Predicting electrodiagnostic outcome in patients with upper limb symptoms:Are the history and physical examination helpful?

Objective: To determine the effectiveness of medical history and physical e xamination in predicting electrodiagnostic out-come in patients with suspec ted cervical radiculopathy. Methods: Data on 183 subjects prospectively collected at five different ele ctrodiagnostic laboratories were analyzed (96 cervical radiculopathies, 45 normal studies, and 42 abnormal electrodiagnostic findings other than radic ulopathy). The sensitivity, specificity, positive predictive value, negativ e predictive value, and odds ratios were determined for symptoms and neurol ogic signs. Results: Symptoms of numbness, weakness, and tingling were associated with twice the probability of having abnormal electrodiagnostic study results in general, yet were not helpful in identifying a cervical radiculopathy. All single and combined physical examination components had poor sensitivities , with the exception of weakness, but much higher specificities. Patients w ith either weakness or reduced reflexes on physical examination were up to five times more likely to have abnormal electrodiagnostic findings. In subj ects with any abnormal neurologic sign, the sensitivity improved to 84%, th e positive predictive value was 79%, but the specificity was low (44%). Of those subjects with normal physical examination results, almost one half ha d an abnormal electrodiagnostic study result (negative predictive value 52% ). Conclusions: In a population of patients with suspected cervical radiculopa thy, medical history and physical examination are helpful yet not sufficien t to predict the electrodiagnostic outcome,