Mental workload under time pressure can trigger frequent hot flashes in menopausal women

Systemic physiology augmented functional near-infrared spectroscopy hyperscanning: a first evaluation investigating entrainment of spontaneous activity of brain and body physiology between subjects

Significance: Functional near-infrared spectroscopy (fNIRS) enables measuring the brain activity of two subjects while they interact, i.e., the hyperscanning approach. Aim: In our exploratory study, we extended classical fNIRS hyperscanning by adding systemic physiological measures to obtain systemic physiology augmented fNIRS (SPA-fNIRS) hyperscanning while blocking and not blocking the visual communication between the subjects. This approach enables access brain-to-brain, brain-to-body, and body-to-body coupling between the subjects simultaneously. Approach: Twenty-four pairs of subjects participated in the experiment. The paradigm consisted of two subjects that sat in front of each other and had their eyes closed for 10 min, followed by a phase of 10 min where they made eye contact. Brain and body activity was measured continuously by SPA-fNIRS. Results: Our study shows that making eye contact for a prolonged time causes significant changes in brain-to-brain, brain-to-body, and body-to-body coupling, indicating that eye contact is followed by entrainment of the physiology between subjects. Subjects that knew each other generally showed a larger trend to change between the two conditions. Conclusions: The main point of this study is to introduce a new framework to investigate brain-to-brain, body-to-body, and brain-to-body coupling through a simple social experimental paradigm. The study revealed that eye contact leads to significant synchronization of spontaneous activity of the brain and body physiology. Our study is the first that employed the SPA-fNIRS approach and showed its usefulness to investigate complex interpersonal physiological changes.

Decreased Frequency of Mental Workload-Induced Subjective Hot Flashes Through Gum Massage: An Open-Label, Self-Controlled Crossover Trial

Objective:

Hot flashes, a symptom of menopause, can decrease women's quality of life. Sympathetic nervous system activation has been identified as an important factor in the occurrence of hot flashes. Given that somatosensory stimulation of the oral cavity can affect autonomic nervous activity, we aimed to investigate the possibility that somatosensory stimulation of the gums (i.e., gum massage) could improve hot flashes.

Materials and Methods:

Nineteen women experiencing at least one hot flash per day were instructed to perform a gum massage on themselves before undertaking mental workload, using arithmetic task, and the frequency of hot flashes experienced during this task was measured. Changes in autonomic nervous activity were assessed based on heart rate variability.

Results:

Massage conditions promoted a significantly lower arithmetic task-induced hot flash frequency compared with nonmassage conditions (p < 0.05). During gum massage, the ratio between low and high frequency (LF/HF) values decreased significantly under massage conditions compared with nonmassage conditions (p < 0.01). During the arithmetic task, the gum massage-induced reduction in LF/HF, which changed from baseline, was significantly correlated with the gum massage-induced reduction in hot flash frequency.

Conclusions:

The results of this study indicate that gum massage can reduce the subjective frequency of hot flashes over a certain period under mental workload. Our study also indicates that gum massage can potentially decrease sympathetic nerve activity, which is known to be involved in the occurrence of hot flashes.

Clinical Trial Registration number 328 (the institutional review board of Lion Corporation).

The relationship between sympathetic nervous activity and cerebral hemodynamics and oxygenation: a study using skin conductance measurement and functional near-infrared spectroscopy

Simultaneous measurement of cortical and peripheral affective processing is relevant in many neuroscientific research fields. The aim was to investigate the influence of different affective task components on the coherence between cortical hemodynamic signals and peripheral autonomic skin potential signals. Seventeen healthy subjects performed four tasks, i.e. a finger-tapping task, a hyperventilation task, a working memory task and a risk-taking task. Cortical hemodynamic responses were measured using functional near-infrared spectroscopy (fNIRS). Peripheral skin conductance responses (SCRs) were assessed using electrodermal activity (EDA). Coherence between the fNIRS and the EDA time series was calculated using the S transform coherence (STC), a method that tests the temporal dynamics between two time series for consistent phase relationships and thus for a functional relationship. The following characteristics of fNIRS-EDA coherence were observed: (1) Simple motor performance was not a contributor to enhanced coherence, as revealed by the finger-tapping task. (2) Changes in respiration rate and/or heart rate acted as relevant contributors to enhanced coherence, as revealed by the hyperventilation task. (3) Working memory performance did not induce changes in coherence, (4) whereas risk-taking behavior was a significant contributor to enhanced coherence. (5) Based on all four tasks, we also observed that coherence may be subject to habituation or sensitization effects over the trial-to-trial course of a task. Increased fNIRS-EDA coherence may be an indicator of a psychophysiological link between the underlying cortical and peripheral affective systems. Our findings are relevant for several neuroscientific research areas seeking to evaluate the interplay between cortical and peripheral affective performance.

