Brain function decline in healthy retired athletes who sustained their last sports concussion in early adulthood

Recent studies have shown that the detrimental effects of sports concussions on cognitive and motor function may persist up to a few years post-injury. The present study sought to investigate the effects of having sustained a sports concussion more than 30 years prior to testing on cognitive and motor functions. Nineteen healthy former athletes, in late adulthood (mean age = 60.79; SD = 5.16), who sustained their last sport-related concussion in early adulthood (mean age = 26.05; SD = 9.21) were compared with 21 healthy former athletes with no history of concussion (mean age = 58.89; SD = 9.07). Neuropsychological tests sensitive to age-related changes in cognition were administered. An auditory oddball paradigm was used to evoke P3a and P3b brain responses. Four TMS paradigms were employed to assess motor cortex excitability: (i) resting motor threshold; (ii) paired-pulse intracortical inhibition and intracortical facilitation; (iii) input/output curve and (iv) cortical silent period (CSP). A rapid alternating movement task was also used to characterize motor system dysfunctions. Relative to controls, former athletes with a history of concussion had: (i) lower performance on neuropsychological tests of episodic memory and response inhibition; (ii) significantly delayed and attenuated P3a/P3b components; (iii) significantly prolonged CSP and (iv) significantly reduced movement velocity (bradykinesia). The finding that the P3, the CSP as well as neuropsychological and motor indices were altered more than three decades post-concussion provides evidence for the chronicity of cognitive and motor system changes consecutive to sports concussion.

Long-term and cumulative effects of sports concussion on motor cortex inhibition

OBJECTIVE

Using transcranial magnetic stimulation paradigms, this study investigated motor cortex integrity as a function of an athlete's prior history of concussions.

PATIENTS AND METHODS

Motor cortex excitatory and inhibitory mechanisms were studied in athletes using four different transcranial magnetic stimulation protocols, namely 1) resting motor threshold, 2) intracortical inhibition and intracortical facilitation in a paired-pulse paradigm, 3) excitability of the corticospinal system using an input-output curve, and 4) intracortical inhibition in a cortical silent-period paradigm. Motor-evoked potentials were recorded from the first dorsal interosseous muscle of the right hand.

RESULTS

Cortical silent-period duration in athletes who have experienced multiple concussions was prolonged when compared to that of normal control participants. Linear regression suggested that concussion severity was the main factor explaining motor cortex dysfunction. Moreover, when we retested the athletes, the cortical silent period was more prolonged in those who sustained another concussion after baseline testing had occurred.

CONCLUSION

Findings from this study indicate that sports-related concussions result in long-term motor system dysfunctions that seem to be attributable to subclinical intracortical inhibitory system abnormalities. This study also shows that sustaining subsequent concussions exacerbates this deficit, and thus provides additional support for the contention that the adverse effects of sports-related concussions on intracortical inhibitory systems are cumulative.

Long-term electrophysiological changes in athletes with a history of multiple concussions

PRIMARY OBJECTIVE

This event-related potentials study investigated the long-term effects associated with a history of one or multiple concussions on the N2pc and P3 components using a visual search oddball paradigm.

METHODS AND PROCEDURE

A total of 47 university football players were assigned to three experimental groups based on prior concussion history: Athletes with a history of one concussion (single-concussion group); Athletes with two or more concussions (multi-concussion group); non-concussed athletic controls. The average post-concussion period was 31 months for athletes in the multi-concussion group and 59 months for the single-concussion group.

RESULTS

This study found significantly suppressed P3 amplitude in the multi-concussed athletes group compared to the single-concussion and non-concussed athletes even when using the time since the latest concussion as a covariate.

CONCLUSION

This finding suggests that the multi-concussed athletes group showed long-lasting P3 amplitude suppression when compared with single-concussion or non-concussed athletes despite equivalent neuropsychological test scores and post-concussion symptoms self-reports. This pattern of results is important because it shows that 'old' concussions do not cause general or ubiquitous electrophysiological suppression. The specificity of the long-term effects of previous concussions to the P3, along with an intact N2pc response, suggests that further work may allow one to pinpoint the cognitive system that is specifically affected by multiple concussions.

