Prediction of recovery of continuous memory after traumatic brain injury

Prognostication of traumatic brain injury outcomes in older trauma patients: A novel risk assessment tool based on initial cranial CT findings

Introduction:

Advanced age has been traditionally associated with worse traumatic brain injury (TBI) outcomes. Although prompt neurosurgical intervention (NSI, craniotomy or craniectomy) may be life-saving in the older trauma patient, it does not guarantee survival and/or return to preinjury functional status. The aim of this study was to determine whether a simple score, based entirely on the initial cranial computed tomography (CCT) is predictive of the need for NSI and key outcome measures (e.g., morbidity and mortality) in the older (age 45+ years) TBI patient subset. We hypothesized that increasing number of categorical CCT findings is independently associated with NSI, morbidity, and mortality in older patients with severe TBI.

Methods:

After IRB approval, a retrospective study of patients 45 years and older was performed using our Regional Level 1 Trauma Center registry data between June 2003 and December 2013. Collected variables included patient demographics, Injury Severity Score (ISS), Abbreviated Injury Scale Head (AISh), brain injury characteristics on CCT, Glasgow Coma Scale (GCS), Intensive Care Unit (ICU) and hospital length of stay (LOS), all-cause morbidity and mortality, functional independence scores, as well as discharge disposition. A novel CCT scoring tool (CCTST, scored from 1 to 8+) was devised, with one point given for each of the following findings: subdural hematoma, epidural hematoma, subarachnoid blood, intraventricular blood, cerebral contusion/intraparenchymal blood, skull fracture, pneumocephalus, brain edema/herniation, midline shift, and external (skin/face) trauma. Descriptive statistics and univariate analyses were conducted with 30-day mortality, in-hospital morbidity, and need for NSI as primary end-points. Secondary end-points included the length of stay in the ICU (ICULOS), step-down unit (SDLOS), and the hospital (HLOS) as well as patient functional outcomes, and postdischarge destination. Factors associated with the need for NSI were determined using matched NSI (n = 310) and non-NSI (n = 310) groups. All other analyses examined the combined patient sample (n = 620). Variables achieving a significance level of P < 0.20 were included in the logistic regression. Receiver operating characteristic curves, with corresponding area under the curve (AUC) determinations, were also analyzed. Statistical significance was set at α = 0.05. Data are presented as percentages, mean ± standard deviation, or adjusted odds ratios (AORs) with 95% confidence intervals (95% CIs).

Results:

A total of 620 patients were analyzed, including 310 patients who underwent NSI and 310 age- and ISS-matched non-NSI controls. Average patient age was 72.8 ± 13.4 years (64.1% male, 99% blunt trauma, mean ISS 25.1 ± 8.68, and mean AISh/GCS of 4.63/10.9). CCTST was the only variable independently associated with NSI (AOR 1.23, 95% CI 1.06–1.42) and was inversely proportional to initial GCS and functional outcome scores on discharge. Increasing CCTST was associated with greater mortality, morbidity, HLOS, SDLOS, ICULOS, and ventilator days. On multivariate analysis, factors independently associated with mortality included AISh (AOR 2.70, 95% CI 1.21–6.00), initial GCS (AOR 1.14, 1.07–1.22), and CCTST (AOR 1.31, 1.09–1.58). Variables independently associated with in-hospital morbidity included CCTST (AOR 1.16, 1.02–1.34), GCS (AOR 1.05, 1.01–1.09), and NSI (AOR 2.62, 1.69–4.06). Multivariate models incorporating factors independently associated with each respective outcome displayed good overall predictive characteristics for mortality (AUC 0.787) and in-hospital morbidity (AUC 0.651). Finally, modified CCTST demonstrated good overall predictive ability for NSI (AUC 0.755).

Conclusion:

This study found that the number of discrete findings on CCT is independently associated with major TBI outcome measures, including 30-day mortality, in-hospital morbidity, and NSI. Of note, multivariate models with best predictive characteristics incorporate both CCTST and GCS. CCTST is easy to calculate, and this preliminary investigation of its predictive utility in older patients with TBI warrants further validation, focusing on exploring prognostic synergies between CCTST, GCS, and AISh. If independently confirmed to be predictive of clinical outcomes and the need for NSI, the approach described herein could lead to a shift in both operative and nonoperative management of patients with TBI.

Acute predictors of real-world outcomes following traumatic brain injury: a prospective study

PRIMARY OBJECTIVE

To determine whether the recovery of acute attention and memory improves the prediction of real-world outcomes over that provided by standard demographic and injury-severity measures.

RESEARCH DESIGN

Participants were recruited consecutively at the time of injury and followed prospectively at 1 (time 1, or T1) and 4 years (time 2, or T2).

