Frequency-following response effect according to gender using a 10-Hz binaural beat stimulation.

BACKGROUND: Several studies have continuously investigated FFRs using binaural beat (BB) stimulations and their related effects. However, only a few studies have investigated the differences in BB stimulation effects according to basic demographic characteristics, such as gender and age. OBJECTIVE: This study aimed to determine the alpha wave activity after a 10-Hz BB stimulation and subsequently identify differences according to gender across all brain areas (frontal, central, parietal, temporal, and occipital areas). METHODS: A total of 23 healthy adults (11 male and 12 female), aged 20-29, participated in the study. For the 10-Hz BB stimulation, pure tone auditory stimuli of 250 and 260 Hz were given to the left and right ear, respectively. Through a power spectrum analysis of the phase-excluding BBs (non-BBs) and phase-including 10-Hz BBs (α-BBs), the alpha power at each brain area was estimated. These values were compared using a mixed-design ANOVA. RESULTS: With the exception of the temporal area, all other brain areas showed a significant increase in alpha power for α-BBs compared to those of non-BBs. However, the difference according to gender was not significant. CONCLUSION: The results indicated the lack of gender effects in alpha wave generation through a 10-Hz BB stimulation.

Effect of binaural beat in the inaudible band on EEG (STROBE).

This study aimed to determine the effects of the binaural beat (BB) on brainwave induction using an inaudible baseline frequency outside the audible frequency range. Experiments were conducted on 18 subjects (11 males [mean age: 25.7 ± 1.6 years] and 7 females [mean age: 24.0 ± 0.6 years]). A BB stimulation of 10 Hz was exerted by presenting frequencies of 18,000 Hz and 18,010 Hz to the left and right ears, respectively. A power spectrum analysis was performed to estimate the mean of the absolute power of the alpha frequency range (8-13 Hz). The variation in the mean alpha power during the rest and stimulation phases in each brain area was compared using the Wilcoxon signed-rank test. Compared to the rest phase, the stimulation phase with BB showed an increasing trend in the mean alpha power across all 5 brain areas. Notably, a significant increase was found in the frontal, central, and temporal areas. This is a significant study in that it determines the effects of only BB without the influence of auditory perception, which has been overlooked in previous studies.

Clinical significance of hemodialysis quality of care indicators in very elderly patients with end stage kidney disease.

INTRODUCTION: Improvement in life expectancy has increased the number of very elderly patients undergoing hemodialysis. However, it is not clear which quality measures for hemodialysis should be employed in this population. Therefore, in this paper we investigated the association between major adverse cardiovascular and cerebrovascular events (MACCE) indicators of hemodialysis quality in very elderly patients. PATIENTS AND METHODS: Data regarding a total of 29,692 patients undergoing maintenance hemodialysis (median age 61 years, 41.5% females) who participated in a national hemodialysis quality assessment program were analyzed. They were divided into < 80 years and ≥ 80 years age groups. The primary and secondary outcomes were MACCE and all-cause mortality, respectively. The association between the outcomes and some of the most widely used standard hemodialysis quality-of-care indicators, including spKt/V, hemoglobin, serum calcium, serum phosphate, and albumin levels, was evaluated. To explore the association between Cox proportional hazard models were constructed. Model 1 was adjusted for age and sex. Model 2 included additional demographic characteristics, such as Charlson Comorbidity Index (excluding diabetes), diabetes, cause of ESKD, dialysis vintage, BMI, and pre-dialysis systolic blood pressure. Model 3 was further adjusted for the main medications. To evaluate the relationship between MACCE risk and quality assessment indicators as a continuous variable, cubic spline analyses were conducted. RESULTS: During a median follow-up of 3.7 years, MACCE occurred at a higher rate in the ≥ 80-years group than in the < 80-years group (282.0 vs. 110.1 events/1000 person-years). Multivariate Cox regression analysis revealed that spKt/V, serum calcium and phosphate, and hemoglobin levels were associated with MACCE and all-cause mortality risk in patients aged < 80 years. However, these indicators showed no significant relationship with MACCE and all-cause mortality in patients aged ≥ 80 years. Low serum albumin levels were significantly associated with increased MACCE and all-cause mortality risks, regardless of age. CONCLUSION: In conclusion, hemodialysis quality-of-care indicators including spKt/V, serum calcium and phosphate levels, and hemoglobin were not related to MACCE or all-cause mortality in very elderly hemodialysis patients. However, lower serum albumin levels were associated with poor outcomes, regardless of patient age. Assuring nutritional status rather than improving hemodialysis management adequacy may be more beneficial for improving outcomes in very elderly hemodialysis patients. Further prospective evaluations are needed to confirm these findings.