Sports concussions and aging: a neuroimaging investigation

Recent epidemiological and experimental studies suggest a link between cognitive decline in late adulthood and sports concussions sustained in early adulthood. In order to provide the first in vivo neuroanatomical evidence of this relation, the present study probes the neuroimaging profile of former athletes with concussions in relation to cognition. Former athletes who sustained their last sports concussion >3 decades prior to testing were compared with those with no history of traumatic brain injury. Participants underwent quantitative neuroimaging (optimized voxel-based morphometry [VBM], hippocampal volume, and cortical thickness), proton magnetic resonance spectroscopy ((1)H MRS; medial temporal lobes and prefrontal cortices), and neuropsychological testing, and they were genotyped for APOE polymorphisms. Relative to controls, former athletes with concussions exhibited: 1) Abnormal enlargement of the lateral ventricles, 2) cortical thinning in regions more vulnerable to the aging process, 3) various neurometabolic anomalies found across regions of interest, 4) episodic memory and verbal fluency decline. The cognitive deficits correlated with neuroimaging findings in concussed participants. This study unveiled brain anomalies in otherwise healthy former athletes with concussions and associated those manifestations to the long-term detrimental effects of sports concussion on cognitive function. Findings from this study highlight patterns of decline often associated with abnormal aging.

Persistent motor system abnormalities in formerly concussed athletes

CONTEXT

The known detrimental effects of sport concussions on motor system function include balance problems, slowed motor execution, and abnormal motor cortex excitability.

OBJECTIVE

To assess whether these concussion-related alterations of motor system function are still evident in collegiate football players who sustained concussions but returned to competition more than 9 months before testing.

DESIGN

Case-control study.

SETTING

University laboratory.

PATIENTS OR OTHER PARTICIPANTS

A group of 21 active, university-level football players who had experienced concussions was compared with 15 university football players who had not sustained concussions.

INTERVENTION(S)

A force platform was used to assess center-of-pressure (COP) displacement and COP oscillation regularity (approximate entropy) as measures of postural stability in the upright position. A rapid alternating-movement task was also used to assess motor execution speed. Transcranial magnetic stimulation over the motor cortex was used to measure long-interval intracortical inhibition and the cortical silent period, presumably reflecting y-aminobutyric acid subtype B receptor-mediated intracortical inhibition.

MAIN OUTCOME MEASURE(S)

COP displacement and oscillation regularity, motor execution speed, long-interval intracortical inhibition, cortical silent period.

RESULTS

Relative to controls, previously concussed athletes showed persistently lower COP oscillation randomness, normal performance on a rapid alternating-movement task, and more M1 intracortical inhibition that was related to the number of previous concussions.

CONCLUSIONS

Sport concussions were associated with pervasive changes in postural control and more M1 intracortical inhibition, providing neurophysiologic and behavioral evidence of lasting, subclinical changes in motor system integrity in concussed athletes.

Altered bidirectional plasticity and reduced implicit motor learning in concussed athletes

Persistent motor/cognitive alterations and increased prevalence of Alzheimer's disease are known consequences of recurrent sports concussions, the most prevalent cause of mild traumatic brain injury (TBI) among youth. Animal models of TBI demonstrated that impaired learning was related to persistent synaptic plasticity suppression in the form of long-term potentiation (LTP) and depression (LTD). In humans, single and repeated concussive injuries lead to lifelong and cumulative enhancements of gamma-aminobutyric acid (GABA)-mediated inhibition, which is known to suppress LTP/LTD plasticity. To test the hypothesis that increased GABAergic inhibition after repeated concussions suppresses LTP/LTD and contributes to learning impairments, we used a paired associative stimulation (PAS) protocol to induce LTP/LTD-like effects in primary motor cortex (M1) jointly with an implicit motor learning task (serial reaction time task, SRTT). Our results indicate that repeated concussions induced persistent elevations of GABA(B)-mediated intracortical inhibition in M1, which was associated with suppressed PAS-induced LTP/LTD-like synaptic plasticity. This synaptic plasticity suppression was related to reduced implicit motor learning on the SRTT task relative to normal LTP/LTD-like synaptic plasticity in unconcussed teammates. These findings identify GABA neurotransmission alterations after repeated concussions and suggest that impaired learning after multiple concussions could at least partly be related to compromised GABA-dependent LTP/LTD synaptic plasticity.

