Ugur Dal

Vagus nerve signals from the gut to brain carry information about nutrients and drive food reward. Such signals are disrupted by consuming large amounts of high-calorie foods, necessitating greater food intake to elicit a similar neural response. Non-invasive vagus nerve stimulation (nVNS) via a branch innervating the ear is a candidate treatment for obesity in humans. There is disagreement on the optimal location of nVNS in the ear for experimental and clinical studies. There are also no studies comparing nVNS in hungry and full states. We aimed to compare ear position(s) for nVNS and explore the effects of nVNS during hungry and full states on proxies for autonomic outflow (heart-rate variability) and efferent metabolism (gastric frequency and resting energy expenditure). In a within-subject design, 14 participants (10 women, on average 29.4 +/- 6.7 years old) received nVNS in four different locations (cymba conchae, tragus, earlobe, or tragus AND cymba conchae) on separate days. In each session, participants were asked to consume a palatable chocolate flavored milk. With electrography on the abdomen and indirect calorimetry in a canopy, we measured electro-cardiogram, electro-gastrogram and resting energy expenditure for 15 minutes before and at least 35 minutes after consumption of the palatable drink. We also collected ratings of the palatable drink and internal and other states. Pre-drink consumption (in a hungry state) we observed no differences in the effect of location of acute nVNS on resting energy expenditure and gastric frequency. However, nVNS in cymba conchae decreases heart-rate variability and ratings of how much participants want to consume the drink. After drink consumption and with continued nVNS, gastric frequency is unchanged, and resting energy expenditure increases regardless of stimulation location. Heart-rate variability decreases in all locations, except cymba conchae. We also observe a trend for an increase in gastric frequency in late post-drink consumption time-points in cymba conchae. These results suggest that nVNS in the cymba conchae in a hungry state has a similar acute effect on vagal tone as food consumption: to decrease heart rate variability. This effect then negates the usual postprandial effects of a decrease in heart rate variability as seen in the other nVNS locations. This suggests that nVNS in cymba conchae may act primarily on vagal afferent autonomic (and only modestly on metabolic output) in a similar way as food consumption does. Highlights: We measured autonomic outflow and efferent metabolism before and after consumption We manipulated the location of nVNS stimulation in the outer ear The different locations were earlobe, cymba conchae, tragus, cymba conchae+tragus nVNS in cymba conchae decreases pre -consumption heart-rate variability and wanting nVNS in other locations decreases post -consumption heart-rate variabilty

Objective: Alterations in the autonomic nervous system (ANS) may cause impairment in the metabolic processes that can lead to weight gain. The purpose of this study was to determine the difference between the resting energy expenditure (REE) and the resting ANS activity in overweight/obese and normal-weight healthy subjects. Method: Group 1 consisted of 18 subjects with BMI > 25 kg/m2, and 20 subjects with BMI ranging from 20 to 25 kg/m2 formed group 2. Measurements of low-frequency (LF) and high-frequency (HF) power components expressed in normalized units (LFnu, HFnu) and LF/HF ratio were assessed for analysis of heart rate variability, and simultaneously REE measurement was performed. Results: The mean LFnu (27.2% increased) and the LF/HF were higher and the mean HFnu was lower (29.9% decreased) in group 1 than in group 2 (p < 0.01). Although a statistical difference was observed in REE between groups, REE per kilogram corrected for fat-free mass (REEFFMcorr) was 21.47 ± 2.92 kcal/day/kg in group 1, and 21.56 ± 1.90 kcal/day/kg in group 2, and this difference was not statistically significant (p > 0.05). Conclusion: We concluded that REEFFMcorr in overweight/obese and normal-weight subjects were similar despite elevated sympathovagal balance in overweight/obese individuals, and REEFFMcorr should be used to avoid misestimating the REE in obese and normal-weight subjects.

The aim of the study is to investigate the effect of fibromyalgia syndrome [FMS] on the preferred walking speed [PWS], energy expenditure at rest, and oxygen cost of walking. Fifteen women with FMS and 15 healthy matched female subjects participated in our study. All patients were newly diagnosed and had no medication for FMS. The energy expenditure of FMS individuals was measured by using indirect calorimetry during resting and walking at PWS. The resting energy expenditure in healthy subjects [Group 1] was 1115.08 ± 154.33 kcal/day and that in FMS patients [Group 2] was 1253.48 ± 212.94 kcal/day; there was no statistical difference between the groups [P > 0.05]. The mean PWSs in Groups 1 and 2 were 81.22 ± 9.10 and 71.42 ± 6.61 m/min, respectively. The difference between the PWSs in Groups 1 and 2 was statistically significant [P < 0.05]. The mean oxygen consumption in the first walking trail was 12.95 ± 2.62 and 11.83 ± 1.68 mL/kg/min in Groups 1 and 2, respectively [P > 0.05]. The mean oxygen cost of the first walking trial in Groups 1 and 2 was 0.16 ± 0.02 and 0.17 ± 0.02 mL/kg/m, respectively; the difference was not significant [P > 0.05]. The PWS of patients with FMS was lower than that of healthy controls. The oxygen cost and consumption were similar in both groups in our study. This study demonstrates that FMS individuals optimize the oxygen cost of walking by preferring a lower walking speed.

