Susanne Meares

Mild traumatic brain injury does not predict acute postconcussion syndrome

Background: The aetiology of postconcussion syndrome (PCS) following mild traumatic brain injury (mTBI) remains controversial. Identifying acute PCS (within the first 14 days after injury) may optimise initial recovery and rehabilitation, identify those at risk and increase understanding of PCS. Objective: To examine predictors of acute outcome by investigating the relationship between preinjury psychiatric disorder, demographic factors, injury related characteristics, neuropsychological and psychological variables and acute PCS. Methods: Prospective study of consecutive trauma admissions to a level 1 trauma hospital. The final sample comprised 90 patients with mTBI and 85 non-brain injured trauma controls. Individuals were administered a PCS checklist, and neuropsychological and psychological measures. Multiple imputation of missing data in multivariable logistic regression and bivariate logistic regressions were used to predict acute PCS at a mean of 4.90 days after injury. Results: Diagnosis of acute PCS was not specific to mTBI (mTBI 43.3%; controls 43.5%). Pain was associated with acute PCS in mTBI. The strongest effect for acute PCS was a previous affective or anxiety disorder (OR 5.76, 95% CI 2.19 to 15.0). Females were 3.33 times more likely than males to have acute PCS (95% CI 1.20 to 9.21). The effect of acute post-traumatic stress and neuropsychological function on acute PCS was relatively small. Higher IQ was associated with acute PCS. Conclusions: There is a high rate of acute PCS in both mTBI and non-brain injured trauma patients. PCS was not found to be specific to mTBI. The use of the term PCS may be misleading as it incorrectly suggests that the basis of PCS is a brain injury.

The prospective course of postconcussion syndrome: The role of mild traumatic brain injury.

OBJECTIVE To investigate whether postconcussion syndrome (PCS) represents long-term sequelae associated with mild traumatic brain injury (mTBI). METHODS Prospective consecutive admissions to a Level 1 trauma hospital were assessed a mean 4.9 days and again 106.2 days post-injury. The final sample comprised 62 mTBI and 58 nonbrain injured trauma controls (TC). Change or lack of change in individual PCS-like symptoms and PCS was examined. Multilevel logistic regression was used to analyze whether mTBI predicts 3-month PCS (Time 2; T2); whether predictors of PCS (within 14 days of injury, Time 1; T1) predict 3-month PCS, and how change in these predictors from T1 to T2 were associated with change in PCS status. Variables included demographic, injury-related, financial incentives, neuropsychological, and psychiatric disorder. RESULTS MTBI did not predict PCS. PCS was comparable (T1: mTBI: 40.3%, TC: 50.0%; T2: mTBI: 46.8%, TC: 48.3%). At T2, 38.6% were new cases of PCS; between 30.8% and 86.2% reported either a new or more frequent symptom. A pre-injury depressive or anxiety disorder (OR = 2.99, 95% CI [1.38, 6.45]), and acute posttraumatic stress (OR = 1.05, 95% CI [1.00, 1.00]) were early markers of PCS, regardless of mTBI. An interaction between time and posttraumatic stress disorder (PTSD) suggested the relationship between the severity of PTSD symptoms and PCS strengthened over time (OR = 2.66, 95% CI [1.08, 6.55]). Pain was related to PCS. Females were more likely than males to have PCS. CONCLUSION The data suggest the phenomenon of PCS in trauma patients does not show an association with mTBI.

The relationship of psychological and cognitive factors and opioids in the development of the postconcussion syndrome in general trauma patients with mild traumatic brain injury

The relationship of psychological and cognitive factors in the development of the postconcussion syndrome (PCS) following mild uncomplicated traumatic brain injury (mTBI) has received little study. This may be because of the widely held belief that neurological factors are the cause of early PCS symptoms, whereas psychological factors are responsible for enduring symptoms. To further understand these relationships, the association between PCS and neuropsychological and psychological outcome was investigated in 122 general trauma patients, many of whom had orthopedic injuries, around 5 days following mTBI. Apart from verbal fluency, participants with a PCS did not differ in their performances on neuropsychological measures compared to those without a PCS. Individuals with a PCS reported significantly more psychological symptoms. Large effect sizes present on the psychological measures showed that the difference between participants with a PCS and without was greater on psychological than on neuropsychological measures. Analyses also revealed a relationship between opioid analgesia and depression, anxiety and stress, and opioids and reduced learning. The results suggest that psychological factors are present much earlier than has previously been considered in the development of the PCS.

