A longitudinal proton magnetic resonance spectroscopy study of mild traumatic brain injury

Despite the prevalence and impact of mild traumatic brain injury (mTBI), common clinical assessment methods for mTBI have insufficient sensitivity and specificity. Moreover, few researchers have attempted to document underlying changes in physiology as a function of recovery from mTBI. Proton magnetic resonance spectroscopy (1H-MRS) was used to assess neurometabolite concentrations in a supraventricular tissue slab in 30 individuals with semi-acute mTBI, and 30 sex-, age-, and education-matched controls. No significant group differences were evident on traditional measures of attention, memory, working memory, processing speed, and executive skills, though the mTBI group reported significantly more somatic, cognitive, and emotional symptoms. At a mean of 13 days post-injury, white matter concentrations of creatine (Cre) and phosphocreatine (PCre) and the combined glutamate-glutamine signal (Glx) were elevated in the mTBI group, while gray matter concentrations of Glx were reduced. Partial normalization of these three neurometabolites and N-acetyl aspartate occurred in the early days post-injury, during the semi-acute period of recovery. In addition, 17 mTBI patients (57%) returned for a follow-up evaluation (mean?=?120 days post-injury). A significant group?×?time interaction indicated recovery in the mTBI group for gray matter Glx, and trends toward recovery in white matter Cre and Glx. An estimate of premorbid intelligence predicted the magnitude of neurometabolite normalization over the follow-up interval for the mTBI group, indicating that biological factors underlying intelligence may also be associated with more rapid recovery.     

Assessment of metabolic cerebral damage using proton magnetic resonance spectroscopy in mild traumatic brain injury

AIM: We want to appraise, through proton magnetic resonance spectroscopy (H1-MRI), the NAA's values and it's changing in cerebral tissue in consequence of cranial trauma. METHODS: Six patients with TBI undergo to H1-MRI to asses the changes occurring briefly after trauma in the spectrum's composition. RESULTS: As far as the first two cases we founded a lowering of the NAA's values. In the other four cases the NAA values were normal in all but one, which slightly brought the values of the NAA/Cr and NAA/Cho lower in comparison to the standard values. CONCLUSIONS: Existing a correlation between NAA and ATP it can be drawn that the reduction of NAA is correlated to energetic type damage. Despite the smallness of data, it remains really important that we should have a tool to monitor the cerebral metabolic picture after a mild trauma.     

Magnetic resonance spectroscopy in traumatic brain injury

Magnetic resonance spectroscopy (MRS) offers a unique non-invasive approach for assessing the metabolic status of the brain in vivo and is particularly suited to studying traumatic brain injury (TBI). In particular, MRS provides a noninvasive means for quantifying such neurochemicals as N-acetylaspartate (NAA), creatine, phosphocreatine, choline, lactate, myo-inositol, glutamine, glutamate, adenosine triphosphate (ATP), and inorganic phosphate in humans following TBI and in animal models. Many of these chemicals have been shown to be perturbed following TBI. NAA, a marker of neuronal integrity, has been shown to be reduced following TBI, reflecting diffuse axonal injury or metabolic depression, and concentrations of NAA predict cognitive outcome. Elevation of choline-containing compounds indicates membrane breakdown or inflammation or both. MRS can also detect alterations in high energy phosphates reflecting the energetic abnormalities seen after TBI. Accordingly, MRS may be useful to monitor cellular response to therapeutic interventions in TBI.     

Prognostic role of proton magnetic resonance spectroscopy in acute traumatic brain injury

Proton magnetic resonance spectroscopy (MRS) is being used to evaluate individuals after acute traumatic brain injury. These studies have shown that changes in certain brain metabolites are associated with poor neurologic outcomes. The majority of MRS studies have been obtained relatively late after injury, but there have been a few reports of use early after injury to assist with outcome prediction. Altered brain metabolites may be sensitive indicators of injury and thus provide additional prognostic information when spectroscopy is done early after injury. This technology may provide a noninvasive means to evaluate early excitotoxic injury, and show changes associated with both neuronal injury and membrane disruption secondary to diffuse axonal injury. This article will review the technology of MRS, discuss its role in patient assessment after traumatic brain injury, and present a summary of our published and ongoing research.     

