Comparison of MRI and motor evoked potential with triple stimulation technique for the detection of brachial plexus abnormalities in multifocal motor neuropathy

• Published in: Muscle & nerve Vol. 61; no. 3; pp. 325 - 329
• Main Authors: Corazza, Giovanni, Le Corroller, Thomas, Grapperon, Aude‐Marie, Salort‐Campana, Emmanuelle, Verschueren, Annie, Attarian, Shahram, Delmont, Emilien
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.03.2020; Wiley Subscription Services, Inc; Wiley
• Subjects: Abnormalities; Aged; Brachial plexus; Brachial Plexus - diagnostic imaging; Brachial Plexus - pathology; Brachial Plexus - physiopathology; brachial plexus MRI; Diagnostic systems; Electric Stimulation - methods; Engineering Sciences; Enlargement; Evoked Potentials, Motor; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; motor evoked potential; Motor evoked potentials; Motor Neuron Disease - diagnosis; Motor Neuron Disease - pathology; Motor Neuron Disease - physiopathology; Motor task performance; multifocal motor neuropathy with conduction blocks; Nerve conduction; Neural Conduction; Polyneuropathies - diagnosis; Polyneuropathies - pathology; Polyneuropathies - physiopathology; Progressive motor neuropathy; proximal conduction block; Stimulation; triple stimulation technique; brachial plexus; multifocal motor neuropathy with conduction blocks; motor evoked potential; proximal conduction block; triple stimulation technique; brachial plexus MRI
• ISSN: 0148-639X; 1097-4598; 1097-4598
• DOI: 10.1002/mus.26773

Background Conduction blocks (CB) are the diagnostic hallmark of multifocal motor neuropathy (MMN). Conventional nerve conduction studies cannot detect CB above Erb's point. Our purpose was to compare the performance of the motor evoked potential with triple stimulation technique (MEP‐TST) and MRI in the detection of abnormalities of the brachial plexus. Methods Examinations were performed on 26 patients with MMN (11 definite, 6 probable, 9 possible), of whom 7 had no CB. Results MEP‐TST detected proximal CB in 19/26 patients. Plexus MRI showed T2 hyperintensity in 18/26 patients, with nerve enlargement in 14/18. A combination of both techniques increased the detection rate of brachial plexus abnormalities to 96% of patients (25/26). Conclusions MEP‐TST and MRI have high sensitivities for detecting brachial plexus abnormalities. A combination of the two techniques increases the detection rate of supportive criteria for the diagnosis of MMN.