The differentiation of mild frontotemporal dementia from Alzheimer's disease and healthy aging by neuropsychological tests

BACKGROUND Frontotemporal dementia (FTD) is difficult to diagnose in the early stages and may be misdiagnosed as Alzheimers disease (AD) or as a psychiatric disorder. This study aimed to investigate neuropsychological function in FTD of mild severity and compare it to that of mild AD and healthy control participants. METHODS The study comprised 11 individuals with FTD, 29 with AD and 27 healthy controls. Participants completed a comprehensive neuropsychological assessment in which each area of cognitive function was examined with several widely used clinical tests. Test scores were converted to age-corrected scaled scores and combined to form indices for six areas of cognitive function. These indices were attention, psychomotor speed, memory acquisition, memory recall, executive function and constructional ability. RESULTS The FTD group performed below the level of the controls in all areas except constructional ability. FTD and AD groups showed distinct patterns of neuropsychological performance. The FTD group showed predominantly executive dysfunction with less impaired memory function, while the AD group showed the opposite pattern. The capacity of the tests to discriminate between groups was good overall, with 90% of the total sample correctly classified. Predictive success for the FTD group was 64%, given a base rate of 16%. CONCLUSION Administration of a comprehensive neuropsychological protocol including several tests of executive function allows increased certainty about accurate clinical diagnosis of mild FTD.

Validation of the Abbreviated Westmead Post-traumatic Amnesia Scale: A brief measure to identify acute cognitive impairment in mild traumatic brain injury

Objective: To validate the use of the Abbreviated Westmead Post-traumatic Amnesia Scale (A-WPTAS) in the assessment of acute cognitive impairment in mild traumatic brain injury (mTBI). Methods: Data previously collected from 82 mTBI and 88 control participants using the Revised Westmead Post-traumatic Amnesia Scale (R-WPTAS) was converted to A-WPTAS scores and pass/fail classifications were calculated for both scales. Results: The proportion of failures on the R-WPTAS and the A-WPTAS did not differ and a similar number of mTBIs were classified on each. For mTBIs the relationship between the independent memory test and a pass/fail classification was the same for both scales. Bivariate logistic regressions revealed that mTBIs, relative to controls, were around 8 times more likely to fail the assessment (R-WPTAS: 95% CI: 3.70–18.87; A-WPTAS: 95% CI: 3.70–20.14). As verbal learning improved the likelihood of failure was reduced. Greater education was associated with a decreased likelihood of failure. The relationship between education and a fail performance was not sustained when education was adjusted for the effect of age, prior mTBI, blood alcohol level, injury status, verbal learning, and morphine administration. Conclusions: The A-WPTAS is a valid measure. The A-WPTAS may reduce the risk of failing to classify patients with mTBI by identifying and documenting acute cognitive impairment.

Effort Test Failure: Toward a Predictive Model

Predictors of effort test failure were examined in an archival sample of 555 traumatically brain-injured (TBI) adults. Logistic regression models were used to examine whether compensation-seeking, injury-related, psychological, demographic, and cultural factors predicted effort test failure (ETF). ETF was significantly associated with compensation-seeking (OR = 3.51, 95% CI [1.25, 9.79]), low education (OR:. 83 [.74, . 94]), self-reported mood disorder (OR: 5.53 [3.10, 9.85]), exaggerated displays of behavior (OR: 5.84 [2.15, 15.84]), psychotic illness (OR: 12.86 [3.21, 51.44]), being foreign-born (OR: 5.10 [2.35, 11.06]), having sustained a workplace accident (OR: 4.60 [2.40, 8.81]), and mild traumatic brain injury severity compared with very severe traumatic brain injury severity (OR: 0.37 [0.13, 0.995]). ETF was associated with a broader range of statistical predictors than has previously been identified and the relative importance of psychological and behavioral predictors of ETF was evident in the logistic regression model. Variables that might potentially extend the model of ETF are identified for future research efforts.

