Bloorview Research Institute

Toronto, Canada

Bloorview Research Institute

Toronto, Canada
SEARCH FILTERS
Time filter
Source Type

Baribeau D.A.,University of Toronto | Anagnostou E.,Bloorview Research Institute
Frontiers in Neuroscience | Year: 2015

Oxytocin and vasopressin are pituitary neuropeptides that have been shown to affect social processes in mammals. There is growing interest in these molecules and their receptors as potential precipitants of, and/or treatments for, social deficits in neurodevelopmental disorders, including autism spectrum disorder. Numerous behavioral-genetic studies suggest that there is an association between these peptides and individual social abilities; however, an explanatory model that links hormonal activity at the receptor level to complex human behavior remains elusive. The following review summarizes the known associations between the oxytocin and vasopressin neuropeptide systems and social neurocircuits in the brain. Following a micro- to macro- level trajectory, current literature on the synthesis and secretion of these peptides, and the structure, function and distribution of their respective receptors is first surveyed. Next, current models regarding the mechanism of action of these peptides on microcircuitry and other neurotransmitter systems are discussed. Functional neuroimaging evidence on the acute effects of exogenous administration of these peptides on brain activity is then reviewed. Overall, a model in which the local neuromodulatory effects of pituitary neuropeptides on brainstem and basal forebrain regions strengthen signaling within social neurocircuits proves appealing. However, these findings are derived from animal models; more research is needed to clarify the relevance of these mechanisms to human behavior and treatment of social deficits in neuropsychiatric disorders. © 2015 Baribeau and Anagnostou.


Faress A.,Bloorview Research Institute | Faress A.,University of Toronto | Chau T.,Bloorview Research Institute | Chau T.,University of Toronto
NeuroImage | Year: 2013

Previous brain-computer interface (BCI) research has largely focused on single neuroimaging modalities such as near-infrared spectroscopy (NIRS) or transcranial Doppler ultrasonography (TCD). However, multimodal brain-computer interfaces, which combine signals from different brain modalities, have been suggested as a potential means of improving the accuracy of BCI systems. In this paper, we compare the classification accuracies attainable using NIRS signals alone, TCD signals alone, and a combination of NIRS and TCD signals. Nine able-bodied subjects (mean age = 25.7) were recruited and simultaneous measurements were made with NIRS and TCD instruments while participants were prompted to perform a verbal fluency task or to remain at rest, within the context of a block-stimulus paradigm. Using Linear Discriminant Analysis, the verbal fluency task was classified at mean accuracies of 76.1 ± 9.9%, 79.4 ± 10.3%, and 86.5 ± 6.0% using NIRS, TCD, and NIRS-TCD systems respectively. In five of nine participants, classification accuracies with the NIRS-TCD system were significantly higher (p < 0.05) than with NIRS or TCD systems alone. Our results suggest that multimodal neuroimaging may be a promising method of improving the accuracy of future brain-computer interfaces. © 2013 Elsevier Inc.


Anagnostou E.,Bloorview Research Institute | Taylor M.J.,University of Toronto
Molecular Autism | Year: 2011

Autism spectrum disorder (ASD) refers to a syndrome of social communication deficits and repetitive behaviors or restrictive interests. It remains a behaviorally defined syndrome with no reliable biological markers. The goal of this review is to summarize the available neuroimaging data and examine their implication for our understanding of the neurobiology of ASD. Although there is variability in the literature on structural magnetic resonance literature (MRI), there is evidence of volume abnormalities in both grey and white matter, with a suggestion of some region-specific differences. Early brain overgrowth is probably the most replicated finding in a subgroup of people with ASD, and new techniques, such as cortical-thickness measurements and surface morphometry have begun to elucidate in more detail the patterns of abnormalities as they evolve with age, and are implicating specific neuroanatomical or neurodevelopmental processes. Functional MRI and diffusion tensor imaging techniques suggest that such volume abnormalities are associated with atypical functional and structural connectivity in the brain, and researchers have begun to use magnetic resonance spectroscopy (MRS) techniques to explore the neurochemical substrate of such abnormalities. The data from multiple imaging methods suggests that ASD is associated with an atypically connected brain. We now need to further clarify such atypicalities, and start interpreting them in the context of what we already know about typical neurodevelopmental processes including migration and organization of the cortex. Such an approach will allow us to relate imaging findings not only to behavior, but also to genes and their expression, which may be related to such processes, and to further our understanding of the nature of neurobiologic abnormalities in ASD. © 2011 Anagnostou and Taylor; licensee BioMed Central Ltd.


