Oscillatory EEG Changes During Arithmetic Learning in Children

Most studies have investigated brain activation changes after the course of arithmetic learning, and the question remains whether these changes are detectable during the course of learning, i.e., before memory consolidation. Twenty-four fifth graders solved multiplication problems while ongoing electroencephalography (EEG) was recorded. The arithmetic training revealed reduced errors together with a power increase in theta (4–7 Hz) but not in lower alpha (8–10 Hz) or upper alpha (10–13 Hz) bands. We conclude that increases in theta power subserved a shift from slow, procedural strategies to more efficient, automated procedural and retrieval strategies, which led to more efficient performance.     

Gender specific activation patterns of trunk muscles during whole body tilt

Gender specific differences as evidenced in both anthropometric data and physical performance of healthy persons have been broadly demonstrated. Recently advancements in surface electromyography (SEMG) have shown possible differences in men’s and women’s muscle coordination patterns. However, quantitative information about gender related muscle co-ordination patterns are rare. This investigation was carried out to both verify if trunk muscle SEMG amplitude–force relationship differs between men and women and refine techniques of measurement and data analysis using SEMG. Thirty-one healthy volunteers (16 women, 15 men) were investigated during whole body tilt at angles from 5° to 90° (from quasi vertical to horizontal position). Subjects had to maintain body in body axis while their lower body was fixed and the upper body remained unsupported. SEMG was taken from five different trunk muscles of both sides simultaneously. At corresponding tilt angles women exhibited higher amplitude levels of their abdominal muscles in comparison to men, who were characterized by higher back muscle amplitudes. Abdominal muscles showed a non-linear SEMG amplitude–force relationship but differed between genders with more linearity in women. Back muscles showed a linear amplitude–force relationship with no differences between genders. Women were characterized by higher levels of co-contraction of all investigated muscles. The data are in accordance with histological investigations, which already proved specific fiber distribution patterns in both abdominal and back muscles and gender related differences in relative area of Type 1 fibers of back muscles. The observed differences in SEMG–force relationship for the abdominal muscles remain hypothetical because of lack of histological information.     

Myocardial ischemia detection with single-phase CT perfusion in symptomatic patients using high-pitch helical image acquisition technique

Coronary CT angiography (CCTA) suffers from a reduced diagnostic accuracy in patients with heavily calcified coronary arteries or prior myocardial revascularisation due to artefacts caused by calcifications and stent material. CT myocardial perfusion imaging (CTMPI) yields high potential for the detection of myocardial ischemia and might help to overcome the above mentioned limitations. We analysed CT single-phase perfusion using high-pitch helical image acquisition technique in patients with prior myocardial revascularisation. Thirty-six patients with an indication for invasive coronary angiography (28 with coronary stents, 2 with coronary artery bypass grafts and 6 with both) were included in this prospective study at two study sites. All patients were examined on a 2nd generation dual-source CT system. Stress CT images were obtained using a prospectively ECG-triggered single-phase high-pitch helical image acquisition technique. During stress the tracer for myocardial perfusion (MP) SPECT imaging was administered. Rest CT images were acquired using prospectively ECG-triggered sequential CT. MP-SPECT imaging and invasive coronary angiography served as standard of reference. In this heavily diseased patient cohort CCTA alone showed a low overall diagnostic accuracy for detection of hemodynamically relevant coronary artery stenosis of only 31% on a per-patient base and 60% on a per-vessel base. Combining CCTA and CTMPI allowed for a significantly higher overall diagnostic accuracy of 78% on a per-patient base and 92% on a per-vessel base (p?<?0.001). Mean radiation dose for stress CT scans was 0.9 mSv, mean radiation dose for rest CT scans was 5.0 mSv. In symptomatic patients with known coronary artery disease and prior myocardial revascularization combining CCTA and CTMPI showed significantly higher diagnostic accuracy in detection of hemodynamically significant coronary artery stenosis when compared to CCTA alone.     

In vivo study for tooth colour determination—visual versus digital

Objectives

Tooth colour determination is an essential component in the preservative and prosthetic workflow during production of tooth-coloured restorations. The aim of the study was to compare the clinical suitability of conventional, visual tooth colour determination and digital methods.

Materials and methods

Tooth colour of vital, natural central incisors among a total of 107 subjects was determined visually by a dentist (VD) and dental technician (VDT) using VITA Toothguide 3D-MASTER®, digitally by the spectrophotometer VITA Easyshade Advance 4.0 (reference instrument) and Trios®Color intra-oral scanner (test subject). Reliability was examined by repeating the digital measurements of 20 teeth three times. The analysis was based on the recorded 3D-MASTER values and L*a*b/L*C*h parameters.

Results

The measuring accuracy was 43.9% with the Trios®Color scanner, 35.5% for VD and 34.6% for VDT. In 25.5% of cases, the scanner’s results corresponded with VD and in 33.6% with VDT. The visual methods corresponded with 45.8%. All mean values of the recorded colour differences fell within the clinically acceptable range of ΔE ≤ 6.8. The intra-oral scanner attained repeatability of 78.3% and the VITA Easyshade system of 76.6%.

Conclusions

The Trios®Color intra-oral scanner appears to be a good alternative to the current standard of visual tooth colour determination. The new module attains better results than the visual method and is comparable to the reference instrument.

Clinical relevance

Dentistry becomes increasingly digitalized and tooth colour determination devices have generally to be improved. Therefore, the investigation of a new digital device is important for future developments.

     

TaqIA polymorphism in dopamine D2 receptor gene complicates weight maintenance in younger obese patients

ObjectiveThe A1 allele of the TaqIA polymorphism in the dopamine D2 receptor gene (rs1800497) has been associated with obesity. However, the effect of the polymorphism on the success in weight loss and/or weight maintenance during weight-loss programs has not been evaluated thus far.MethodsThe rs1800497 was genotyped in 202 (135 female, 67 male) severely obese individuals with an initial body mass index of 41.7 ± 0.5 kg/m² who participated in a weight-loss program consisting of a weight-loss phase with a formula diet (12 wk) and a weight-maintenance phase (40 wk). Measurements were collected at baseline, after the weight-loss phase, and at the end of the weight-maintenance phase at 1 y.ResultsGenotyping revealed 4 A1A1, 67 A1A2, and 131 A2A2 genotype carriers. Of the 202 subjects in the program, 66.8% completed the program and 33.2% terminated prematurely. Neither the attrition rate (P = 0.44) nor the overall weight loss was influenced by the different genotypes (P = 0.96). However, younger A1⁺ participants (A1A1 and A1A2) had a higher body mass index at all time points (baseline, P = 0.04; after weight loss, P = 0.05; after weight maintenance, P = 0.02). They also showed less overall weight loss (P = 0.05), which derived mainly from a greater weight regain during the maintenance phase (P = 0.02).ConclusionIn this program, younger A1⁺ participants exhibited problems in maintaining weight loss during a weight-loss program.