INTRODUCTION: Identifying postures and behaviors during keyboard use that can discriminate between individuals with and without musculoskeletal disorders of the upper extremity (MSD-UE) is important for developing intervention strategies. This study explores the ability of models built from items of the Keyboard-Personal Computer Style instrument (K-PeCS) to discriminate between subjects who have MSD-UE and those who do not.
METHODS: Forty-two subjects, 21 with diagnosed MSD-UE (cases) and 21 without MSD-UE (controls), were videotaped while using their keyboards at their onsite computer workstations. These video clips were rated using the K-PeCS. The K-PeCS items were used to generate models to discriminate between cases and controls using Classification and Regression Tree (CART) methods.
RESULTS: Two CART models were generated; one that could accurately discriminate between cases and controls when the cases had any diagnosis of MSD-UE (69% accuracy) and one that could accurately discriminate between cases and controls when the cases had neck-related MSD-UE (93% accuracy). Both models had the same single item, "neck flexion angle greater than 20 degrees ". In both models, subjects who did not have a neck flexion angle of greater than 20 degrees were accurately identified as controls.
CONCLUSIONS: The K-PeCS item "neck flexion greater than 20 degrees " can discriminate between subjects with and without MSD-UE. Further research with a larger sample is needed to develop models that have greater accuracy.
OBJECTIVES: This study attempted to determine whether musculoskeletal health is influenced by mouse-intensive computer work.
METHODS: The neck-upper limbs of 148 air-traffic controllers (71 women, 77 men) with demanding computer work were examined before (baseline) and a median of 20 months after (follow-up) a change from varied computer work to a mouse-based system, causing a significant change in the physical exposure of the workers (eg, lower variation of work postures and less rest in the forearm extensor muscles, as assessed by technical measurements). Complaints (according to a Nordic questionnaire), diagnoses (standardized physical examination), and psychosocial work environment (Copenhagen Psychosocial Questionnaire) were recorded.
RESULTS: The air traffic controllers had consistently higher prevalences of disorders in the elbows-hands in the follow-up than at the baseline (complaints 30% versus 18%, P=0.03; diagnoses 10% versus 3.4%, P=0.02). The predominance of right-arm disorders was more pronounced in the follow-up than at the baseline. For the neck-shoulders-upper back, there was no consistent difference between the baseline and follow-up values; disorders increased significantly among the "young" controllers (< or =37 years), but not among the "older" ones. Perceived decision latitude decreased, while social support increased, but these changes did not explain the disorders that appeared in the elbows-hands.
CONCLUSIONS: Intensive mouse-based computer work, with constrained posture and little rest in the forearm muscles, was associated with an increased risk of disorders in the elbows-hands. This finding should be considered for similar technological developments in other settings.
AIM:The aim of this study was to determine whether upper extremity musculoskeletal disorders are more prevalent in intense computer users and the relation between cumulative hours of computer use and symptoms.MATRIALS AND METHODS:The study group included 100 bank workers, who worked more than 6 h per day for at least 2 years on a video display unit and were recruited through convenience sampling. Sixty-five age and sex matched healthy subjects who worked not more than 2 h on computer keyboards for office work constituted the control group.RESULTS:There were no significant differences between groups when the age and sex of the participants were considered. The results suggest a high prevalence of musculoskeletal disorders of the upper extremities among intensive computer users. The differences were statistically significant except in neck range of motion and left cubital tunnel syndrome. As the time spent on video display unit increased, there is a tendency in occurrence of symptoms, but only in carpal tunnel syndrome the relation is significant.CONCLUSIONS:The findings showed that cumulative computer use time increased the risk of musculoskeletal disorders in the upper extremities. As the duration of job increased, the risk for carpal tunnel syndrome significantly increased. Further studies with the inclusion of a larger number of cases and potential risk factors would help clarify the role of variables in the aetiology of work-related neck and upper limb disorders.
OBJECTIVES: The aim of this intervention study was to determine the effects of an alternative mouse and/or a forearm support board on the change in upper body discomfort scores and the development of incident musculoskeletal disorders. METHODS: This randomised controlled intervention trial followed 206 engineers for one year. Participants were randomised to receive (1) a conventional mouse only, (2) an alternative mouse only, (3) a forearm support board, or (4) an alternative mouse plus forearm support board. Outcome measures included weekly upper body discomfort scores and incident musculoskeletal disorders. RESULTS: During the study, 42 participants were diagnosed with an incident musculoskeletal disorder. The group that received the forearm support board experienced a reduction in their right upper extremity discomfort (beta-coefficient -0.35, 95% CI -0.67 to -0.03) in comparison to those who did not receive a forearm board. The group that received the alternative mouse had a protective, but non-significant (p = 0.20), effect on incident cases of right upper extremity musculoskeletal disorders (HR 0.57, 95% CI 0.24 to 1.34) and a non-significant reduction in neck/shoulder discomfort (beta-coefficient -0.23, 95% CI -0.056 to 0.10) in comparison to those who received a conventional mouse. CONCLUSIONS: In engineers who use a computer for more than 20 h per week, a forearm support board may reduce right upper extremity discomfort attributed to computer use.