The malingering of multiple sclerosis and mild traumatic brain injury

In this investigation, neuropsychological testing was conducted with 69 college students that were instructed to malinger either multiple sclerosis MS or traumatic brain injury TIB or were non malingering controls. The two malingering groups were divided into informed and non informed groups. The informed groups received information concerning their respective condition, and the non informed groups were asked simply to malinger. Generally, all malingering groups performed considerably below the levels of non malingering controls on measures of attention, learning and memory, word fluency, abstract reasoning, visuoconstruction and manual dexterity. There appeared to be no difference in the manner in which subjects attempted to malinger MS as opposed to TBI. However, the severity of the portrayed deficit suggested by the test scores was disproportionate to the severity of the injury being requested. The pattern of deficit presented was quite global, with well below average performance demonstrated by all malingering groups across all domains.     

Contribution of magnetic resonance spectroscopy in predicting severity and outcome in traumatic brain injury

Nuclear magnetic spectroscopy (MRS) is a useful method for noninvasively studying intracerebral metabolism. Proton MRS can identify markers of the neuronal viability (N-acetyl-aspartate, NAA), of the metabolism of cellular membranes (choline), of the cellular energy metabolism (creatine, lactate). In Phosphorus MRS, the peaks most readily identified are involved in the high-energy cellular metabolism (ATP, phosphocreatine, inorganic phosphate), and intracellular pH (pHi) can be determined using this method. MRS has been used in experimental models of traumatic brain injury (TBI), primarily to study the cellular metabolism and the relation between biochemical and histological changes after trauma. In trauma patients, significant changes in NAA, choline and pHi were found in both grey and white matter comparing with controls, and these alterations correlated with injury severity. Correlations have been reported between these biochemical changes (reduction in NAA, increase in choline) measured at 1 to 6 months after TBI and the clinical outcome of the patients. However, there are methodological issues which still impede to recommend MRS as a tool for predicting neurological outcome in the clinical setting.     

Exploring the use of social comparison by individuals recovering from traumatic brain injury

Objective: To explore if and how individuals with traumatic brain injury (TBI) use social comparison during adjustment to disability. It was hypothesized that comparison activity may change with time since injury. Methods: Fifty-eight participants with TBI were surveyed within 1 or 6 months of discharge from inpatient rehabilitation. Group responses to instruments measuring social comparison and other measures of emotional and physical functioning were compared. Results: Both groups expressed a need for social comparison at a rate comparable to non-clinical populations. The group surveyed at 6 months expressed a greater need for social comparison and scored lower on a measure of mental health, as compared to the group surveyed earlier. Conclusions: Individuals with TBI appear to successfully use social comparison, at least early in recovery, with a possible reduction in effectiveness of use with increased time from injury. Possible mediating factors and implications for adjustment and future study are discussed.     

Quantitative magnetic resonance imaging in traumatic brain injury

Quantitative neuroimaging has now become a well-established method for analyzing magnetic resonance imaging in traumatic brain injury (TBI). A general review of studies that have examined quantitative changes following TBI is presented. The consensus of quantitative neuroimaging studies is that most brain structures demonstrate changes in volume or surface area after injury. The patterns of atrophy are consistent with the generalized nature of brain injury and diffuse axonal injury. Various clinical caveats are provided including how quantitative neuroimaging findings can be used clinically and in predicting rehabilitation outcome. The future of quantitative neuroimaging also is discussed.     

Assessment of mitochondrial impairment in traumatic brain injury using high-resolution proton magnetic resonance spectroscopy

