Joint angle variability in 3D bimanual pointing: uncontrolled manifold analysis

The structure of joint angle variability and its changes with practice were investigated using the uncontrolled manifold (UCM) computational approach. Subjects performed fast and accurate bimanual pointing movements in 3D space, trying to match the tip of a pointer, held in the right hand, with the tip of one of three different targets, held in the left hand during a pre-test, several practice sessions and a post-test. The prediction of the UCM approach about the structuring of joint angle variance for selective stabilization of important task variables was tested with respect to selective stabilization of time series of the vectorial distance between the pointer and aimed target tips (bimanual control hypothesis) and with respect to selective stabilization of the endpoint trajectory of each arm (unimanual control hypothesis). The components of the total joint angle variance not affecting (V_COMP) and affecting (V_UN) the value of a selected task variable were computed for each 10% of the normalized movement time. The ratio of these two components R_V=V_COMP/V_UN served as a quantitative index of selective stabilization. Both the bimanual and unimanual control hypotheses were supported, however the R_V values for the bimanual hypothesis were significantly higher than those for the unimanual hypothesis applied to the left and right arm both prior to and after practice. This suggests that the CNS stabilizes the relative trajectory of one endpoint with respect to the other more than it stabilizes the trajectories of each of the endpoints in the external space. Practice-associated improvement in both movement speed and accuracy was accompanied by counter-intuitive lack of changes in R_V. Both V_COMP and V_UN variance components decreased such that their ratio remained constant prior to and after practice. We conclude that the UCM approach offers a unique and under-explored opportunity to track changes in the organization of multi-effector systems with practice and allows quantitative assessment of the degree of stabilization of selected performance variables.     

Mobile Application for Promoting Gluten-Free Diet Self-Management in Adolescents with Celiac Disease: Proof-of-Concept Study

Celiac disease (CD) is a chronic disease treated by maintaining and managing a lifelong restrictive gluten-free diet. The purpose of this study was to develop a mobile application, Plan My C-Day, to promote self-management skills among youth with CD during adolescence—a time when decreased adherence often occurs—and examine its usability among adolescents with CD. Plan My C-Day contains three simulations of activities involving eating out and actions to take when preparing for these events. It was developed and pilot tested by 13 adolescents with CD. Application use and user perception data were collected and analyzed. Participants chose 160 actions within the simulations. For over 75% of participants, the time to complete the simulation decreased from the first to the third (last) simulation by an average of 50%. The average reported usability perception was 3.71 on a scale of 1 to 5, with system ease of use and ease of learning obtaining the highest scores. This study demonstrated that the Plan My C-Day mobile application’s self-management content, features, and functions operated well and that the simulations were easy to understand and complete. Further development will include the option to add self-created activities and adaptation to different languages and cultures.     

The slow and infraslow oscillations of cortical neural network

ObjectiveIn this study we investigated the properties of infraslow oscillations (ISOs) ?0.05 Hz and delta frequency band in the patients during the epileptic discharges and in healthy persons who performed a variety of mental and physical tasks.MethodsThe EEG signals were recorded on the subjects who were divided into three groups. In the first group were patients with global epileptic seizures, while in the second group were patients with focal epileptic seizures. In the third group were healthy volunteers who performed different mental and physical tasks.ResultsBy analyzing EEG data of epileptic patients, we showed that frequency peak exists at 1.5 Hz which is typical for general and focal epileptic seizures. In the type of general epileptic discharges the role of the slow rhythms at 0.05 Hz, was particularly pronounced and their origin was in fluctuations of cortical neural network. The properties of parameter spectral coherency of ISOs in healthy persons point to their important role in brain functioning.ConclusionsOur results suggested that the role of ISOs could be extended, because they were detected in healthy human subjects during carrying out different tasks. Investigating the properties of parameter spectral coherency, we showed that in this case correlation between different regions of the brain was significantly modulated with ISOs.     

