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INTRODUCTION: Disparities in physical fitness between immediately before dialysis (pre-D) and the day following dialysis (non-D) have not been investigated despite potential adverse factors such as fluid status, uremia, and electrolyte levels in the pre-dialysis period. The effect of acute exercise immediately before hemodialysis (HD) on HD-related hypotension remains unclear. We hypothesized that cardiopulmonary performance and muscular strength would be inferior in the immediate pre-D period compared to those non-D. METHODS: Twenty patients receiving chronic HD treatments underwent symptom-limited incremental cardiopulmonary exercise testing (CPET) and isokinetic testing both 1-2 h prior to dialysis (pre-D) and non-D. This investigation was a sub-study of a clinical trial assessing the efficacy of a pre-D exercise training program. Blood pressure profiles during HD post-CPET and pre-D exercise training were compared with those during usual HD sessions. RESULTS: No adverse events were observed during the 80 exercise tests. Prior to dialysis, the nadir of the ventilatory equivalent of CO2 was slightly elevated, the resting heart rate was lower, and the peak systolic blood pressure was higher than those non-D. Contrary to our hypothesis, peak V˙O2 and quadriceps peak torque showed no differences. Blood pressure profiles during HD post-exercise were similar to those during sessions without prior exercise, except for a lower resting systolic blood pressure at the beginning of HD. CONCLUSION: Cardiopulmonary response and muscular strength in the 1-2 h prior to HD were comparable with those on the day following HD, with only minor clinically insignificant differences. Acute exercise prior to HD did not affect the magnitude of hypotension during HD. This study suggests a potential alternative timing for exercise training or testing in patients undergoing chronic HD.

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The present study found that using viral filters at the proximal end of a spirometry and CPET test circuit did not significantly alter the test results, with the exception of a marginal decrease noted in peak work rate https://bit.ly/3Vkew95.

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Background: Unilateral vocal fold paralysis (UVFP) affects the glottal gap, voice, and aerodynamics, whereas injection laryngoplasty (IL) using hyaluronate is an effective treatment for UVFP by decreasing the glottal gap to improve voice. Previous studies have shown that the involvement of cricothyroid (CT) muscle in UVFP patients further affects patients' aerodynamics, but it remains unclear whether the difference remains after IL. This study investigates whether the aerodynamic features observed in UVFP with CT involvement could still be observed after IL. Methods: This study recruited UVFP patients with dysphonia, and IL was performed within 6 months of initial symptoms. All subjects received assessments including videolaryngoscopy, voice analysis, and aerodynamics at three time points: before IL, 1 month after IL, and 6 months after IL. The glottal gap, voice, and aerodynamics between patients with and without CT involvement (the CT+ and CT- groups) were compared, and the change (Δ) before and after IL and repeated-measures analysis of variance (ANOVA) were also compared between the two groups. Result: A total of 71 patients with UVFP (22 in the CT+ group and 49 in the CT- group) were analyzed. After IL, the CT+ group showed a lower sound pressure level (SPL), higher Δair pressure, and smaller Δaerodynamic power than the CT- group. Conclusion: The CT+ group had a lower SPL, even after elevating air pressure to attempt to achieve a higher vocal intensity. The results suggest that although closure of the glottal gap was achieved by IL, the CT+ group still had a lower loudness and needed to sustain a higher peak air pressure when producing voice. Level of evidence: Level 4.

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Unilateral vocal fold paralysis (UVFP) causes glottal incompetence and poor vocal efficiency. The influence of laryngeal neuromuscular control on aerodynamics in UVFP remains unclear. This study investigated the relationship between laryngeal muscle activities using quantitative laryngeal electromyography (LEMG) and aerodynamics in UVFP. This prospective study recruited patients with UVFP, and the diagnosis was confirmed with videolaryngostroboscopy and LEMG. The patient received aerodynamic assessment and LEMG of the thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex and the cricothyroid (CT) muscle. The relationship between quantitative LEMG and aerodynamic parameters was analyzed. A total of 134 UVFP patients without concurrent CT muscle involvement were enrolled. Compared with the normal side, the peak turn frequency of the lesioned side was lower in the TA-LCA (p < 0.001) and CT (p = 0.048) muscles. Stepwise linear regression revealed that the turn ratio of TA-LCA muscles was a robust factor in the decrease in peak expiratory airflow (ß = −0.34, p = 0.036), mean airflow during voicing (ß = −0.28, p = 0.014), and aerodynamic power (ß = −0.42, p = 0.019), and an increase in aerodynamic efficiency (ß = 27.91, p = 0.012). In addition, the turn ratio of CT muscles was a potent factor in inducing an increase in aerodynamic resistance (ß = 14.93, p = 0.029). UVFP without CT involvement still showed suppression of CT muscles on the lesioned side, suggesting that neurological impairment of the TA-LCA complex could cause asymmetrical compensation of CT muscles, further impeding aerodynamics. The residual function of TA-LCA muscle complexes facilitates less air leakage and power dissipation, enhancing aerodynamic efficiency. On the other hand, the symmetrical compensation of the CT muscles improves aerodynamic resistance.