A Comparison of the Degree of Effort Involved in the TOMM and the ACS Word Choice Test Using a Dual-Task Paradigm

The aims of the current study were to: (a) examine the predictive validity and efficacy of the Advanced Clinical Solutions Word Choice Test (WCT) as a measure of effort relative to the Test of Memory Malingering (TOMM); (b) investigate whether performing a dual (distraction) task would undermine performance on either test; (c) assess the effect of coaching on the diagnostic accuracy of both the WCT and the TOMM; and (d) establish an optimal cut score for the WCT. The current study used a simulation design based on an analogue design in which normal participants were instructed to either apply full effort or simulate a brain injury on the tasks without being detected. Participants included 93 undergraduate university students who were randomly assigned to 1 of 4 conditions: (a) distraction, (b) uncoached traumatic brain injury (TBI) simulators, (c) coached TBI simulators, or (d) full effort. The results demonstrated that the WCT and the TOMM were effective in detecting simulated cognitive impairment. Both tests were resistant to the effects of distraction and were equally effective in detecting coached and uncoached simulators. A cut score of 42 on the WCT was found to provide optimal specificity and sensitivity on the test.

Applicability of neural reserve theory in mild traumatic brain injury

Objective: The aim of the current study was to examine whether neural reserve influenced the duration of post-traumatic amnesia (PTA) following mild traumatic brain injury (MTBI). Method: The relationship between duration of PTA and both IQ and education was examined in a group of 59 MTBI patients. In addition, the effects of factors that could potentially diminish neural reserve, namely pre-injury hazardous alcohol consumption, pre-injury marijuana use, previous neurological damage, age and post-injury emotional distress on PTA duration were analysed. Results: Significant, negative associations between PTA duration and both IQ and education were revealed. None of the other variables that were examined were significantly related to PTA duration. Conclusion: The findings were interpreted as providing preliminary evidence to suggest that reference to neural reserve may help explain between-subject variability in acute response to MTBI.

The role of cognition in fitness to stand trial: a systematic review

The aim of the current paper was to systematically review the quality and design of the literature examining cognition and fitness to stand trial (FST). Ten empirical studies published between 1970 and July 2013 met the inclusion criteria. All studies utilised cross-sectional designs and six were prospective. Study quality was appraised based on FST research guidelines. The study quality was highly variable. Intelligence was controlled statistically in only half of the included studies. Cognitive processes, specifically, processing speed, verbal memory and visuoperceptual skills differentiated fit and unfit groups. Aspects of executive functioning, including social knowledge and abstract thinking, influenced FST. Future studies should use prospective consecutive designs and multivariate statistical strategies that control for potential confounds. Comprehensive assessment across a number of cognitive domains is needed in order to validate research conducted to date and guide forensic assessment of FST.

An exploratory study of the association of acute posttraumatic stress, depression, and pain to cognitive functioning in mild traumatic brain injury.

OBJECTIVE Few studies have examined whether psychological distress and pain affect cognitive functioning in the acute to subacute phase (up to 30 days postinjury) following mild traumatic brain injury (mTBI). The current study explored whether acute posttraumatic stress, depression, and pain were associated with performance on a task of selective and sustained attention completed under conditions of increasing cognitive demands (standard, auditory distraction, and dual-task), and on tests of working memory, memory, processing speed, reaction time (RT), and verbal fluency. METHOD At a mean of 2.87 days (SD = 2.32) postinjury, 50 adult mTBI participants, consecutive admissions to a Level 1 trauma hospital, completed neuropsychological tests and self-report measures of acute posttraumatic stress, depression, and pain. A series of canonical correlation analyses was used to explore the relationships of a common set of psychological variables to various sets of neuropsychological variables. RESULTS Significant results were found on the task of selective and sustained attention. Strong relationships were found between psychological variables and speed (r(c) = .56, p = .02) and psychological variables and accuracy (r(c) = .68, p = .002). Pain and acute posttraumatic stress were associated with higher speed scores (reflecting more correctly marked targets) under standard conditions. Acute posttraumatic stress was associated with lower accuracy scores across all task conditions. Moderate but nonsignificant associations were found between psychological variables and most cognitive tasks. CONCLUSIONS Acute posttraumatic stress and pain show strong associations with selective and sustained attention following mTBI.