Yoshinao Nagashima

Autonomic responses during inhalation of natural fragrance of “Cedrol” in humans

It is well known that odors affect behaviors and autonomic functions. Previous studies reported that some compounds in cedar wood essence induced behavioral changes including sedative effects. In the present study, we analyzed cardiovascular and respiratory functions while subjects were inhaling fumes of pure compound (Cedrol) which was extracted from cedar wood oil. Vaporized Cedrol (14.2+/-1.7 microg/l, 5 l/min) and blank air (5 l/min) were presented to healthy human subjects (n=26) via a face mask, while ECGs, heart rate (HR), systolic blood pressure (SBP), diastolic BP (DBP), and respiratory rates (RR) were monitored. Statistical analyses indicated that exposure to Cedrol significantly decreased HR, SBP, and DBP compared to blank air while it increased baroreceptor sensitivity. Furthermore, respiratory rate was reduced during exposure to Cedrol. These results, along with the previous studies reporting close relationship between respiratory and cardiovascular functions, suggest that these changes in respiratory functions were consistent with above cardiovascular alterations. Spectral analysis of HR variability indicated an increase in high frequency (HF) component (index of parasympathetic activity), and a decrease in ratio of low frequency to high frequency components (LF/HF) (index of sympathovagal balance) during Cedrol inhalation. Furthermore, Cedrol inhalation significantly decreased LF components of both SBP and DBP variability, which reflected vasomotor sympathetic activity. Taken together, these patterns of changes in the autonomic parameters indicated that Cedrol inhalation induced an increase in parasympathetic activity and a reduction in sympathetic activity, consistent with the idea of a relaxant effect of Cedrol.

Significant correlation between autonomic nervous activity and cerebral hemodynamics during thermotherapy on the neck

Although local thermotherapy reduces mental stress and neck stiffness, its physiological mechanisms are still not fully understood. We speculated that local thermotherapy exerts its effect, in addition to its direct peripheral effects, through the central nervous system that is involved in controlling stress responses. In the present study, we investigated the effects of a heat- and steam-generating (HSG) sheet on cerebral hemodynamics and autonomic nervous activity using near-infrared spectroscopy (NIRS) and the electrocardiograms (ECGs). Thirteen healthy young female subjects participated in this study. HSG or simple (control) sheets were repeatedly applied to the neck for 120 s with 180 s intervals of rest between applications. During the experiment, brain hemodynamic responses (changes in Oxy-Hb, Deoxy-Hb, and Total-Hb) and autonomic nervous activity based on heart rate variability (HRV) were monitored. Subjective perception of neck stiffness and fatigue was significantly improved after application of the HSG sheet. NIRS findings indicated that the application of HSG sheets decreased Oxy-Hb concentration in the anterior-dorsal region of the medial prefrontal cortex (adMPFC), while increasing parasympathetic nervous activity and decreasing sympathetic nervous activity. Furthermore, changes in Oxy-Hb in the adMPFC were significantly and negatively correlated with those in parasympathetic nervous activity during application of the HSG sheet. These findings suggest that application of the HSG sheet to the neck region induced mental relaxation and ameliorated neck stiffness by modifying activity of the adMPFC.

Application of heat- and steam-generating sheets to the lumbar or abdominal region affects autonomic nerve activity.

Effects of applying a heat- and steam-generating (HSG) sheet on peripheral hemodynamics and autonomic nerve activity were examined. An HSG sheet was applied to the lumbar or abdominal region. Measurements included skin temperature at the lumbar and abdominal regions and the fingertip, total hemoglobin, tissue oxygen saturation ratio (StO2), pupillary light reflex, changes in ECG R-R interval blood pressure and percutaneous electrogastrography (EGG). A heat-generating sheet without steam was used as the control. Based on the present findings, application of the HSG sheet to the lumbar or abdominal region may improve peripheral hemodynamics and inhibit sympathetic nerve activity, resulting in parasympathetic nerve activity dominance.

Effects of direct cedrol inhalation into the lower airway on brain hemodynamics in totally laryngectomized subjects

A previous study reported that when cedrol (odorant) is inhaled directly through the lower airway of the trachea, it decreases the sympathetic nervous activity and blood pressure in totally laryngectomized subjects (Umeno et al., 2008). In the present study, totally laryngectomized subjects were asked to inhale cedrol into the lower airway in the same manner and its effects on regional cerebral blood flow (rCBF) were analyzed. Our results indicated that hippocampal rCBF was bilaterally increased during cedrol inhalation as compared to the inhalation of blank air. These results provide the first evidence that an odorant in the lower airway modulates autonomic activity via the central nervous system.

Thermotherapy to the facial region in and around the eyelids altered prefrontal hemodynamic responses and autonomic nervous activity during mental arithmetic

To investigate neural mechanisms of local thermotherapy to reduce mental stress, participants were required to perform mental arithmetic after treatment by a heat- and steam-generating sheet on the facial eyelid region while hemodynamic activity and ECGs were monitored. The results indicated that thermotherapy decreased hemodynamic activity in the anterior dorsomedial prefrontal cortex (aDMPFC) involved in sympathetic activity. Consistently, thermotherapy increased parasympathetic activity while it decreased sympathetic activity. Furthermore, thermotherapy increased hemodynamic activity in the dorsolateral prefrontal cortex (DLPFC) during mental arithmetic. These hemodynamic responses in the DLPFC during mental arithmetic were negatively correlated with that in the aDMPFC during thermotherapy. The results suggest that thermotherapy in the facial eyelid region is useful to ameliorate mental fatigue through its effects on the prefrontal cortex.

