Auditory orienting and inhibition of return in mild traumatic brain injury: A FMRI study

Mayer, Andrew R.; Mannell, Maggie V.; Ling, Josef M.; Elgie, Robert; Gasparovic, Charles; Phillips, J. P.; Doezema, David; Yeo, Ronald A.

doi:10.1002/hbm.20836

Cited by 83 publications

(81 citation statements)

References 70 publications

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“…This finding is consistent with previous results from our group in a largely independent cohort, 46 with null findings on traditional neuropsychological testing occurring potentially as a result of several different factors. First, previous data have indicated that cognitive deficits and other neurobehavioral sequelae may resolve within the first week of injury, 55 whereas our clinical data were collected approximately 2 weeks post-injury.…”

Section: Discussionsupporting

confidence: 93%

“…Of note, 24 of the patients with mTBI presented in the current study are independent from our two previous publications examining evoked BOLD responses. 18,46 Inclusion criteria for the current study were based on the American Congress of Rehabilitation Medicine and included a Glasgow Coma Scale score of 13-15 (at presentation in the emergency department), loss of consciousness (if present) limited to 30 min, and post-traumatic amnesia limited to a 24-h period. 3 All patients with mTBI experienced a closed head injury resulting in an alteration in mental status at minimum (see online Supplementary Table 1 at ftp.liebertpub.com).…”

Section: Participantsmentioning

confidence: 99%

“…To reduce redundancy among similar neuropsychological measures, composite indices were calculated for the cognitive domains of attention, working memory, processing speed, executive function, and memory. 46 Self-report of emotional status (State-Trait Anxiety Index and Beck Depression Inventory-Second Edition), somatic complaints (Neurobehavioral Symptom Inventory), and cognitive complaints (Neurobehavioral Symptom Checklist) were also assessed. When possible, raw test scores were converted to T-scores (mean = 50, SD = 10) using published age-specific norms and then averaged to provide an overall composite score.…”

Section: Clinical Assessmentmentioning

confidence: 99%

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Investigating the Properties of the Hemodynamic Response Function after Mild Traumatic Brain Injury

Mayer

Toulouse

Klimaj

et al. 2014

Journal of Neurotrauma

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Although several functional magnetic resonance imaging (fMRI) studies have been conducted in human models of mild traumatic brain injury (mTBI), to date no studies have explicitly examined how injury may differentially affect both the positive phase of the hemodynamic response function (HRF) as well as the post-stimulus undershoot (PSU). Animal models suggest that the acute and semi-acute stages of mTBI are associated with significant disruptions in metabolism and to the microvasculature, both of which could impact on the HRF. Therefore, fMRI data were collected on a cohort of 30 semi-acute patients with mTBI (16 males; 27.83 -9.97 years old; 13.00 -2.18 years of education) and 30 carefully matched healthy controls (HC; 16 males; 27.17 -10.08 years old; 13.37 -2.31 years of education) during a simple sensory-motor task. Patients reported increased cognitive, somatic, and emotional symptoms relative to controls, although no group differences were detected on traditional neuropsychological examination. There were also no differences between patients with mTBI and controls on fMRI data using standard analytic techniques, although mTBI exhibited a greater volume of activation during the task qualitatively. A significant Group · Time interaction was observed in the right supramarginal gyrus, bilateral primary and secondary visual cortex, and the right parahippocampal gyrus. The interaction was the result of an earlier time-to-peak and positive magnitude shift throughout the estimated HRF in patients with mTBI relative to HC. This difference in HRF shape combined with the greater volume of activated tissue may be indicative of a potential compensatory mechanism to injury. The current study demonstrates that direct examination and modeling of HRF characteristics beyond magnitude may provide additional information about underlying neuropathology that is not available with more standard fMRI analyses.

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Section: Discussionsupporting

confidence: 93%

Section: Participantsmentioning

confidence: 99%

Section: Clinical Assessmentmentioning

confidence: 99%

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Investigating the Properties of the Hemodynamic Response Function after Mild Traumatic Brain Injury

Mayer

Toulouse

Klimaj

et al. 2014

Journal of Neurotrauma

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“…13,14 Several neuroimaging methods have been applied to study brain function in patients with TBI, including positron emission tomography (PET), 15 cerebral blood flow (CBF), 9 cerebral blood volume (CBV), 16 and functional magnetic resonance imaging (fMRI). [17][18][19] The major limitation in patient studies relates to the lack of histological verification of imaging findings. Even though several clinically relevant animal models of TBI are available, 20 studies applying functional imaging after experimental TBI are scarce.…”

Section: Introductionmentioning

confidence: 99%

Monitoring Functional Impairment and Recovery after Traumatic Brain Injury in Rats by fMRI

