Mary R. T. Kennedy

Intervention for executive functions after traumatic brain injury: A systematic review, meta-analysis and clinical recommendations

A systematic review of studies that focused on the executive functions of problem solving, planning, organising and multitasking by adults with traumatic brain injury (TBI) was performed through 2004. Qualitative and quantitative methods were used to evaluate the 15 studies that met inclusion criteria. Demographic variables, design and intervention features, and impairment and activity/participation outcomes (ICF) (World Health Organization, 2001) were documented. Five randomised control treatment (RCT) studies used step-by-step, metacognitive strategy instruction (MSI) and outcomes were evaluated in a meta-analysis. Effect sizes (ESs) from immediate impairment outcomes after MSI and “control” intervention were similar to each other, and both were significantly larger than chance. ESs from immediate activity/participation outcomes after MSI were significantly larger than the ESs from control intervention, and both were significantly larger than chance. These results, along with positive outcomes from the other group, single-subject design and single case studies, provided sufficient evidence to make the clinical recommendation that MSI should be used with young to middle-aged adults with TBI, when improvement in everyday, functional problems is the goal (Level A) (American Academy of Neurology, 2004). Although maintenance effects were generally positive, there was insufficient data quantitatively to evaluate this. Furthermore, there was insufficient evidence to make clinical recommendations for children or older adults. Intervention that trained verbal reasoning and multi-tasking was promising, although the evidence is insufficient to make clinical recommendations at this time. Additional research needs were highlighted.

Behavioural interventions for children and adults with behaviour disorders after TBI: A systematic review of the evidence

Objective: To systematically review the evidence for the effectiveness of behavioural interventions for children and adults with behaviour disorders after TBI. Design: Using a variety of search procedures, 65 studies were identified. This literature was reviewed using a set of questions about participants, interventions, outcomes and research methods. Participants: The 65 studies included 172 experimental participants, including children and adults. Interventions: A number of specific intervention procedures were used, falling into three general categories: traditional contingency management, positive behaviour interventions and supports and combined. Results: All of the studies reported improvements in behavioural functioning. Conclusions: Behavioural intervention, not otherwise specified, can be considered a treatment guideline for children and adults with behaviour disorders after TBI. Both traditional contingency management procedures and positive behaviour support procedures can be said to be evidence-based treatment options. However, a variety of methodological concerns block stronger conclusions.

Evidence-based practice guidelines for instructing individuals with neurogenic memory impairments: What have we learned in the past 20 years?

This article examines the instructional research literature pertinent to teaching procedures or information to individuals with acquired memory impairments due to brain injury or related conditions. The purpose is to evaluate the available evidence in order to generate practice guidelines for clinicians working in the field of cognitive rehabilitation. A systematic review of the instructional literature from 1986 to 2006 revealed 51 studies meeting search criteria. Studies were analysed and coded within the following four key domains: Population Sample, Intervention, Study Design, and Treatment Outcomes. Coding included 17 characteristics of the population sample; seven intervention parameters; five study design features; and five treatment outcome parameters. Interventions that were evaluated included systematic instructional techniques such as method of vanishing cues and errorless learning. The majority of the studies reported positive outcomes in favour of systematic instruction. However, issues related to the design and execution of effective instruction lack clarity and require further study. The interaction between the target learning objective and the individual learner profile is not well understood. The evidence review concludes with clinical recommendations based on the instructional literature and a call to clinicians to incorporate these methods into their practice to maximise patient outcomes.

White matter and neurocognitive changes in adults with chronic traumatic brain injury.

Diffusion tensor imaging was used to investigate white matter (WM) integrity in adults with traumatic brain injury (TBI) and healthy adults as controls. Adults with TBI had sustained severe vehicular injuries on the average of 7 years earlier. A multivariate analysis of covariance with verbal IQ as the covariate revealed that adults with TBI had lower fractional anisotropy and higher mean diffusivity than controls, specifically in the three regions of interest (ROIs), the centrum semiovale (CS), the superior frontal (SPF), and the inferior frontal (INF). Adults with TBI averaged in the normal range in motor speed and two of three executive functions and were below average in delayed verbal recall and inhibition, whereas controls were above average. Time since injury, but not age, was associated with WM changes in the SPF ROI, whereas age, but not time since injury, was associated with WM changes in the INF ROI, suggesting that the effects of WM on time since injury may interact with age. To understand the utility of WM changes in chronic recovery, larger sample sizes are needed to investigate associations between cognition and WM integrity of severely injured individuals who have substantial cognitive impairment compared to severely injured individuals with little cognitive impairment. (JINS, 2009, 15, 130-136.).

INCOG recommendations for management of cognition following traumatic brain injury, part III: executive function and self-awareness.

