Biomechanical analysis of upper extremity risk in Sign Langauge Interpreting

Range of motion required for Auslan: a biomechanical analysis

BACKGROUND

Auslan is used by the Australian deaf community and relies heavily on hand, wrist, and elbow movement. Upper limb injury or dysfunction may require surgical intervention to alleviate pain and provide a stable skeleton for function, leading to partial or complete reduction in motion. The aim of this study was to assess the wrist, forearm, and elbow motion required to communicate via Auslan, to tailor optimal interventions in this population.

METHODS

A biomechanical analysis was conducted on two native Auslan communicators, who signed 28 pre-selected and common Auslan words and phrases.

RESULTS

Sagittal plane wrist and elbow motion was found to be of greater importance than axial plane forearm rotation. Relative elbow flexion and generous wrist motion was common for many of the words and phrases, while end-range elbow extension was not recorded.

CONCLUSION

The maintenance of wrist and elbow motion should be prioritized when selecting surgical interventions for patients who communicate using Auslan.

Wrist Arthroplasty to Facilitate Communication in the Hearing Impaired

Management of wrist arthritis may involve many options, including motion preserving and motion sacrificing procedures. Total wrist arthrodesis is often considered the gold standard for severe wrist arthritis, failing non-operative management. We present the first case to our knowledge of total wrist arthroplasty (TWA) for patient with rheumatoid arthritis who is also deaf, requiring sign language for communication with excellent results.

One-Dimensional Scales for Pain Evaluation Adopted in Italian Nursing Practice: Giving Preference to Deaf Patients

Despite the increasing attention given to pain, little is known about how deaf patients communicate their pain and which pain scales they prefer to use. Studies of the validity of various scales often specify conditions that exclude them. With the aim to explore the preferred pain evaluation scale and the method of administration when evaluating deaf patients, a descriptive phenomenology of qualitative research study was undertaken and articulated in two phases. In the first phase, a purposeful sample of 10 nurses with experience in the care of deaf clients was studied using focus groups to collect data regarding which pain scale they used and the methods they used to administer the scales in clinical settings during care to deaf patients. In the second phase, a purposeful sample of 16 deaf people was engaged in multiple focus groups to analyze a set of one-dimension scales that emerged from the first phase of the study with nurses and to discuss their preferences for pain scales. Nurses who participated in the focus group reported using the numerical rating scale, visual analogue scale, Faces Pain Scale, and the Iowa Pain Thermometer (IPT) scale when caring for deaf people. Deaf patients involved in the second phase of this study preferred the IPT scale. Participants also noted the interference of environmental factors such as dimly lit rooms or glaring lights in situations that required lipreading for communication of pain such as in operating rooms. It was concluded that decisions regarding how to administer pain scales to deaf persons need to consider the preferences and the values of the patients. To avoid the risk of misunderstanding the pain of deaf patients, practice guidelines and strategies related to measuring pain in deaf persons should be specified by deaf associations at international, national, and local levels. Utilization of a simple sign language even at an international level could guarantee security in the communication of the pain between patients and health care workers and may help in the assessment of acute pain even in emergency conditions.

Effects of pace and stress on upper extremity kinematic responses in sign language interpreters

Sign language interpreters suffer from high levels of upper extremity disorders and burnout due to the physical and cognitive demands of interpreting. The objective of this research was to quantify the wrist kinematics of interpreting and to assess how speaker pace and psychosocial stress influence wrist kinematics. Professional interpreters interpreted a pre-recorded lecture, while the speaking pace of the lecture varied. One group of subjects was exposed to environmental conditions intended to induce stress. Several wrist kinematic variables of interpreting exceeded previously established high risk benchmarks for development of upper extremity disorders in industrial tasks. Wrist velocity and acceleration increased significantly with pace, with increases ranging from 10.7-18.6%. Increased psychosocial stress resulted in significant increase of left hand (non-dominant) wrist velocity and acceleration, with increases ranging from 14.8-19.5%. These results provide an objective assessment of the biomechanical demands of interpreting and support earlier research into different types of work, which found deleterious effects of psychosocial stress on the biomechanical responses of the lower back.

