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Grigorovich A.,Clinical Research | Gomez M.,Clinical Research | Gomez M.,University of Toronto | Psych C.,Baycrest Center for Geriatric Care | Fish J.,Hospital for Sick Children
Journal of Burn Care and Research | Year: 2013

To examine neuropsychological functioning in survivors of electrical injury with posttraumatic stress disorder (PTSD) and depression. This was a prospective research study that was done in an outpatient clinic of a rehabilitation hospital. Thirty participants were recruited for the study between January 2008 and December 2010. All participants completed questionnaires measuring depression, PTSD, and a series of standardized psychometric measures of neuropsychological functioning. Domains tested included verbal and visual memory, attention, and executive functioning. A correlation analysis was performed to explore association between variables. Based on the level of PTSD symptoms, subjects were divided into three groups: no PTSD, subclinical PTSD, and PTSD, and a series of one-way analyses of variance were done to explore this association further. A series of analyses of covariance were done to control for depression. PTSD had a significant (P < .05) negative association with immediate verbal memory and immediate and delayed visual memory. Subjects with PTSD had significantly (P < .05) worse scores on immediate and delayed verbal memory and visual memory than those with subclinical PTSD or no PTSD. Measures of attention, working memory, and executive functioning were not significantly different between PTSD groups. When depression was introduced as a covariate, verbal and visual memory scores were not significantly different between PTSD groups. The findings suggest that there is a negative association between PTSD and cognitive performance that may be related to depression among those with electrical injury. A larger sample size is warranted to explore this further. Copyright © 2013 by the American Burn Association.


Monette M.C.E.,University of Windsor | Leach L.,Baycrest Center for Geriatric Care
Canadian Journal of Neurological Sciences | Year: 2013

Objective: The current study sought to determine if the Kaplan-Baycrest Neurocognitive Assessment (KBNA) was capable of discriminating individuals with subjective memory complaints associated with depression from individuals with mild cognitive impairment (MCI). Methods: Scores on 12 subtests of the KBNA were compared for 27 participants with MCI and 28 participants being treated for depression using Bonferroni correct between-group comparisons for each subtest. KBNA subtest scores were corrected for age and education. Results: Significant between-group differences were obtained on six subtests with large effect sizes (Cohen's d) ranging from 1.19-1.58. The six subtests involved encoding and delayed episodic memory for verbal and visual information. Using logistic regression analysis, five subtests of the KBNA were able to correctly classify 96.4% of study participants. Conclusion: The results from this preliminary investigation indicate that the KBNA has the potential to serve as a brief and reliable assessment tool capable of distinguishing individuals with subjective memory complaints associated with depression from individuals with MCI in a clinical setting. Limitations of the current study and future research are discussed.


Ossher L.,University of Michigan | Bialystok E.,York University | Bialystok E.,Rotman Research Institute | Craik F.I.M.,Rotman Research Institute | And 5 more authors.
Journals of Gerontology - Series B Psychological Sciences and Social Sciences | Year: 2013

Objectives.Previous reports have found that lifelong bilingualism is associated with a delay in the onset of dementia, including Dementia of the Alzheimer's Type (DAT). Because amnestic mild cognitive impairment (aMCI) is often a transition stage between normal aging and DAT, our aim in this paper was to establish whether this delay in symptom onset for bilinguals would also be seen in the onset of symptoms of aMCI and whether this delay would be consistent in different subtypes of aMCI.Method.We examined the effect of bilingualism on the age of diagnosis in individuals with single- or multiple-domain aMCI who were administered a battery of neuropsychological tests and questionnaires about their language and social background.Results.Our results showed an interaction between aMCI type and language history. Only individuals diagnosed with single-domain aMCI demonstrated a later age of diagnosis for bilinguals (M = 79.4 years) than monolinguals (M = 74.9 years).Discussion.This preliminary evidence suggests that the early protective advantage of bilingualism may be specific to single-domain aMCI, which is the type of aMCI most specifically associated with progression to DAT. © 2012 The Author. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved.