The objectives of this study were to investigate the rate of cumulative trauma disorders (CTDs) in the upper body and to describe the associations of such disorders with ergonomic parameters in a group of data entry operators. A total of 173 data entry operators volunteered to take part in the study. Questionnaires were used to investigate their medical history. Diagnoses of CTDs were made with clinical tests. A visual posture analysis of the workers and an ergonomic analysis of workstations and workload were used to reveal risk factors. Neck and shoulder pain, extensor tendonitis of the wrists and De Quervain's disease were common in the study population. An assessment of risk factors showed that leaning wrists on the keyboard, hard keystrokes, extreme wrist joint and thumb positions and working in poor ergonomic design were correlated to pain and development of CTDs.
OBJECTIVE: To investigate the relationship between carpal tunnel syndrome (CTS) and keyboard use at work in a general population.
METHODS: A health status questionnaire was mailed to 2,465 persons of working age (25-65 years) who were randomly selected from the general population of a representative region of Sweden. The questionnaire required the subjects to provide information about the presence and severity of pain, numbness and tingling in each body region, employment history, and work activities, including average time spent using a keyboard during a usual working day. Those reporting recurrent hand numbness or tingling in the median nerve distribution were asked to undergo a physical examination and nerve conduction testing. The prevalence of CTS, defined as symptoms plus abnormal results on nerve conduction tests, was compared between groups of subjects that differed in their intensity of keyboard use, adjusting for age, sex, body mass index, and smoking status.
RESULTS: Eighty-two percent responded to the questionnaire, and 80% of all symptomatic persons attended the examinations. Persons who had reported intensive keyboard use on the questionnaire were significantly less likely to be diagnosed as having CTS than were those who had reported little keyboard use, with a prevalence that increased from 2.6% in the highest keyboard use group (> or = 4 hours/day), to 2.9% in the moderate use group (1 to <4 hours/day), 4.9% in the low use group (<1 hour/day), and 5.2% in the no keyboard use at work group (P for trend = 0.032). Using > or = 1 hour/day to designate high keyboard use and <1 hour/day to designate low keyboard use, the prevalence ratio of CTS in the groups with high to low keyboard use was 0.55 (95% confidence interval 0.32, 0.96).
CONCLUSION: Intensive keyboard use appears to be associated with a lower risk of CTS.
<b>BACKGROUND: </b>Call centre work with computers is associated with increased rates of upper body pain and musculoskeletal disorders.<b>METHODS: </b>This one year, randomised controlled intervention trial evaluated the effects of a wide forearm support surface and a trackball on upper body pain severity and incident musculoskeletal disorders among 182 call centre operators at a large healthcare company. Participants were randomised to receive (1) ergonomics training only, (2) training plus a trackball, (3) training plus a forearm support, or (4) training plus a trackball and forearm support. Outcome measures were weekly pain severity scores and diagnosis of incident musculoskeletal disorder in the upper extremities or the neck/shoulder region based on physical examination performed by a physician blinded to intervention. Analyses using Cox proportional hazard models and linear regression models adjusted for demographic factors, baseline pain levels, and psychosocial job factors.<b>RESULTS: </b>Post-intervention, 63 participants were diagnosed with one or more incident musculoskeletal disorders. Hazard rate ratios showed a protective effect of the armboard for neck/shoulder disorders (HR = 0.49, 95% CI 0.24 to 0.97) after adjusting for baseline pain levels and demographic and psychosocial factors. The armboard also significantly reduced neck/shoulder pain (p = 0.01) and right upper extremity pain (p = 0.002) in comparison to the control group. A return-on-investment model predicted a full return of armboard and installation costs within 10.6 months.<b>CONCLUSION: </b>Providing a large forearm support combined with ergonomic training is an effective intervention to prevent upper body musculoskeletal disorders and reduce upper body pain associated with computer work among call centre employees.
Carpal Tunnel Syndrome (CTS) is an important problem among computer professionals. Hence the prevalence of CTS among computer professionals and risk factors were studied. 648 subjects were selected from 4,276 computer professionals from 21 companies by with simple random sampling method. CTS was diagnosed based on clinical features. The prevalence of CTS was found to be 13.1% (95% CI 10.5-15.7%). Subjects with over 8 years of computer work, over 12 hrs of work per day and system administrators were at a higher risk for CTS (OR 3.3, 4.9 and 2.5 respectively). Flexed or extended hand position had higher risk for CTS. Higher risk for CTS was found with higher exposure to computer work. Ergonomic considerations are important in facilitating proper positioning of hand while working with a computer. Further studies on CTS risk factors among computer professionals are essential for planning prevention.
