No abstract

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that is applied during stroke rehabilitation. The purpose of this study was to examine diachronic intracranial hemodynamic changes using near-infrared spectroscopy (NIRS) during tDCS applied to the primary motor cortex (M1). Seven healthy volunteers were tested during real stimulation (anodal and cathodal) and during sham stimulation. Stimulation lasted 20 min and NIRS data were collected for about 23 min including the baseline. NIRS probe holders were positioned over the entire contralateral sensory motor area. Compared to the sham condition, both anodal and cathodal stimulation resulted in significantly lower oxyhemoglobin (O2Hb) concentrations in the contralateral premotor cortex (PMC), supplementary motor area (SMA), and M1 (p<0.01). Particularly in the SMA, the O2Hb concentration during anodal stimulation was significantly lower than that during the sham condition (p<0.01), while the O2Hb concentration during cathodal stimulation was lower than that during anodal stimulation (p<0.01). In addition, in the primary sensory cortex, the O2Hb concentration during anodal stimulation was significantly higher than the concentrations during both cathodal stimulation and the sham condition (p<0.05). The factor of time did not demonstrate significant differences. These results suggest that both anodal and cathodal tDCS cause widespread changes in cerebral blood flow, not only in the area immediately under the electrode, but also in other areas of the cortex.

Near-infrared spectroscopy (NIRS) is a widely used noninvasive method for measuring human brain activation based on the cerebral haemodynamic response. However, systemic changes can influence the signal's parameters. Our study aimed to investigate the relationships between NIRS signals and skin blood flow (SBF) or blood pressure during dynamic movement. Nine healthy volunteers (mean age, 21.3 ± 0.7 years; 6 women) participated in this study. The oxyhaemoglobin (O2Hb) signal, SBF, and mean arterial pressure (MAP) were measured while the volunteers performed multi-step incremental exercise on a bicycle ergometer, at workloads corresponding to 30, 50, and 70 % of peak oxygen consumption (VO2peak) for 5 min. The Pearson's correlation coefficients for the O2Hb signal and SBF at 50 and 70 % VO2peak were 0.877 (P < 0.01) and -0.707 (P < 0.01), respectively. The correlation coefficients for O2Hb and MAP during warm-up, 30 % VO2peak, and 50 % VO2peak were 0.725 (P < 0.01), 0.472 (P < 0.01), and 0.939 (P < 0.01), respectively. Changes in the state of the cardiovascular system influenced O2Hb signals positively during low and moderate-intensity exercise, whereas a negative relationship was observed during high-intensity exercise. These results suggest that the relationship between the O2Hb signal and systemic changes is affected by exercise intensity.

Aim Intensive rehabilitation effectively improves physical functions in patients with acute stroke, but the frequency of intervention and its cost‐effectiveness are poorly studied. This study aimed to examine the effect of early high‐frequency rehabilitation intervention on inpatient outcomes and medical expenses of patients with stroke. Methods The study retrospectively included 1759 patients with acute stroke admitted to the Kobe City Medical Center General Hospital between 2013 and 2016. Patients with a transient ischemic attack, subarachnoid hemorrhage, and those who underwent urgent surgery were excluded. Patients were divided into two groups according to the frequency of rehabilitation intervention: the high‐frequency intervention group (>2 times/day, n = 1105) and normal‐frequency intervention group (<2 times/day, n = 654). A modified Rankin scale score ≤2 at discharge, immobility‐related complications and medical expenses were compared between the groups. Results The high‐frequency intervention group had a significantly shorter time to first rehabilitation (median [interquartile range], 19.0 h [13.1–38.4] vs. 24.7 h [16.1–49.4], P < 0.001) and time to first mobilization (23.3 h [8.7–47.2] vs. 22.8 h [5.7–62.3], P = 0.65) than the normal‐frequency intervention group. Despite higher disease severity, the high‐frequency intervention group exhibited favorable outcomes at discharge (modified Rankin scale, ≤2; adjusted odds ratio, 1.89; 95% confidence interval, 1.25–2.85; P = 0.002). No significant differences were observed between the two groups concerning the rate of immobility‐related complications and total medical expenses during hospitalization. Conclusions High‐frequency intervention was associated with improved outcomes and decreased medical expenses in patients with stroke. Our results may contribute to reducing medical expenses by increasing the efficiency of care delivery. Geriatr Gerontol Int 2021; 21: 623–628.

No specific hip joint anatomy has been identified as a risk factor for anterior cruciate ligament (ACL) injury in females. This study was conducted to elucidate the correlation of hip rotation with ACL injury incidence in female handball players, and to clarify the association of hip rotation with knee valgus motion, during ACL injury screening tasks, that is a strong predictor of ACL injury. Of 17 female university handball players, the 8 ACL-injured players displayed greater internal and smaller external rotation of the hip than the 9 uninjured players. Logistic regression analyses demonstrated significant association between hip rotation and ACL injury. Hip internal rotation dominance (internal rotation range is greater than external one) was found in 7 out of the 8 ACL-injured females in contrast to 3 out of the 9 uninjured. Knee valgus was induced in 24 and 22 of the 31 healthy female volunteers by vertical jump and single-leg squat tests, respectively. The knee valgus-positive females showed a smaller range of hip external rotation than the negative ones, which was significantly associated with knee valgus during the screening tests. Hip internal rotation dominance was significantly related to knee valgus induced by each screening test. In contrast to the females, male subjects showed lower rates of knee valgus induction by the screening tests, whereas there was no clear association between hip internal rotation dominance and the knee valgus induction. The present findings may indicate the important role of hip rotation measurement in identification of females at risk for ACL injury.