Passive ankle movement increases cerebral blood oxygenation in the elderly: an experimental study.

BACKGROUND: Ankle exercise has been proven to be an effective intervention to increase venous velocity. However, the efficacy of ankle exercise for improving cerebral circulation has not been determined. We hypothesized that ankle exercise in the supine position would be able to increase oxyhemoglobin levels measured at the forehead. METHODS: Seventeen community-dwelling elderly women participated in this study. We recorded blood pressure, heart rate (HR), and oxyhemoglobin (OxyHb) levels from the participants in the supine position. Participants repeated ankle plantar flexion and dorsiflexion movements for 1 min. Two types of exercise were used: active movement and passive movement. We used two-way analysis of variance to assess the differences in mean arterial blood pressure (MAP), HR, and OxyHb between different exercises (active and passive) and times (before and after exercise). RESULTS: The HR and MAP increased during active exercise but not during passive exercise. On the other hand, the levels of OxyHb measured at the forehead were elevated during both active and passive exercises. This increase lasted at least 1 min after exercise. There was no significant difference between active and passive exercise with regard to OxyHb; however, a significant difference was observed between before and after exercise (p < 0.05, η(2) G = 0.153). CONCLUSIONS: The physiological response of OxyHb to ankle exercise was different from that of the other cardiovascular functions. Both active and passive ankle exercises were able to increase cerebral blood oxygenation, whereas the other cardiovascular functions did not respond to passive exercise.

Combined effects of age and gender on gait symmetry and regularity assessed by autocorrelation of trunk acceleration.

BACKGROUND: The gait of a healthy person is believed to be more regular and symmetrical than those of an individual with a disease. Thus, symmetry and regularity are important indicators of human gait. METHODS: The effects of age and gender on gait symmetry and regularity were investigated in 87 Japanese participants by measuring trunk accelerometry during a 7-m walk. The younger group included 26 female and 21 male students, and the elderly group included 24 females and 16 males. Average age for each group was 20 and 70 years, respectively. Gait symmetry and regularity were evaluated on the basis of autocorrelation functions of trunk accelerations of vertical and anteroposterior axes. RESULTS: The relationship between age and gait symmetry and regularity was statistically significant for both vertical and anteroposterior axes. Elderly participants showed lower symmetry and regularity in their gait than young participants. A significant gender effect was observed for the symmetry index of both axes but not for the regularity index. Male participants showed lower gait symmetry than females. An interaction effect between age and gender was significant in the symmetry index of anteroposterior acceleration. Gender effect was appeared more clearly in elderly than young participants. CONCLUSION: Elderly participants showed a more asymmetrical and irregular gait than young participants. In addition to age, a significant gender effect was observed on gait symmetry. However, the effect size of gender was smaller than that of age, and it was not significant for gait regularity. The gait indices obtained by autocorrelation of trunk acceleration can be considered useful to evaluate aging effect on gait.

Effect of nutritional status on occurrence of pneumonia after traumatic cervical spinal cord injury.

Pneumonia after cervical spinal cord injury (CSCI) is a common and serious complication; however, its nutrition-related etiology has not yet been elucidated. This study aimed to elucidate the effects of nutritional factors on pneumonia after CSCI. Patients with acute traumatic CSCI who were admitted within 3 days after injury and followed up for at least 3 months were retrospectively examined. Occurrence of pneumonia, nutritional status, severity of dysphagia, vital capacity, use of respirators, and motor scores for paralysis were evaluated. Of 182 patients included in this study, 33 (18%) developed pneumonia. Multiple logistic regression analysis revealed that low nutritional status, severe paralysis, and low vital capacity were significant risk factors for pneumonia. The severity of paralysis, respiratory dysfunction, and poor nutritional status can affect the occurrence of pneumonia after CSCI. In addition to respiratory management, nutritional assessment and intervention may play key roles in preventing pneumonia associated with spinal cord injury-induced immune depression. Nutritional care should be provided as soon as possible when the nutritional status of a patient worsens after an injury.

Impact of the width and shape of the sliding board on design evaluation.

This study aimed to investigate how width affects the design evaluation of sliding boards with a new shape. Ten caregivers at a senior facility evaluated five types of boards every two weeks. The new shape board received high ratings as the width increased, with a SUS (System Usability Scale) score of 68.5 points (95% CI 60.6-76.4). Compared to the traditional rectangular board, which had a width of 250 mm and a thickness of 5 mm, the new shape board (with a central width of 163 mm and a thickness of 8 mm) received higher ratings by 0.68 points (95% CI 0.31-1.05)using a paired comparison method. The results of a quantitative study on the usability of sliding boards from the perspective of caregivers indicated that for similar board shapes with a length of 650 mm and a thickness of 8 mm, the evaluation increases as the width increases in the range of 130 mm to 163 mm at the center.

