Exploring Functional Connectivity Among Adults with Persistent Post-Concussion Syndrome Using Functional Near Infrared Spectroscopy
Creators: name: Du Plessis, Sané
Publisher: name: Cumming School of Medicine
Year: 2022
Subjects: subject: Post Concussion Syndrome
subject: Concussion
subject: Functional Near Infrared Spectroscopy
subject: fNIRS
subject: Functional Connectivity
subject: Persistent Post Concussion Syndrome
subject: Mild Traumatic Brain Injury
subject: Traumatic Brain Injury
subject: mTBI
subject: Education--Sciences
subject: Neuroscience
subject: Medicine and Surgery
subject: Rehabilitation and Therapy

description: Approximately one third of all concussions lead to persistent post concussion syndrome (PPCS). Functional near infrared spectroscopy (fNIRS) is a non-invasive imaging technique that measures the differences in the absorption of local oxy- and deoxyhemoglobin in the brain. The changes in cerebral tissue oxygenation are then used to monitor brain activity. fNIRS has demonstrated comparability to fMRI for reliably detecting changes in cerebral vascular reactivity and may provide insight into the pathophysiology of PPCS. The aim of this study was to compare the hemodynamic response of participants with PPCS to symptom burden using fNIRS in frontal and motor brain regions. Thirty-four adults (18-65) with PPCS (&gt;3 months - 5 years) were asked to complete a series of clinical questionnaires including the Rivermead Post-Concussion Symptom Questionnaire (RPQ) to assess symptom burden and complete a resting task, motor task, and working memory task during fNIRS assessments. Demographic information including age, sex, education level and employment status, and participant characteristics including concussion history, past medical history, medication use, and family medical history were also collected. A multiple regression analysis was conducted to assess the relationship between functional connectivity measures and symptom severity scores after consideration for age, sex, and time since injury. RPQ scores were not found to be significantly related to connectivity measures for oxy- (β = -0.02, p = 0.90) or deoxyhemoglobin (β = 0.31, p = 0.08) between the right and left dorsolateral prefrontal cortex (DLPFC) during the working memory task. However, increased deoxyhemoglobin functional connectivity measures between the left and right DLPFC during the working memory task were significantly related to higher depression scores (β = 0.44, p &lt; 0.05), anxiety scores (β = 0.54, p &lt; 0.05), somatoform symptom scores (β = 0.43, p &lt; 0.05), and post-traumatic stress injury scores (β = 0.43, p &lt; 0.05). Furthermore, the relationship between working memory fNIRS connectivity values and RPQ was further explored by analyzing the relationship between specific symptoms and fNIRS outcomes. Several RPQ items were significantly related to task-evoked deoxyhemoglobin functional connectivity scores between the left and right DLPFC including “feeling depressed or tearful” (β = 0.41, p &lt; 0.05), “poor memory or forgetting” (β = 0.34, p &lt; 0.05), and “difficulty concentrating” (β = 0.34, p &lt; 0.05). The preliminary data and results from this study may contribute to a better understanding of brain function and specific symptoms in patients with PPCS.