A screening test for early signs of carpal tunnel syndrome among new workers prior to job placement does not help prevent the disorder, according to a NIOSH-funded study at Washington University School of Medicine in St. Louis, Missouri.

Carpal tunnel syndrome is a common, often disabling work-related disorder affecting the muscles and bones of the arms and hands. Risk factors include repetitive hand movements, forceful grip, and intensive hand use. In addition, older age and obesity may increase the risk among some workers.

How they did it

In this study, researchers looked at a popular screening test used prior to job placement to identify new workers at risk for developing carpal tunnel syndrome. Known as a nerve-conduction velocity test, this non-invasive screening test can help identify nerve damage by measuring how fast an electrical impulse travels through a nerve. Some employers use the screening test prior to placing new workers in jobs to identify those who may be at risk for carpal tunnel syndrome. Since previous studies have shown that abnormal screening test results do not always accurately predict the disorder, researchers compared screening test results among a large group of workers to subsequent cases of carpal tunnel syndrome. They found no link between abnormal screening test results and the development of carpal tunnel syndrome. In fact, the rate of carpal tunnel syndrome was slightly lower among workers with abnormal results on the screening test, compared to those with normal results. In addition, increased work-related hand and wrist activity was a risk factor for developing carpal tunnel syndrome, which is a finding consistent with other studies.

Study participants included 1,777 workers hired for production jobs; 1,648 had post-offer pre-placement test results available. Most were male and, on average, nearly 35 years old. Seventeen percent of participants had abnormal screening test results. Follow-up was up to 6 years, with an average of nearly 3 years. Based on their findings, the researchers concluded that the screening test is ineffective and that employers should not use it to identify workers at risk for carpal tunnel syndrome. This study is part of a larger project looking at the causes, long-term outcome, and prevention of carpal tunnel syndrome.

The study appeared in the Journal of Occupational and Environmental Medicine.

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