METHODS AND PROCEDURES

Measures of attention and memory and the Galveston Orientation and Amnesia Test (GOAT) were administered to 94 participants daily from the time of injury until the criterion was met. Sixty-three per cent returned at T1 and 53% returned at T2. Outcomes were psychosocial distress, return to work and/or school, and quality of life.

MAIN OUTCOMES AND RESULTS

Recovery of attention, memory and orientation did not significantly improve prediction of outcomes at T1, but did so at T2. At T2, recovery of free recall of three words over 24 h was a more sensitive predictor of psychosocial distress and return to productivity than the GOAT.

CONCLUSIONS

Free recall of three words may be a useful acute clinical test to enhance prediction of long-term outcomes.

Cerebral atrophy after traumatic white matter injury: correlation with acute neuroimaging and outcome

Traumatic brain injury (TBI) is a pathologically heterogeneous disease, including injury to both neuronal cell bodies and axonal processes. Global atrophy of both gray and white matter is common after TBI. This study was designed to determine the relationship between neuroimaging markers of acute diffuse axonal injury (DAI) and cerebral atrophy months later. We performed high-resolution magnetic resonance imaging (MRI) at 3 Tesla (T) in 20 patients who suffered non-penetrating TBI, during the acute (within 1 month after the injury) and chronic stage (at least 6 months after the injury). Volume of abnormal fluid-attenuated inversion-recovery (FLAIR) signal seen in white matter in both acute and follow-up scans was quantified. White and gray matter volumes were also quantified. Functional outcome was measured using the Functional Status Examination (FSE) at the time of the chronic scan. Change in brain volumes, including whole brain volume (WBV), white matter volume (WMV), and gray matter volume (GMV), correlates significantly with acute DAI volume (r = -0.69, -0.59, -0.58, respectively; p <0.01 for all). Volume of acute FLAIR hyperintensities correlates with volume of decreased FLAIR signal in the follow-up scans (r = -0.86, p < 0.001). FSE performance correlates with acute hyperintensity volume and chronic cerebral atrophy (r = 0.53, p = 0.02; r = -0.45, p = 0.03, respectively). Acute axonal lesions measured by FLAIR imaging are strongly predictive of post-traumatic cerebral atrophy. Our findings suggest that axonal pathology measured as white matter lesions following TBI can be identified using MRI, and may be a useful measure for DAI-directed therapies.

Impact of age on long-term recovery from traumatic brain injury

OBJECTIVE

To determine whether older persons are at increased risk for progressive functional decline after traumatic brain injury (TBI).

DESIGN

Longitudinal cohort study.

SETTING

Traumatic Brain Injury Model Systems (TBIMS) rehabilitation centers.

PARTICIPANTS

Subjects enrolled in the TBIMS national dataset.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Disability Rating Scale (DRS), FIM instrument cognitive items, and the Glasgow Outcome Scale-Extended.

RESULTS

Participants were separated into 3 age tertiles: youngest (16-26y), intermediate (27-39y), and oldest (> or =40y). DRS scores were comparable across age groups at admission to a rehabilitation center. The oldest group was slightly more disabled at discharge from rehabilitation despite having less severe acute injury severity than the younger groups. Although DRS scores for the 2 younger groups improved significantly from year 1 to year 5, the greatest magnitude of improvement in disability was seen among the youngest group. In addition, after dividing patients into groups according to whether their DRS scores improved (13%), declined (10%), or remained stable (77%) over time, the likelihood of decline was found to be greater for the 2 older groups than for the youngest group. A multiple regression model showed that age has a significant negative influence on DRS score 5 years post-TBI after accounting for the effects of covariates.

CONCLUSIONS

This study supported our primary hypothesis that older patients show greater decline over the first 5 years after TBI than younger patients. In addition, the greatest amount of improvement in disability was observed among the youngest group of survivors. These results suggest that TBI survivors, especially older patients, may be candidates for neuroprotective therapies after TBI.

New approaches to physiological informatics in neurocritical care

INTRODUCTION

A fundamental purpose of neurocritical care is the management of secondary brain injury. This is often accomplished by monitoring and managing individual patient parameters including physiological vital signs. Yet, the ability to record physiological data exceeds our ability to fully integrate it into patient care. We propose that advances in monitoring must be accompanied by advances in methods of high-frequency, multivariate data analysis that integrate the multiple processes occurring in critically ill patients.