Effect of measurement duration on accuracy of pulse-counting.

In this study, the relation between the measurement duration and accuracy of pulse-counting was quantitatively examined with special reference to low-frequency fluctuations in heart rate variability. The interbeat intervals of 70 healthy male subjects were measured in standing, sitting and supine positions. Pulse rates for various durations were calculated by objective-scoring simulation based on the heartbeat recordings of the subjects. The duration of pulse-counting continuously varied from 6 to 60 s in the simulation. Simulated pulse rates were compared with the rate calculated from the 60 s that includes the given duration, and the absolute difference between the two rates was defined as the error. Average errors of pulse-counting for 15 s were 1.89, 1.89 and 1.80 bpm for standing, sitting and supine positions, respectively. No difference in error was observed between standing and sitting positions; however, smaller errors were observed in the supine position.

Combined Effect of Walking and Forest Environment on Salivary Cortisol Concentration.

We investigated the effects of walking in a forest environment on salivary cortisol concentrations. Seventy-four young male participants walked for 15 min in forested and urban environments, and saliva was collected before and after walking. Our previous study reported salivary cortisol concentrations after walking only. This study was aimed at clarifying the combined effects of walking and environment by comparing post-walking data with pre-walking data. Walking in a forest environment decreased mean cortisol concentration from 9.70 to 8.37 nmol/L, whereas walking in an urban environment barely changed mean cortisol concentration, from 10.28 to 10.01 nmol/L. Two-way repeated analysis of variance revealed a significant interaction effect between the environment and walking (p < 0.001) in addition to the main effects of each (p < 0.001 and p = 0.001, for walking and environment, respectively). For further analysis, the proportion of participants who exhibited decreased cortisol after forest-walking was compared with the previously reported proportion of participants who exhibited decreased cortisol after viewing forest landscapes. Although the proportion of positive responders was slightly higher after walking (69%) than it was after viewing (60%), this difference was not statistically significant (p = 0.093). The present study revealed a significant combined effect of walking and the environment on cortisol concentrations.

Physiological and Psychological Effects of Forest and Urban Sounds Using High-Resolution Sound Sources.

Exposure to natural sounds is known to induce feelings of relaxation; however, only few studies have provided scientific evidence on its physiological effects. This study examined prefrontal cortex and autonomic nervous activities in response to forest sound. A total of 29 female university students (mean age 22.3 ± 2.1 years) were exposed to high-resolution sounds of a forest or city for 60 s, using headphones. Oxyhemoglobin (oxy-Hb) concentrations in the prefrontal cortex were determined by near-infrared spectroscopy. Heart rate, the high-frequency component of heart rate variability (which reflects parasympathetic nervous activity), and the ratio of low-frequency to high-frequency (LF/HF) components (which reflects sympathetic nervous activity) were measured. Subjective evaluation was performed using the modified semantic differential method and profiles of mood states. Exposure to the forest sound resulted in the following significant differences compared with exposure to city sound: decreased oxy-Hb concentrations in the right prefrontal cortex; decreased ln(LF/HF); decreased heart rate; improved feelings described as "comfortable,'' "relaxed," and "natural"; and improved mood states. The findings of this study demonstrated that forest-derived auditory stimulation induced physiological and psychological relaxation effects.

Forest Walking Affects Autonomic Nervous Activity: A Population-Based Study.

The present study aimed to evaluate the effect of walking in forest environments on autonomic nervous activity with special reference to its distribution characteristics. Heart rate variability (HRV) of 485 male participants while walking for ~15 min in a forest and an urban area was analyzed. The experimental sites were 57 forests and 57 urban areas across Japan. Parasympathetic and sympathetic indicators [lnHF and ln(LF/HF), respectively] of HRV were calculated based on ~15-min heart rate recordings. Skewness and kurtosis of the distributions of lnHF and ln(LF/HF) were almost the same between the two environments, although the means and medians of the indicators differed significantly. Percentages of positive responders [presenting an increase in lnHF or a decrease in ln(LF/HF) in forest environments] were 65.2 and 67.0%, respectively. The percentage of lnHF was significantly smaller than our previous results on HRV during the viewing of urban or forest landscapes, whereas the percentage of ln(LF/HF) was not significantly different. The results suggest that walking in a forest environment has a different effect on autonomic nervous activity than viewing a forest landscape.

