Cardiovascular autonomic function testing in multiple system atrophy and Parkinson's disease: an expert-based blinded...

Area of Science:

• Neurodegenerative diseases
• Autonomic nervous system disorders
• α-synucleinopathies

Background:

• Multiple system atrophy (MSA) and Parkinson's disease (PD) are neurodegenerative disorders marked by α-synuclein accumulation.
• Both conditions can cause cardiovascular autonomic failure, but lesion sites may differ.
• Distinguishing between MSA-parkinsonian variant (MSA-P) and PD can be challenging.

Purpose of the Study:

• To determine if cardiovascular autonomic function testing (CAFT) can differentiate between MSA-P and PD.
• To assess if expert-based blinded evaluation or systematic comparison of CAFT indices aids differential diagnosis.

Main Methods:

• Included 22 patients (11 MSA-P, 11 PD) with neurogenic orthostatic hypotension (nOH).
• Three CAFT experts blinded to diagnosis evaluated CAFT recordings using a self-created scheme.
• Systematic comparison of clinical-demographic data and CAFT parameters between groups.

Main Results:

• Neither blinded raters (58.46% accuracy) nor the evaluation scheme (72.73% accuracy) reliably discriminated between MSA-P and PD.
• Inter-rater reliability was very low (κ = 0.01).
• No significant differences in cardiovascular autonomic indices were found between PD and MSA-P patients.

Conclusions:

• CAFT, while a gold standard for autonomic failure assessment, appears to have limited utility in differentiating MSA-P from PD when nOH is present.
• Further research may be needed to identify reliable diagnostic markers.