Hemodialysis Treatment in Patients with Balkan Endemic Nephropathy: An Epidemiological Study

Aim. To analyze hemodialysis (HD) treatment of patients with Balkan endemic nephropathy (BEN) from five endemic villages in the South Morava Region of Serbia. Analyses of patterns of incidence may generate hypotheses about the underlying causes of BEN, and prevalence data provide information on the current and likely future burden on health services for managing BEN. Methods. A total of 143 end-stage kidney disease patients (ESKD) with BEN were admitted to the renal replacement program from 1974 to 2004: 121 to HD, 15 peritoneal dialysis, and 7 kidney transplantation. As a control group, 117 patients with other kidney disease (chronic pyelonephritis, glomerulonephritis, and ischemic nephropathy) admitted to HD at the time of BEN patients and matched by age and gender were studied. Results. Most of the BEN patients (93.4%) treated by HD were born from 1917 to 1941. The majority of patients (79.3%) started HD from 1977 to 1991 (period of 15 years). The mean age of BEN patients starting HD treatment was 49.1 years in the period from 1974 to 1978, and increased steadily in the following years, being 72.5 years in the last period of study (2004–2006) The mean survival time of BEN males was 4.70 (95% CI 3.66–5.75) and for females was 5.02 (95% CI 1.47–4.53). Difference between males and females was not statistically significant (log rank 0.14, p?=?0.7, P > 0.5). Mean survival times of 4.84 (95% CI 3.97–5.70) in BEN patients and 3.1 (95% CI 2.78–3.84) in other kidney disease patients were found. Difference between BEN patients and controls was statistically significant (log rank 8.38, p?=?0.0038, P < 0.01). Conclusion. The population of endemic villages around the South Morava River admitted to HD treatment after 1974 was exposed to environmental toxicant(s) from 1917 to 1941. The most intense effect of environmental exposure was in that period, with ESKD in patients in their forties. The exposure to environmental toxicants has diminished, so ESKD of BEN has become less frequent and manifested in the older age, mean 72.5 in the period from 2004 to 2006. Different type of exposure was registered in some other endemic regions in Serbia and abroad.     

Language development in preschool children born after asymmetrical intrauterine growth retardation

BackgroundAfter intrauterine growth retardation, many minor neurodevelopmental disorders may occur, especially in the motor skills domain, language and speech development, and cognitive functions.AimThe assessment of language development and impact of postnatal head growth in preschool children born with asymmetrical intrauterine growth retardation.MethodsExaminees were born at term with birth weight below the 10th percentile for gestational age, parity and gender. Mean age at the time of study was six years and four months. The control group was matched according to chronological and gestational age, gender and maternal education with mean age six years and five months. There were 50 children with intrauterine growth retardation and 50 controls, 28 girls and 22 boys in each group. For the assessment of language development Reynell Developmental Language Scale, the Naming test and Mottier test were performed.ResultsThere were statistically significant differences (p < 0.05) in language comprehension, total expressive language (vocabulary, structure, content), naming skills and non-words repetition. Statistically significant positive correlations were found between relative growth of the head [(Actual head circumference ? head circumference at birth)/(Body weight ? birth weight)] and language outcome. Children with neonatal complications had lower results (p < 0.05) in language comprehension and total expressive language.ConclusionIntrauterine growth retardation has a negative impact on language development which is evident in preschool years. Slow postnatal head growth is correlated with poorer language outcome. Neonatal complications were negatively correlated with language comprehension and total expressive language.     

Dental age estimation on Bosnian–Herzegovinian children aged 6–14 years: Evaluation of Chaillet's international maturity standards

BackgroundDental age estimation in children plays an important role in forensic dentistry. The most commonly used method for age estimation was developed by Demirjian in 1973 on a French–Canadian sample. It generally overestimates dental age in many populations. International maturity standards were formed to obtain a predicted age with more confidence when ethnic origin was not available.ObjectivesThe aim of this study was to evaluate the applicability of Chaillet's international scores in the dental age assessment on Bosnian Herzegovinian (BH) children.MethodsOrthopantomograms of 1772 children, 980 girls and 792 boys aged 6.04–14.90 years, were assessed using Chaillet's international maturity tables and curves. The dental ages for both genders were compared to the chronological ages through a paired t-test.ResultsMean overestimation using Chaillet's international maturity standards were 0.09 ± 0.83 for girls and 0.28 ± 0.90 for boys. The absolute accuracy of residuals between the dental and chronological age were 0.65 ± 0.52 years for girls (Median: 0.52 years) and 0.73 ± 0.60 years for boys (Median: 0.57 years).ConclusionThe Polynomial compound formula was recommended to predict dental age with more accuracy for results of international maturity standards on BH children.