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BACKGROUND: Emerging evidence has revealed that cricothyroid (CT) muscle dysfunction in unilateral vocal fold paralysis (UVFP) further impairs patients' voices. Given that CT muscle dysfunction does not influence vocal fold position, the mechanism of voice dysfunction induced by dysfunction of CT muscle in UVFP patients remains controversial. This study compares aerodynamics between UVFP patients with and without CT muscle involvement. METHODS: This cross-sectional study recruited patients with UVFP manifesting dysphonia, and UVFP was confirmed with videolaryngoscopy and laryngeal electromyography (LEMG). Voice analysis and aerodynamic tests were further performed. Patients with (CT+ group) and without (CT- group) CT muscle involvement were compared. RESULT: A total of 175 patients (40 in the CT+ group and 135 in the CT- group) with UVFP were analyzed. The CT+ group showed lower maximal sound pressure level (SPL) (P=0.039), mean SPL (P=0.042), peak air pressure (P<0.001), mean peak air pressure (P<0.001) and aerodynamic power (P=0.004) than the CT- group. CONCLUSION: The decrease in SPL, peak air pressure, and aerodynamic power in UVFP patients with CT muscle dysfunction suggests that the effect of CT muscle dysfunction is mediated by a change in aerodynamics.

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It is important to use short breaks to accelerate post-exercise recovery in sports. Previous studies have revealed that vibration can reduce post-exercise muscle soreness. However, there is still high heterogeneity in the effects of vibration on cardiovascular autonomic activities, and most studies to date have focused on high-frequency vibration. This study aimed to investigate the effect of low-frequency lower-body vibration (LBV) on post-exercise changes in heart rate variability and peripheral arterial tone. Ten men and 9 women aged 20 to 25 were recruited for this study. Each subject visited the testing room three times with at least 2 days in between. Each time, the subject received one of the three different vibration frequencies (0, 5, and 15 Hz) in a random order in the sitting position for 10 minutes. LBV was performed immediately after a static standing (control) test and 3-min-step test. Heart rate variability and digital volume pulse wave were recorded during the vibration phase (V1: vibration 0-5 minutes; V2: 6-10 minutes) and the recovery phase (Rc1: recovery phase 11-15 minutes; Rc2: 16-20 minutes). The result of digital pulse wave analysis showed that the reflection index (RI) under 15 Hz decreased during V1. Heart rate of the 15-Hz group also decreased during Rc1 and Rc2. According to the analysis of heart rate variability, low-frequency power/high-frequency power (LF/HF) decreased and normalized high-frequency power (nHF) increased during V2, Rc1 and Rc2 under 15 Hz and, during Rc2 under 5 Hz vibration. This study confirmed that the application of low-frequency LBV after exercise can reduce peripheral vascular tone, accelerate heart rate recovery, decrease cardiac sympathetic nerve activity, and promote parasympathetic nerve activity. The effect was more pronounced at 15 Hz than at 5 Hz. The findings provide a method to accelerate cardiovascular autonomic recovery after exercise.

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We hypothesized that blood lactate concentration([Lac]blood) is a function of cardiopulmonary variables, exercise intensity and some anthropometric elements during aerobic exercise. This investigation aimed to establish a mathematical model to estimate [Lac]blood noninvasively during constant work rate (CWR) exercise of various intensities. 31 healthy participants were recruited and each underwent 4 cardiopulmonary exercise tests: one incremental and three CWR tests (low: 35% of peak work rate for 15 min, moderate: 60% 10 min and high: 90% 4 min). At the end of each CWR test, venous blood was sampled to determine [Lac]blood. 31 trios of CWR tests were employed to construct the mathematical model, which utilized exponential regression combined with Taylor expansion. Good fitting was achieved when the conditions of low and moderate intensity were put in one model; high-intensity in another. Standard deviation of fitting error in the former condition is 0.52; in the latter is 1.82 mmol/liter. Weighting analysis demonstrated that, besides heart rate, respiratory variables are required in the estimation of [Lac]blood in the model of low/moderate intensity. In conclusion, by measuring noninvasive cardio-respiratory parameters, [Lac]blood during CWR exercise can be determined with good accuracy. This should have application in endurance training and future exercise industry.