Diffuse white matter tract abnormalities in clinically normal ageing retired athletes with a history of sports-related concussions

Sports-related concussions have been shown to lead to persistent subclinical anomalies of the motor and cognitive systems in young asymptomatic athletes. In advancing age, these latent alterations correlate with detectable motor and cognitive function decline. Until now, the interacting effects of concussions and the normal ageing process on white matter tract integrity remain unknown. Here we used a tract-based spatial statistical method to uncover potential white matter tissue damage in 15 retired athletes with a history of concussions, free of comorbid medical conditions. We also investigated potential associations between white matter integrity and declines in cognitive and motor functions. Compared to an age- and education-matched control group of 15 retired athletes without concussions, former athletes with concussions exhibited widespread white matter anomalies along many major association, interhemispheric, and projection tracts. Group contrasts revealed decreases in fractional anisotropy, as well as increases in mean and radial diffusivity measures in the concussed group. These differences were primarily apparent in fronto-parietal networks as well as in the frontal aspect of the corpus callosum. The white matter anomalies uncovered in concussed athletes were significantly associated with a decline in episodic memory and lateral ventricle expansion. Finally, the expected association between frontal white matter integrity and motor learning found in former non-concussed athletes was absent in concussed participants. Together, these results show that advancing age in retired athletes presenting with a history of sports-related concussions is linked to diffuse white matter abnormalities that are consistent with the effects of traumatic axonal injury and exacerbated demyelination. These changes in white matter integrity might explain the cognitive and motor function declines documented in this population.

Neurometabolic and microstructural alterations following a sports-related concussion in female athletes

BACKGROUND

Sports-related concussions are a major public health concern affecting millions of individuals annually. Neurometabolic and microstructural alterations have been reported in the chronic phase following a concussion in male athletes, while no study has investigated these alterations in female athletes.

METHODS

Neurometabolic and microstructural alterations following a concussion were investigated by comparing 10 female athletes with a concussion and 10 control female athletes, using magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI). Athletes with concussion were scanned at least 7 months post-concussion (mean = 18.9 months).

RESULTS

MRS revealed a significant lower level of myo-inositol in the hippocampus and the primary motor cortices (M1) bilaterally. DTI analysis using Tract-Based Spatial Statistics (TBSS) showed no difference in fractional anisotropy (FA) while higher level of mean diffusivity (MD) in athletes with concussion was detected in large white matter tracts including the forceps minors, inferior/superior longitudinal fasciculi, inferior fronto-occipital fasciculus, cingulum, uncinate fasciculus, anterior thalamic radiations and corticospinal tract. Moreover, a region of interest approach for the corpus callosum revealed a significant lower level of FA in the segment containing fibres projecting to M1.

CONCLUSIONS

This study demonstrates persistent neurometabolic and microstructural alterations in female athletes suffering a sports-related concussion.

Electrophysiological abnormalities in well functioning multiple concussed athletes

OBJECTIVE

The present study was aimed at characterizing the short- and long-term effects of multiple concussions using an electrophysiological approach.

METHOD

Participants for this study were recruited from college football teams. They included athletes who never sustained concussions compared to two groups of asymptomatic multiple concussed athletes, one that sustained their last concussion within the year and the other more than 2 years prior to testing. All participants were submitted to an auditory three-tone Oddball paradigm while event-related potentials (ERP) were recorded.

RESULTS

Results from ERP recordings reveal significantly reduced P3a and P3b amplitudes in the recent concussed group in the three-tone task compared to control athletes. In contrast, athletes who sustained their concussions more than 2 years prior to testing had equivalent P3a and P3b amplitude to that of controls.

CONCLUSION

These findings suggest that, despite functioning normally in their daily lives, concussed athletes still show subtle neuronal changes in information processing. Thus, the persistence of sub-clinical abnormalities on ERP components despite normal overt functioning may indicate sub-optimal compensation in multiple concussed athletes and leave them vulnerable to subsequent concussions.

Electrophysiological markers of voice familiarity

Our ability to discriminate and recognize human voices is amongst the most important functions of the human auditory system. The current study sought to determine whether electrophysiological markers could be used as objective measures of voice familiarity, by looking at the electrophysiological responses [mismatch negativity (MMN) and P3a] when the infrequent stimulus presented is a familiar voice as opposed to an unfamiliar voice. Results indicate that the MMN elicited by a familiar voice is greater than that elicited by an unfamiliar voice at FCz. The familiar voice also produced a greater P3a wave than that triggered by the unfamiliar voice at Fz. As both the MMN and the P3a were elicited as participants were instructed not to pay attention to incoming stimulation, these findings suggest that voice recognition is a particularly potent preattentive process whose neural representations can be objectively described through electrophysiological assessments.

