Autonomic Function in Parkinson's Disease Subjects Across Repeated Short-Term Dry Immersion: Evidence From Linear and Non-linear HRV Parameters

Abstract

Several studies have shown that “dry” immersion appears as a promising method of rehabilitation for Parkinson's disease. Still, little is known about the cardiovascular reaction in “dry” immersion (DI), especially in Parkinson's disease (PD). Therefore, this study was aimed to evaluate the effect of repeated 45-min DI sessions on autonomic function in subjects with PD. The study group consisted of 20 subjects with PD [13 men, seven women, aged 51–66 years old, Hoehn & Yahr (H&Y) staged 1–3] were enrolled in the study according to inclusion and non-inclusion criteria. The DI program was comprised of seven 45-min DI sessions, applied within 25–30 days. Blood pressure (BP), heart rate (HR), and electrocardiogram (ECG) in the standard lead II were recorded at 1st, 4th, and 7th DI, before, on the 15, 30, and 40th min of DI session. Autonomic function was assessed with analysis of heart rate variability (HRV) using Kubios Standard version 2 software. Linear (time- and frequency-domain) and non-linear (correlation dimension, entropies, DFA1 and DFA2, percent of determinism, and recurrence) were computed. At baseline condition, time- and frequency-domain HRV parameters showed low variability of HR, which indicates reduced autonomic neurogenic control of HR. Throughout the DI session, systolic and diastolic BP has decreased by 5–7 mm Hg (p < 0.001), and time- and frequency-domain parameters of HRV have significantly increased, what can be regarded as compensatory mechanisms of hemodynamics during DI. The structure of the regulatory input to the heart seen by HRV was characterized by low complexity and reduced autonomic neurogenic control of HR. Across the program of DI sessions, the hypotensive effect was documented, but no notable modification of the HRV-parameters was found. The absence of long-term modification of the studied parameters can be attributed both to deconditioning environmental effect of DI and limited adaptation of the organism due to neurodegeneration in PD. That should be taken into consideration when planning rehabilitation measures in subjects of older age and chronic somatic diseases with modeled microgravity.

Gait Characteristics Analyzed with Smartphone IMU Sensors in Subjects with Parkinsonism under the Conditions of “Dry” Immersion

“…Their anthropometric and clinical data and the medication they use is presented in Table 1 . All of them are from the same cohort of subjects who participated in our earlier studies [ 7 , 8 , 9 , 10 ]. The data on gait characteristics presented in this article were obtained from these studies.…”

“…The on-Earth microgravity was modeled using the conditions of a “dry” immersion (DI). This method of DI has already been presented in detail in our earlier papers [ 7 , 8 , 9 , 10 ]. In brief, the condition of DI was created with the help of MEDSIM (Medical simulator of weightlessness, Center for Aerospace Medicine and Technology, IMBP, Moscow, Russia), which is housed in the Laboratory of Novel Methods in Physiology (Petrozavodsk State University).…”

“…Earlier, we have shown that in subjects with PD that both single session of Earth-based microgravity—modeled with “dry” immersion conditions (DI) [ 7 ]—and a program of repeated DI sessions [ 8 ] attenuates muscle rigidity and tremors and improves some aspects of activity of daily living. Additionally, some motor-cognition tests [ 9 ] and characteristics of hemodynamics and heart rate variability were improved after a program of DI sessions [ 10 ]. On the other hand, the function of a patient’s spatial orientation in a vertical stance and the function of postural transition proved non-responsive to the condition of DI [ 7 ].…”

“…Among them are optical motion trackers, biopotential devices, audio and video recording, and, especially, wearable sensors, such as smart glasses, hats, insole sensors of ground-reaction force and smartphones [ 22 ]. Previously, we evaluated the effect of DI on PD subjects with conventional laboratory tools (EMG, reaction time, tapping test, posturography) [ 7 , 8 , 9 , 10 ].…”

Cold for gravity, heat for microgravity: A critical analysis of the “Baby Astronaut” concept

“…For a more profound substantiation of the concept of Baby Astronaut, more physiological systems can be taken into consideration, for example, hemodynamics and blood. There are studies, which provide evidence that the effect of exposure to heat ("warm water" effect, "passive heat therapy") and microgravity, modeled with either water or "dry" immersion, exert a similar relaxing effect on smooth musculature of vessels (Brunt et al, 2016;Sugawara and Tomoto, 2020;Gerasimova-Meigal et al, 2021). Then, Lossec et al (1999) evidenced rapid postnatal improvement of cardiovascular adjustments favoring blood perfusion and probably heat production during cold-induced shivering in the most oxidative muscles studied.…”