Contralateral electrodiagnosis in patients with abnormal median distal sensory latency.

BACKGROUND

We hypothesized that electrodiagnostic evidence of carpal tunnel syndrome (CTS) on the contralateral, less-severe side correlates with disease severity.

METHODS

We retrospectively reviewed 285 adults that had bilateral electrodiagnostic testing and a median distal sensory latency (DSL) greater than 3.6 ms on at least one side. Variables associated with abnormal contralateral median DSL were analyzed in bivariable and multivariable analysis.

RESULTS

Patients with a nonrecordable median DSL on the worst side were significantly more likely to have electrodiagnostic evidence of contralateral CTS compared to patients with a prolonged DSL on the worst side (90 versus 65 %, respectively; p < 0.001). Bilateral symptoms were reported by 75 % of patients. The best logistic regression model for electrodiagnostic evidence of contralateral CTS included nonrecordable median DSL of the worst side and polyneuropathy (p < 0.001 and p = 0.14, respectively).

CONCLUSIONS

The finding that disease severity relates to the probability of contralateral abnormalities is consistent with the concept that CTS is typically bilateral. Patients with CTS on one side should be advised of the likelihood that it can be present or may develop on the other side.