Evaluating the cognitive consequences of mild traumatic brain injury and concussion by using electrophysiology

OBJECT

Mild traumatic brain injury (MTBI), often referred to as concussion when it occurs in sports, produces persistent cognitive problems in at least 15% of patients. Unfortunately, conventional neuropsychological tests usually yield results within normal limits in this population. The main objective of this event-related potential (ERP) study was to understand brain functioning during the performance of a working memory (WM) task in patients who have sustained an MTBI, mostly due to motor vehicle accident or sports concussion. This study also aimed for a better understanding of the association between brain functioning as measured with ERP, behavioral performance on the WM task, postconcussion symptoms, type of injury (that is, sports concussion vs other types), and time since the injury.

METHODS

Forty-four patients with MTBI (7.6 ± 8.4 months postinjury) were tested on a visual WM task with simultaneous recording of ERP, and were compared with 40 control volunteers who were their equivalent for age and sex. Amplitude and latency of frontal (N200 and N350) and parietal (P200 and P300) ERP waves were measured and were compared between groups. Correlation analyses were also performed between ERP characteristics, clinical variables, and behavioral performance.

RESULTS

A significant group difference was found for behavioral performance on the WM task, in which the MTBI group had a lower percentage of correct answers than the control group (p < 0.05). The patients with MTBI also had smaller amplitudes of both frontal N350 and parietal P300 ERP components when compared with control volunteers (p < 0.05). No changes were found for latency of ERP components. Smaller ERP amplitudes were associated with slower reaction times and worse accuracy on the WM task among patients with MTBI (p < 0.05). Types of injury (that is, sports concussion vs other mechanisms) were not associated with different ERP characteristics.

CONCLUSIONS

Abnormal ERP results are observed in patients after MTBI or sports concussion, even for those in the nonacute stage after their injury. Current standard clinical evaluations most often fail to detect cerebral dysfunction after MTBI, even when patients or athletes report symptoms. Clinicians should be aware that patients with MTBI, including sports concussion, probably have underlying mild but persistent cerebral dysfunctions that require further investigation.

HMGCR is a genetic modifier for risk, age of onset and MCI conversion to Alzheimer's disease in a three cohorts study

Several retrospective epidemiological studies report that utilization of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) inhibitors called statins at mid-life can reduce the risk of developing sporadic Alzheimer's disease (AD) by as much as 70%. Conversely, the administration of these inhibitors in clinically diagnosed subjects with AD confers little or no benefits over time. Here, we investigated the association between AD and HMGCR rs3846662, a polymorphism known to be involved in the regulation of HMGCR exon 13 skipping, in a founder population and in two distinct mixed North American populations of converting mild cognitively impaired (MCI) subjects (Alzheimer's disease Cooperative study (ADCS) and Alzheimer's disease Neuroimaging Initiative (ADNI) cohorts). Targeting more specifically women, the G allele negative (G-) AD subjects exhibit delayed age of onset of AD (P=0.017) and significantly reduced risk of AD (OR: 0.521; P=0.0028), matching the effect size reported by the apolipoprotein E type 2 variant. Stratification for APOE4 in a large sample of MCI patients from the ADCS cohort revealed a significant protective effect of G negative carriers on AD conversion 3 years after MCI diagnosis (odds ratio (OR): 0.554; P=0.041). Conversion rate among APOE4 carriers with the HMGCR's G negative allele was markedly reduced (from 76% to 27%) to levels similar to APOE4 non-carriers (27.14%), which strongly indicate protection. Conversion data from the independent ADNI cohort also showed significantly reduced MCI or AD conversion among APOE4 carriers with the protective A allele (P=0.005). In conclusion, HMGCR rs3846662 acts as a potent genetic modifier for AD risk, age of onset and conversion.

Long-term functional alterations in sports concussion

In this review the authors discuss persistent and cumulative alterations in both cognitive and motor function after sports concussions detected with some of the newest, most sophisticated brain investigation techniques. Ranging from subclinical neurophysiological alterations in young concussed athletes to quantifiable cognitive and motor function declines in former athletes in late adulthood with concussions sustained decades earlier, this review is also intended to provide new insights into the neuropathophysiology of sports concussion.

Parallel recovery of consciousness and sleep in acute traumatic brain injury

OBJECTIVE

To investigate whether the progressive recuperation of consciousness was associated with the reconsolidation of sleep and wake states in hospitalized patients with acute traumatic brain injury (TBI).

METHODS

This study comprised 30 hospitalized patients (age 29.1 ± 13.5 years) in the acute phase of moderate or severe TBI. Testing started 21.0 ± 13.7 days postinjury. Consciousness level and cognitive functioning were assessed daily with the Rancho Los Amigos scale of cognitive functioning (RLA). Sleep and wake cycle characteristics were estimated with continuous wrist actigraphy. Mixed model analyses were performed on 233 days with the RLA (fixed effect) and sleep-wake variables (random effects). Linear contrast analyses were performed in order to verify if consolidation of the sleep and wake states improved linearly with increasing RLA score.

