Accurate and Rapid Estimation of Phosphene Thresholds (REPT)

To calibrate the intensity of transcranial magnetic stimulation (TMS) at the occipital pole, the phosphene threshold is used as a measure of cortical excitability. The phosphene threshold (PT) refers to the intensity of magnetic stimulation that induces illusory flashes of light (phosphenes) on a proportion of trials. The existing PT estimation procedures lack the accuracy and mathematical rigour of modern threshold estimation methods. We present an improved and automatic procedure for estimating the PT which is based on the well-established Ψ Bayesian adaptive staircase approach. To validate the new procedure, we compared it with another commonly used procedure for estimating the PT. We found that our procedure is more accurate, reliable, and rapid when compared with an existing PT measurement procedure. The new procedure is implemented in Matlab and works automatically with the Magstim Rapid2 stimulator using a convenient graphical user interface. The Matlab program is freely available for download

Transcranial Magnetic Stimulation Intensities in Cognitive Paradigms

BACKGROUND: Transcranial magnetic stimulation (TMS) has become an important experimental tool for exploring the brain's functional anatomy. As TMS interferes with neural activity, the hypothetical function of the stimulated area can thus be tested. One unresolved methodological issue in TMS experiments is the question of how to adequately calibrate stimulation intensities. The motor threshold (MT) is often taken as a reference for individually adapted stimulation intensities in TMS experiments, even if they do not involve the motor system. The aim of the present study was to evaluate whether it is reasonable to adjust stimulation intensities in each subject to the individual MT if prefrontal regions are stimulated prior to the performance of a cognitive paradigm. METHODS AND FINDINGS: Repetitive TMS (rTMS) was applied prior to a working memory task, either at the 'fixed' intensity of 40% maximum stimulator output (MSO), or individually adapted at 90% of the subject's MT. Stimulation was applied to a target region in the left posterior middle frontal gyrus (pMFG), as indicated by a functional magnetic resonance imaging (fMRI) localizer acquired beforehand, or to a control site (vertex). Results show that MT predicted the effect size after stimulating subjects with the fixed intensity (i.e., subjects with a low MT showed a greater behavioral effect). Nevertheless, the individual adaptation of intensities did not lead to stable effects. CONCLUSION: Therefore, we suggest assessing MT and account for it as a measure for general cortical TMS susceptibility, even if TMS is applied outside the motor domain

MS

thesisThe purpose of this study was to identify some of the factors associated with a woman's decision to breast feed and those factors associated with a women's decision to bottle feed her newborn infant. The study was conducted in the prenatal-postpartum clinic and the in-patient maternity service of a 277 bed general teaching hospital, in the office of an obstetrician in private practice, and in the in-patient maternity service of a 570 bed general hospital. The sample included 57 women who were interviewed during the third trimester of pregnancy. In this sample 25 women planned to bottle feed their infants, and 32 planned to breast feed. A second part of this study was designed to investigate whether encouragement and support of breast feeding provided to one-half of the breast feeding women by a nurse-midwife would 'increase the frequency of success with breast feeding, as compared to the other one-half of the breast feeding group who did not receive the encouragement and support. Differences between the bottle feeding group and the breast feeding group were identified by means of analysis of variance, The three variables that were found to be statistically significant were: paternal attitude toward method of infant feeding (P=.004), maternal education (P = .01), and the number of children at home (P=.048). The difference in the means of the breast feeding group and the bottle feeding group suggests that a favorable paternal attitude toward breast feeding was found more often in the breast feeding group, that the breast feeding group had a significantly higher level of formal maternal education, and that the bottle feeding group had more than twice as many children at home than the breast feeding group. Success with breast feeding was found to be significantly correlated (P <.01) to age, socio-economic level, and total parental education. Encouragement and support given by the nurse-midwife did not yield statistically significant results in increasing the frequency of breast feeding success

Training Primary Care Providers in the Use of Motivational Interviewing for Youth Behavior Change.

