Mild traumatic brain injury recovery: a growth curve modelling analysis over 2 years.

BACKGROUND: An improved understanding of the trajectory of recovery after mild traumatic brain injury is important to be able to understand individual patient outcomes, for longitudinal patient care and to aid the design of clinical trials. OBJECTIVE: To explore changes in health, well-being and cognition over the 2 years following mTBI using latent growth curve (LGC) modelling. METHODS: Sixty-one adults with mTBI presenting to a UK Major Trauma Centre completed comprehensive longitudinal assessment at up to five time points after injury: 2 weeks, 3 months, 6 months, 1 year and 2 years. RESULTS: Persisting problems were seen with neurological symptoms, cognitive issues and poor quality of life measures including 28% reporting incomplete recovery on the Glasgow Outcome Score Extended at 2 years. Harmful drinking, depression, psychological distress, disability, episodic memory and working memory did not improve significantly over the 2 years following injury. For other measures, including the Rivermead Post-Concussion Symptoms and Quality of Life after Brain Injury (QOLIBRI), LGC analysis revealed significant improvement over time with recovery tending to plateau at 3-6 months. INTERPRETATION: Significant impairment may persist as late as 2 years after mTBI despite some recovery over time. Longitudinal analyses which make use of all available data indicate that recovery from mTBI occurs over a longer timescale than is commonly believed. These findings point to the need for long-term management of mTBI targeting individuals with persisting impairment.

Influence of Concomitant Extracranial Injury on Functional and Cognitive Recovery From Mild Versus Moderateto Severe Traumatic Brain Injury.

OBJECTIVE: To determine the effect of extracranial injury (ECI) on 6-month outcome in patients with mild traumatic brain injury (TBI) versus moderate-to-severe TBI. PARTICIPANTS/SETTING: Patients with TBI (n = 135) or isolated orthopedic injury (n = 25) admitted to a UK major trauma center and healthy volunteers (n = 99). DESIGN: Case-control observational study. MAIN MEASURES: Primary outcomes: (a) Glasgow Outcome Scale Extended (GOSE), (b) depression, (c) quality of life (QOL), and (d) cognitive impairment including verbal fluency, episodic memory, short-term recognition memory, working memory, sustained attention, and attentional flexibility. RESULTS: Outcome was influenced by both TBI severity and concomitant ECI. The influence of ECI was restricted to mild TBI; GOSE, QOL, and depression outcomes were significantly poorer following moderate-to-severe TBI than after isolated mild TBI (but not relative to mild TBI plus ECI). Cognitive impairment was driven solely by TBI severity. General health, bodily pain, semantic verbal fluency, spatial recognition memory, working memory span, and attentional flexibility were unaffected by TBI severity and additional ECI. CONCLUSION: The presence of concomitant ECI ought to be considered alongside brain injury severity when characterizing the functional and neurocognitive effects of TBI, with each presenting challenges to recovery.

Neurocognitive testing in the emergency department: A potential assessment tool for mild traumatic brain injury.

OBJECTIVE: Despite mild traumatic brain injury (mTBI) accounting for 80% of head injury diagnoses, recognition of individuals at risk of cognitive dysfunction remains a challenge in the acute setting. The objective of this study was to evaluate the feasibility and potential role for computerised cognitive testing as part of a complete ED head injury assessment. METHODS: mTBI patients (n = 36) who incurred a head injury within 24 h of presentation to the ED were compared to trauma controls (n = 20) and healthy controls (n = 20) on tests assessing reaction time, speed and attention, episodic memory, working memory and executive functioning. Testing occurred during their visit to the ED at a mean of 12 h post-injury for mTBI and 9.4 h for trauma controls. These tasks were part of the Cambridge Neuropsychological Test Automated Battery iPad application. Healthy controls were tested in both a quiet environment and the ED to investigate the potential effects of noise and distraction on neurocognitive function. RESULTS: Reaction time was significantly slower in the mTBI group compared to trauma patients (P = 0.015) and healthy controls (P = 0.011), and deficits were also seen in working memory compared to healthy controls (P ≤ 0.001) and in executive functioning (P = 0.021 and P < 0.001) compared to trauma and healthy controls. Performances in the control group did not differ between testing environments. CONCLUSION: Computerised neurocognitive testing in the ED is feasible and can be utilised to detect deficits in cognitive performance in the mTBI population as part of a routine head injury assessment.

Neural correlates of visual memory in patients with diffuse axonal injury.

PRIMARY OBJECTIVE: To investigate the neural substrates of visual memory in a sample of patients with traumatic brain injury (TBI). We hypothesized that patients with decreased grey and white matter volume in frontal and parietal cortices as well as medial temporal and occipital lobes would perform poorly on the tests of visual memory analysed. METHODS AND PROCEDURES: 39 patients and 53 controls were assessed on tests of visual memory and learning from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Patients with TBI were scanned with magnetic resonance imaging (MRI). Partial correlations and multiple regression analyses were used to examine relationships between cognitive variables and MRI volumetric findings. This study complements and extends previous studies by performing volumetric comparisons on a variety of resolution levels, from whole brain to voxel-based level analysis. MAIN OUTCOMES AND RESULTS: Patients with TBI performed significantly worse than controls in all the tasks assessed. Performance was associated with wide-spread reductions in grey and white matter volume of several cortical and subcortical structures as well as with cerebrospinal fluid space enlargement in accordance with previous studies of memory in patients with TBI and cognitive models suggesting that memory problems involve the alteration of multiple systems. CONCLUSIONS: Our results propose that compromised visual memory in patients with TBI is related to a distributed pattern of volume loss in regions mediating memory and attentional processing.

Involvement of Spearman's g in conceptualisation versus execution of complex tasks.

Strong correlations between measures of fluid intelligence (or Spearman's g) and working memory are widely reported in the literature, but there is considerable controversy concerning the nature of underlying mechanisms driving this relationship. In the four experiments presented here we consider the role of response conflict and task complexity in the context of real-time task execution demands (Experiments 1-3) and also address recent evidence that g confers an advantage at the level of task conceptualisation rather than (or in addition to) task execution (Experiment 4). We observed increased sensitivity of measured fluid intelligence to task performance in the presence (vs. the absence) of response conflict, and this relationship remained when task complexity was reduced. Performance-g correlations were also observed in the absence of response conflict, but only in the context of high task complexity. Further, we present evidence that differences in conceptualisation or 'modelling' of task instructions prior to execution had an important mediating effect on observed correlations, but only when the task encompassed a strong element of response inhibition. Our results suggest that individual differences in ability reflect, in large part, variability in the efficiency with which the relational complexity of task constraints are held in mind. It follows that fluid intelligence may support successful task execution through the construction of effective action plans via optimal allocation of limited resources.