What are the predictors of TOMM failure in clinical TBI populations? A retrospective analysis.

OBJECTIVES: To determine base rates of invalid performance on the Test of Memory Malingering (TOMM) in patients with traumatic brain injury (TBI) undertaking rehabilitation who were referred for clinical assessment, and the factors contributing to TOMM failure. METHODS: Retrospective file review of consecutive TBI referrals for neuropsychological assessment over seven years. TOMM failure was conventionally defined as performance <45/50 on Trial 2 or Retention Trial. Demographic, injury, financial compensation, occupational, and medical variables were collected. RESULTS: Four hundred and ninety one TBI cases (Median age = 40 years [IQR = 26-52], 79% male, 82% severe TBI) were identified. Overall, 48 cases (9.78%) failed the TOMM. Logistic regression analyses revealed that use of an interpreter during the assessment (adjusted odds ratio [aOR] = 8.25, 95%CI = 3.96-17.18), outpatient setting (aOR = 4.80, 95%CI = 1.87-12.31) and post-injury psychological distress (aOR = 2.77, 95%CI = 1.35-5.70) were significant multivariate predictors of TOMM failure. The TOMM failure rate for interpreter cases was 49% (21/43) in the outpatient setting vs. 7% (2/30) in the inpatient setting. By comparison, 9% (21/230) of non-interpreter outpatient cases failed the TOMM vs. 2% (4/188) of inpatient cases. CONCLUSIONS: TOMM failure very rarely occurs in clinical assessment of TBI patients in the inpatient rehabilitation setting. It is more common in the outpatient setting, particularly in non-English-speaking people requiring an interpreter. The findings reinforce the importance of routinely administering stand-alone performance validity tests in assessments of clinical TBI populations, particularly in outpatient settings, to ensure that neuropsychological test results can be interpreted with a high degree of confidence.

Associations Between Ambient Particulate Air Pollution and Cognitive Function in Indonesian Children Living in Forest Fire-Prone Provinces.

Smoke from forest fires can reach hazardous levels for extended periods of time. We aimed to determine if there is an association between particulate matter ≤2.5 µm in aerodynamic diameter (PM2.5) and living in a forest fire-prone province and cognitive function. We used data from the Indonesian Family and Life Survey. Cognitive function was assessed by the Ravens Colored Progressive Matrices (RCPM). We used regression models to estimate associations between PM2.5 and living in a forest fire-prone province and cognitive function. In multivariable models, we found very small positive relationships between PM2.5 levels and RCPM scores (PM2.5 level at year of survey: ß = 0.1%; 95% confidence interval (CI) [0.01, 0.19%]). There were no differences in RCPM scores for children living in forest fire-prone provinces compared with children living in non-forest fire-prone provinces (mean difference = -1.16%, 95% CI [-2.53, 0.21]). RCPM scores were lower for children who had lived in a forest fire-prone province all their lives compared with children who lived in a non-forest fire-prone province all their life (ß = -1.50%; 95% CI [-2.94, -0.07]). Living in a forest fire-prone province for a prolonged period of time negatively affected cognitive scores after adjusting for individual factors.

Measuring reliable change in traumatic brain injury (TBI): The pitfalls of using readily available formulae.

Individuals with a traumatic brain injury (TBI) frequently undergo repeat neuropsychological assessments. Reliable change (RC) methodologies based on general population normative data are often used to assess for clinically significant change. The consequence of applying such methodologies to an individual with a TBI needs investigation. The current study tested the validity of readily available formulae in moderate to severe TBI participants who were >2 years postinjury. Participants were administered the Wechsler Adult Intelligence Scale-IV/Wechsler Memory Scale-IV (WAIS/WMS-IV) battery on two occasions across an approximate 1 year interval. Index scores were entered into 10 RC formulae to assess their validity in individuals with a TBI. Findings revealed that the formulae used in the study are relatively interchangeable in regards to WAIS-IV assessment, but that many of the formulae identified statistically unexpected rates of RC change in memory tasks assessed by the WMS-IV. Two formulae that did not contain statistical manipulations for practice effects performed relatively well in regards to memory assessment. Therefore, indiscriminate use of RC formulae could lead to over identifying memory decline in the TBI populations. The results suggest that either Iverson or Jacobson and Truax formulae can be used to assess RC for memory in moderate to severe TBI populations.

An examination of the heterogeneity of cognitive outcome following severe to extremely severe traumatic brain injury.

Objective: The current study aimed to explore neuropsychological outcomes in the initial recovery period following severe to extremely severe traumatic brain injury (TBI).Method: Using reliable change statistics, individuals were categorized as demonstrating cognitive improvement, stability or decline based on performance on 11 neuropsychological measures relative to scores returned during an initial assessment conducted in the acute post-injury stage. The study explored injury, demographic, and other variables as predictors of group membership. A total of 79 individuals were recruited from retrospective neuropsychological records between 2009 and 2017. Individuals were assessed on two occasions as per routine clinical practice. Approximately 10% of subjects sustained a severe TBI, 52% sustained a very severe TBI, and 38% sustained an extremely severe TBI.Results: Of the 79 participants, two individuals (2.5%) demonstrated cognitive decline, 28 individuals (35.4%) demonstrated cognitive stability, and 49 individuals (62%) demonstrated cognitive improvement. A binary logistic regression indicated that length of post-traumatic amnesia, as a categorical variable, was significantly predictive of group membership in that those with extremely severe TBIs were more likely to show improvement over time. Additionally, high levels of stress at review assessment, as measured on the Depression Anxiety Stress Scales, was predictive of membership in the cognitive improvement group.Conclusion: The results highlighted the heterogeneity of recovery in the initial recovery period following severe to extremely severe TBI and have the potential to inform clinical advice regarding outcome trajectories.

The role of personal biases in the explanation of confabulation.

INTRODUCTION: Previous research has demonstrated that motivational forces play an important role in determining the content of confabulation. In particular the content of confabulation has been shown to contain a positive emotional bias. This study investigated the role of personal biases in the confabulations of six patients with diverse aetiologies. METHOD: Confabulations were elicited with a series of structured interviews. We then compared the patients' confabulations to their actual situations. Further analyses compared confabulations about current (i.e., the postmorbid period) and past (i.e., premorbid events and general life circumstances) events. RESULTS: Group analysis confirmed a general bias to recall events that were more positive than the reality. However, examination of individual cases revealed that positive biases were not universal. Confabulations about current circumstances showed the positive bias, whereas an emotional bias was not evident in past confabulations. CONCLUSION: We conclude that motivational forces play a role in determining the content of confabulations but conceive of this role primarily in terms of a need to maintain a consistent self-concept (whether positive or negative) overlaid upon the ease with which an individual can retrieve familiar premorbid daily activities and routines.

Models of confabulation: a critical review and a new framework.

Confabulation can be defined as statements or actions that involve distortions of memories. This paper reviews current theories of confabulation focusing on source monitoring, temporal-context, and retrieval theories. The attributes and criticisms of these three models are discussed. From this review, a three-factor cognitive-neuropsychological framework is proposed, which can be used to explain the variable symptoms of confabulation. The framework takes its basis from the Langdon and Coltheart (2000a, 2000b) cognitive model of delusional belief formation. The model suggests that two deficits are likely in most cases of confabulation - an executive control retrieval deficit and an evaluation deficit. It also takes into consideration how the general organization of the autobiographical memory store and a person's individual emotional/motivational biases can influence confabulatory symptoms and content. This is an overarching framework that can be used to model confabulations, and it builds upon links between delusions and confabulation.