Adult-onset neuronal intranuclear inclusion disease presented transient global amnesia-a case report.

A 65-year-old man had a transient amnesia for about 3 hours. Similar symptoms appeared three years ago. He did not manifest dementia, cerebellar ataxia and involuntary movements. Peripheral neuropathy was observed by the neurophysiological examinations. Diffusion weighted image showed high intensity signal in the area of the corticomedullary junction of the frontal to parietal lobes and immunohistochemical studies of biopsied skin revealed many intranuclear inclusion bodies. Adult-onset neuronal intranuclear inclusion disease was diagnosed. As there was no similar member in his family, he was a sporadic case. Clinical characteristics of his amnesia was fulfilled with the criteria of transient global amnesia (TGA). The transient disturbance of limbic system was suspected.

Diurnal Changes in Distribution Characteristics of Salivary Cortisol and Immunoglobulin A Concentrations.

Salivary cortisol and secretory immunoglobulin A (S-IgA) are important biomarkers for environmental and public health research. The present study investigated the diurnal variations of these salivary biomarkers, with a focus on the change of distribution characteristics (i.e., skewness and kurtosis) of the concentrations. The participants in this study were 113 healthy young males. Salivary samples were collected in the morning (6:30-7:30 a.m.) and afternoon (1:00-4:00 p.m.). The skewness and kurtosis of salivary cortisol concentrations in afternoon samples (skewness = 1.06, kurtosis = 4.78) were significantly higher than those in morning samples (skewness = 0.49, kurtosis = 2.80). The differences in skewness and kurtosis of S-IgA concentrations were non-significant; however, the standard deviation and interquartile ranges for afternoon S-IgA concentrations were significantly smaller than those for morning S-IgA concentrations. Logarithmic transformation improved the distribution of afternoon cortisol values, making it an almost normal distribution, but the transformation showed no improvement in the distribution of morning cortisol or S-IgA values. The present study explored diurnal changes in the distribution characteristics of salivary cortisol and S-IgA. Consideration of a possible diurnal change in the distribution characteristics is needed when we compare the difference in these salivary biomarkers between different times of day.

Population-Based Study on the Effect of a Forest Environment on Salivary Cortisol Concentration.

The purpose of this study was to evaluate the effect of a forest environment on salivary cortisol concentration, particularly on the characteristics of its distribution. The participants were 348 young male subjects. The experimental sites were 34 forests and 34 urban areas across Japan. The subjects viewed the landscape (forest or urban environment) for a period of 15 min while sitting in a chair. Saliva was sampled from the participants at the end of this 15-min period and then analyzed for cortisol concentration. Differences in the skewness and kurtosis of the distributions between the two environments were tested by performing a permutation test. The cortisol concentrations exhibited larger skewness (0.76) and kurtosis (3.23) in a forest environment than in an urban environment (skewness = 0.49; kurtosis = 2.47), and these differences were statistically significant. The cortisol distribution exhibited a more peaked and longer right-tailed curve in a forest environment than in an urban environment.

Distribution characteristics of salivary cortisol measurements in a healthy young male population.

BACKGROUND: Salivary cortisol has been used in various fields of science as a non-invasive biomarker of stress levels. This study offers the normative reference values of cortisol measurement for healthy young males. FINDINGS: Salivary cortisol levels were measured in 267 healthy young males (age: 21.7 ± 1.5 years) in the early morning on two consecutive days and were analyzed by radioimmunoassay. Frequency distribution analysis was conducted with mean values of the measurements taken on the 2 days. The mean salivary cortisol level was 20.39 ± 7.74 nmol/l (median: 19.31 nmol/l). The skewness and kurtosis of the distribution of the raw data were 0.72 and 0.68, respectively. They were both improved by a square root transformation but not by a logarithmic transformation. CONCLUSIONS: The skewness of the distribution for salivary cortisol measured in the early morning is considerably smaller than that previously reported from afternoon measurements. A "floor effect" may be an explanation for the difference in the distribution characteristics of salivary cortisol.

Seasonality in physical activity and walking of healthy older adults.