Purpose: The metabolic energy cost of walking is altered by pathological changes in gait. It is thought that anterior cruciate ligament (ACL) deficiency alters the energy requirement for level walking through its effect on gait pattern. In this study, it is hypothesised that the metabolic energy cost of walking would improve after ACL reconstruction.Methods: Eight patients who were undergoing ACL reconstruction for an isolated rupture were included in this prospective study. Clinical examinations, Lysholm scores and metabolic tests were performed preoperatively and at 3, 6 and 12 months after ACL reconstruction using autologous quadruple hamstring tendons. For the metabolic evaluation, net oxygen cost was calculated while walking on a treadmill at 50‐, 70‐ and 90‐m/min velocities. A two‐way factorial ANOVA was performed in order to evaluate the primary effects and interactions of the time point and velocity variables on net oxygen cost.Results: All patients had positive Lachman and anterior drawer tests preoperatively that became negative postoperatively and remained negative until the last follow‐up point. The mean preoperative Lysholm score was 66, whereas the mean postoperative follow‐up scores were 85, 91 and 94, respectively. The interaction between follow‐up time point and velocity was not significant. Regardless of the selected velocity, the net oxygen cost was lower than that at preoperative levels at each postoperative time point (p < 0.05).Conclusion: The results of the present study indicate that the energy cost of level walking in chronic ACL‐deficient patients improves after ACL reconstruction. Cause–effect‐based studies with correlation evaluations that compare kinetic, kinematic and electromyographic data and metabolic cost calculations should facilitate more accurate analyses.Level of evidence: Therapeutic study, Level 4.

Türkiye Fiziksel Tıp ve Rehabilitasyon Dergisi

A preventable occupational disease, pneumoconiosis that is often widespread on to a very kind of quartz, carbon and metal dust exposed work place.The data for the prevalence of pneumoconiosis and respiratory findings among dental laboratory technician is insufficient. The aim of this study is to determine the prevalence of pneumoconiosis and respiratory findings among dental laboratory technicians, working in province of Sivas. For this reason all the dental technicians (except 2, totally 36) participated in the study. A questionnaire which contains demographic characteristics, work conditions and symptoms were applied to all participants. Also spirometric measurements and chest x-rays were performed. The x-rays of dental technicians were evaluated by a radiologist and a chest disease specialist according to the ILO-2000 classification of pneumoconiosis. Almost half of the all participants have dyspnea and phlegm expectoration. The prevalence of pneumoconiosis was 5 (13.8%) among 36 dental technicians. There were no statistically significant differences between two groups with regard to respiratory symptoms. Values of lung function parameters of the dental technician group were not significantly different from those of control group except FEV(1). In conclusion, dental laboratory technicians are at significant risks for occupational respiratory diseases so the primary prevention rules are essential for these work places.

Objectives: The purpose of this study was to determine the relationship between autonomic nervous system dysfunction and basal metabolic rate (BMR), and the effect of spasticity on basal metabolic rate.Research Method and Procedures: Twenty men (11 paraplegic and 9 tetraplegic) with American Spinal Injury Association (ASIA)‐A and ‐B grade chronic spinal cord injury (SCI) participated in this study. Total body fat mass and lean tissue mass were measured in all participants using DXA by standard methods. Patients were allocated into 2 groups to determine the effect of autonomic nervous system dysfunction on BMR: Group I (T6 and upper‐level injuries with history of autonomic dysreflexia) and Group II (T7 and lower‐level injuries without history of autonomic dysreflexia). Measurements of BMR were determined by indirect calorimetry under standardized conditions.Results: There were 13 patients in Group I and 7 patients in Group II and the difference between these two in terms of time since injury, BMI, age, weight, lean tissue mass, BMR, and BMR/kg were not significant.Conclusion: We concluded that autonomic nervous system dysfunction does not affect BMR, and it might be ignored in considering energy needs in spinal cord injury.