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

Abstract

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.

Investigating the Effect of Experience and Duration on Kinematics During 1 Hour of Sign Language Interpreting

“…V mean for each trial was calculated as the mean of the absolute value of the time-series joint angular velocity data (Marras & Schoenmarklin, 1993;Qin et al, 2008) from each 15-minute interpreting sample. In addition, time series of joint angular velocity data were also used to assess the number of MBs, which was used to determine MB time .…”

“…Previous research has reported mean angular velocities of 53-84 /s and 28-47 /s about the flexion/extension and radial/ulnar deviation axis of the wrist on the dominant hand during signing (Delisle et al, 2005;Qin et al, 2008). While these ranges are large, the consistency in mean velocities between studies is important.…”

“…Recording data from interpreters while they were working is a noted strength of their work; however, it is difficult to generalize their findings to those interpreting using American Sign Language (ASL). By contrast, Qin et al (2008) measured the kinematics of experienced interpreters during a carefully controlled lab-based experiment while SLIs interpreted (in ASL) from a video recording. This may limit the ability to generalize their findings to novice interpreters.…”

“…Without a clearer understanding of the movement demands imposed on SLIs and an understanding of how different factors, such as experience or time, may affect those demands, it remains difficult to establish appropriate controls, such as implementing rest break requirements. In an extensive search of English language literature , only two peer-reviewed studies reported on objective measures of signing kinematics from a sample population of interpreters (Delisle et al, 2005;Qin et al, 2008). Delisle et al (2005) measured interpreters' kinematics while they interpreted (using la langue des signes qu eb ecoise [LSQ]) during actual classroom appointments.…”

“…SLIs are exposed to repetitive upper-extremity movements when interpreting, where the rate of movement and repetition can be modulated by several factors. For example, since the gestures correspond to the content of language to be interpreted, a faster speaker's pace can substantially increase the velocity of the interpreters' wrist movements (Qin et al, 2008).…”