This is an interesting Swedish study. As you may know, a test that examines how well the anal sphincter works is a good test to differentiate Parkinson’s Disease from multiple system atrophy (MSA). According to the abstract of this article, that test only differentiates PD and MSA “many years into the disease.”
In the Swedish study, they examined 148 newly-diagnosed patients — 100 definite PD, 21 probable PD, 16 MSA, 11 progressive supranuclear palsy, and 40 controls. They gave them all an external anal sphincter electromyography (EAS-EMG) within 3 months of their first visit. They found: “No EAS-EMG differences were found between the patient groups, especially not between PD and MSA.” So they concluded that this test cannot differentiate PD and MSA early in the disease course.
The abstract to the medical journal article is copied below.
Robin
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Acta Neurologica Scandinavica. 2012 Jan 3. [Epub ahead of print]
Anal sphincter electromyography in patients with newly diagnosed idiopathic parkinsonism.
Linder J, Libelius R, Nordh E, Holmberg B, Stenlund H, Forsgren L.
Department of Pharmacology and Clinical Neuroscience, Epidemiology and Public Health Sciences, Umeå University, Umeå, Sweden.
Abstract
OBJECTIVES:
The differential diagnosis of patients with idiopathic parkinsonism is difficult, especially early in the course of the disease. External anal sphincter electromyography (EAS-EMG) has been reported to be of value in the differential diagnosis between Parkinson’s disease (PD) and multiple system atrophy (MSA). Patients with MSA are reported to have pathological EAS-EMG and patients with PD are reported to have significantly less pathological EAS-EMG results. Comparisons between patients with parkinsonian disorders have usually been made many years into the disease, and thus it is largely unknown if the results of EAS-EMG can be used to distinguish the different diagnoses in the early phase of the disease.
MATERIALS AND METHODS:
We investigated 148 newly diagnosed patients with idiopathic parkinsonism from a population-based incidence cohort (100 definite PD, 21 probable PD, 16 MSA, 11 progressive supranuclear palsy, and 40 controls) with EAS-EMG within 3 months of their first visit and, in the majority of patients, before start of treatment with dopaminergic drugs. The clinical diagnoses were made using established clinical diagnostic criteria after a median follow-up of 3 years.
RESULTS:
All patient groups had more pathological EAS-EMG results than controls. No EAS-EMG differences were found between the patient groups, especially not between PD and MSA.
CONCLUSIONS:
External anal sphincter electromyography examination cannot separate the different parkinsonian subgroups from each other in early course of the diseases.
© 2012 John Wiley & Sons A/S.
PubMed ID#: 22211900 (see pubmed.gov for this abstract only)