The spectrum of mild traumatic brain injury

Mayer, Andrew R.; Quinn, Davin K.; Master, Christina L.

doi:10.1212/wnl.0000000000004214

Cited by 188 publications

(126 citation statements)

References 68 publications

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“…Previous literature has suggested that there is a wide spectrum of mTBIs. 18 The results reported in the present study indicate that an HHI may be another grade on the concussion spectrum that cannot be captured by standard clinical testing.…”

Section: Discussionmentioning

confidence: 55%

Pupillary changes after clinically asymptomatic high-acceleration head impacts in high school football athletes

Joseph¹,

Swallow

Willsey

et al. 2020

Journal of Neurosurgery

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OBJECTIVEPrevious studies have shown that clinically asymptomatic high-acceleration head impacts (HHIs) may be associated with neuronal and axonal injury, as measured by advanced imaging and biomarkers. Unfortunately, these methods of measurement are time-consuming, invasive, and costly. A quick noninvasive measurement tool is needed to aid studies of head injury and its biological impact. Quantitative pupillometry is a potential objective, rapid, noninvasive measurement tool that may be used to assess the neurological effects of HHIs. In this study, the authors investigated the effect of HHIs on pupillary metrics, as measured using a pupillometer, in the absence of a diagnosed concussion.METHODSA prospective observational cohort study involving 18 high school football athletes was performed. These athletes were monitored for both the frequency and magnitude of head impacts that they sustained throughout a playing season by using the Head Impact Telemetry System. An HHI was defined as an impact exceeding 95g linear acceleration and 3760 rad/sec2 rotational acceleration. Pupillary assessments were performed at baseline, midseason, after occurrence of an HHI, and at the end of the season by using the NeurOptics NPi-200 pupillometer. The Sport Concussion Assessment Tool, 5th Edition (SCAT5), was also used at each time point. Comparisons of data obtained at the various time points were calculated using a repeated-measures analysis of variance and a t-test.RESULTSSeven athletes sustained HHIs without a related diagnosed concussion. Following these HHIs, the athletes demonstrated decreases in pupil dilation velocity (mean difference 0.139 mm/sec; p = 0.048), percent change in pupil diameter (mean difference 3.643%; p = 0.002), and maximum constriction velocity (mean difference 0.744 mm/sec; p = 0.010), compared to measurements obtained at the athletes’ own midseason evaluations. No significant changes occurred between the SCAT5 subtest scores calculated at midseason and those after a high impact, although the effect sizes (Cohen’s d) on individual components ranged from 0.41 to 0.65.CONCLUSIONSMeasurable changes in pupil response were demonstrated following an HHI. These results suggest that clinically asymptomatic HHIs may affect brain reflex pathways, reflecting a biological injury previously seen when more invasive methods were applied.

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Section: Discussionmentioning

confidence: 55%

Pupillary changes after clinically asymptomatic high-acceleration head impacts in high school football athletes

Joseph¹,

Swallow

Willsey

et al. 2020

Journal of Neurosurgery

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“…30 It is less clear why a similar spatial shift should result from a diffuse problem like mTBI, which by most definitions excludes focal lesions on imaging. 31…”

mentioning

confidence: 99%

Vision Therapy: Ocular Motor Training in Mild Traumatic Brain Injury

Barton

Ranalli

2020

Annals of Neurology

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Vision therapy in the form of ocular motor training is increasingly used to treat visual complaints, particularly in the setting of persistent symptoms after mild traumatic brain injury (mTBI). In this review, we discuss the rationale behind this intervention and the evidence for its utility. Although the efficacy of exercises for primary convergence insufficiency is plausible and supported by data, there is not yet strong evidence of benefit for the post‐traumatic variant. It is not established that abnormalities in fixation, pursuit, and saccades in mTBI are the cause of post‐concussive symptoms, or that these abnormalities arise from ocular motor damage rather than being secondary effects of cognitive problems with attention or executive control. The few studies to date have significant methodological weaknesses. More substantial evidence is required before vision therapy can be accepted as a useful tool in the rehabilitation of patients with brain trauma. ANN NEUROL 2020;88:453–461

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“…Interestingly, Hou and colleagues also reported alterations within auditory and visual networks associated with persistent symptoms. Functional outcome, persistent symptoms, preinjury mental health, psychological mechanisms (e.g., coping), and injury effects are intricately linked in mTBI, and therefore, we realize that measuring functional outcome does not fully capture the patterns of recovery after mTBI (Mayer, Quinn, & Master, ; van der Horn et al, ). However, the Glasgow Outcome Scale Extended is widely used internationally for studying outcome after mTBI, and for the development of prediction models (Nelson et al, ; van der Naalt et al, ).…”

Section: Discussionmentioning

confidence: 99%

Functional outcome is tied to dynamic brain states after mild to moderate traumatic brain injury

Horn

Vergara

Espinoza

et al. 2019

Human Brain Mapping

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The current study set out to investigate the dynamic functional connectome in relation to long-term recovery after mild to moderate traumatic brain injury (TBI). Longitudinal resting-state functional MRI data were collected (at 1 and 3 months postinjury) from a prospectively enrolled cohort consisting of 68 patients with TBI (92% mild TBI) and 20 healthy subjects. Patients underwent a neuropsychological assessment at 3 months postinjury. Outcome was measured using the Glasgow Outcome Scale Extended (GOS-E) at 6 months postinjury. The 57 patients who completed the GOS-E were classified as recovered completely (GOS-E = 8; n = 37) or incompletely (GOS-E < 8; n = 20). Neuropsychological test scores were similar for all groups. Patients with incomplete recovery spent less time in a segregated brain state compared to recovered patients during the second visit. Also, these patients moved less frequently from one meta-state to another as compared to healthy controls and recovered patients. Furthermore, incomplete recovery was associated with disruptions in cyclic state transition patterns, called attractors, during both visits. This study demonstrates that poor long-term functional recovery is associated with alterations in dynamics between brain networks, which becomes more marked as a function of time. These results could be related to psychological processes rather than injury-effects, which is an interesting area for further work.Another natural progression of the current study is to examine whether these dynamic measures can be used to monitor treatment effects. K E Y W O R D S brain dynamics, fMRI, functional connectivity, mild traumatic brain injury, networks, outcome, recovery

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The spectrum of mild traumatic brain injury

Cited by 188 publications

References 68 publications

Pupillary changes after clinically asymptomatic high-acceleration head impacts in high school football athletes

Pupillary changes after clinically asymptomatic high-acceleration head impacts in high school football athletes

Vision Therapy: Ocular Motor Training in Mild Traumatic Brain Injury

Functional outcome is tied to dynamic brain states after mild to moderate traumatic brain injury

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