Anal sphincter EMG does not distinguish between multiple system atrophy and Parkinson's disease

• Published in: Muscle & nerve 2000-05, Vol.23 (5), p.731-734
• Main Authors: Giladi, Nir, Simon, Ely S., Korczyn, Amos D., Groozman, Galina B., Orlov, Yivgeny, Shabtai, Herzel, Drory, Vivian E.
• Format: Article
• Language: English
• Subjects: Aged; Anal Canal - physiopathology; anal sphincter; autonomic nervous system; Biological and medical sciences; diagnosis; Diagnosis, Differential; Electrodiagnosis. Electric activity recording; Electromyography; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; multiple system atrophy; Multiple System Atrophy - diagnosis; Multiple System Atrophy - physiopathology; Nervous system; Parkinson Disease - diagnosis; Parkinson Disease - physiopathology; Parkinson's disease
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/(SICI)1097-4598(200005)23:5<731::AID-MUS10>3.0.CO;2-#

Clinical distinction of multiple system atrophy (MSA) from Parkinson's disease (PD) is often difficult. Several recent reports indicate that objective classification may be accomplished using electromyographic (EMG) testing of the anal or urethral sphincters, but some authors have found that these tests are not reliable for this purpose. We studied 13 patients with PD and 10 with probable MSA, as diagnosed by consensus of four movement disorders specialists, according to accepted clinical criteria. Anal sphincter EMG was performed blind to the clinical diagnosis. We found no significant differences in the mean duration of motor unit potentials (MUPs), mean MUP amplitude, or prevalence of polyphasic potentials, satellite potentials, very long duration MUPs, or spontaneous activity between the two groups. Thus, anal sphincter EMG does not differentiate between PD and MSA. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 731–734, 2000