Differential effects of mass-loading the eardrum and stiffening the middle ear on wideband absorbance.

The current work investigated the effects of mass-loading the eardrum on wideband absorbance in humans. A non-invasive approach to mass-loading the eardrum was utilized in which water was placed on the eardrum via ear canal access. The mass-loaded absorbance was compared to absorbance measured for two alternative middle ear states: normal and stiffened. To stiffen the ear, subjects pressurized the middle ear through either exsufflation or insufflation concurrent with Eustachian tube opening. Mass-loading the eardrum was hypothesized to reduce high-frequency absorbance, whereas pressurizing the middle ear was hypothesized to reduce low- to mid-frequency absorbance. Discriminant linear analysis classification was performed to evaluate the utility of absorbance in differentiating between conditions. Water on the eardrum reduced absorbance over the 0.7- to 6-kHz frequency range and increased absorbance at frequencies below approximately 0.5 kHz; these changes approximated the pattern of changes reported in both hearing thresholds and stapes motion upon mass-loading the eardrum. Pressurizing the middle ear reduced the absorbance over the 0.125- to 4-kHz frequency range. Several classification models based on the absorbance in two- or three-frequency bands had accuracy exceeding 88%.

Cardiovascular Effects From Venous Blood Pooling in the Lower Limbs During Prolonged Sitting.

PURPOSE: To investigate whether venous blood pooling in the lower limbs from prolonged sitting induces harmful cardiovascular effects by reducing stroke volume (SV) and cardiac output (CO). METHODS: A randomized crossover trial involving 16 participants (mean age = 24.8 years ± 6.0 years, 44% women, 1 dropout) was conducted. The trial consisted of 2 conditions: cuff and noncuff, both involving 2 hours of prolonged sitting with tourniquets placed proximal to each knee. In the cuff condition, the tourniquets were inflated to subdiastolic pressure, allowing arterial inflow but preventing venous outflow. Venous blood pooling was assessed by measuring calf circumference. Cardiac Doppler sonography was used to measure CO, SV, and heart rate (HR) before and after the sitting period. RESULTS: Although the interaction effect between venous blood pooling and CO was not statistically significant (P = .190), there was a significant main effect for time (effect size [ES] = 0.36, ß = -0.238, 5.42% decrease). A medium-sized time-by-condition interaction effect for SV was observed (ES = 0.37, ß = 6.165), with a 5.87% decrease in the cuff condition and a 2.81% increase in the noncuff condition. Furthermore, there was a large interaction effect for venous blood pooling as measured by calf circumference (ES = 1.98, ß = -0.987), with a 3.69% increase in the cuff condition and a 0.03% increase in the noncuff condition. DISCUSSION: Understanding the physiological adaptations that occur during prolonged sitting can provide insight into how and how often to interrupt sitting to prevent deleterious cardiovascular effects. SV decreased during the sitting period of 120 minutes in the cuff condition and increased slightly during in the noncuff condition. However, the changes in CO and HR were more variable and were not perfectly in line with the authors' hypotheses. CONCLUSION: The findings indicate that as venous blood pooling increases during prolonged sitting, SV decreases, suggesting venous blood pooling influences certain hemodynamic changes associated with prolonged sitting.

COVID-19 Impact on Behaviors across the 24-Hour Day in Children and Adolescents: Physical Activity, Sedentary Behavior, and Sleep.

In the wake of the COVID-19 pandemic, social restrictions to contain the spread of the virus have disrupted behaviors across the 24-h day including physical activity, sedentary behavior, and sleep among children (5-12 years old) and adolescents (13-17 years old). Preliminary evidence reports significant decreases in physical activity, increases in sedentary behavior, and disrupted sleep schedules/sleep quality in children and adolescents. This commentary discusses the impact of COVID-19-related restrictions on behaviors across the 24-h day in children and adolescents. Furthermore, we suggest recommendations through the lens of a socio-ecological model to provide strategies for lasting behavior change to insure the health and well-being of children and adolescents during the COVID-19 pandemic.

Submandibular Duct Fistula Caused by a Large Sialolith: Incidental Finding in a Barium Swallow Study.

BACKGROUND: This case report details an incidental finding of a submandibular duct fistula to a patient's posterior mouth floor found on a barium swallow examination that was performed to rule out gastrological causes of substernal chest pain. The radiologist was unable to determine the cause of the filling defect at the time of the study. The patient's history revealed that a large calculus of unknown size had been passed spontaneously through the floor of the mouth, rupturing the proximal gland duct and creating the fistula. DISCUSSION: Sialolithiasis is the formation of calculi in the salivary gland and is the most common disease of the salivary glands, with the submandibular glands affected more often than others. The condition is more common in men than in women and most often affects individuals aged between 30 and 60 years. CONCLUSION: In general, the etiology of sialolithiasis is unknown. However, examining comorbidities and possible risk factors, such as tobacco use, and how they alter the saliva and the function of the salivary glands might lead to a better understanding of their cause.