Effect of connectivity measures on the identification of brain functional core network at rest.

Magneto/Electro-encephalography (M/EEG) source connectivity is an emergent tool to identify brain networks with high time/space resolution. Here, we aim to identify the brain core network (s-core decomposition) using dense-EEG. We also evaluate the effect of the functional connectivity methods used and more precisely the effect of the correction for the so-called source leakage problem. Two connectivity measures were evaluated: the phase locking value (PLV) and phase lag index (PLI) that supposed to deal with the leakage problem by removing the zero-lag connections. Both methods were evaluated on resting state dense-EEG signals recorded from 19 healthy participants. Core networks obtained by each method was compared to those computed using fMRI from 487 healthy participants at rest (from the Human Connectome Project - HCP). The correlation between networks obtained by EEG and fMRI was used as performance criterion. Results show that PLV networks are closer to fMRI networks with significantly higher correlation values with fMRI networks, than PLI networks. Results suggest caution when selecting the functional connectivity methods and mainly methods that remove the zero-lag connections as it can severely affect the network characteristics. The choice of functional connectivity measure is indeed crucial not only in cognitive neuroscience but also in clinical neuroscience.

Dynamic reshaping of functional brain networks during visual object recognition.

OBJECTIVE: Emerging evidence shows that the modular organization of the human brain allows for better and efficient cognitive performance. Many of these cognitive functions are very fast and occur in a sub-second time scale such as the visual object recognition. APPROACH: Here, we investigate brain network modularity while controlling stimuli meaningfulness and measuring a participant's reaction time. We particularly raised two questions: i) does the dynamic brain network modularity change during the recognition of meaningful and meaningless visual images? And (ii) is there a correlation between network modularity and the reaction time of the participants? To tackle these issues, we collected dense-electroencephalography (EEG, 256 channels) data from 20 healthy human subjects performing a cognitive task consisting of naming meaningful (tools, animals…) and meaningless (scrambled) images. Functional brain networks in both categories were estimated at the sub-second time scale using the EEG source connectivity method. By using multislice modularity algorithms, we tracked the reconfiguration of functional networks during the recognition of both meaningful and meaningless images. MAIN RESULTS: Results showed a difference in the module's characteristics of both conditions in term of integration (interactions between modules) and occurrence (probability on average of any two brain regions to fall in the same module during the task). Integration and occurrence were greater for meaningless than for meaningful images. Our findings revealed also that the occurrence within the right frontal regions and the left occipito-temporal can help to predict the ability of the brain to rapidly recognize and name visual stimuli. SIGNIFICANCE: We speculate that these observations are applicable not only to other fast cognitive functions but also to detect fast disconnections that can occur in some brain disorders.

Genotype and malocclusion in patients with osteogenesis imperfecta.

OBJECTS: To investigate the relationship between genotype and severity of malocclusion in osteogenesis imperfecta (OI). SETTING AND SAMPLE POPULATION: A total of 49 patients participated in this cross-sectional study (age range: 5-19 years; 28 females; diagnoses: OI type I, N = 7; OI type III, N = 11; OI type IV, N = 27; OI type V, N = 2; OI type VI, N = 2). MATERIALS AND METHODS: Sequence analysis of COL1A1/COL1A2 and other OI-related genes was compared to the Peer Assessment Rating (PAR), an index reflecting the severity of malocclusion. RESULTS: The mutation spectrum was as follows: COL1A1, N = 22; COL1A2, N = 22, IFITM5, N = 2; SERPINF1, N = 2; no mutation detected, N = 1). Compared to patients with COL1A1 mutations, patients with COL1A2 mutations had significantly higher scores for total PAR, anterior cross-bite, anterior open bite and anteroposterior buccal occlusion. Males with COL1A2 mutations had significantly higher total PAR scores than females (median 36 vs 30, P = .047, Mann-Whitney test). Exploratory correlation between age and buccal vertical occlusion was noted in patients with COL1A2 mutations (Spearman correlation: r = .46, P = .03, power = .50). Two patients with OI type V (caused by IFITM5 mutations) had total PAR scores of 44 and 21. Both patients scored high for "segment." Patients with OI type VI (due to SERPINF1 mutations) scored similar to OI type V for "centreline." Considerable difference was observed in the total PAR score between the 2 patients with OI type VI. They had total PAR of 43 and 2. CONCLUSION: Type of disease-causing mutation affects the severity of malocclusion in individuals with OI.

