Nerve stimulator for regional anaesthesia procedures with automatic interactive closed-loop control

Abstract

Peripheral nerve stimulators have widespread among anaesthesiologists and remain a popular technique. However, in commercial devices, the user has to manually adjust stimulus intensity. Thus, the aim of this study is to propose a method that allows automating the current intensity control. An earlier nerve stimulator prototype was modified to add an accelerometer and an sEMG module. The choice of these two sensors is aimed at the possibility of observing the mechanical and electrical responses of the muscle contraction evoked by the stimulation. The tests were performed in two steps. The first step was to observe how the sensors behave during stimulation and muscle contraction. The second step was to implement a control algorithm and to validate the automation technique. Comparing the two methods, no significant differences were found on procedure time (manual: 12.5?±?2.3; automatic: 11.6?±?1.9; ρ?=0.380) and blockade latency time (manual: 11.6?±?1.1; automatic: 11.9?±?1.2; ρ?=0.524). Comparing needle-nerve distance in manual or automatic mode, no significant differences were found for 1.0?mA, 0.8?mA, 0.5?mA and 0.3?mA. We conclude that the technique for automating the current intensity update, using accelerometer and/or electromyography, is satisfactory. Furthermore, we conclude that the use of the accelerometer alone is sufficient for detection of muscle contraction.     

The timing between REM sleep behavior disorder and Parkinson’s disease

Purpose

In Parkinson’s disease (PD) patients, REM sleep behavior disorder (RBD) might precede PD or develop with or after the onset of PD. No previous study has explored differences between these two groups. The aim of this study was therefore to compare clinical features and REM sleep chin electromyographic patterns between patients in whom RBD heralded PD and those in whom RBD occurrence coincided with or followed the clinical manifestations of PD.

Method

Twenty-seven consecutive PD patients (mean age 67.9 years) were enrolled. Detailed clinical, laboratory, and polysomnographic studies were obtained in all participants.

Results

Sixteen of the 27 patients were affected by RBD. These had a significantly higher stage of PD and took significantly higher doses of dopaminergic therapy; their disease duration tended to be longer, and their cognitive status tended to be lower. PD patients in whom RBD preceded PD (n?=?6) did not differ from PD patients without RBD in disease parameters, while PD patients in whom RBD developed with or after PD (n?=?10) showed a significantly higher disease stage, took significantly higher dopaminergic therapy, and had a longer disease duration.

Conclusion

Our findings are compatible with the hypothesis that patients in whom RBD precedes, or does not precede, PD might constitute two possibly distinct clinical and physiopathological groups, based on different progressive neuropathological sequences of events.     

The pathogenesis of the anaemia of chronic disorders

Anemia of chronic disorders is a typical condition of infective, immunological and neoplastic diseases. Hepcidin and proinflammatory cytokines play a leading role in its pathogenesis. Hepcidin is a hormone produced by the liver that controls iron metabolism. It ensures that iron is retained by enterocytes (where the metal is absorbed) and by macrophages (that store the iron that results from the physiological breakdown of erythrocytes). Cytokines play a role in hepcidin synthesis, and in the proliferation and the maturation of the erythroid components within bone marrow. This paper discusses the pathogenetic mechanisms of anemia in chronic disorders.     

Evaluation of oral health related to body mass index

Oral Diseases (2012) 18 , 748–755 Objective: Poor oral health has previously been related to high body mass index (BMI). We aimed at exploring the link between BMI and several oral health markers, after adjustment for dietary patterns and plasma insulin, both of which could act as mediators. Subjects and Methods: Dental examination was performed in a sample of 186 French subjects aged 35–64 years and selected from the general population to assess number of missing teeth, periodontitis, clinical attachment loss (CAL), probing pocket depth (PD), gingival index (GI) and plaque index (PI). Data collection also included a food‐frequency questionnaire. BMI (considered as outcome variable) was categorized into quartiles, and as BMI<25; 25 ≤BMI<30; and BMI ≥ 30 kg m^?2. Results: After adjustment for age, gender, education level, smoking, physical activity, energy intake and C‐reactive protein, BMI was statistically associated with missing teeth, PD and PI, but not with CAL, GI or periodontitis. After additional adjustment for ‘high‐carbohydrate’ diet and plasma insulin or HOMA (homeostasis model assessment) index for insulin resistance, the statistical relationship between BMI and oral variables remained significant only for PD and PI. Conclusions: Plaque index, reflecting dental plaque, and PD, closely linked with periodontal inflammation and infection, are statistically associated with high BMI and obesity, independently of dietary patterns and insulin resistance.     

Benefits in Cognitive Function, Blood Pressure, and Insulin Resistance Through Cocoa Flavanol Consumption in Elderly Subjects With Mild Cognitive Impairment: The Cocoa, Cognition, and Aging (CoCoA) Study

Flavanol consumption is favorably associated with cognitive function. We tested the hypothesis that dietary flavanols might improve cognitive function in subjects with mild cognitive impairment. We conducted a double-blind, parallel arm study in 90 elderly individuals with mild cognitive impairment randomized to consume once daily for 8 weeks a drink containing ≈990 mg (high flavanols), ≈520 mg (intermediate flavanols), or ≈45 mg (low flavanols) of cocoa flavanols per day. Cognitive function was assessed by Mini Mental State Examination, Trail Making Test A and B, and verbal fluency test. At the end of the follow-up period, Mini Mental State Examination was similar in the 3 treatment groups (P=0.13). The time required to complete Trail Making Test A and Trail Making Test B was significantly (P<0.05) lower in subjects assigned to high flavanols (38.10±10.94 and 104.10±28.73 seconds, respectively) and intermediate flavanols (40.20±11.35 and 115.97±28.35 seconds, respectively) in comparison with those assigned to low flavanols (52.60±17.97 and 139.23±43.02 seconds, respectively). Similarly, verbal fluency test score was significantly (P<0.05) better in subjects assigned to high flavanols in comparison with those assigned to low flavanols (27.50±6.75 versus 22.30±8.09 words per 60 seconds). Insulin resistance, blood pressure, and lipid peroxidation also decreased among subjects in the high-flavanol and intermediate-flavanol groups. Changes of insulin resistance explained ≈40% of composite z score variability through the study period (partial r(2)=0.4013; P<0.0001). To the best of our knowledge, this is the first dietary intervention study demonstrating that the regular consumption of cocoa flavanols might be effective in improving cognitive function in elderly subjects with mild cognitive impairment. This effect appears mediated in part by an improvement in insulin sensitivity.