Introduction:Traumatic brain injury (TBI) results in complex cognitive (and other) sequelae. Impairments in executive function and self-awareness are among the most characteristic neuropsychological sequelae and can exert a profound effect on resuming previous life roles. An international group of researchers and clinicians (known as INCOG) convened to develop recommendations for interventions to improve impairments in executive functioning and self-awareness after TBI. Methods:The team reviewed the available literature and ensured the recommendations were current. To promote implementation, the team developed decision algorithms incorporating the recommendations based on inclusion and exclusion criteria of published trials. The team then prioritized the recommendations for implementation and developed audit criteria to evaluate the adherence to the best practice recommendations. Results:Intervention programs incorporating metacognitive strategy instruction for planning, problem-solving, and other cognitive-executive impairments have a solid evidence base. New evidence supports the use of strategies to specifically improve reasoning skills. Substantial support exists for use of direct corrective feedback to improve self-awareness. Conclusions:An increasing number of scientifically well-designed studies are available that demonstrate the effectiveness of a variety of interventions for the remediation of impairments in executive function and self-awareness after TBI.

Group intervention studies in the cognitive rehabilitation of individuals with traumatic brain injury: challenges faced by researchers.

There are many factors to consider in designing and interpreting group studies. These include both analytic considerations, such as the selection of valid and reliable outcome measures, and subjective considerations, such as the selection of outcomes that are perceived to be important to participants and researchers. In this paper, we review key issues to consider in the design of group studies in neurorehabilitation, using problem-solving studies in traumatic brain injury as an example.

Predictions of recall and study strategy decisions after diffuse brain injury

Objective: To investigate relationships between self-monitoring operationalized by predicting recall and study strategy decisions made by adults with diffuse, acquired brain injury (ABI) and adults without ABI. Research design and methods: Eighteen adults with ABI and 16 without ABI studied two lists of unrelated noun-pairs, made item-by-item immediate and delayed recall predictions and selected items (after predictions) to restudy again. The computer selected items for restudy based on the lowest prediction rating (i.e. unlikely to recall). A mixed list design was used to balance item selection (self or computer, within-lists) by type of prediction (immediate or delayed, between-lists). Recall was tested prior to and after restudying. Hypotheses: Delayed recall predictions would be more accurate than immediate recall predictions; participants would select items for restudy that corresponded with ‘lower’ delayed predictions (i.e. less likely to recall) and ‘higher’ immediate predictions (i.e. more likely to recall); for adults with ABI, recall would improve the most from restudying items selected after delayed predictions; and that recall predictive accuracy and study selection decisions are independent processes. Results: Delayed recall predictions were more accurate than immediate recall predictions, though adults with ABI tended to be less accurate than controls. Both groups selected items for restudy that had relatively low prediction ratings irrespective of prediction timing. Of adults with ABI, those with low recall prior to restudy selected items that had ‘high’ immediate predictions (i.e. likely to recall). However, there was no greater benefit to recall using this strategy. For adults with ABI, recall improved the most from restudying items that were self-selected after delayed predictions, whereas controls’ recall improved, irrespective of prediction and selection timing. Between-person correlations revealed no relationship between recall predictive accuracy and study selection strategies. Conclusions: These findings imply that adults with ABI should base strategy decisions on delayed predictions rather than on ‘in the moment’ immediate ones, selecting items that they have predicted will be difficult to recall. Continued efforts to disambiguate self-monitoring from strategy decisions are required before direct clinical applications can be made.

Topic Scenes in Conversations With Adults With Right-Hemisphere Brain Damage

Eight adults with right hemisphere damage (RHD) and seven non-brain-damaged (NBD) matched controls participated in first-encounter conversations. The incidence and nature of topic scenes, as well a...

Metamemory adjustments over time in adults with and without traumatic brain injury

Primary objective: This study explored whether adults with and without traumatic brain injury (TBI) adjust their judgements of learning (JOLs) over the course of a verbal learning task. Research design: Regression analyses were performed of JOLs and recall over time, for both group means and individual performance. Procedures: Twenty adults with TBI and 16 healthy controls studied lists of noun-pairs, making Likert scale JOLs for each item during the study phase. Half of the JOLs were made immediately following item study; the other half after several minutes delay. Recall was tested for each list after all JOLs were complete. Outcomes: Analyses revealed significant differences between participants with TBI and controls in how JOLs changed over time. As a group, TBI survivors increased JOLs over the course of the learning experiment in the delayed condition, whereas the control group decreased JOL predictions in the immediate condition. Conclusions: These results support previous work showing that metamemory abilities of adults with TBI are heterogeneous, but show some differences from those of healthy adults. Possible explanations are derived from Koriats findings that, with practice, individuals tend to shift toward basing metamemory predictions on mnemonic cues rather than cues intrinsic to task items.

Masking release, processing speed and listening effort in adults with traumatic brain injury

Abstract Purpose: This preliminary study explored differences between adults with and without traumatic brain injury (TBI) for speech processing accuracy, processing speed and effort in various conditions of interference. Methods: Ten adults with TBI and six adults without TBI participated. Speech processing was studied using sentence repetition in six listening conditions with different types of interference, including noise and two simultaneous talkers. Participants repeated sentences and rated effort. Participants also completed standardized tests of cognition, including working memory and processing speed measures. Results: Sentence repetition accuracy did not differ between groups. However, the TBI group demonstrated slower processing speed than the control group and also reported significantly greater effort in the two-talker condition. Faster processing speed was also correlated with higher accuracy in the two-talker condition. Conclusions: Results of this study show group similarities in repetition accuracy across listening conditions, but group differences in speed and effort. This preliminary finding, as well as the relationship between processing speed and repetition accuracy, suggests that it is only in the most complex listening conditions that the effects of brain injury may be detectable.