Browsing by Author "Dleikan, Diane"
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- ItemOpen AccessMeasuring Cerebral Oxygenation in Healthy and Concussed Brain Using Frequency Domain Near-Infrared Spectroscopy (fdNIRS)(2018-06-14) Dleikan, Diane; Dunn, Jeff F.; Yeates, Keith Owen; Debert, Chantel T.Concussion or mild traumatic brain injury (mTBI) is a major public health concern that affects millions of people annually. The current metrics used to assess and diagnose concussion are largely subjective. There is a need for an objective neuroimaging tool to directly measure brain physiology and provide insight into recovery. Such a tool would supplement current subjective metrics used to monitor and index severity of injury. There is also a need to better understand the pathophysiology of concussion. Near-infrared spectroscopy (NIRS) is a non-invasive optical imaging tool used to measure aspects of microvascular hemoglobin oxygenation. In this study, we apply NIRS to quantify cerebral oxygenation (StO2), which has been used as an indicator of oxygen delivery to assess injury severity and tissue damage. We measured StO2 in a large cohort population with varying ages, and compared this to two post-concussive groups. In the first, a small varsity cohort, cerebral oxygenation was reduced in athletes who reported increased symptom severity. In the second, a pediatric sports-related concussion (SRC) cohort, cerebral oxygenation was increased when compared to age and gender matched controls. We also found that exercise is a potential confounding variable to consider when assessing concussion on the sideline, as we reported increases in StO2 in most varsity football players after practice. We report intriguing but not conclusive evidence that concussion can cause acute reduction in oxygenation, which may indicate changes in brain physiology immediately after injury. Overall, this thesis demonstrated that prefrontal cortex StO2, measured by NIRS, has the potential for monitoring brain physiology during concussion recovery in a clinical and sport setting.
- ItemOpen AccessReduced Functional Connectivity in Adults with Persistent Post-Concussion Symptoms: A Functional Near-Infrared Spectroscopy Study(Mary Ann Liebert, Inc., 2018-06-01) Hocke, Lia Maria; Duszynski, Chris C.; Debert, Chantel T.; Dleikan, Diane; Dunn, Jeff F.Concussion, or mild traumatic brain injury (mTBI), accounts for ∼80% of all TBIs across North America. The majority of mTBI patients recover within days to weeks; however, 14-36% of the time, acute mTBI symptoms persist for months or even years and develop into persistent post-concussion symptoms (PPCS). There is a need to find biomarkers in patients with PPCS, to improve prognostic ability and to provide insight into the pathophysiology underlying chronic symptoms. Recent research has pointed toward impaired network integrity and cortical communication as a biomarker. In this study we investigated functional near-infrared spectroscopy (fNIRS) as a technique to assess cortical communication deficits in adults with PPCS. Specifically, we aimed to identify cortical communication patterns in prefrontal and motor areas during rest and task, in adult patients with persistent symptoms. We found that (1) the PPCS group showed reduced connectivity compared with healthy controls, (2) increased symptom severity correlated with reduced coherence, and (3) connectivity differences were best distinguishable during task and in particular during the working memory task (n-back task) in the right and left dorsolateral prefrontal cortex (DLPFC). These data show that reduced brain communication may be associated with the pathophysiology of mTBI and that fNIRS, with a relatively simple acquisition paradigm, may provide a useful biomarker of this injury.