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Yu V.Y.,Hospital for Sick Children | Yu V.Y.,Sick Kids Research Institute | De Nil L.F.,University of Toronto | Pang E.W.,Hospital for Sick Children | Pang E.W.,Sick Kids Research Institute
Language and Speech | Year: 2015

Voice onset time (VOT) is a temporal acoustic parameter that reflects motor speech coordination skills. This study investigated the patterns of age and sex differences across development of voice onset time in a group of 70 English-speaking children, ranging in age from 4.1 to 18.4 years, and 12 young adults. The effect of the number of syllables on VOT patterns was also examined. Speech samples were elicited by producing syllables /pa/ and /pataka/. Results supported previous findings showing that younger children produce longer VOT values with higher levels of variability. Markedly higher VOT values and increased variability were found for boys at ages between 8 and 11 years, confirming sex differences in VOT patterns and patterns of variability. In addition, all participants consistently produced shorter VOT with higher variability for multisyllables than monosyllables, indicating an effect of syllable number. Possible explanations for these findings and clinical implications are discussed. © The Author(s) 2014.

Yu V.Y.,Sick Kids Research Institute | MacDonald M.J.,Sick Kids Research Institute | Oh A.,Sick Kids Research Institute | Hua G.N.,Sick Kids Research Institute | And 2 more authors.
Developmental psychology | Year: 2014

It is well supported by behavioral and neuroimaging studies that typical language function is lateralized to the left hemisphere in the adult brain and this laterality is less well defined in children. The behavioral literature suggests there maybe be sex differences in language development, but this has not been examined systematically with neuroimaging. In this study, magnetoencephalography was used to investigate the spatiotemporal patterns of language lateralization as a function of age and sex. Eighty typically developing children (46 female, 34 male; 4-18 years) participated in an overt visual verb generation task. An analysis method called differential beamforming was used to analyze language-related changes in oscillatory activity referred to as low-gamma event-related desynchrony (ERD). The proportion of ERD over language areas relative to total ERD was calculated. We found different patterns of laterality between boys and girls. Boys showed left-hemisphere lateralization in the frontal and temporal language-related areas across age groups, whereas girls showed a more bilateral pattern, particularly in frontal language-related areas. Differences in patterns of ERD were most striking between boys and girls in the younger age groups, and these patterns became more similar with increasing age, specifically in the preteen years. Our findings show sex differences in language lateralization during childhood; however, these differences do not seem to persist into adulthood. We present possible explanations for these differences. We also discuss the implications of these findings for presurgical language mapping in children and highlight the importance of examining the question of sex-related language differences across development.

Manca A.,University of York | Willan A.R.,Sick Kids Research Institute | Willan A.R.,University of Toronto
PharmacoEconomics - Italian Research Articles | Year: 2010

Cost-effectiveness analysis has gained status over the last 15 years as an important tool for assisting resource allocation decisions in a budget-limited environment such as healthcare. Randomised (multicentre) multinational controlled trials are often the main vehicle for collecting primary patient-level information on resource use, cost and clinical effectiveness associated with alternative treatment strategies. However, trial-wide cost effectiveness results may not be directly applicable to any one of the countries that participate in a multinational trial, requiring some form of additional modelling to customise the results to the country of interest. This article proposes an algorithm to assist with the choice of the appropriate analytical strategy when facing the task of adapting the study results from one country to another. The algorithm considers different scenarios characterised by: (a) whether the country of interest participated in the trial; and (b) whether individual patient-level data (IPD) from the trial are available. The analytical options available range from the use of regression-based techniques to the application of decision-analytic models. Decision models are typically used when the evidence base is available exclusively in summary format whereas regression-based methods are used mainly when the country of interest actively recruited patients into the trial and there is access to IPD (or at least country-specific summary data). Whichever method is used to reflect between-country variability in costeffectiveness data, it is important to be transparent regarding the assumptions made in the analysis and (where possible) assess their impact on the study results. © 2010 Adis Data Information BV.

Pang E.W.,Hospital for Sick Children | Pang E.W.,Sick Kids Research Institute | Pang E.W.,University of Toronto
Frontiers in Psychiatry | Year: 2015

Mental flexibility is a core executive function that underlies the ability to adapt to changing situations and respond to new information. Individuals with post-traumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) complain of a number of executive function difficulties, one of which is mental inflexibility or an inability to switch between concepts. While the behavioral presentation of mental inflexibility is similar in those with PTSD or mTBI, we hypothesized that the differences in their etiology would manifest as differences in their underlying brain processing. The neural substrates of mental flexibility have been examined with a number of neuroimaging modalities. Functional magnetic resonance imaging has elucidated the brain regions involved, whereas electroencephalography has been applied to understand the timing of the brain activations. Magnetoencephalography, with its high temporal and spatial resolution, has more recently been used to delineate the spatiotemporal progression of brain processes involved in mental flexibility and has been applied to the study of clinical populations. In a number of separate studies, our group has compared the source localization and brain connectivity during a mental flexibility set-shifting task in a group of soldiers with PTSD and civilians with an acute mTBI. In this article, we review the results from these studies and integrate the data between groups to compare and contrast differences in behavioral, neural, and connectivity findings. We show that the different etiologies of PTSD and mTBI are expressed as distinct neural profiles for mental flexibility that differentiate the groups despite their similar clinical presentations. © 2015 Pang.

Nyamori J.M.,University of Nairobi | Kimani K.,University of Nairobi | Njuguna M.W.,University of Nairobi | Dimaras H.,University of Nairobi | And 3 more authors.
Middle East African Journal of Ophthalmology | Year: 2014

Purpose: Kenya is a large country with a widely dispersed population. As retinoblastoma requires specialized treatment, we determined the referral pattern for patients with retinoblastoma in Kenya to facilitate the formulation of a national policy.Materials and Methods: A retrospective study was performed for retinoblastoma patients who presented from January 1, 2006 to December 31, 2007. Data were collected on the referral process from presenting health facility to the hospital where patient was treated. Data were also collected on the time interval when the first symptoms were noticed to the time of presentation at a health facility (lag time). For cases that could be traced to a referral hospital, the time delay due to referral (referral lag time) was recorded.Results: There were 206 patients diagnosed with retinoblastoma in 51 Kenyan and 2 foreign healthcare facilities, and they received final treatment at a Kenyan hospital. Mean lag time was 6.8 months. Of all patients, 18% (38/206) were treated at the hospital where they first presented and 82% (168/206) were referred elsewhere. Of those referred, 35% (58/168) were lost to follow-up. The mean referral lag time was 1.7 months (5).Conclusions: A significant proportion of cases presented late, and either delayed seeking further treatment or were lost after initial referral. We recommend the implementation of a national strategy that emphasizes early detection, documentation and follow up of retinoblastoma patients.

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