Niskanen

Airaksinen

Sierra

et al. 2013

Journal of Neurotrauma

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The present study was designed to test a hypothesis that functional magnetic resonance imaging (fMRI) can be used to monitor functional impairment and recovery after moderate experimental traumatic brain injury (TBI). Moderate TBI was induced by lateral fluid percussion injury in adult rats. The severity of brain damage and functional recovery in the primary somatosensory cortex (S1) was monitored for up to 56 days using fMRI, cerebral blood flow (CBF) by arterial spin labeling, local field potential measurements (LFP), behavioral assessment, and histology. All the rats had reduced bloodoxygen-level-dependent (BOLD) responses during the 1st week after trauma in the ipsilateral S1. Forty percent of these animals showed recovery of the BOLD response during the 56 day follow-up. Unexpectedly, no association was found between the recovery in BOLD response and the volume of the cortical lesion or thalamic neurodegeneration. Instead, the functional recovery occurred in rats with preserved myelinated fibers in layer VI of S1. This is, to our knowledge, the first study demonstrating that fMRI can be used to monitor post-TBI functional impairment and consequent spontaneous recovery. Moreover, the BOLD response was associated with the density of myelinated fibers in the S1, rather than with neurodegeneration. The present findings encourage exploration of the usefulness of fMRI as a noninvasive prognostic biomarker for human post-TBI outcomes and therapy responses.

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“…Similar to previous studies, 20 composite indices were calculated for attention, working memory, process- ing speed, executive function, memory, and emotional status based on participants' mean t score in each of the domains (appendix e-1 on the Neurology ® Web site at www.neurology.org).…”

mentioning

confidence: 99%

A prospective diffusion tensor imaging study in mild traumatic brain injury

Mayer

Mannell²,

Gasparovic³

et al. 2010

Neurology

401

306

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Objectives: Only a handful of studies have investigated the nature, functional significance, and course of white matter abnormalities associated with mild traumatic brain injury (mTBI) during the semi-acute stage of injury. The present study used diffusion tensor imaging (DTI) to investigate white matter integrity and compared the accuracy of traditional anatomic scans, neuropsychological testing, and DTI for objectively classifying mTBI patients from controls. Methods:Twenty-two patients with semi-acute mTBI (mean ϭ 12 days postinjury), 21 matched healthy controls, and a larger sample (n ϭ 32) of healthy controls were studied with an extensive imaging and clinical battery. A subset of participants was examined longitudinally 3-5 months after their initial visit.Results: mTBI patients did not differ from controls on clinical imaging scans or neuropsychological performance, although effect sizes were consistent with literature values. In contrast, mTBI patients demonstrated significantly greater fractional anisotropy as a result of reduced radial diffusivity in the corpus callosum and several left hemisphere tracts. DTI measures were more accurate than traditional clinical measures in classifying patients from controls. Longitudinal data provided preliminary evidence of partial normalization of DTI values in several white matter tracts.Conclusions: Current findings of white matter abnormalities suggest that cytotoxic edema may be present during the semi-acute phase of mild traumatic brain injury (mTBI). Initial mechanical damage to axons disrupts ionic homeostasis and the ratio of intracellular and extracellular water, primarily affecting diffusion perpendicular to axons. Diffusion tensor imaging measurement may have utility for objectively classifying mTBI, and may serve as a potential biomarker of recovery. Neurology® 2010;74:643-650 GLOSSARY ADC ϭ apparent diffusion coefficient; CC ϭ corpus callosum; CCI ϭ cortical impact injury model; CR ϭ corona radiata; DTI ϭ diffusion tensor imaging; EC ϭ external capsule; FA ϭ fractional anisotropy; FPI ϭ fluid percussion injury model; HC ϭ healthy controls; IC ϭ internal capsule; JHU ϭ Johns Hopkins University; MANCOVA ϭ multivariate analysis of covariance; mTBI ϭ mild traumatic brain injury; RD ϭ radial diffusivity; ROI ϭ region of interest; SCR ϭ superior corona radiata; SLF ϭ superior longitudinal fasciculus; UF ϭ uncinate fasciculus.Complex cognitive processes such as attention, executive functions, and memory depend on intact white matter tracts among frontal, parietal, and medial temporal lobes, 1 which are likely disrupted following mild traumatic brain injury (mTBI). Histologic evidence of white matter changes have been observed in both human autopsy 2,3 and animal 4 studies of mTBI. Although traditional neuroimaging sequences (i.e., T1-and T2-weighted imaging) are typically insensitive to these putative white matter changes, diffusion tensor imaging (DTI) is capable of measuring white matter pathology with histologic correlates in animal models of injury...

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Auditory orienting and inhibition of return in mild traumatic brain injury: A FMRI study

Cited by 83 publications

References 70 publications

Investigating the Properties of the Hemodynamic Response Function after Mild Traumatic Brain Injury

Investigating the Properties of the Hemodynamic Response Function after Mild Traumatic Brain Injury

Monitoring Functional Impairment and Recovery after Traumatic Brain Injury in Rats by fMRI

A prospective diffusion tensor imaging study in mild traumatic brain injury

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