The effect of oral evening primrose oil on menopausal hot flashes: a randomized clinical trial

PURPOSE

Hot flashes are common experience for menopausal women, and for many, are severe enough to significantly compromise their overall sense of well being and quality of life. The aim of this study was to compare the efficacy of evening primrose with placebo in improvement of menopausal hot flashes.

METHODS

In a 6-week randomized clinical trial, a total of 56 menopausal women aged 45-59 years were participated in this study. The patients were asked for their hot flashes characteristics and responded to HFRDIS (hot flash related daily interference scale) questionnaire before and after the intervention. The participants were randomly assigned to take two capsules per day (totally 90 capsules for 6 weeks) of placebo or evening primrose (500 mg) for continuous 6 weeks. Then, the improvement in hot flashes was compared between two groups.

RESULTS

The percent of improvement in hot flash frequency, severity and duration were 39, 42 and 19 %, in evening primrose group compared with 32, 32 and 18 % in placebo group, respectively. Although all three characters of hot flash was ameliorated in evening primrose arm, only its severity was significantly better in this arm compared with placebo group (P < 0.05). All HFRDIS score were significantly improved in two groups, but the percentage of improvement in social activities, relations with others, and sexuality was significantly superior to placebo group (P < 0.05).

CONCLUSIONS

The application of oral evening primrose oil compared with placebo for controlling hot flashes may decrease more the intensity of attacks as well as ameliorating the HFRDIS score.

Factors that may influence the experience of hot flushes by healthy middle-aged women

BACKGROUND

Interest in menopausal symptoms in general and hot flushes (HFs) in particular has grown in recent years. This is mostly due to increased awareness and the vast impact these symptoms have on women's lives. Despite the high prevalence of women who experience HFs, a definitive etiology for HFs is yet to be found. Our objective was to review the current literature dealing with associated factors for experiencing HFs and to provide a synthesized overview on this common and often debilitating condition.

METHODS

We systematically searched the English-language literature in the PubMed database using relevant key words and included only those articles that contained information on associated factors for HFs in generally healthy midlife women.

RESULTS

Both conflicting scientific results between studies documenting factors that influence HFs and the lack of validated measuring tools make it difficult to truly pinpoint associated factors for HFs. Nonetheless, we identified the following clusters of associated factors: the menopausal stages, sex steroid hormones, other endocrine agents, genetic polymorphisms, race/ethnicity, body mass index (BMI) and obesity, mood disorders, smoking, soy isoflavones and phytoestrogens, alcohol consumption, and physical activity.

CONCLUSIONS

No single associated factor was consistently identified as having a major role in experiencing HFs. More resources should be directed to develop a unified study system along with multivariable analyses to get a better understanding of this condition, which often imposes a tremendous social and personal toll on the women who experience it.

Effects of menopausal hot flashes on mental workload

This study examined the differences in psychophysiological responses during mental task performance between women with (Group S) and without (Group A) menopausal hot flashes. Twelve women who reported experiencing daily moderate or severe menopausal hot flashes (Group S) and twelve women who reported having no hot flashes (Group A) participated in a mental arithmetic (Task) and a control (Non-task) experiment that occurred twice during 30 min. Although Group S experienced frequent hot flashes during mental arithmetic task, no significant differences between the two groups emerged for the percentage of correct responses and reaction time, and cardiovascular and thermoregulatory responses. However, the STAI state anxiety score was significantly higher in Group S than in Group A during both rest and mental tasks, and stress-related cortisol secretion showed a tendency to increase in Group S compared with Group A after task. The present study indicates that there were no significant differences in physiological responses and cognitive performance between women with and without menopausal hot flashes during mental arithmetic, but women with menopausal hot flashes might perceive higher psychological stress during rest and mental arithmetic tasks than asymptomatic women.