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Huang, Shu-Chun, Kuo-Cheng Liu, Alice M.K. Wong, Shih-Chieh Chang, and Jong-Shyan Wang. Cardiovascular autonomic response to orthostatic stress under hypoxia in patients with spinal cord injury. High Alt Med Biol. 19:201-207, 2018. AIMS: Determining whether systemic hypoxia aggravates the severity of autonomic cardiovascular dysfunction in orthostatic stress among patients with spinal cord injuries (SCIs). METHODS: Twenty-four male patients with chronic SCI whose neurological levels were above T6 were recruited. Twenty-five healthy men were enrolled in the control group. Five-minute supine rest (SR) and head-up tilt (HUT) at 60° were performed in normoxia and after 1 hour, 13.5% fraction of inspired O2 exposure. A noninvasive cardiac output (CO) monitor was used to measure stroke volume (SV), CO, total peripheral resistance (TPR), and blood pressure (BP), whereas heart rate variability (HRV) was performed to determine cardiac autonomic activity. Digital volume pulse analysis was applied to measure arteriolar tone. RESULTS: In normoxia from SR to HUT, systolic and diastolic BPs declined, SV decreased, and heart rate increased, whereas CO and TPR showed a declining trend in the SCI group. Sympathetic activation and vagal withdrawal were also disclosed in the HRV analysis. In hypoxia, the change of these cardiovascular responses from SR to HUT exhibited no difference to normoxia in the SCI group. No significant difference in arterial desaturation was observed between the two groups (82.9% vs. 80.4%). CONCLUSIONS: Cardiovascular adaptation to orthostatic stress is not affected by subacute steady-state hypoxia in chronic SCI patients with neurological levels higher than T6.

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OBJECTIVE: This study explored auditory and visual attention in children with ADHD. METHOD: In a randomized, two-period crossover design, 50 children with ADHD and 50 age- and sex-matched typically developing peers were measured with the Test of Various Attention (TOVA). RESULTS: The deficiency of visual attention is more serious than that of auditory attention in children with ADHD. On the auditory modality, only the deficit of attentional inconsistency is sufficient to explain most cases of ADHD; however, most of the children with ADHD suffered from deficits of sustained attention, response inhibition, and attentional inconsistency on the visual modality. Our results also showed that the deficit of attentional inconsistency is the most important indicator in diagnosing and intervening in ADHD when both auditory and visual modalities are considered. CONCLUSION: The findings provide strong evidence that the deficits of auditory attention are different from those of visual attention in children with ADHD.

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Transparency and robustness are two conflicting requirements demanded by digital image watermarking for copyright protection and many other purposes. A feasible way to simultaneously satisfy the two conflicting requirements is to embed high-strength watermark signals in the host signals that can accommodate the distortion due to watermark insertion as part of perceptual redundancy. The search of distortion-tolerable host signals for watermark insertion and the determination of watermark strength are hence crucial to the realization of a transparent yet robust watermark. This paper presents a color image watermarking scheme that hides watermark signals in most distortion-tolerable signals within three color channels of the host image without resulting in perceivable distortion. The distortion-tolerable host signals or the signals that possess high perceptual redundancy are sought in the wavelet domain for watermark insertion. A visual model based on the CIEDE2000 color difference equation is used to measure the perceptual redundancy inherent in each wavelet coefficient of the host image. By means of quantization index modulation, binary watermark signals are embedded in qualified wavelet coefficients. To reinforce the robustness, the watermark signals are repeated and permuted before embedding, and restored by the majority-vote decision making process in watermark extraction. Original images are not required in watermark extraction. Only a small amount of information including locations of qualified coefficients and the data associated with coefficient quantization is needed for watermark extraction. Experimental results show that the embedded watermark is transparent and quite robust in face of various attacks such as cropping, low-pass filtering, scaling, media filtering, white-noise addition as well as the JPEG and JPEG2000 coding at high compression ratios.