Value of electrocardiograms ordered by junior medical officers in the emergency department.

The diagnostic rationale for patients with chest pain requires an electrocardiogram (ECG) often limited by low pretest values and widely variable post-test values. We assess the value of ECG ordered and interpreted by internal medicine junior medical officers in our emergency department (ED). Participants enrolled in this study included patients who presented to the ED for chest pain between June and October 2014. Seventeen leads ECG were performed systematically when an ECG was judged required by the medical officer in charge and interpreted by a blinded medical officer and ED attending. Ultrasensitive troponin T (usTrop T) and creatinine were also withdrawn. Junior medical officers ordered ECG more commonly for atypical chest pain (57 vs 43%, P = 0.049). Univariate and multivariate analysis did not demonstrate a statistically discordant diagnosis between the medical officer and the attending throughout the study period and between the different rotations. We demonstrated 97% sensitivity, 95% specificity, 92% positive predictive value, 98% negative predictive value and 96% accuracy. Our junior medical officers demonstrated an overall high proficiency in the clinical and bedside setting. This finding reinforces our ECG education in the undergraduate curriculum, highlights the importance of the intensive recapitulation sessions undergone at the beginning of the training programme and our daily internal medicine staff discussions rarely performed in other EDs as reported with our experience.

Bicycle helmet prevalence two years after the introduction of mandatory use legislation for under 18 year olds in Alberta, Canada.

OBJECTIVE: To determine changes in helmet use in cyclists following the introduction of a bicycle helmet law for children under age 18. METHODS: Cyclists were observed by two independent observers from July to August 2004 (post-legislation) in Edmonton, Alberta. The data were compared with a similar survey completed at the same locations and days in July to August 2000 (pre-legislation). Data were collected for 271 cyclists in 2004 and 699 cyclists in 2000. RESULTS: The overall prevalence of helmet use increased from 43% (95% CI 39 to 47%) in 2000 to 53% (95% CI 47 to 59%) in 2004. Helmet use increased in those under 18, but did not change in those 18 and older. In the cluster adjusted multivariate Poisson regression model, the prevalence of helmet use significantly increased for those under age 18 (adjusted prevalence ratio (APR) 3.69, 95% CI 2.65 to 5.14), but not for those 18 years and older (APR 1.17, 95% CI 0.95 to 1.43). CONCLUSION: Extension of legislation to all age groups should be considered.

[Acute neonatal appendicitis in an inguinal hernia]. / Appendicite aiguë néonatale intra-herniaire.

UNLABELLED: Acute neonatal appendicitis is a rare surgical emergency. Prognosis depends on early diagnosis and management. CASE REPORT: A three and a half-month-old premature infant needed an urgent laparotomy because of an occlusive syndrome and sepsis with an inflammatory skin reaction. The per-operative diagnosis was suppurative acute appendicitis with local peritonitis, the appendix being strangulated into the inguinal hernia. DISCUSSION: Neonatal appendicitis represents 0.1% of all infantile appendicitis. Fifty percent of such cases occur in premature infants. Two clinical presentations exist, whose diagnosis is often made during surgery. The abdominal presentation (2/3 of the cases) can mimic necrotizing enterocolitis; the diagnosis is often late and evolution leads to diffuse peritonitis in the majority of the cases, while the mortality rate is higher than 50%. The intra-hernial presentation (1/3 of the cases), instead, is usually diagnosed and managed early due to the inguino-scrotal induration, while mortality rate is near zero. CONCLUSION: The high frequency of inguinal hernia in premature infants should not mask the risk for intra-hernial appendicitis. Inguino-scrotal inflammation should evoke the diagnosis. Prognosis depends on early and urgent surgical management.