RESULTS

Associations were found between scores on the consciousness/cognitive functioning scale and measures of sleep-wake cycle consolidation (p < 0.001), nighttime sleep duration (p = 0.018), and nighttime fragmentation index (p < 0.001). These associations showed strong linear relationships (p < 0.01 for all), revealing that consciousness and cognition improved in parallel with sleep-wake quality. Consolidated 24-hour sleep-wake cycle occurred when patients were able to give context-appropriate, goal-directed responses.

CONCLUSIONS

Our results showed that when the brain has not sufficiently recovered a certain level of consciousness, it is also unable to generate a 24-hour sleep-wake cycle and consolidated nighttime sleep. This study contributes to elucidating the pathophysiology of severe sleep-wake cycle alterations in the acute phase of moderate to severe TBI.

Function and comorbidities of apolipoprotein e in Alzheimer's disease

Alzheimer's disease (AD)—the most common type of dementia among the elderly—represents one of the most challenging and urgent medical mysteries affecting our aging population. Although dominant inherited mutation in genes involved in the amyloid metabolism can elicit familial AD, the overwhelming majority of AD cases, dubbed sporadic AD, do not display this Mendelian inheritance pattern. Apolipoprotein E (APOE), the main lipid carrier protein in the central nervous system, is the only gene that has been robustly and consistently associated with AD risk. The purpose of the current paper is thus to highlight the pleiotropic roles and the structure-function relationship of APOE to stimulate both the functional characterization and the identification of novel lipid homeostasis-related molecular targets involved in AD.

Cerebral white matter diffusion properties and free-water with obstructive sleep apnea severity in older adults

Characterizing the effects of obstructive sleep apnea (OSA) on the aging brain could be key in our understanding of neurodegeneration in this population. Our objective was to assess white matter properties in newly diagnosed and untreated adults with mild to severe OSA. Sixty‐five adults aged 55 to 85 were recruited and divided into three groups: control (apnea‐hypopnea index ≤5/hr; n = 18; 65.2 ± 7.2 years old), mild (>5 to ≤15 hr; n = 27; 64.2 ± 5.3 years old) and moderate to severe OSA (>15/hr; n = 20; 65.2 ± 5.5 years old). Diffusion tensor imaging metrics (fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity, and mean diffusivity) were compared between groups with Tract‐Based Spatial Statistics within the white matter skeleton created by the technique. Groups were also compared for white matter hyperintensities volume and the free‐water (FW) fraction. Compared with controls, mild OSA participants showed widespread areas of lower diffusivity (p < .05 corrected) and lower FW fraction (p < .05). Participants with moderate to severe OSA showed lower AD in the corpus callosum compared with controls (p < .05 corrected). No between‐group differences were observed for FA or white matter hyperintensities. Lower white matter diffusivity metrics is especially marked in mild OSA, suggesting that even the milder form may lead to detrimental outcomes. In moderate to severe OSA, competing pathological responses might have led to partial normalization of diffusion metrics.

Pilot case study of the therapeutic potential of hyperbaric oxygen therapy on chronic brain injury

BACKGROUND

Recently, the effect of hyperbaric oxygen (HBO(2)) therapy was explored in the treatment of chronic TBI. It has been speculated that idling neurons in the penumbra zone remain viable several years after injury and might be reactivated by enhanced oxygenation. We studied the therapeutic potential of HBO(2) therapy in a 54-year-old man who had sustained traumatic brain injuries one year before testing that resulted in permanent neurological symptoms.

METHODS

Two treatment series separated by a one-year inter-session interval were administered. Treatment series consisted of 20 and 60 daily one-hour exposures to 100% oxygen at 2 ATA. Electrophysiological (event-related potentials), metabolic and behavioral (sensorimotor and neuropsychological) measurements were obtained to evaluate the effects of hyperbaric oxygen therapy on neurocognitive functioning.

RESULTS

Following the initial treatment, the patient showed improvements in sensorimotor functions, as well as enhanced P300 amplitude in the damaged hemisphere. Although most of these gains were no longer observed one year after treatment, these were reinstated with an additional series of 60 exposures. Neuropsychological improvements were also observed after the completion of the second series of treatments.