St-Laurent M.,Toronto Western Hospital | St-Laurent M.,University of Toronto | St-Laurent M.,Rotman Research Institute | Moscovitch M.,University of Toronto | And 5 more authors.
Hippocampus | Year: 2014

Perceptual richness, a defining feature of episodic memory, emerges from the reliving of multimodal sensory experiences. Although the importance of the medial temporal lobe (MTL) to episodic memory retrieval is well documented, the features that determine its engagement are not well characterized. The current study assessed the relationship between MTL function and episodic memory's perceptual richness. We designed a laboratory memory task meant to capture the complexity of memory for life episodes, while manipulating memory's perceptual content. Participants encoded laboratory episodes with rich (film clips) and impoverished (written narratives) perceptual content that were matched for other characteristics such as personal significance, emotionality and story content. At retrieval, participants were probed to describe the stories' perceptual features and storyline. Participants also recalled autobiographical memories (AMs) in a comparison condition. We compared the performance of patients with unilateral medial temporal lobe epilepsy (mTLE) and healthy controls to assess how damage to the MTL affects retrieval in these conditions. We observed an overall decrease in detail count in the mTLE group, along with a disproportionate deficit in perceptual details that was most acute in the AM and the perceptually enriched film clip conditions. Our results suggest that the impaired sense of reliving the past that accompanies MTL insult is mediated by a paucity of perceptual episodic memory details. We also introduce a new protocol that successfully mimics naturalistic memories while benefiting from the experimental control provided by using laboratory stimuli. © 2014 Wiley Periodicals, Inc.


PubMed | Baycrest Center for Geriatric Care and University of Memphis
Type: Journal Article | Journal: Journal of cognitive neuroscience | Year: 2016

Musicianship has been associated with auditory processing benefits. It is unclear, however, whether pitch processing experience in nonmusical contexts, namely, speaking a tone language, has comparable associations with auditory processing. Studies comparing the auditory processing of musicians and tone language speakers have shown varying degrees of between-group similarity with regard to perceptual processing benefits and, particularly, nonlinguistic pitch processing. To test whether the auditory abilities honed by musicianship or speaking a tone language differentially impact the neural networks supporting nonlinguistic pitch processing (relative to timbral processing), we employed a novel application of brain signal variability (BSV) analysis. BSV is a metric of information processing capacity and holds great potential for understanding the neural underpinnings of experience-dependent plasticity. Here, we measured BSV in electroencephalograms of musicians, tone language-speaking nonmusicians, and English-speaking nonmusicians (controls) during passive listening of music and speech sound contrasts. Although musicians showed greater BSV across the board, each group showed a unique spatiotemporal distribution in neural network engagement: Controls had greater BSV for speech than music; tone language-speaking nonmusicians showed the opposite effect; musicians showed similar BSV for both domains. Collectively, results suggest that musical and tone language pitch experience differentially affect auditory processing capacity within the cerebral cortex. However, information processing capacity is graded: More experience with pitch is associated with greater BSV when processing this cue. Higher BSV in musicians may suggest increased information integration within the brain networks subserving speech and music, which may be related to their well-documented advantages on a wide variety of speech-related tasks.


PubMed | Sunnybrook Health science Center, North York General Hospital, Baycrest Center for Geriatric Care, Sunnybrook Research Institute and University of Toronto
Type: | Journal: Parkinsonism & related disorders | Year: 2015

