Workplace surveillance for carpal tunnel syndrome using hand diagrams

Abstract

Four hundred and eleven workers from 4 different companies participated in a worksite screening program designed, in part, to estimate the prevalence of carpal tunnel syndrome (CTS). Each worker completed a discomfort survey and underwent limited nerve conduction testing of the median and ulnar sensory nerves in both wrists. The discomfort survey included a hand diagram which allowed subjects to shade in area(s) affected by numbness, burning, tingling, or pain. The discomfort survey also asked each worker to indicate whether she or he had experienced neuropathic symptoms (i.e., numbness, burning, tingling, or pain) in the wrist, hand or fingers of each hand, without regard to localization (i.e., median versus ulnar versus radial distribution), and also nocturnal occurrence of symptoms. Analyses involved comparing hand diagram scores and non localized wrist/hand/finger symptoms with electrodiagnostic test results. All configurations of hand diagram scores of the dominant hands had a statistically significant association with electrophysiologically determined median nerve dysfunction, but so did non localized symptom reports. The sensitivity, specificity, and positive predicted values of hand diagrams were poorer than those reported previously. While some test performance characteristics of hand diagrams were better than those for non localized distal extremity symptoms consistent with CTS, some were worse. Overall, our data suggest that hand diagrams are no better than using a questionnaire to determine if workers have experienced symptoms consistent with CTS in their wrists, hands or fingers without regard to localization. The choice of screening tool would depend on the goal of screening, in particular, whether it is more desirable to have slightly higher sensitivity or positive predictive value.

Reliability of Hand Diagrams for the Epidemiologic Case Definition of Carpal Tunnel Syndrome

“…The questionnaire incorporated items from previous research on upper extremity disorders, including items previously shown to have good to excellent test-retest reliability [19,24,[28][29][30][31][32]. Follow-up questionnaires with similar questions to the baseline questionnaire were completed at approximately 6 months, 18 months, and 36 months after baseline testing.…”

“…Three expert raters including two occupational medicine physicians and one occupational therapist independently scored each hand diagram following the scoring criteria described by Franzblau et al [24]. All raters had prior research and clinical experience addressing upper extremity problems.…”

“…Despite varying validity, reliability has shown consistently high results with kappa and intraclass correlation coefficients of 0.89 to 0.93 [24,25].…”

“…It was originally designed by Katz [22,23] with simplifying modifications made by Franzblau [24]. Diagrams are completed by the subject indicating the location of symptoms, and are then scored by a rater on a four point ordinal scale expressing the likelihood of CTS (unlikely, possible, probable, or classic).…”

“…The self-administered drawings rated by consensus have been described as a valid method for classifying pathology with sensitivity of 80% and specificity of 90% in a referral patient-based population [23]. Work-based population studies that screen workers who were not seeking medical attention showed lower sensitivity (0.19-0.40) with high specificity (0.83-0.95), using NCS results for case classification [24].…”