OBJECTIVES: The goal of this study was to demonstrate the posttraumatic neurochemical damage in normal-appearing brain and to assess mitochondrial dysfunction by measuring N-acetylaspartate (NAA) levels in patients with severe head injuries, using proton (1H) magnetic resonance (MR) spectroscopy. METHODS: Semiquantitative analysis of NAA relative to creatine-containing compounds (Cr) and choline (Cho) was carried out from proton spectra obtained by means of chemical shift (CS) imaging and single-voxel (SV) methods in 25 patients with severe traumatic brain injuries (TBIs) (Glasgow Coma Scale scores < or = 8) using a 1.5-tesla MR unit. Proton MR spectroscopy was also performed in 5 healthy volunteers (controls). RESULTS: The SV studies in patients with diffuse TBI showed partial reduction of NAA/Cho and NAA/Cr ratios within the first 10 days after injury (means +/- standard deviations 1.59 +/- 0.46 and 1.44 +/- 0.21, respectively, in the patients compared with 2.08 +/- 0.26 and 2.04 +/- 0.31, respectively, in the controls; nonsignificant difference). The ratios gradually declined in all patients as time from injury increased (mean minimum values NAA/Cho 1.05 +/- 0.44 and NAA/Cr 1.05 +/- 0.30, p < 0.03 and p < 0.02, respectively). This reduction was greater in patients with less favorable outcomes. In patients with focal injuries, the periphery of the lesions revealed identical trends of NAA/Cho and NAA/Cr decrease. These reductions correlated with outcome at 6 months (p < 0.01). Assessment with multivoxel methods (CS imaging) demonstrated that, in diffuse injury, NAA levels declined uniformly throughout the brain. At 40 days postinjury, initially low NAA/Cho levels had recovered to near baseline in patients who had good outcomes, whereas no recovery was evident in patients with poor outcomes (p < 0.01). CONCLUSIONS: Using (1)H-MR spectroscopy, it is possible to detect the posttraumatic neurochemical damage of the injured brain when conventional neuroimaging techniques reveal no abnormality. Reduction of NAA levels is a dynamic process, evolving over time, decreasing and remaining low throughout the involved tissue in patients with poor outcomes. Recovery of NAA levels in patients with favorable outcomes suggests marginal mitochondrial impairment and possible resynthesis from vital neurons.     

Altered cellular metabolism following traumatic brain injury: a magnetic resonance spectroscopy study

Experimental studies have reported early reductions in pH, phosphocreatine, and free intracellular magnesium following traumatic brain injury using phosphorus magnetic resonance spectroscopy. Paradoxically, in clinical studies there is some evidence for an increase in the pH in the subacute stage following traumatic brain injury. We therefore performed phosphorus magnetic resonance spectroscopy on seven patients in the subacute stage (mean 9 days postinjury) following traumatic brain injury to assess cellular metabolism. In areas of normal-appearing white matter, the pH was significantly alkaline (patients 7.09 +/- 0.04 [mean +/- SD], controls 7.01 +/- 0.04, p = 0.008), the phosphocreatine to inorganic phosphate ratio (PCr/Pi) was significantly increased (patients 4.03 +/- 1.18, controls 2.64 +/- 0.71, p = 0.03), the inorganic phosphate to adenosine triphosphate ratio (Pi/ATP) was significantly reduced (patients 0.37 +/- 0.10, controls 0.56 +/- 0.19, p = 0.04), and the PCr/ATP ratio was nonsignificantly increased (patients 1.53 +/- 0.29, controls 1.34 +/- 0.19, p = 0.14) in patients compared to controls. Furthermore, the calculated free intracellular magnesium was significantly increased in the patients compared to the controls (patients 0.33 +/- 0.09 mM, controls 0.22 +/- 0.09 mM, p = 0.03)). Proton spectra, acquired from similar regions showed a significant reduction in N-acetylaspartate (patients 9.64 +/- 2.49 units, controls 12.84 +/- 2.35 units, p = 0.03) and a significant increase in choline compounds (patients 7.96 +/- 1.02, controls 6.67 +/- 1.01 units, p = 0.03). No lactate was visible in any patient or control spectrum. The alterations in metabolism observed in these patients could not be explained by ongoing ischemia but might be secondary to a loss of normal cellular homeostasis or a relative alteration in the cellular population, in particular an increase in the glial cell density, in these regions.     

Prolonged recovery of memory functioning after mild traumatic brain injury in adolescent athletes

OBJECT: The current body of sports-related concussion literature is hampered by a lack of research conducted in high school athletes. Accordingly, the authors sought to examine the neuropsychological deficits and recovery patterns after concussive injuries in this population. METHODS: Participants included 419 male and female athletes with a mean age of 15.69 years who underwent baseline testing of their neuropsychological functioning prior to their sports season. Fourteen participants sustained an in-season concussion and were serially reassessed at ~2.5, 6, and 10 days postinjury. Fourteen uninjured matched control participants were also reassessed at the end of the school year. RESULTS: Individuals who sustained in-season concussions demonstrated impairments in reaction time, processing speed, and had delayed memory functioning. Although reaction time and processing speed deficits returned to baseline levels by ~6 days postinjury, participants continued to show memory impairments up to 7 days postinjury. Memory impairments were found to resolve by Day 10, however. CONCLUSIONS: The results of the present study suggest that high school athletes demonstrate prolonged memory dysfunction compared with college athletes, and should therefore be treated more conservatively.     