CONCLUSION

The present single-case study provides preliminary evidence of neuropsychological and electrophysiological improvements after series of 20 and 60 treatments, although the first dosage appeared to be insufficient to produce permanent benefits. Longitudinal studies using different treatment parameters should be conducted if we are to systematically investigate long-term improvements resulting from HBO(2) therapy.

Electrophysiological correlates of motor sequence learning

Background

The Error-related negativity (ERN) is a component of the event-related brain potentials elicited by error commission. The ERN is thought to reflect cognitive control processes aiming to improve performance. As previous studies showed a modulation of the ERN amplitude throughout the execution of a learning task, this study aims to follow the ERN amplitude changes from early to late learning blocks in relation with concomitant motor sequence learning using a serial reaction time (SRT) task. Twenty-two healthy participants completed a SRT task during which continuous EEG activity was recorded. The SRT task consists of series of stimulus-response pairs and involves motor learning of a repeating sequence. Learning was computed as the difference in mean response time between the last sequence block and the last random blocks that immediately follows it (sequence-specific learning). Event-related potentials were analysed to measure ERN amplitude elicited by error commission.

Results

Mean ERN amplitude difference between the first four learning blocks and the last four learning blocks of the SRT task correlated significantly with motor sequence learning as well as with overall response time improvement, such that those participants whose ERN amplitude most increased through learning blocks were also those who exhibited most SRT task improvements. In contrast, neither sequence-specific learning nor overall response time improvement across learning blocks were found to be related to averaged ERN amplitude from all learning blocks.

Conclusion

Findings from the present study suggest that the ERN amplitude changes from early to late learning blocks occurring over the course of the SRT task, as opposed to the averaged ERN amplitude from all learning blocks, is more closely associated with learning of a motor sequence. These findings propose an improved electrophysiological marker to index change in cognitive control efficiency during motor sequence learning.

Long-Term Effects of Sports Concussions: Bridging the Neurocognitive Repercussions of the Injury with the Newest Neuroimaging Data

Little is known of the long-term effects of sports-related concussion. Within the scientific literature, conclusions vary substantially where some work suggests there are no long-term consequences at all and other studies show rampant neurodegeneration thought to be caused by sometimes even a single concussive blow to the head. There is growing evidence that supports multiple long-term outcomes, showing both subclinical and clinically relevant changes in the brains of athletes, young and old alike. This article reviews the pathohistology of cerebral concussions and examines the extant literature with a focus on electrophysiological and neuroimaging findings. Neurobehavioral and neurocognitive changes are also reviewed, particularly as they are related to chronic traumatic encephalopathy. Lacunae within the literature are explored, and future research directions are proposed.

Incidence rate of mild traumatic brain injury among patients who have suffered from an isolated limb fracture: Upper limb fracture patients are more at risk

OBJECTIVES

This study compares the incidence rate of mild traumatic brain injury (mild TBI) detected at follow-up visits (retrospective diagnosis) in patients suffering from an isolated limb trauma, with the incidence rate held by the hospital records (prospective diagnosis) of the sampled cohort. This study also seeks to determine which types of fractures present with the highest incidence of mild TBI.

PATIENTS AND METHODS

Retrospective assessment of mild TBI among orthopaedic monotrauma patients, randomly selected for participation in an Orthopaedic clinic of a Level I Trauma Hospital. Patients in the remission phase of a limb fracture were recruited between August 2014 and May 2015. No intervention was done (observational study).

MAIN OUTCOME MEASUREMENTS

Standardized semi-structured interviews were conducted with all patients to retrospectively assess for mild TBI at the time of the fracture. Emergency room related medical records of all patients were carefully analyzed to determine whether a prospective mild TBI diagnosis was made following the accident.

RESULTS

A total of 251 patients were recruited (54% females, Mean age=49). Study interview revealed a 23.5% incidence rate of mild TBI compared to an incidence rate of 8.8% for prospective diagnosis (χ(2)=78.47; p<0.0001). Patients suffering from an upper limb monotrauma (29.6%; n=42/142) are significantly more at risk of sustaining a mild TBI compared to lower limb fractures (15.6%; n=17/109) (χ(2)=6.70; p=0.010). More specifically, patients with a proximal upper limb injury were significantly more at risk of sustaining concomitant mild TBI (40.6%; 26/64) compared to distal upper limb fractures (20.25%; 16/79) (χ(2)=7.07; p=0.008).

CONCLUSIONS

Results suggest an important concomitance of mild TBI among orthopaedic trauma patients, the majority of which go undetected during acute care. Patients treated for an upper limb fracture are particularly at risk of sustaining concomitant mild TBI.