Sports Concussions and Aging: A Neuroimaging Investigation

Centre de Recherche en Neuropsychologie et Cognition.
Cerebral Cortex (Impact Factor: 8.67). 05/2012; 23(5). DOI: 10.1093/cercor/bhs102
Source: PubMed


Recent epidemiological and experimental studies suggest a link between cognitive decline in late adulthood and sports concussions sustained in early adulthood. In order to provide the first in vivo neuroanatomical evidence of this relation, the present study probes the neuroimaging profile of former athletes with concussions in relation to cognition. Former athletes who sustained their last sports concussion >3 decades prior to testing were compared with those with no history of traumatic brain injury. Participants underwent quantitative neuroimaging (optimized voxel-based morphometry [VBM], hippocampal volume, and cortical thickness), proton magnetic resonance spectroscopy ((1)H MRS; medial temporal lobes and prefrontal cortices), and neuropsychological testing, and they were genotyped for APOE polymorphisms. Relative to controls, former athletes with concussions exhibited: 1) Abnormal enlargement of the lateral ventricles, 2) cortical thinning in regions more vulnerable to the aging process, 3) various neurometabolic anomalies found across regions of interest, 4) episodic memory and verbal fluency decline. The cognitive deficits correlated with neuroimaging findings in concussed participants. This study unveiled brain anomalies in otherwise healthy former athletes with concussions and associated those manifestations to the long-term detrimental effects of sports concussion on cognitive function. Findings from this study highlight patterns of decline often associated with abnormal aging.

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Available from: Sebastien Tremblay
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    • "A growing body of research has also highlighted an association between increases in variability resulting from age-related changes in cerebral blood flow, cortical thinning, vascular injury, and neurological conditions with structural and functional alterations in frontal gray and white matter (Britton et al., 1991; Bunce et al., 2007; Sowell et al., 2003; Stuss et al., 2003; Walhovd and Fjell, 2007; but see Garrett et al., 2013 for review). Relative to concussion related injuries; in contrast to claims that concussion related impairments resolve within 10 to 14 days (McCrea et al., 2009; McCrory et al., 2013), a growing body of literature has observed decreased gray matter volumes in formerly concussed individuals in areas supporting high level cognitive operations , including the dorsolateral prefrontal cortex, anterior cingulate cortex (Chen et al., 2004, 2008) and hippocampus (Tremblay et al., 2013). Further, evidence from human autopsy and animal investigations implicate axonal pathology – hypothesized to be the result of stretching and shearing of axonal fibers when the concussive impact is transmitted throughout the brain – as potentially underlying clinical symptomologies of a traumatic brain injury such as a concussion (Bigler, 2013). "
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    ABSTRACT: Associations between a history of concussion and variability in behavioral and neuroelectric indices of cognition were assessed in college-aged adults with a history of concussion and a healthy control group, in response to a stimulus discrimination task and a more attentionally demanding flanker task. Greater intra-individual variability was observed only for behavioral indices of reaction time in response to the flanker task for those with a history of concussion. An association was also observed between the number of concussions resulting in a loss of consciousness and greater variability of reaction time regardless of the type of task. Relative to neuroelectric measures, a concussive history was associated with smaller P3 amplitude only in response to the flanker task; with no differences between groups observed in response to the oddball task or for intra-individual variability measures. Thus, increased variability associated with a history of concussion appears to be behavior and process specific. The behavioral metrics and functions assessed are important considerations for identifying subtle, yet persistent influences of concussion on cognitive performance. Further, factors such as loss of consciousness associated with a concussive injury may moderate the extent to which these increases in behavioral variability manifest. Thus, the identification of persistent cognitive impairment following concussive injuries necessitates the utilization of appropriate tasks and may be facilitated by going beyond behavioral measures of central tendency. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Sep 2015 · International Journal of Psychophysiology
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    • "We believe these observations suggest that the concussed brain is more vulnerable to the pathological effects of normal ageing. This interpretation would be in line with findings of exacerbated cortical thinning and ventricular expansion with advancing age in the same sample of former concussed athletes (Tremblay et al., 2013). Overall, these results provide support for the notion that structural injury from TBI, even if not grossly apparent, might reduce the resilience of the brain and expedite the degenerative effects of ageing (Moretti et al., 2012). "
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    ABSTRACT: Sports-related concussions have been shown to lead to persistent subclinical anomalies of the motor and cognitive systems in young asymptomatic athletes. In advancing age, these latent alterations correlate with detectable motor and cognitive function decline. Until now, the interacting effects of concussions and the normal ageing process on white matter tract integrity remain unknown. Here we used a tract-based spatial statistical method to uncover potential white matter tissue damage in 15 retired athletes with a history of concussions, free of comorbid medical conditions. We also investigated potential associations between white matter integrity and declines in cognitive and motor functions. Compared to an age- and education-matched control group of 15 retired athletes without concussions, former athletes with concussions exhibited widespread white matter anomalies along many major association, interhemispheric, and projection tracts. Group contrasts revealed decreases in fractional anisotropy, as well as increases in mean and radial diffusivity measures in the concussed group. These differences were primarily apparent in fronto-parietal networks as well as in the frontal aspect of the corpus callosum. The white matter anomalies uncovered in concussed athletes were significantly associated with a decline in episodic memory and lateral ventricle expansion. Finally, the expected association between frontal white matter integrity and motor learning found in former non-concussed athletes was absent in concussed participants. Together, these results show that advancing age in retired athletes presenting with a history of sports-related concussions is linked to diffuse white matter abnormalities that are consistent with the effects of traumatic axonal injury and exacerbated demyelination. These changes in white matter integrity might explain the cognitive and motor function declines documented in this population.
    Full-text · Article · Sep 2014 · Brain
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    • "Compared to former college athletes without a history of mTBI, those who had sustained mTBI during their college career showed deficits in figural memory tasks, such as the Rey–Osterrieth Complex Figure. The poorer memory function was accompanied by metabolic abnormalities within the medial temporal lobe (MTL) of the group with a history of mTBI, as well as greater cortical thinning in frontal, parietal, and temporal cortices, compared to the control group (Tremblay et al., 2013). Taken together, these studies indicate prior history of mTBI may exacerbate and/or accelerate age-related memory decrements and neural changes. "
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    ABSTRACT: Evidence suggests that a history of head trauma is associated with memory deficits later in life. The majority of previous research has focused on moderate-to-severe traumatic brain injury (TBI), but recent evidence suggests that even a mild TBI (mTBI) can interact with the aging process and produce reductions in memory performance. This study examined the association of mTBI with memory and the brain by comparing young and middle-aged adults who have had mTBI in their recent (several years ago) and remote (several decades ago) past, respectively, with control subjects on a face-scene relational memory paradigm while they underwent functional magnetic resonance imaging (fMRI). Hippocampal volumes were also examined from high-resolution structural images. Results indicated middle-aged adults with a head injury in their remote past had impaired memory compared to gender, age, and education matched control participants, consistent with previous results in the study of memory, aging, and TBI. The present findings extended previous results by demonstrating that these individuals also had smaller bilateral hippocampi, and had reduced neural activity during memory performance in cortical regions important for memory retrieval. These results indicate that a history of mTBI may be one of the many factors that negatively influence cognitive and brain health in aging.
    Full-text · Article · Aug 2013 · Frontiers in Aging Neuroscience
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