Needle Electromyography, F-Wave, and H-Reflex: A Critical Reappraisal of Their Utility in the Diagnosis of Various Sensory Symptoms in the Extremities and Spine in the Setting of Normal Neurological Examination

Objective: Health care providers refer their patients to electromyography (EMG) laboratories for the evaluation of various sensory symptoms in the extremities and spine. The procedure is usually performed in conjunction with transcutaneous electrical stimulation of peripheral nerves and elicitation of the F-wave and H-reflex. The present study aimed to determine the real value of these procedures in the diagnosis of sensory symptoms in the setting of a normal neurologic examination. Method: The EMG reports and clinical histories of 100 patients, including 10 patients evaluated by other electromyographers, were reviewed. The study was focused on those with normal neurological examinations and those without histories of ongoing medical disorders and major surgeries to the extremities and spine. Results: All EMGs, F-wave, and H-reflex reports reviewed were normal, including those obtained from the second procedure performed in some patients and of those who subsequently underwent spinal surgery. Neurologic examination in all patients was normal. Conclusion: Needle EMG, F-wave and H-Reflex examinations are predictably normal in patients with non-dermatomal, non-neuropathic sensory symptoms with normal neurologic examination and without history of preexisting medical and surgical disorders. A good neurologic examination should determine the need to perform these procedures. Our findings have important diagnostic, therapeutic, prognostic, economic and legal implications.