Nurse Caseload and Patient Survival in Hemodialysis Units: A Korean Nationwide Cohort Study.

INTRODUCTION: The patient-to-nurse ratio is highly variable among dialysis facilities. However, there is little known about the association between nurse caseload and hemodialysis (HD) patient outcomes. We evaluated the association between patient-to-nurse ratio and mortality in the Korean patients undergoing HD. METHODS: We used HD quality assessment data and National Health Insurance Service claim data from the year of 2013 for collecting demographic and clinical data. Altogether, 21,817 patients who participated in the HD quality assessment in 2013 were included in the study. Nurse caseload was defined as the number of HD sessions performed by a nurse per working day. The patients were divided into two groups according to the nurse caseload as follows: low nurse caseload group (≤6.0) and high nurse caseload group (>6.0). We analyzed mortality risk based on nurse caseload using the Cox proportional hazard model. RESULTS: The mean age was 59.1 years, and males accounted for 58.5%. The mean hemoglobin was 10.6 g/dL and albumin was 3.99 g/dL. At the mean follow-up duration of 51.7 (20.6) months, the ratio between low and high groups was 69.6% (15,184 patients) versus 30.4% (6,633 patients). The patients in the high nurse caseload group were older and showed lower levels of hemoglobin, albumin, calcium, and iron saturation and higher levels of phosphorus than those in the low nurse caseload group. A high nurse caseload was associated with a lower survival rate. In the adjusted Cox analysis, a high nurse caseload was an independent risk factor for all-cause mortality (hazard ratio 1.08; 95% confidence interval, 1.02-1.14; p = 0.01). CONCLUSION: High nurse caseload was associated with an increased mortality risk among the patients undergoing HD. Further prospective studies are needed to determine whether a caseload of nursing staff can improve the prognosis of HD patients.

Dialysis Adequacy and Risk of Dementia in Elderly Hemodialysis Patients.

Objective: Dementia is prevalent among elderly patients undergoing hemodialysis. However, the association between dialysis adequacy and the risk of dementia is uncertain. Methods: A total of 10,567 patients aged >65 years undergoing maintenance hemodialysis who participated in a national hemodialysis quality assessment program were analyzed. The patients were classified into quartile groups based on single-pool Kt/V levels. The associations between single-pool Kt/V and the development of dementia, Alzheimer's disease (AD), and vascular dementia (VD) were examined. Results: The mean age of the patients was 72.9 years, and 43.4% were female. The mean baseline single-pool Kt/V level was 1.6 ± 0.3. During a median follow-up of 45.6 (45.6-69.9) months, there were 27.6, 23.9, and 2.8 events/1,000 person-years of overall dementia, AD, and VD, respectively. The incidences of overall dementia, AD, and VD were lowest in the highest single-pool Kt/V quartile group. Compared with the lowest single-pool Kt/V quartile, the risks of incident overall dementia and AD were significantly lower in the highest quartile [sub-distribution hazard ratio (sHR): 0.69, 95% confidence interval (CI): 0.58-0.82 for overall dementia; sHR: 0.69, 95% CI: 0.57-0.84 for AD]. Inverse relationships were found between the risks of developing overall dementia and AD, and single-pool Kt/V. However, no significant relationship was observed between single-pool Kt/V levels and VD development. Conclusions: Increased dialysis clearance was associated with a lower risk of developing dementia in elderly hemodialysis patients.

Mid-Air Tactile Sensations Evoked by Laser-Induced Plasma: A Neurophysiological Study.

