Time and frequency domain analysis for the assessment of heart autonomic control in Parkinson's disease

In order to evaluate autonomic regulation in Parkinson's disease, the heart-rate responses to passive head-up tilt and the spectral analysis of spontaneous heart rate variability in supine position were studied in 18 young (30.8 +/- 1.38 years old) and 13 aged (61.9 +/- 1.61 years) healthy controls and 13 patients with Parkinson's disease (62.9 +/- 1.55 years). Patients were evaluated in the University Hospital of the Canary Islands by a neurologist and a specialist in rehabilitation. Finally, a computerized procedure developed in the Dept. of Physiology of La Laguna University was used to quantify the autonomic regulation of heart-rate (HR) variability. In relation to the younger group, elderly controls showed a reduction in the amplitude and no differences in the latency of the three successive peaks of HR response to tilt. In relation to the elderly matched controls, the Parkinson group showed a slight decrease for the second response amplitude and no differences for both the first or third response amplitude and the latency of the three responses. In the frequency domain analysis of the spontaneous HR oscillation in supine position recording, the elderly and Parkinson groups showed a decrease in the power spectrum for low frequency (<0.04Hz; thermoregulation related band), mid frequency (0.04-0.15Hz; related to sympathetic activity in response to baroreceptors stimulation) and high frequency (0.15-0.4Hz; related to sympathovagal tonus activated by respiratory movements). In relation to elderly controls, the Parkinson group showed lower power in the three spectral bands studied. Present data support the hypothesis that both sympathetic and parasympathetic control of heart activity are impaired in Parkinson's disease and that this dysfunction can be assessed by combining time-domain and frequency-domain analysis of HR changes.