Baribeau D.A.,University of Toronto | Anagnostou E.,Bloorview Research Institute
Frontiers in Psychiatry | Year: 2013

Background: Autism spectrum disorder (ASD) and childhood onset schizophrenia (COS) are pediatric neurodevelopmental disorders associated with significant morbidity. Both conditions are thought to share an underlying genetic architecture. A comparison of neuroimaging findings across ASD and COS with a focus on altered neurodevelopmental trajectories can shed light on potential clinical biomarkers and may highlight an underlying etiopathogenesis. Methods: A comprehensive review of the medical literature was conducted to summarize neuroimaging data with respect to both conditions in terms of structural imaging (including volumetric analysis, cortical thickness and morphology, and region of interest studies), white matter analysis (include volumetric analysis and diffusion tensor imaging) and functional connectivity. Results: In ASD, a pattern of early brain overgrowth in the first few years of life is followed by dysmaturation in adolescence. Functional analyses have suggested impaired long-range connectivity as well as increased local and/or subcortical connectivity in this condition. In COS, deficits in cerebral volume, cortical thickness, and white matter maturation seem most pronounced in childhood and adolescence, and may level off in adulthood. Deficits in local connectivity, with increased long-range connectivity have been proposed, in keeping with exaggerated cortical thinning. Conclusion: The neuroimaging literature supports a neurodevelopmental origin of both ASD and COS and provides evidence for dynamic changes in both conditions that vary across space and time in the developing brain. Looking forward, imaging studies which capture the early post natal period, which are longitudinal and prospective, and which maximize the signal to noise ratio across heterogeneous conditions will be required to translate research findings into a clinical environment. © 2013 Baribeau and Anagnostou.


Biddiss E.,Bloorview Research Institute | Irwin J.,University of Toronto
Archives of Pediatrics and Adolescent Medicine | Year: 2010

Objectives: To systematically review levels of metabolic expenditure and changes in activity patterns associated with active video game (AVG) play in children and to provide directions for future research efforts. Data Sources: A review of the English-language literature (January 1, 1998, to January 1, 2010) via ISI Web of Knowledge, PubMed, and Scholars Portal using the following keywords: video game, exergame, physical activity, fitness, exercise, energy metabolism, energy expenditure, heart rate, disability, injury, musculoskeletal, enjoyment, adherence, and motivation. Study Selection: Only studies involving youth (≤21years) and reporting measures of energy expenditure, activity patterns, physiological risks and benefits, and enjoyment and motivation associated with mainstream AVGs were included. Eighteen studies met the inclusion criteria. Articles were reviewed and data were extracted and synthesized by 2 independent reviewers. Main Outcome Exposures: Energy expenditure during AVG play compared with rest (12 studies) and activity associated with AVG exposure (6 studies). Main Outcome Measures: Percentage increase in energy expenditure and heart rate (from rest). Results: Activity levels duringAVGplay were highly variable, with mean (SD) percentage increases of 222% (100%) in energy expenditure and 64% (20%) in heart rate. Energy expenditure was significantly lower for games played primarily through upper body movements compared with those that engaged the lower body (difference, -148%; 95% confidence interval, -231% to -66%; P=.001). Conclusions: The AVGs enable light to moderate physical activity. Limited evidence is available to draw conclusions on the long-term efficacy of AVGs for physical activity promotion. ©2010 American Medical Association. All rights reserved.


Hunt A.W.,Bloorview Research Institute
Journal of Head Trauma Rehabilitation | Year: 2015

OBJECTIVE:: The purpose of this article is to synthesize and appraise the evidence regarding the use of oculomotor-based vision assessment to identify and monitor recovery from mild traumatic brain injury (mTBI). Specific objectives are to (1) identify changes in oculomotor-based vision following mTBI; (2) distinguish methods of assessment; (3) appraise the level and quality of evidence; and, if warranted, (4) determine clinical recommendations for assessment. METHODS:: A systematic review was undertaken to identify and appraise relevant literature. A search was conducted of 7 databases of peer-reviewed literature from January 1990 to January 2015. Articles were included if study populations were clearly identified as having mTBI and used an assessment of oculomotor-based vision. Articles with pooled data (eg, mTBI and stroke), addressing afferent visual function (eg, visual field deficits) or using single case designs, were excluded. RESULTS:: Twenty articles were selected for inclusion. Exploratory findings suggest that measurements of saccades, smooth pursuit, and vergence are useful in detecting changes associated with mTBI. Assessment methods included eye tracker protocols, optometric assessment, and the King-Devick test. CONCLUSION:: The strength of this evidence is not yet sufficient to warrant clinical recommendations. Research using rigorous methods is required to develop reliable, valid, and clinically useful assessment protocols. © 2015 Wolters Kluwer Health, Inc. All rights reserved.