METHODS

We describe initial work in the emerging field of physiological informatics in critical care medicine. We analyzed data on 23 patients with brain injury from our Neurotrauma and Critical Care Database, which contains more than 20 physiological parameters recorded automatically at one-minute intervals via bedside monitors connected to standard personal computers. We performed exploratory data analysis, studied two patient cases in detail, and implemented a data-driven classification approach using hierarchical clustering.

RESULTS

In this study, we present challenges and opportunities for high-frequency multimodal monitoring to quantitatively detect secondary brain insults, and develop clustering methodology to construct multivariate physiological data "profiles" to classify patients for diagnosis and treatment.

CONCLUSIONS

Recording of many physiological variables across multiple patients is feasible and can lead to new clinical insights. Computational and analytical methods previously used primarily for basic science may have clinical relevance and can potentially be adapted to provide physicians with improved ability to integrate complex information for decision making in neurocritical care.

The Effect of Moderate to Severe Traumatic Brain Injury (TBI) on Different Aspects of Memory:A Selective Review

Deficient learning and memory are frequently reported as a consequence of traumatic brain injury (TBI). Because of the diffuse nature of the injury, patients with TBI are not the ideal group for studying brain-behavior relations. Nevertheless, characterization of the memory breakdown following TBI could contribute to the assessment and rehabilitation of this patient population. It is well documented that memory is not a unitary system. Accordingly, in this article I review studies that have investigated the long-term effect of moderate to severe TBI on different memory aspects, including explicit and implicit tests of memory. This review demonstrates that TBI affects a large range of memory aspects. One of the conclusions is that the memory impairment observed in TBI patients could be viewed, at least to some degree, as a consequence of a more general cognitive deficit. Thus, unlike patients suffering from global amnesia, memory in patients with TBI is not selectively impaired. Nevertheless, it is possible to detect a subgroup of patients that do meet the criteria of amnesia. However, the most common vulnerable memory processes following TBI very much resemble the memory deficits reported in patients following frontal lobe damage, e.g., difficulties in applying active or effortful strategy in the learning or retrieval process. The suggested similarity between patients with TBI and those suffering from frontal lobe injury should be viewed cautiously; considering the nature of TBI, patients suffering from such injuries are not a homogeneous group. In view of this limitation, the future challenge in this field will be to identify subgroups of patients, either a priori according to a range of factors such as severity of injury, or a posteriori based on their specific memory deficit characteristics. Such a research approach has the potential of explaining much of the variability in findings reported in the literature on the effect of TBI on memory.

Cognitive rehabilitation in the elderly: a randomized trial to evaluate a new protocol

This study provides an introduction to, and overview of, several papers that resulted from a randomized control trial that evaluated a new cognitive rehabilitation protocol. The program was designed to improve general strategic abilities in ways that would be expressed in a broad range of functional domains. The trial, which was conducted on a sample of older adults who had experienced normal age-related cognitive decline, assessed performance in the following domains: memory, goal management, and psychosocial status. The general rationale for the trial, the overall experimental design, and the approach to statistical analyses that are relevant to each paper are described here. The results for each functional domain are reported in separate papers in this series.

Community Integration Status 4 Years After Traumatic Brain Injury

OBJECTIVES

To measure the level of agreement on community integration outcomes 4 years after traumatic brain injury (TBI) in relation to injury severity, proxy-participant relationship, and type of question.

PARTICIPANTS

Thirty-one survivors of TBI (14 with mild TBI and 17 with moderate-severe TBI) and 31 significant other proxies.

MEASURES

General and leisure activity scales of the Katz Adjustment Scale (KAS).

RESULTS

Agreement was highest between proxies and participants with mild versus moderate-severe TBIs, between spouse proxies and TBI participants compared to nonspouse proxies and on the more objective subscales (frequency of participation) compared to the expectation and satisfaction scales regardless of injury severity or proxy-participant relationship.

CONCLUSIONS

For research purposes, proxy data are acceptable but clinicians should assess outcomes and set goals with input from both persons with TBIs and their proxies.

Neuropsychological studies of mild traumatic brain injury: a meta-analytic review of research since 1995

A meta-analysis conducted by Binder, Rohling and Larrabee established a relationship between mild traumatic brain injury (TBI) and small reductions in cognitive functioning in individuals assessed more than 3 months post-injury. As a follow-up, this study summarized similar research that (1) was published since the previous meta-analysis, and (2) included data collected at any stage post-injury. An extensive literature search revealed 17 suitable studies from which effect sizes were aggregated. The overall effect size was g = 0.32, p < .001. Speed of processing measures had the largest effect, g = 0.47, p < .001. The merging of post-acute effect sizes with those reported in Binder et al.'s review yielded a nonsignificant result, g = 0.11. Time since injury was found to be a significant moderator variable, with effect sizes tending to zero with increasing time post injury.