BACKGROUND AND PURPOSE: Adolescent obesity is a global epidemic. Motivational interviewing (MI) is a promising strategy to address adolescent obesity risk behaviors. However, primary care providers (PCPs) tend to express discomfort with learning and adopting MI practices and with addressing patient weight issues. PCP proficiency in using MI to discuss body mass index, health screening results, and nutrition and physical activity behaviors after receiving training and coaching from an MI expert and practicing the technique was evaluated. We hypothesized that comfort with MI would increase consistently over time. METHODS: Self-assessment surveys in MI proficiency were administered to PCPs after every youth participant MI session. MI comfort as determined by proficiency was categorized into low, medium, and high comfort according to survey Likert scale responses. Data were analyzed using analysis of variance (ANOVA) and Fisher\u27s exact tests. RESULTS: Two hundred twenty-seven youth were seen for MI-based discussions by 4 PCPs. Two hundred twenty-six surveys had complete data for analysis. As anticipated, overall PCPs reported significantly more comfort with MI from the first to the final MI session over a 2- to 3-month period (p\u3c .001). Comfort scores did not increase linearly over time for all PCPs. Despite standard training practices, overall MI proficiency as measured by comfort scores varied by PCP (p\u3c .01). IMPLICATIONS FOR PRACTICE: This type of MI training program should be considered for clinical nurses and nurse practitioners during their nursing education training to facilitate their ability to consistently and effectively support youth behavior change for conditions such as obesity (ClinicalTrials.gov Number NCT02502383)

Training Primary Care Providers in the Use of Motivational Interviewing for Youth Behavior Change.

BACKGROUND AND PURPOSE: Adolescent obesity is a global epidemic. Motivational interviewing (MI) is a promising strategy to address adolescent obesity risk behaviors. However, primary care providers (PCPs) tend to express discomfort with learning and adopting MI practices and with addressing patient weight issues. PCP proficiency in using MI to discuss body mass index, health screening results, and nutrition and physical activity behaviors after receiving training and coaching from an MI expert and practicing the technique was evaluated. We hypothesized that comfort with MI would increase consistently over time. METHODS: Self-assessment surveys in MI proficiency were administered to PCPs after every youth participant MI session. MI comfort as determined by proficiency was categorized into low, medium, and high comfort according to survey Likert scale responses. Data were analyzed using analysis of variance (ANOVA) and Fisher\u27s exact tests. RESULTS: Two hundred twenty-seven youth were seen for MI-based discussions by 4 PCPs. Two hundred twenty-six surveys had complete data for analysis. As anticipated, overall PCPs reported significantly more comfort with MI from the first to the final MI session over a 2- to 3-month period (p\u3c .001). Comfort scores did not increase linearly over time for all PCPs. Despite standard training practices, overall MI proficiency as measured by comfort scores varied by PCP (p\u3c .01). IMPLICATIONS FOR PRACTICE: This type of MI training program should be considered for clinical nurses and nurse practitioners during their nursing education training to facilitate their ability to consistently and effectively support youth behavior change for conditions such as obesity (ClinicalTrials.gov Number NCT02502383)

Molecular Structure, Phase Composition, Melting Behavior, and Chain Entanglements in the Amorphous Phase of High-Density Polyethylenes

A methodology for estimating the entanglement density in the amorphous phase of semicrystalline polyolefins was developed. The method is based on the analysis of the density of physical network junctions in the amorphous phase by 1H NMR T2 relaxation experiments. The density of the entanglement network was estimated for melt- and high-pressure-crystallized high-density polyethylenes (HDPEs) at temperatures close to and gradually approaching melting. Its value is lower for high-pressure-crystallized HDPE than for the same melt-crystallized polymer. The network of entanglements is characterized by the fraction of entangled network chains, the weight-average molecular weight of the network chains between apparent chain entanglements, Me, and the volume average density of apparent chain entanglements. The entanglement network was studied in a series of low- and high-molecular-weight HDPEs and bimodal HDPE samples with different molecular weight characteristics and densities controlled by different contents of the 1-butene comonomer. It turns out that the molecular weight characteristics of the HDPEs influence the entanglement network. The fraction of network chains and the average density of apparent chain entanglements decrease with decreasing molecular weight Mn due to the “dilution” effect caused by disentangled chain-end segments increasing the Me. The current methodology is of interest for studying the effect of crystallization conditions, molecular structures, and short-chain branches on phase composition, melting behavior, and chain entanglements in the amorphous phase of polyolefins. The method allows estimation of the fraction of network chains, which potentially can form tie-chain segments during deformation. The effect of short-chain branches and molecular weight characteristics on the creep response of polyolefins is discussed