Age-related changes in gingival blood flow parameters measured using laser speckle flowmetry

Previous studies have suggested a possible relationship between age-related changes to human gingival hemodynamics and periodontal disease. However, firmly establishing this has been difficult because of a lack of suitable tools. Our study investigated whether a non-invasive laser speckle flowgraphy (LSFG)-based 2-dimensional technique could be used to assess maxillary anterior gingival blood flow under resting conditions. In total, 124 healthy male volunteers aged between 22 and 69 years were included in the study and delineated into young (Y; 22-37 years, n = 45), middle-aged (M; 38-53 years, n = 43), and elderly groups (E; 54-69 years, n = 36). The differences in gingival hemodynamics were compared among age groups and pulse waveform analysis performed to calculate blood flow indices, mean blur rate (MBR), gingival vascular conductance (MBR/mean blood pressure [MBP]), and three pulse waveform parameters (acceleration time index [ATI], falling rate, and blowout time [BOT]). Although no statistically significant differences were observed in the MBR of the three age groups, vascular conductance (MBR/MBP) was lower in groups M and E compared to group Y and correlated negatively with age. ATI and falling rates were also significantly higher in group E relative to group Y, whereas average BOT was significantly lower. All of the assessed parameters correlated with age. These data suggest that there are age-related decreases in the ability to maintain blood flow in the human maxillary anterior gingiva under resting conditions which may impact the likelihood of periodontal disease.

Assessment of laser speckle flowgraphy: Development of novel cutaneous blood flow measurement technique

We experimentally prepared a laser speckle flowgraphy (LSFG) device, and investigated whether it can accurately measure cutaneous blood flow. Cutaneous blood flow was measured in healthy adults using the thermal diffusion method (TDM) and strain-gauge plethysmography (SPG) established as blood flow measurement methods, along with LSFG. The correlation properties between the values measured by LSFG and TDM, and LSFG and SPG, were investigated. Results found that a significant positive correlation is noted between the two conventional methods and LSFG. It is suggested that LSFG is a useful device for cutaneous blood flow evaluation, and that its applications in medical care and esthetic fields are expected.

Effects of heat steam-generating sheets on the face regions on cerebral hemodynamics, autonomic nervous activity, and facial expression in fatigued subjects

The circadian rhythm of QT interval variability is still unclear, although it is known that QT interval prolongation is a predictor of sudden cardiac death. The aim of present study is to establish a dynamical model between RR interval variability and QT interval variability, and to identify its dynamical parameters in 24-hr circadian rhythms. A linear mathematical dynamical model is established between RR-interval variability and QT-interval variability. The model parameters can be identified using system identification technique. Simulated data show that the mathematical model fit well to the dynamics of QT-interval variability. Eight-young healthy subjects are recruited in the study. The results show that dynamics between RR variability and QT variability is individual-specific,and their dynamical parameters express distinct circadian rhythms. The results suggest that the circadian properties of QT interval dynamics may play a prominent role in sudden cardiac death prevention.

P2-20 Gastric movement under mental calculation

Objectives: Clarify neurological complications in xeroderma pigmentosum (XP). Methods: Neurological examinations and nerve conduction studies were performed in 14 patients with XP-A (1 20 years old). Results: Despite normal at birth, walking tended to delay. Gait disturbance developed insidiously until wheel chair bound at 13 18 years old. Dysphagia and frequent inspiration pneumonia required PEG and tracheotomy at 16 20 years old. Early abnormalities found in neurological examination were decreased tendon reflexes and positive Babinski signs inevitable after 6 years old. Various degree of trunkal ataxia was noticed all of the patients. Nerve conduction studies revealed decreased SNAP, especially in the lower extremities and totally lost over the age of 14. CMAP and MCV were relatively preserved in the median nerves, but lost in the peroneal nerves after the age of 12. Conclusion: In all of the patients with XP-A, neurological deteriorations start since early in their life and progress in their adolescence.

P35.26 Application of a heat- and steam-generating sheet produces parasympathetic predominance and increases peripheral blood flow

Background: The prevalence of Visual hallucination (VH) in Parkinson’s disease (PD) has been reported to be between 6% and 60%. VH were a risk factor for permanent nursing home placement, with its associated high mortality rate. Some report mentioned that autonomic dysfunction was associated with VH. Objective: We clarify the relationship between the extent and pattern of autonomic dysfunction and VH in patients with PD. Methods: The subjects were 92 patients with PD (30 men and 62 women, age 66.2 years, range 41–88 years) with disease duration of 1–12 years (mean 2.8 years). Autonomic nervous function, including cardiac sympathetic gain, was evaluated on the basis of cardiac radioiodinated metaiodobenzylguanidine (MIBG) uptake and hemodynamic testing using the Valsalva maneuver (VM). The systolic blood pressure and the plasma norepinephrine concentration (NE) were also measured in supine and standing position on tilt table test. Results: MIBG uptakes in heart were significantly lower in PD patients with VH than in patients without VH. Hemodynamic studies using the VM revealed that PD patients with VH had reduced vasomotor sympathetic function, but not parasympathetic function. No significant difference in blood pressure response on the tilt table test was found between control and patients without VH, while the blood pressure response was significantly reduced in patients with VH as compared with control. The NE level of PD patients without VH was similar to those of controls in the supine and standing positions. However, PD patients with VH had a significantly lower NE level than controls in the supine and standing positions. Conclusion: Our results show that cardiac and vasomotor sympathetic dysfunction is more severe in PD patients with VH than in patients without VH, but not parasympathetic dysfunction. Theses findings may be due to postganglionic sympathetic dysfunction and suggest widespread Lewy body pathology in PD with VH.