Lindsay S.,Bloorview Research Institute
Qualitative Health Research | Year: 2014

In this article, I explore the experiences and perspectives of youth living with spina bifida, the second most common congenital condition in North America, to inform the development of health programs. I undertook a thematic metasynthesis to integrate qualitative evidence across studies examining the experiences of youth with spina bifida. I used 10 electronic databases to search for and review 4,051 abstracts, and identified 12 articles meeting the inclusion criteria. I examined those articles using a constant comparative approach, drawing on concepts of normalcy and biographical disruption to inform understanding of three emergent themes: (a) the medical management of spina bifida; (b) the importance of peer and family relationships (i.e., social support, belonging, and challenges in peer connections); and (c) identity and self-concept (i.e., normalization). This metasynthesis provides insight for youth, parents, and clinicians on areas of life in which youth could use further support. © The Author(s) 2014.


Lindsay S.,Bloorview Research Institute
Disability and Rehabilitation | Year: 2011

Purpose. Little is known about the work experiences of youth as they transition to adulthood. The purpose of this study is to explore the characteristics associated with disabled youth who are employed and the types of employment they are engaged in. Method. Data were analysed using the 2006 Participation and Activity Limitation Survey. Youth aged 15-29 and 20-24 were selected to explore the characteristics of adolescents who are employed and where they are working (n = 2534). Results. Several differences in who was employed and the characteristics of their employers were noted between the two age groups. Geographic location played a more significant role for employment among youth (15-19 year olds) with mobility impairments compared to other disability types. Employed youth from both age groups had their disability a long time while few people who were recently diagnosed were working. Transportation was a significant predictor of employment for both age groups. Young adults (20-24) worked more hours per week, in different industries, and more of them were self-employed compared to the 15-19 year olds. Employment status and work characteristics also differed by type of disability. Conclusions. Rehabilitation and life skills counsellors need to pay particular attention to youth who may need extra help in gaining employment. © 2011 Informa UK, Ltd.


Lindsay S.,Bloorview Research Institute
Disability and Rehabilitation | Year: 2011

Purpose. Having a disability is a barrier to securing and maintaining employment. Most research has focussed on employment barriers among adults, while very little is known about young people's experience finding paid work. Method. Young people aged 15-24 were selected from the 2006 Participation and Activity Limitation Survey to explore the barriers and discrimination they experienced in seeking employment (n=1898). Results. Our findings show that teens and young adults with disabilities encountered several barriers and discrimination in seeking paid employment. The types of barriers that these young people encountered varied by age and type of disability. There were fewer yet different types of barriers to working that were encountered between the two age groups (teens and young adults). Several socio-demographic factors also influenced barriers to working. Severity of disability, type and duration of disability, level of education, gender, low income, geographic location and the number of people living in the household all influenced the kind of barriers and work discrimination for these young people. Conclusions. Rehabilitation and life skills counsellors need to pay particular attention to age, type of disability and socio-demographic factors of teens and young adults who may need extra help in gaining employment. © 2011 Informa UK, Ltd.


Andrysek J.,Bloorview Research Institute
Prosthetics and Orthotics International | Year: 2010

In the mid-1990s, a number of key publications and meetings of experts identified major technical issues associated with prosthetic technologies intended for developing countries. These included inadequate durability of prosthetic feet, poor socket quality and prosthetic fit, improper alignment of prostheses, and inferior function of components. To examine the progress that has been made since then in addressing these issues, a comprehensive review of literature was performed. In total, 106 articles were selected and included in the review. The review examined prosthetic technologies categorized into feet and ankles, knees, sockets and suspension, and materials, structures, and alignment methods. Moreover, publications were categorized as technical development, clinical lab-based testing, or clinical field testing studies. The results reveal important work that has been carried out to develop and implement standardized outcome measures during field testing, allowing various existing prosthetic technologies to be evaluated in terms of their use, function, durability, and other factors. Progress has also been made toward addressing the aforementioned limitations of prosthetic technologies, however, more research and development is required. This includes improving the durability of the external cosmetic features of prosthetic feet, developing more functional prosthetic knee joints, and simplifying fabrication techniques to further improve outcomes associated with socket fit and prosthetic alignment. Research and development collaborations between developed and developing countries, and the dissemination of ongoing research, development, and evaluation activities are essential to the advancement of prosthetic technologies in these regions. © 2010 ISPO.

Loading Bloorview Research Institute collaborators
Loading Bloorview Research Institute collaborators