Spectrum of traumatic brain injury from mild to severe

Traumatic brain injury (TBI) involves significant damage of the brain parenchyma, and is the leading cause of morbidity and mortality after trauma. It is thus essential for all physicians involved in acute care medicine and surgery to have a thorough understanding of TBI. Management of the patient with TBI is a rapidly advancing field, characterized by an improved understanding of intracranial pathophysiology and decreasing overall mortality largely because of improved neurocritical and surgical care. This article summarizes the classification system, management approaches, and recent controversies in the care of mild, moderate, and severe TBI.     

Late proton magnetic resonance spectroscopy following traumatic brain injury during early childhood: relationship with neurobehavioral outcomes

We sought to extend previous research that demonstrates reduced neurometabolite concentrations during the chronic phase of pediatric traumatic brain injury (TBI) in children injured during early childhood. We hypothesized that young children with TBI in the chronic phase post-injury would have lower N-acetyl aspartate (NAA) metabolite concentrations in gray and white matter in comparison to controls. We also hypothesized that metabolite levels would be correlated with acute TBI severity and neurobehavioral skills. Ten children with a history of TBI between the ages of 3 and 6 years were compared to an age, gender, and race-matched group of 10 children with a history of an orthopedic injury (OI). Children completed neurobehavioral testing at 12 months post-injury. Proton magnetic resonance (MR) spectroscopy was completed at least 12 months post-injury when the children were 6-9 years old. Groups were compared on metabolite concentrations in the medial frontal gray matter and left frontal white matter. Metabolite levels were correlated with Glasgow Coma Scale (GCS) scores and neurobehavioral functioning. There was a trend for lower NAA concentrations in the medial frontal gray matter for the TBI group. Late NAA and Cr levels in the medial frontal gray matter and NAA levels in the left frontal white matter were strongly positively correlated with initial GCS score. Metabolite levels were correlated with some neurobehavioral measures differentially for children with TBI or OI. Some neurometabolite levels differed between the TBI and OI groups more than 1 year post-injury and were related to injury severity, as well as some neurobehavioral outcomes following TBI during early childhood.     

Definition and epidemiology of mild traumatic brain injury

Background/objectivesThe definition of mild traumatic brain injury (mTBI), also known as concussion, has been a matter of controversy, which makes comparison between studies difficult. Incidence varies greatly from one country to another. The present article reviews definitions and epidemiology.MethodsLiterature review.ResultsAccording to the Mild TBI Committee of the American Congress of Rehabilitation Medicine, revised by the World Health Organization (WHO), mTBI is defined by a Glasgow Coma Scale score between 13 and 15 at 30 minutes post-injury, and one or more of the following symptoms: <30 min loss of consciousness; <24 hours post-traumatic amnesia (PTA); impaired mental state at time of accident (confusion, disorientation, etc.); and/or transient neurological deficit. If a focal lesion is found on computed tomography (CT) or magnetic resonance imaging (MRI), the term “complicated mild TBI” has been proposed. Incidence of mTBI is 200–300/100,000 persons per year for hospitalized patients and probably twice as high if non-hospitalized patients are included. However, a few recent population-based studies reported a much higher rate (>700/100,000). A changing pattern of epidemiology has been found in high-income countries, related to a decrease in road-accident injuries in young adults, while conversely the proportion of falls has increased with population aging.ConclusionMild TBI is a major public health concern, the epidemiology of which has greatly changed in the last twenty years.     

Diffusion-weighted magnetic resonance imaging improves outcome prediction in adult traumatic brain injury

In patients with traumatic brain injury (TBI), diffuse axonal injury (DAI) accounts for a significant amount of parenchymal injury. Diffusion weighted magnetic resonance imaging (DWI) is known to be sensitive for detecting visible DAI lesions. We focused on detection of non-visible, quantifiable diffusion changes in specific normal-appearing brain regions, using apparent diffusion coefficient (ADC) maps. Thirty-seven adults with TBI were compared to 35 age-matched control patients. DWI was performed and ADC maps were generated. Thirty-one regions of interest (ROI) were manually drawn on ADC maps and ADC values extracted. Brain ROIs were categorized into five zones: peripheral gray matter, peripheral white matter, deep gray matter, deep white matter, and posterior fossa. ADC results were compared with the severity of injury based on the admission Glasgow Coma Scale (GCS 3-8; severe; GSC 9-15 mild/moderate) and with long-term outcome (6-12 months after injury) using the Glasgow Outcome Scale (GOS 1-3, unfavorable; GOS: 4-5, favorable) score. Mean ADC values in all five brain zones were significantly different between TBI subjects and controls (p相似文献   