BACKGROUND: An increasing number of older adults require improvements in their quality of life. Physical activities, particularly walking ability, are of primary importance for older adults. The influence of season on physical activity has not been sufficiently studied among older adults. Therefore, this report compared the physical activity and walking of older individuals between summer and winter seasons using a longitudinal study design in a community in a mid-latitude area. METHODS: Participants in the study comprised 39 healthy community-dwelling adults ranging in age from 65 to 80 years. Physical parameters and activities as well as the preferred speed of walking were measured at half-year intervals. RESULTS: Significant seasonal differences from summer to winter and from winter to summer were detected. Specifically, body fat percentage, single-leg stance, walking speed, cadence, stride length, and trunk and head-trunk pitch ranges were greater in winter than in summer, whereas grip strength and steps per day were greater in summer. Temperature and total activity level were considered to be related to body fat percentage. Grip strength was thought to be affected by outdoor temperature. The possibility of relationships between increased activity per unit time in older adults and increased preferred walking speed, cadence, and stride length in winter temperatures was discussed. CONCLUSION: The seasonal climatic environment of the geographic area of this study affected the activity level of the participants. These results indicate that seasonality should be considered when analyzing physical activity and walking in older adults.

Analysis of Individual Variations in Autonomic Responses to Urban and Forest Environments.

Autonomic responses to urban and forest environments were studied in 625 young male subjects. The experimental sites were 57 forests and 57 urban areas across Japan. The subjects viewed the landscape (forest or urban environment) for a period of 15 min while sitting on a chair. During this period, heart rate variability (HRV) was monitored continuously. The results were presented as histograms and analyzed with special reference to individual variations. Approximately 80% of the subjects showed an increase in the parasympathetic indicator of HRV (lnHF), whereas the remaining subjects showed a decrease in the parasympathetic activity. Similarly, 64.0% of the subjects exhibited decreases in the sympathetic indicator of HRV (ln[LF/HF]), whereas the remaining subjects showed opposite responses. Analysis of the distribution of HRV indices (lnHF and ln[LF/HF]) demonstrated the effect of forest environments on autonomic activity more specifically than the conventional analysis based on the difference in mean values.

[A Clinical and Radiological Comparison of Adult- and Childhood-onset Tuberous Sclerosis Complex].

In this study, we assessed 11 patients who were definitively diagnosed with tuberous sclerosis complex (TSC) based on the accepted clinical diagnostic criteria (Roach, 1998). We compared the clinical and radiological findings of six adult-onset TSC cases (group A) and five child-onset TSC cases (group B). The prevalence rates of generalized tonic-clonic convulsions at onset, mental retardation, facial angiofibroma, and epilepsy were lower in group A than in B group. The number of cortical tubers and subependymal nodules on brain magnetic resonance (MR) and computed tomography (CT) images were also lower in group A. The number of cerebral white matter radial migration lines was similar in both groups. Cortical tubers were most frequently observed in the frontal lobe in both groups. The number of cortical tubers and subependymal nodules did not correlate with the presence of epilepsy or mental retardation. Extra-brain lesions in lung, kidney, and bone were recognized in both groups, and no specific lesions were noted in group A.

Acute ischemic stroke associated with nephrotic syndrome: Incidence and significance - Retrospective cohort study.

We report 10 cases with arterial ischemic stroke (AIS) with nephrotic syndrome (NS), and clarified its incidence and clinical characteristics. The patients having albumin less than 3.0 g/dl and serum cholesterol greater than 250 mg/dl at the same time were retrospectively screened from 11,161 cases of stroke. Furthermore, the patients of AIS showing heavy proteinuria were selected. The 10 cases were diagnosed as AIS with NS. Its incidence was 0.09% of all kinds of stroke and 0.12% of AIS. Their subtypes were 6 large-artery atherosclerosis, 3 small-vessel occlusion, and 1 cardioembolism. We carried out a retrospective cohort study to assess the association between NS and atherosclerosis progression in AIS patients. Seven AIS patients with NS due to diabetic nephropathy (cases; NS group) were compared with patients with AIS and diabetes mellitus (DM) without NS (control group). Control group subjects were matched in a 2:1 ratio to cases by age, sex, use of medications for DM, and hemoglobin A1c (HbA1c) level. The NS group had high cerebral artery atherosclerosis scores, especially in the anterior circulation. The NS group demonstrated atherosclerosis of the internal carotid and lower extremity arteries, although there were no statistical differences between the two groups. Study subjects had high serum fibrinogen and D-dimer levels, suggesting that AIS patients with NS have a greater degree of hypercoagulability than AIS patients without NS.

Normative references of heart rate variability and salivary alpha-amylase in a healthy young male population.

