Temperature-dependent Physio-psychological Changes by Footbath-Changes in electroencephalogram, cerebral circulation, R-R variability and comfort-
- Author:
Kazuo UEBABA
;
Feng Hao XU
- Publication Type:Journal Article
- Keywords:
footbath;
EEG;
cerebral circulation;
Lorenz plots;
comfort
- From:The Journal of The Japanese Society of Balneology, Climatology and Physical Medicine
2004;67(2):119-129
- CountryJapan
- Language:English
-
Abstract:
We studied temperature-dependent effects of the footbath on heart rate variability, EEG (F3, F4, P3, P4 of 10/20 international method), cerebral circulation, and subjective comfort, using electrocardiography (ECG), electroencephalography (EEG), near-infrared spectroscopy (NIRS), transcranial Doppler (TCD) and face scale. Subjects were 14 healthy adult women (32±6 years old) who took 3 types of footbath (10cm below the knee at 38°C, 40°C, and 42°C) and the control sitting position without footbath in a randomized sequence after providing written informed consent. Their ECG, EEG, NIRS on the forehead, and TCD findings for the middle cerebral artery were monitored for 50min including a 30min footbath. Subjective changes were monitored every 5min using the face scale. LF (low frequency; 0.04-0.15Hz) and HF (high frequency; 0.15-0.4Hz) components and Lorenz plots parameters were obtained from ECG R-R variability. EEG power and EEG right-left coherence were also calculated.
At 42°C footbath, total hemoglobin (Hb) concentration of the forehead, LF/HF ratio, Pulsatility Index (PI: a marker of intracranial circulation and intracranial pressure obtained from TCD), and parietal β1 wave power increased significantly. HF power and EEG coherence of θ and α1 wave of the parietal and frontal leads decreased significantly with decline of comfort. At 40°C, cerebral circulation, LF/HF and PI changed less, but EEG power of the frontal α1 and α2, and parietal β1 waves increased significantly after the cessation of footbath with simultaneous increase of comfort. At 38°C, transient but significant decrease of PI value after footbath was associated with significant increase of EEG power of the frontal θ and parietal α2 waves after footbath. Parameters having statistically significant correlation with subjective comfort were HF power, Lorenz plots parameters, EEG power and coherence, and frontal Oxy Hb (r=0.150-0.231, p<0.0001 by Spearman's method). The EEG power of frontal α1 waves had the largest correlation coefficient with subjective comfort (r=0.231, p<0.0001).
It was assumed that temperature-dependent changes of autonomic nervous activity and cerebral circulation caused changes of EEG and comfort during footbath. It was indicated that frontal α1 wave power of EEG and Lorenz plots parameters obtained from R-R variability may be usable as indices of comfort in hot bathing.
