Follow-up evaluation of oculomotor performance with fMRI in the subacute phase of concussion

Abstract

Objective: To expand on our previous study by performing a follow-up testing session in the subacute phase of injury for participants recently diagnosed with a concussion.Methods: A battery of oculomotor tests were administered to participants 30 days postconcussion while simultaneous fMRI was performed.Results: Three of the 7 oculomotor tasks (antisaccade, self-paced saccade, and memory-guided saccade) administered showed significant differences between the recently concussed group compared with normal volunteers. However, performance in these 3 tasks did show improvement from the acute phase of injury. The fMRI analysis revealed significant differences in brain activation patterns compared with normal volunteers, with the concussed group still demonstrating increased and larger areas of activation. Similar to the oculomotor performance, the fMRI analysis showed that at 30 days postinjury, the concussed group more closely mirrored that of the normal volunteer group compared with at 7 days following insult.Conclusions: Even at 30 days postinjury, and despite being clinically asymptomatic, advanced techniques are able to detect subtle lingering alterations in the concussed brain. Therefore, progressive neuroimaging techniques such as fMRI in conjunction with assessment of oculomotor performance may be beneficial in clinical management of concussion. Concussion initiates complex sequelae that produce disturbances in brain function and numerous somatic and cognitive symptoms.1 The majority of sports-related concussions demonstrate spontaneous recovery and resolution of clinical symptoms within 10 days postinjury.2 However, more advanced technologies have highlighted subtle changes and nuances in brain morphology, physiology, and function following concussion even though participants have returned to baseline on clinical measures. The direct relationship between the functional integrity of the brain and corresponding eye movements makes testing of oculomotor behavior a potential tool to allow for objective measures and inferences on brain integrity postconcussion.3 Given that concussion can disrupt multiple brain functional networks, including the oculomotor control networks, our previous study focused on the acute effects of concussion by having participants perform a battery of oculomotor tests while simultaneously undergoing fMRI. Behavioral results revealed that concussed participants performed worse in all oculomotor tasks and had increased fMRI recruitment and larger areas of activation.Here, we performed a follow-up to this study in the subacute phase of concussive injury. Based on our previous findings, we hypothesized that the more complex oculomotor tasks would demonstrate significant behavioral differences that coincide with increased activation areas and patterns. We also expected to still see impaired oculomotor performance, albeit less pronounced than in the acute phase of injury.

Persistent impairment based symptoms post mild traumatic brain injury: Does a standard symptom scale detect them?

“…These results indicate that individuals may not recognise the persistence of symptoms post-mTBI. Collectively the findings from the symptomatic and asymptomatic mTBI groups align with previous research reporting persistent physiological and sensorimotor impairment following mTBI (8,11,13,14).…”

“…Studies have demonstrated persistent multi-system impairments, particularly sensorimotor and physiological disturbances, following mTBI, beyond expected recovery times (8)(9)(10)(11)(12)(13)(14)(15)(16)(17) and following self-reported symptom abatement (8,11,13,14). One recent review (18) identified persistent impairments in 36 individual sensorimotor and/or physiological variables (postural control, oculomotor function, and sleep) in individuals subacutely post mTBI, with additional meta-analysis evidence of impaired heart-beat regulation.…”

Increased Risk of Stroke in Patients of Concussion: A Nationwide Cohort Study

“…The sequelae of concussion, a mild TBI, might be underestimated [19,20]. The World Health Organization Collaborating Center for Neurotrauma Task Force has estimated that up to 70%–90% of all traumatic brain injuries are treated as a mild TBI or concussion [21].…”

Development and validation of a high-speed video system for measuring saccadic eye movement

“…The antisaccade may be a better indicator of impaired brain function in concussion than previous tests have been (Balaban et al, 2016;Heitger et al, 2004;Heitger et al, 2006;Hoffer et al, 2017). For example, persons in the acute and subacute stages of concussion elicited a marked and persistent deficit in antisaccade RTs as compared to age-matched healthy controls, whereas no such persistent deficit was identified via prosaccades (Johnson, Hallett, & Slobounov, 2015a;Johnson, Zhang, Hallett, & Slobounov, 2015b). It therefore may be the case that the executive demands associated with antisaccades provide adequate resolution to detect subtle deficits arising from a concussion and may provide a valid tool for identifying recovery of function and determining a timeline for safe return to play (Webb et al, 2018).…”