The symptom checklist-90-revised and mild traumatic brain injury

OBJECTIVE: Assessment of emotional functioning is a critical aspect of the clinical neuropsychological evaluation of individuals following mild traumatic brain injury (MTBI). The objective of this study was to examine the utility of the Symptom Checklist-90-Revised as a brief tool for assessing psychological and symptomatic distress following MTBI. METHOD: A contrasted groups approach, involving three clinical groups (MTBI, Whiplash Associated Disorder, Type I Diabetes) and a non-clinical control group, was used in this study. RESULTS: The group with MTBI scored significantly higher on the majority of primary symptom dimensions and global distress indices of the SCL-90-R compared to both the diabetes and non-clinical control groups. Analysis of individual cases further revealed that 68.2% of the participants in the group with MTBI were classified as positive cases, a rate significantly higher than that of the diabetes and non-clinical control groups. The group with MTBI did not differ significantly from the group of individuals with whiplash associated disorder with respect to elevation of primary symptom dimensions or global distress indices, or the number of cases classified as positive. CONCLUSION: The results of this study suggest that the SCL-90-R has considerable utility as a general measure of psychological and symptomatic distress following MTBI.     

The relationship between sexual abuse and mild traumatic brain injury

It remains unclear why some individuals with mild traumatic brain injury (MTBI) complain of cognitive deficits many months after the injury. Given neuropathological changes associated with prolonged stress, such as occurs with repeated sexual abuse (SA), it seems possible that individuals who experienced SA might be predisposed to greater deficits after MTBI. Four groups of subjects were administered measures of cognitive and emotional functioning. These groups were those with MTBI (n = 10), those with a history of SA (n = 10), those with both MTBI and SA (n = 10), and normal control NC subjects (n = 10). Copared to the NC subjects, those with MTBI demonstrated deficits in working memory, those with SA demonstrated deficits in executive functioning, and those with both MTBI and SA demonstrated the greatest number of deficits which were in working memory, executive functioning and memory. Tests of anxiety, depression and post traumatic stress disorder, while demonstrating significant symptoms in all clinical groups, did not correlate with the neuropsy chological tests that differentiated the groups.     

The association between mild traumatic brain injury and psychiatric conditions

The majority of patients with mild traumatic brain injury (TBI) recover fairly quickly and are usually restored to their previous level of functioning. However, a significant minority have prolonged, complicated, or incomplete recoveries and have outcomes disproportionately worse than would have been predicted by the objective facts of the injury. This failure to recover as expected was the focus of this study. The participants were 80 adults with actual or suspected mild TBI who were referred to an outpatient mild TBI clinic. Most were characterized by problematic recoveries. The results indicated that those individuals who only had brain injuries made good recoveries, but that those with psychiatric comorbidity did not (χ² = 19.65, p = 0.0002). Most of the new psychiatric conditions responsible for poor recovery consisted of depression, anxiety disorders or conversion disorder. Dissociative phenomena appeared common after mild TBI and scores on the Dissociative Experiences Scale predicted brain injury outcome with 77% accuracy.     

Conventional and diffusion magnetic resonance imaging in the acute phase of severe traumatic brain injury

Neuro-imaging is essential for the initial evaluation and subsequent control in the acute stage of severe head injury. In these indications tomodensitometry (TDM) has a pivotal role. Despite the well recognized contribution of magnetic resonance imaging (MRI) to the investigation of most of acute neurological pathologies, MRI is not still a routine procedure for the initial investigation of patients with acute head injury. The superiority of morphological and functional MRI on TDM in this indication is discussed.     

The use of atypical antipsychotics in traumatic brain injury

The use of antipsychotic medication in treating individuals with traumatic brain injury (TBI) has been controversial. Much of the caution derives from animal studies (and limited human data) with regard to typical antipsychotics. Of note, however, is that similar assumptions have been made about the newer generation of atypical antipsychotics as well. Because these agents have different mechanisms of action as well as different neurotransmitter targets, this may very well be unwarranted. In this article, mechanisms of action of typical and atypical antipsychotics are discussed, with particular attention paid to their use in TBI. Indications and contraindications are presented, and recommendations are made for the responsible prescribing of antipsychotic medications after TBI.