Orthostatic hypotension and cognitive impairment are two non-motor attributes of Lewy body spectrum disorders that impact independence. This proof-of-concept study examined cerebral blood flow (perfusion) as a mediator of orthostatic hypotension and cognition.In fifteen patients with Lewy body disorders, we estimated regional perfusion using pseudo-continuous arterial spin labeling MRI, and quantified orthostatic hypotension from the change in systolic blood pressure between supine and standing positions. Executive, visuospatial, attention, memory, and language domains were characterized by neuropsychological tests. A matching sample of non-demented adults with cerebral small vessel disease was obtained to contrast perfusion patterns associated with comorbid vascular pathology.Compared to the vascular group, patients with Lewy body disorders exhibited lower perfusion to temporal and occipital lobes than to frontal and parietal lobes (q < 0.05). A greater orthostatic drop in systolic pressure was associated with lower occipito-parietal perfusion in these patients (uncorrected p < 0.005; cluster size 20 voxels). Although orthostatic hypotension and supine hypertension were strongly correlated (r = -0.79, p < 0.001), the patterns of association for each with perfusion were distinct. Specifically, supine hypertension was associated with high perfusion to anterior and middle cerebral arterial territories, as well as with low perfusion to posterior regions. Perfusion within orthostatic hypotension-defined regions was directly related to performance on visuospatial and attention tasks, independent of dementia severity (p < 0.05).These findings provide new insight that regional cerebral hypoperfusion is related to orthostatic hypotension, and may be involved in domain-specific cognitive deficits in Lewy body disorders.


PubMed | Rotman Research Institute, Baycrest Center for Geriatric Care and University of Waterloo
Type: | Journal: Neuropsychologia | Year: 2016

We examined the effect of different distracting tasks, performed concurrently during memory retrieval, on recall of a list of words. By manipulating the type of material and processing (semantic, orthographic, and phonological) required in the distracting task, and comparing the magnitude of memory interference produced, we aimed to infer the kind of representation upon which retrieval of words depends. In Experiment 1, identifying odd digits concurrently during free recall disrupted memory, relative to a full attention condition, when the numbers were presented orthographically (e.g. nineteen), but not numerically (e.g. 19). In Experiment 2, a distracting task that required phonological-based decisions to either word or picture material produced large, but equivalent effects on recall of words. In Experiment 3, phonological-based decisions to pictures in a distracting task disrupted recall more than when the same pictures required semantically-based size estimations. In Experiment 4, a distracting task that required syllable decisions to line drawings interfered significantly with recall, while an equally difficult semantically-based color-decision task about the same line drawings, did not. Together, these experiments demonstrate that the degree of memory interference experienced during recall of words depends primarily on whether the distracting task competes for phonological representations or processes, and less on competition for semantic or orthographic or material-specific representations or processes.


Zakzanis K.K.,University of Toronto | McDonald K.,University of Toronto | Troyer A.K.,Baycrest Center for Geriatric Care
Journal of Clinical and Experimental Neuropsychology | Year: 2011

We set out to examine the sensitivity of switching and clustering component scores of verbal fluency in patients with mild traumatic brain injury (mTBI). Clustering and switching scores were compared between patients with mTBI and healthy normal controls as well as those with moderate TBI and severe TBI. Fifty-four healthy controls along with 20 mild TBI, 8 moderate TBI, and 12 severe TBI patients were included in the study. Our findings demonstrate that component score effect sizes were larger than those of total words generated for both phonemic and semantic fluency. This pattern of finding held true regardless of comparison group. In addition, semantic fluency component scores were found to correspond to larger component score effect sizes than did phonemic fluency component scores. Our findings demonstrate that component scores derived from the Controlled Oral Word Association Test may be sufficient to reliably capture the effects of unremitting injury (i.e., more than 3 months post status) to the frontal and temporal brain as evinced in cases of unremitting mTBI. This differential pattern of performance provides preliminary evidence for the potential usefulness of switching and clustering in the assessment of mTBI. Given the small sample sizes employed in our study, however, future studies are needed to determine whether component measures of verbal fluency have discriminative ability. © 2011 Psychology Press.


Patent
Baycrest Center For Geriatric Care | Date: 2012-10-05

The present invention provides methods and systems for assessing cognitive function by comparing a subjects eye movements within and across distinct classes of images.


Patent
Baycrest Center For Geriatric Care | Date: 2013-08-02

In one aspect the application relates to a computing system for providing data for modelling a human brain comprises a database including a plurality of datasets (or allow access to a plurality of datasets), each dataset including at least a dynamical model of the brain including at least one node and a neurodataset of a neuroimaging modality input. The at least one node include a representation of a local dynamic model and a parameter set of the local dynamic model.

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