An interpreter's interpretation: sign language interpreters' view of musculoskeletal disorders

INTRODUCTION

Sign language interpreters are at increased risk for musculoskeletal disorders associated with work. Previous studies have used survey techniques to identify potential risk factors and approaches to their medical management. Little is known about risk factors and management of symptoms in this group from the perspective of the interpreter. Such qualitative information should help inform future research related to this professional group.

METHOD

One thousand ninety-two sign language interpreters recruited from the Registry of Interpreters for the Deaf completed an open-ended question that was a component of a national prevalence survey. Responses were evaluated using content analysis. Inter and intra rater reliability were high (.88 and .92, respectively).

RESULTS

Risk factors for initiation and/or exacerbation of symptoms included: difficult job, interpreting setting (educational), interpreting style (e.g., posture, self generated force), and emotional and physical stressors. Exercise (e.g., stretching, aerobics) was a common prevention strategy. Conventional medical treatment was used as the first line approach to symptom control. Self-care methods such as exercise, diet and warm up prior to interpreting were also reported. While massage and chiropractic care was used as commonly as in the general population, acupuncture was found to be used more often. Coping strategies that were more active (e.g. exercise, diet, more control over work schedule) were also reported as useful.

CONCLUSIONS

These findings provide a description of factors that interpreters view as important in the development and exacerbation of hand and wrist pain. The results also indicate that interpreters used many self-management approaches. Future research should carefully investigate the utility of such approaches using well-controlled designs. Also, because of its widespread use in this group the evaluation of acupuncture in the management of these symptoms appears warranted. The qualitative approach used in the present study permitted an analysis of the worker perspectives regarding risk and management of these work related symptoms. This information can be used to further inform future research.

Physical exposure of sign language interpreters: baseline measures and reliability analysis

Measurement of physical exposure to musculoskeletal disorder risk factors must generally be performed directly in the field to assess the effectiveness of ergonomic interventions. To perform such an evaluation, the reliability of physical exposure measures under similar field conditions must be known. The objectives of this study were to estimate the reliability of physical exposure measures performed in the field and to establish the baseline values of physical exposure in sign language interpreters (SLI) before the implementation of an intervention. The electromyography (EMG) of the trapezius muscles as well as the wrist motions of the dominant arm were measured using goniometry on nine SLI on four different days. Several exposure parameters, proposed in the literature, were computed and the generalizability theory was used as a framework to assess reliability. Overall, SLI showed a relatively low level of trapezius muscle activity, but with little time at rest, and highly dynamic wrist motions. Electromyography exposure parameters showed poor to moderate reliability, while goniometry parameter reliability was moderate to excellent. For EMG parameters, performing repeated measurements on different days was more effective in increasing reliability than extending the duration of the measurement over one day. For goniometry, repeating measurements on different days was also effective in improving reliability, although good reliability could be obtained with a single sufficiently long measurement period.

The effects of complex wrist and forearm posture on wrist range of motion

Previous research on wrist functionally has focused almost entirely on range of motion (ROM) in 2 or 3 isolated planes (flexion/extension, radial/ulnar deviation, and forearm pronation/supination), without investigating the potential effects of complex wrist/forearm posture on ROM. A quantitative analysis of these effects on wrist ROM was performed. ROM was measured in one plane using both a manual method and an electrogoniometer while the participant maintained a fixed, secondary wrist and forearm posture. The study revealed that combinations of wrist/forearm postures have significant effects on wrist ROM; the largest effects are those of wrist flexion/extension on radial deviation ROM. The study also found that, consistent with previous research, wrist deviation measurements obtained with an electrogoniometer were significantly different from those obtained manually. Biomechanical theories for the results obtained are discussed. This research could be used to enhance ergonomic evaluation techniques by providing a more accurate risk assessment of certain complex wrist postures, particularly those in which wrist flexion/extension is combined with radial deviation.