of thumb, index finger and four fingers; as well as pinch and power grips) and thirdly at different wrist positions (neutral; 15°, 30° and 45° of wrist extension; and 15° and 30° of wrist flexion, radial and ulnar deviation, respectively) to examine the median nerve characteristics at carpal tunnel inlet in both hands. Finally, ultrasound examinations during active hand motions (thumb opposition in neutral position; thumb opposition in ulnar deviation; and pinch grip) were conducted to examine the deformation, rotation and displacement of the median nerve at proximal to carpal tunnel inlet in the dominant hand only for simulated hand movements of smartphone use. One-second ultrasound video clips were recorded for analysis.
Results: A total of 503 university students (59% males and 41% females) aged 18-25 years completed the questionnaire. The results showed that almost all respondents (497, 98.8%) used a mobile phone every day, spending an average of 5.1 hours a day, with at least 5 years of usage experience. 368 (73.2%) reported that they either used a combination of tablet, laptop, or desktop computers, or all of them in their daily lives. Half of the respondents (251, 49.9%) reported upper limb MSDs, particularly in the neck and shoulder regions, followed by wrist/hand areas. Among these, 155 (61.8%) indicated that their discomfort was related to electronic device usage. Female gender, use of tablet computers and mobile phones, as well as lateral recumbent position, were significantly associated with a high prevalence of MSDs (p<0.05). In addition, 48 students (50% intensive and 50% non-intensive electronic device users) were randomly selected following the questionnaire responses and evaluated both clinically and by ultrasonography. Intensive electronic device users exhibited significantly more positive test findings than non-intensive users, especially during Durkan's test (p<0.01). They also had significantly larger baseline median nerve CSA, FR, SR and perimeter, as well as greater TCL bulge than non-intensive users (p<0.05). Compared to the neutral wrist position without finger motion, the CSA was decreased under all finger flexion and grips, whereas the FR and perimeter were decreased under flexion of thumb, index finger and four fingers, but increased in pinch and power grips, and vice versa in circularity. The CSA was decreased under wrist extension-flexion and radial-ulnar deviation, whereas the FR and perimeter were increased under wrist extension and radial deviation, but decreased under wrist flexion and ulnar deviation, and vice versa in circularity. During the simulated hand movements of smartphone use, thumb opposition in ulnar deviation caused the greatest deformation, rotation and displacement of the median nerve. All findings were significant (p<0.05). However, kinematic models showed that the motion pathways of median nerve during different hand motions were complex. Conclusion: Prevalence of MSDs among university students in Hong Kong were associated with the use of mobile devices and habitual postures. Intensive electronic device users were more likely to have an enlarged and flattened median nerve, and greater TCL bulge within the carpal tunnel, as well as pain in the fingers and wrists compared with non-intensive users. More importantly, the present study clearly demonstrated the influence of finger and wrist positions on the median nerve deformation and displacement. These findings suggested that performing thumb opposition in ulnar deviation during smartphone use, may cause median nerve compression that increases the risk of carpal tunnel syndrome (CTS). This study has highlighted the need for ergonomics education to teach users to avoid prolonged gripping, repetitive thumb motions, and awkward wrist postures when using mobile devices, as well as to help manufacturers in designing more ergonomically proven smartphones.
Rights: All rights reserved
Access: open access

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