Measuring the Effect of Vision on the Synergy of Lower Extremity Muscles during Walking using Nonnegative Matrix Factorization (NNMF) Algorithm Method.

Introduction: Lack of visual information in blind people during walking can affect the choice of muscle synergy from among the many incoming messages that reach the central nervous system (CNS). This study aimed to determine the effect of vision on the synergy of lower limb muscles during walking using the nonnegative matrix factorization algorithm (NNMF). Methods: Ten blind people and 10 people with normal vision participated in this study. Activities of involved muscles were recorded during walking. Muscle synergy matrix and synergy activation coefficient were calculated using the NNMF algorithm, while the variance accounted for criterion was used to determine the number of synergies required during walking. In order to assess the similarity of muscle synergy pattern and the relative weight of each muscle in each synergy in each group, Pearson correlation and independent samples t-test at a significance level of α ≤ 0.05 were used. Results: Four muscle synergies were extracted from EMG data during walking. The first (r = 0.431) and the second (r = 0.457) synergy patterns showed a moderate correlation between the two groups. However, the third (r = 0.302) and the fourth (r = 0.329) synergy patterns showed a weak correlation between the two groups. In the blind group, the relative weight of the muscles in the first synergy was significant for the external extensor muscle (P = 0.023), and in the second synergy for the biceps femoris. Also, in the third synergy, the relative weight was found to be significant in none of the muscles. In the fourth synergy, however, the relative weight of external extensor muscle in the blind group showed a significant decrease, as compared to the group with normal vision. Conclusions: These changes can be the strategy of the CNS to preserve the optimal functioning in the motor system of blind people.

Prevalence of nasopharyngeal carriage of Streptococcus pneumoniae in children 7 to 14 years in 2016: A survey before pneumococcal conjugate vaccine introduction in Iran.

Streptococcus pneumoniae is a common cause of community-acquired pneumonia, meningitis, and otitis media in children. The aim of this study was to determine the prevalence of nasopharyngeal carriage of Streptococcus pneumoniae among children in the city of Hamadan, west of Iran. In this cross-sectional study, 532 students aged 7 to 14 years old from Hamadan were enrolled during the period from February to April 2016. Children were recruited using multi-stage sampling method. Informed consent form was obtained from parents of children. A researcher developed checklist was completed for every child by interviewer and samples of the throat of children were taken by swap method from the nasopharyngeal area. Descriptive statistics and chi square test were used to describe the study population. This study was approved by the Committee on Ethics of Hamadan University of Medical Sciences (IR.UMSHA.REC.1394.66). Prevalence of nasopharyngeal carriage of S. pneumoniae in children was 12.03% (95%CI: 9.38-15.10). About 37% (196 persons) of study population were male and 63% were female. Sixty four percent (345 people) of the studied population were from district two in Hamadan and others from District one. Prevalence of nasopharyngeal carriage of S. pneumoniae by sex was 13.77% (95% CI: 9.27-19.40) in males and 11.02 % (95% CI: 7.87-14.85) in females (P = 0.345). Considering the high prevalence of nasopharyngeal carriage of Streptococcus pneumoniae in children studied in Hamadan, pneumococcal conjugate vaccine (PCV) is recommended to be integrated into the Iran's National Immunization Program.

Prevalence of pediculosis and its related factors among primary school girls in the north of Iran.

INTRODUCTION: Head lice infestation is one of the main public health problems worldwide and a sanitary, cultural and economic indicator for communities' health. This study aims to estimate the prevalence of head lice infestation among female primary school children in selected districts of Mazandaran Province, Iran. METHODS: In this cross-sectional study, 3033 female school children were recruited using the consensus method. Head lice infestation was defined as visible adult lice, nymph or egg with the naked eye. Data were described by percent frequency and analyzed using the chi-squared test and multivariate logistic regression models. A p-value less than 0.05 was considered significant. RESULTS: Prevalence of head lice infestation among female school children was estimated at 7.9%. The adjusted odds ratios (OR) [95% confidence intervals (CI)] for rural residents, low level educated mothers, family size more than five and not combing their hair were 1.96 (1.41-2.78), 2.46 (1.35-4.49), 2.04 (1.12-3.70) and 3.94 (1.73-8.96), respectively. In addition, considering first grade students as a reference group, the ORs (95% CI) for second and third grades were 1.89 (1.18-3.05) and 1.69 (1.05-2.74), respectively. CONCLUSION: Our study showed that studying in urban schools, low educational level of mothers, grade, family size and no history of regular combing were predictors of head lice infestation.