BACKGROUND: This study aimed to present normative reference values of heart rate variability and salivary alpha-amylase in a healthy young male population with a particular focus on their distribution and reproducibility. METHODS: The short-term heart rate variability of 417 young healthy Japanese men was studied. Furthermore, salivary alpha-amylase was measured in 430 men. The average age of the subjects were 21.9 years with standard deviation of 1.6 years. Interindividual variations in heart rate variability indices and salivary alpha-amylase levels were plotted as histograms. Data are presented as the mean, median, standard deviation, coefficient of variation, skewness, kurtosis, and fifth and 95th percentiles of each physiological index. RESULTS: Mean recorded values were heart period 945.85 ms, log-transformed high frequency component 9.84 ln-ms2, log-transformed low frequency component 10.42 ln-ms2, log-transformed low frequency to high frequency ratio 0.58 ln-ratio, standard deviation of beat-to-beat interval 27.17 ms and root mean square of successive difference 37.49 ms. The mean value of raw salivary alpha-amylase was 17.48 U/mL, square root salivary alpha-amylase 3.96 sqrt[U/mL] and log-transformed salivary alpha-amylase 2.65 ln[U/mL]. Log-transformed heart rate variability indices exhibited almost symmetrical distributions; however, time-domain indices of heart rate variability (standard deviation of beat-to-beat interval and root mean square of successive difference) exhibited right-skewed (positive skewness) distributions. A considerable right-skewed distribution was observed for raw salivary alpha-amylase. Logarithmic transformation improved the distribution of salivary alpha-amylase, although square root transformation was insufficient. The day-to-day reproducibility of these indices was assessed using intraclass correlation coefficients. Intraclass correlation coefficients of most heart rate variability and salivary indices were approximately 0.5 to 0.6. Intraclass correlation coefficients of raw salivary markers were approximately 0.6, which was similar to those of heart rate variability; however, log transformation of the salivary markers did not considerably improve their reproducibility. Correlations between sympathetic indicators of heart rate variability and salivary alpha-amylase were not observed. CONCLUSION: Because the sample population examined in this study involved limited age and gender variations, the present results were independent of these factors and were indicative of pure interindividual variation.

Does paced breathing improve the reproducibility of heart rate variability measurements?

The effects of paced breathing (PB) on the reproducibility of heart rate variability (HRV) measurements were examined in 55 male subjects (age range: 20-54 years). Spectral components of HRV were measured under a combination of two respiratory conditions (spontaneous and 4s PB) and two postures (standing and supine). The procedures were repeated 3 weeks after the first measurement. Log-transformed low-frequency (lnLF) and high-frequency (lnHF) components of HRV were calculated from a 205s electrocardiography (ECG) recording. The coefficients of interindividual variations of lnHF and lnLF (ca. 13-16%) and the intraindividual variations of the frequency components (5-6%) were not significantly affected by PB. The coefficients of intraindividual variation of heart rate, ln HF and ln LF did not correlate with age in either posture. Effect sizes of PB on the intraindividual variation ranged from -0.04 to 0.13. Although intraclass correlation coefficients (ICCs) were slightly improved by PB in some cases, the differences were negligible. The above results suggest that PB provides a limited improvement in the reproducibility of HRV measurements, and metronome-guided respiration is not necessarily required for HRV measurement if subjects are reminded to avoid irregular respiration.

Inter- and intra-individual variations of heart rate variability in Japanese males.

Spectral components of heart rate variability (HRV) were repeatedly measured (4-8 measurements; mean: 6 measurements) in 75 healthy Japanese male subjects (age range: 20-61) under two postural conditions (standing and supine). Low-frequency (LF) and high-frequency (HF) components and mean heart rate (HR) were analyzed with special reference to individual variations, which were classified into two types: inter- (interV) and intra-individual variations (intraV). The percent contributions and coefficients of variations were calculated for both interV and intraV. Percent contributions of intraV (intraV%) of HR with standing and supine postures were 15.8 and 12.9%, respectively. The intraV% of HF and LF on standing were 31.5 and 26.5%, while those in the supine posture were 27.8 and 35.5%, respectively. The coefficients of interV (interCV) and intraV (intraCV) were also calculated. The interCVs of HR, HF, and LF on standing were 14.9, 41.4, and 48.4%, while those in the supine posture registered 16.2, 42.9, and 44.2%, respectively. The intraCVs of HR, HF, and LF on standing were 5.0, 19.7, and 21.2%, while those in the supine posture indicated 4.7, 20.1, and 23.0%, respectively. We also calculated the interV and intraV of logarithmic-transformed HRV indexes. The log-transformation remarkably diminished both variables: interCV and intraCV registered 14-16 and 6-7%, respectively. Although interV variations were considerably large, intraV variations of HRV were negligibly small. The HRV indexes decreased with age, although HR remained unchanged. The coefficients of determination (r2) were 14-34%. In the case of log-transformed HRV indexes, the coefficients of determination registered 9-15%, suggesting that 14-34% (raw) or 9-15% (log) of the observed interV may be due to variations in age.