Reduced Functional Connectivity in Adults with Persistent Post-Concussion Symptoms: A Functional Near-Infrared Spectroscopy Study

Abstract

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.

Near‐Infrared Spectroscopy Reveals Brain Hypoxia and Cerebrovascular Dysregulation in Primary Biliary Cholangitis

“…We found that patients with PBC exhibit significantly reduced cortical hemodynamic coherence (Fig. ), similar in magnitude to reductions we have previously reported in adults with MS and in adults and children with chronic symptoms following mild traumatic brain injury . In particular, our findings of reduced coherence were greatest for frequencies centered around the ~0.1‐Hz oscillation (10‐second rhythm) known as the “Mayer wave,” indicating altered vasomotor regulation of cerebral blood flow .…”

“…2), similar in magnitude to reductions we have previously reported in adults with MS (6) and in adults and children with chronic symptoms following mild traumatic brain injury. (33,34) In particular, our findings of reduced coherence were greatest for frequencies centered around the ~0.1-Hz oscillation (10-second rhythm) known as the "Mayer wave," indicating altered vasomotor regulation of cerebral blood flow. (22) Dysregulation of cerebral blood flow and perfusion in these patients may result from two potential mechanisms: (1) disrupted efferent sympathetic nervous control of arterial blood pressure and/or (2) direct damage or injury to the vascular endothelial cells, both of which may cause dysfunctional vasomotor activity.…”

Neurovascular Coupling by Functional Near Infra-Red Spectroscopy and Sport-Related Concussion in Retired Rugby Players: The UK Rugby Health Project

“…Thus, it has the potential to be used to examine several physiological mechanisms including NVC (Ellis et al, 2016;Epps and Allen, 2017). Few studies have used fNIRS for the assessment and monitoring of post-concussive injury (Urban et al, 2015;Bishop and Neary, 2018;Hocke et al, 2018). Relative changes were observed over time with O 2 Hb decreasing after the initial concussion injury and HHb increasing until day 14 post-injury.…”

Application of functional near-infrared spectroscopy in the healthcare industry: A review

“…294 Compared to healthy persons, the patients with mild TBI also showed lower functional connectivity that was inversely linked with impairment intensity, and the di®erence in connectivity was more pronounced during the task period as compared to the resting state. 295…”

“…[30][31][32][33][34]79,121,236,266,272 Functional and e®ective connectivity analyses are useful to understand the processing that takes place in the human brain, and covering more brain areas will allow for better understanding based on the experimental conditions. 4,271,[295][296][297]352 The bundled optode approach that creates hundreds of channels at di®erent brain depths with high spatial resolution can assuredly assist in the creation of 3D images via fNIRS, which can be compared with those created via fMRI. 7 This technique involves spatially resolved spectroscopy that utilizes multidistance channel formation among groups of sources and detectors placed as close to each other as possible.…”