An evaluation of neurophysiological criteria used in the diagnosis of motor neuron disease

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 81; no. 6; pp. 646 - 649
• Main Authors: Douglass, C P, Kandler, R H, Shaw, P J, McDermott, C J
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01-06-2010; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adult; Aged; Aged, 80 and over; Amyotrophic lateral sclerosis; Amyotrophic Lateral Sclerosis - diagnosis; Amyotrophic Lateral Sclerosis - physiopathology; Biological and medical sciences; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Diagnosis, Differential; electromyography; Electromyography - methods; EMG; Female; Humans; Male; Medical sciences; Middle Aged; motor neuron disease; Motor Neuron Disease - diagnosis; Motor Neuron Disease - physiopathology; Neural Conduction - physiology; Neurology; neurophysiology; Rodents; Spinal cord; Studies; Surveys and Questionnaires; Evaluation; Nervous system diseases; Central nervous system disease; Motor neuron disease; Degenerative disease; Diagnosis; Spinal cord disease
• ISSN: 0022-3050; 1468-330X
• DOI: 10.1136/jnnp.2009.197434

BackgroundNew criteria for the neurophysiological diagnosis of amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) were recently proposed at an international symposium in Awaji-shima, Japan. They differ from the accepted revised El-Escorial criteria by considering fasciculation potentials to be evidence of acute denervation. In addition, when assessing diagnostic certainty, the Awaji-shima criteria equate electrodiagnostic evidence of lower motor neuron dysfunction with clinical examination findings.MethodsA retrospective review of 205 consecutive sets of notes was performed, from patients who underwent neurophysiological assessment for suspected MND. The clinical signs and neurophysiological findings were combined according to the two sets of criteria (revised El-Escorial and Awaji-shima), and the diagnoses reached were compared with the interval diagnosis, to establish the sensitivities and specificities of each protocol.ResultsAn interval diagnosis of MND was recorded in 107 patients. The sensitivity of the Awaji-shima criteria in reaching a diagnosis of MND was 60.7% and the revised El-Escorial 28%, with a specificity of 95.9% for both criteria. The Awaji-shima criteria increased the sensitivity of diagnosis without affecting the specificity.ConclusionAccepting EMG evidence of fasciculations as evidence of acute denervation increases the diagnostic certainty of MND, and the new criteria allow earlier diagnosis of MND without increasing the false-positive rate.