This study demonstrates the feasibility of a mid-air means of haptic stimulation at a long distance using the plasma effect induced by laser. We hypothesize that the stress wave generated by laser-induced plasma in the air can propagate through the air to reach the nearby human skin and evoke tactile sensation. To validate this hypothesis, we investigated somatosensory responses in the human brain to laser plasma stimuli by analyzing electroencephalography (EEG) in 14 participants. Three types of stimuli were provided to the index finger: a plasma stimulus induced from the laser, a mechanical stimulus transferred through Styrofoam stick, and a sham stimulus providing only the sound of the plasma and mechanical stimuli at the same time. The event-related desynchronization/synchronization (ERD/S) of sensorimotor rhythms (SMRs) in EEG was analyzed. Every participant verbally reported that they could feel a soft tap on the finger in response to the laser stimulus, but not to the sham stimulus. The spectrogram of EEG evoked by laser stimulation was similar to that evoked by mechanical stimulation; alpha ERD and beta ERS were present over the sensorimotor area in response to laser as well as mechanical stimuli. A decoding analysis revealed that classification error increased when discriminating ERD/S patterns between laser and mechanical stimuli, compared to the case of discriminating between laser and sham, or mechanical and sham stimuli. Our neurophysiological results confirm that tactile sensation can be evoked by the plasma effect induced by laser in the air, which may provide a mid-air haptic stimulation method.

Effective Connectivity Analysis of Brain Activated Regions during Distracted Driving.

This study aims to use functional magnetic resonance imaging (fMRI) to assess the effective connectivity between the regions of the brain activated when driving and performing a secondary task (addition task). The subjects used an MR-compatible driving simulator ㅊ to manipulate the driving wheel with both hands and control the pedals (accelerator and brake) with their right foot as if they were driving in an actual environment. Effective connectivity analysis was performed for three regions of the right and the left hemispheres with the highest z-scores, and six of the regions of the entire brain (right and left hemisphere) activated during driving by dynamic causal modeling (DCM). In the right hemisphere, a motor control pathway related to movement control for driving performance was discovered; in the left hemisphere, the pathways in the regions related to movement control for driving performance, starting with the region associated with the secondary task, were discovered. In the whole brain, connectivity was discovered in each of the right and left hemispheres. The motor network of declarative memory, which is the connectivity of the right thalamus, left lingual gyrus, and right precentral gyrus, was worth noting. These results seem meaningful, as they demonstrate the connectivity associated with the control of voluntary movement related to memory from human experience, although limited to driving tasks.

Changes in cognitive characteristics according to 3 intensity changes by 8 vibration frequencies (STROBE).

ABSTRACT: In this study, we attempted to observe changes in cognitive characteristics according to 3 intensity changes (Level 1: 0.25 gravity, Level 2: 0.38 gravity, Level 3: 1.3 gravity) at 8 vibration frequencies (10, 50, 100, 150, 200, 225, 250, 300 Hz).The subjects were twelve male (22.1 ±â€Š0.6 years old) and twelve female (21.5 ±â€Š0.8 years old) healthy, right-handed adults with normal cognitive abilities. An experimental trial consisted of a stimulation phase (0.1 sec) in which a vibration stimulus was presented and a rest phase (6 sec) in which no vibration stimulus was presented. A selected stimulus was presented on the first knuckle of the right index finger 5 times (trials). Cognitive characteristics scores according to changes in intensity at each frequency were sampled using a subjective assessment sheet consisting of eighteen items ("ticklish," "shivery," "push," "convex," "thick," "numb," "slow," "fast," "shallow," "strike," "weak," "strong," "dense," "blunt," "heavy," "light," "stab", "no stimulus"). To identify the cognitive characteristics according to intensity changes by frequency, the 3 intensities were designated as variables, and a curve estimation regression analysis was performed.At 10 Hz, cognitive characteristics of 'blunt' increased with the intensity, and 'weak' decreased. In 100 and 225 Hz, increase or decrease in intensity led to opposite cognitive characteristics ('weak-strong' in 100 and 225 Hz, 'light-heavy' in 225 Hz). In 100 and 225 Hz, as the intensity increased, expressions on the sense of surface such as 'blunt' were superior, and the shape of an object (thick) and dynamics (push) differed with the change in intensity. In addition, in 225 Hz, decrease in intensity led to increase in cognitive characteristics such as 'light' and 'shallow. 'Fast' was unique in that it only appeared as the intensity increased at 300 Hz.