Cardiovascular autonomic nervous system evaluation in Parkinson disease and multiple system atrophy.

BACKGROUND: Autonomic nervous system dysfunction (ANSd) heralds or follows motor symptoms (MS) in Parkinson disease (PD), but may precede years and progress more rapidly in multiple system atrophy (MSA). Cardiac dysautonomia severity correlates with disabling symptoms thus a Cardiac Autonomic Nervous System Evaluation protocol (CANSEp) is useful to assess ANSd in PD and MSA patients.

METHODS AND RESULTS: Consecutive patients with PD or MSA were studied. The severity of MS was quantified with UPDR III and Hoehn/Yahr scales. CANSEp consisted of the 5-test Ewing protocol (EP) and Heart Rate Variability analysis (HRVa), in time-domain (TD) and frequency-domain (FD). 36 patients with parkinsonian symptoms (23 PD, 13 MSA) and 40 healthy controls were studied. Parkinsonism was more severe in MSA, comparing UPDR III and Hoehn/Yahr scales (p<0.0001). Higher EP's scores were found in MSA (mean 5.1±1.98) compared to PD (mean 3.5±2) and controls (score 0.25±0.1). TD and FD-HRVa were abnormal in PD and MSA, compared to controls. In PD depression of vagal tone was predominant during sleep, whereas in MSA depression of sympathetic tone prevailed during daily activity.

CONCLUSIONS: Whereas its specificity is very high, the sensitivity of the EP was only 43.5% in PD and 76.9% in MSA. HRVa improved diagnosis accuracy in 10 patients, unidentified by the EP alone, with overall sensitivity of 65.2% in PD and 92.3% in MSA. Thus CANSEp provides a better assessment of cardiovascular dysautonomia in parkinsonian syndromes, useful to differentiate PD from MSA and to address clinical and pharmacological management.