BACKGROUND: The character of upper limb disorder in computer operators is subject to debate. A peripheral nerve-involvement is suggested from the common presence of a triad of symptoms consisting of pain, paraestesiae and subjective weakness, and from physical findings suggesting neuropathy. This study aimed to examine the outcome of a detailed neurological examination in computer operators and to compare findings with the presence of symptoms.
METHODS: 96 graphical computer operators answered a modified Nordic Questionnaire including information on perceived pain in the shoulder, elbow, and wrist/hand scored for each region on a VAS-scale 0-9. In addition, they underwent a physical examination including the subjective assessment of the individual function of 11 upper limb muscles, of algesia in five and vibratory threshold in three territories, respectively, and of mechanosensitivity of nerves at seven locations. In order to reflect an involvement of the brachial plexus (chord level), the posterior interosseous nerve and the median nerve at elbow level we defined three patterns of neurological findings illustrating the course of nerves and their innervation. The pain scores summarized for the three upper limb regions (min. = 0, max = 27) in the mouse-operating and contralateral limbs were compared by a Wilcoxon test and the relation to each physical item analyzed by Kendall's rank correlation. The relation of summarized pain to each pattern was studied by application of a test of the trend across ordered groups (patterns).
RESULTS: Pain, paraestesiae and subjective weakness was reported for 67, 23, and 7 mouse-operating limbs, respectively, with the summarized pain scores exceeding 4 in 33 limbs. Abnormal physical findings were prevalent. The summarized pain was significantly related to a reduced function in five muscles, to mechanical allodynia at one location and to elevated threshold to vibration in two territories. Brachial plexopathy was diagnosed in 9/2, median neuropathy in 13/5 and posterior interosseous neuropathy in 13/8 mouse operating/contralateral limbs, respectively. The summarized pain was significantly higher in the mouse-operating limbs and in limbs with any of the defined patterns. There was a significant trend between the summarized pain and the summarized scores for the items contained in each pattern.
CONCLUSION: This small-scale study of a group of computer-operators currently in work and with no or minor upper limb symptoms has indicated in symptomatic subjects the presence of peripheral nerve-afflictions with specific locations.
BACKGROUND: Few community-based epidemiological investigations of upper limb disorders (ULDs) have classified cases by validated procedures involving a structured clinical examination.
AIM: To compare risk factor profiles for different diagnostic categories of ULD using one such examination scheme.
METHODS: A questionnaire about upper limb pain and demographic, occupational and psychosocial risk factors was mailed to 10,264 adults from two English general practices, followed by standardized physical examination in those with arm or neck pain. Logistic regression was used to compare those with specific ULDs and non-specific arm pain with those who had no neck or arm symptoms.
RESULTS: There was a 59% response rate. A total of 1,197 subjects with arm or neck pain underwent standardized physical examination and were classified as having one or more of 11 specific ULDs or non-specific regional pain. Among these, 250 subjects with specific ULDs and 176 with only non-specific arm pain were compared with 2,248 subjects who had no neck or arm symptoms. Certain physical risk factors were more strongly associated with specific disorders than with non-specific pain. In comparison with pain-free subjects, the odds ratios (ORs) in keyboard users (>or=1 h versus <1 h/day) were 3.1 (95% CI 1.3, 7.8) for hand-wrist tendonitis but 1.3 (0.8, 2.1) for non-specific hand-wrist pain. Other differential associations were found with age, sex, manual versus non-manual employment and smoking. Unexpectedly, low vitality was similarly associated with both specific disorders and non-specific pain.
CONCLUSION: These findings suggest that the schedule may usefully distinguish disorders that differ in their association with physical risk factors.
Identifying postures and behaviors during keyboard use that can discriminate between individuals with and without musculoskeletal disorders of the upper extremity (MSD-UE) is important for developing intervention strategies. This study explores the ability of models built from items of the Keyboard-Personal Computer Style instrument (K-PeCS) to discriminate between subjects who have MSD-UE and those who do not.
METHODS:
Forty-two subjects, 21 with diagnosed MSD-UE (cases) and 21 without MSD-UE (controls), were videotaped while using their keyboards at their onsite computer workstations. These video clips were rated using the K-PeCS. The K-PeCS items were used to generate models to discriminate between cases and controls using Classification and Regression Tree (CART) methods.
RESULTS:
Two CART models were generated; one that could accurately discriminate between cases and controls when the cases had any diagnosis of MSD-UE (69% accuracy) and one that could accurately discriminate between cases and controls when the cases had neck-related MSD-UE (93% accuracy). Both models had the same single item, "neck flexion angle greater than 20 degrees ". In both models, subjects who did not have a neck flexion angle of greater than 20 degrees were accurately identified as controls.
CONCLUSIONS:
The K-PeCS item "neck flexion greater than 20 degrees " can discriminate between subjects with and without MSD-UE. Further research with a larger sample is needed to develop models that have greater accuracy.
