Group treatment of problem‐solving deficits in outpatients with traumatic brain injury: A randomised outcome study

Sixty higher‐level outpatients with traumatic brain injury (TBI), all at least 1 year post‐injury, were randomly assigned to either conventional group neuropsychological rehabilitation or an innovative group treatment focused on the treatment of problem‐solving deficits. Incorporating strategies for addressing underlying emotional self‐regulation and logical thinking/reasoning deficits, the innovative treatment is unique in its attention to both motivational, attitudinal, and affective processes and problem‐solving skills in persons with TBI. Participants in the innovative group improved in problem solving as assessed using a variety of measures, including (1) executive function, (2) problem‐solving self‐appraisal, (3) self‐appraised emotional self‐regulation and clear thinking, and (4) objective observer ratings of roleplayed scenarios. These improvements were maintained at follow‐up. Baseline performance on timed attention tasks was related to improvement; individuals who processed the most slowly benefited the most. These participants did not show improvements on timed attention tasks, but did improve on problem‐solving measures. Such findings are consistent with successful compensatory strategy use—the person may still have deficits and symptoms, but now has effective strategies for reducing their impact on daily functioning.     

Time-based prospective memory in severe traumatic brain injury patients: the involvement of executive functions and time perception

Prospective memory (PM) is the ability to remember to perform a future action at a specified later time, which is investigated through the use of event-based and time-based tasks. Prior investigations have found that PM is impaired following traumatic brain injury (TBI). However, there is limited information regarding the cognitive functions that mediate TBI and PM performance. Thus, this study investigated time-based PM in TBI patients, and the relationship among time-based PM, time perception, and executive functions. To accomplish this objective, 18 severe TBI patients and 18 healthy matched controls performed a time-based PM task, a time reproduction task, and two executive functions (Stroop and n-back) tasks. While both groups increased their monitoring frequency close to the target time, TBI patients monitored more and were less accurate than healthy controls at the target time confirming the time-based PM dysfunction in these patients. Importantly, executive functions, particularly inhibition and updating abilities, were strongly related to time-based PM performance; both time perception and executive functions are involved in time-based prospective memory in controls, whereas, only executive functions appear to be involved in TBI time-based prospective memory performance.     

Cognitive and psychosocial correlates of alexithymia following traumatic brain injury

Changes in emotional and social behaviour are considered to be amongst the most common and debilitating consequences of traumatic brain injury (TBI). Little is known of the effects of TBI on alexithymia, which refers to impairment in aspects of understanding emotions. In the current study TBI patients (N=28) were compared with demographically matched healthy controls (N=31) on the Toronto Alexithymia Scale-20 (TAS-20), a measure that taps three distinct characteristics of the alexithymia concept; difficulty in identifying emotions, difficulty in describing emotions and externally oriented thinking. Patients and controls also completed measures of anxiety, depression, quality of life, and measures of fluency to assess executive function. Patients showed greater levels of alexithymia, in terms of difficulty identifying emotions and reduced introspection. Difficulty in identifying emotions was associated with poorer quality of life, even when depression and anxiety were controlled. Difficulty in identifying emotions was also uniquely associated with executive function deficits. Thus, although studies typically focus on aspects of cognitive change following head injury, these results lend support to Becerra et al.'s (Becerra, R., Amos, A., & Jongenelis, S. (2002). Organic alexithymia: a study of acquired emotional blindness. Brain Injury, 16, 633-645.) notion of an 'organic alexithymia', and suggest that more attention should be focused upon assessment of emotional change post-head injury.     

Decreased prefrontal cortex activity in mild traumatic brain injury during performance of an auditory oddball task

Up to one-third of patients with mild traumatic brain injury (TBI) demonstrate persistent cognitive deficits in the ‘executive’ function domain. Mild TBI patients have shown prefrontal cortex activity deficits during the performance of executive tasks requiring active information maintenance and manipulation. However, it is unclear whether these deficits are related to the executive processes themselves, or to the degree of mental effort. To determine whether prefrontal deficits also would be found during less effortful forms of executive ability, fMRI images were obtained on 31 mild TBI patients and 31 control participants during three-stimulus auditory oddball task performance. Although patients and controls had similar topographical patterns of brain activity, region-of-interest analysis revealed significantly decreased activity in right dorsolateral prefrontal cortex for mild TBI patients during target stimulus detection. Between-group analyses found evidence for potential compensatory brain activity during target detection and default-mode network dysfunction only during the detection of novel stimuli.     

Tonic and phasic alertness training: a novel treatment for executive control dysfunction following mild traumatic brain injury

Many individuals with traumatic brain injury (TBI) suffer difficulty regulating fundamental aspects of attention (focus, sustained attention) and may also exhibit hypo- or hyper-states of alertness. Deficits in the state of attention may underlie or exacerbate higher order executive dysfunction. Recent studies indicate that computerized cognitive training targeting attentional control and alertness can ameliorate attention deficits evident in patients with TBI or acquired brain injury. The current study examined whether improvements in attentional state following training can also influence performance on higher-order executive function and mood in individuals with mild TBI (mTBI). The current study examined five patients with executive control deficits as a result of mTBI, with or without persistent anxiety. Three patients engaged in ~5 hours of an executive control training task targeting inhibitory control and sustained attention; two additional patients were re-tested following the same period of time. Performance on standard neuropsychological measures of attention, executive function, and mood were evaluated pre- and post-training. The results indicate that tonic and phasic alertness training may improve higher-order executive function and mood regulation in individuals with TBI.     

轻度颅脑损伤患者执行功能障碍研究

目的探讨轻度颅脑损伤(mild traumatic brain injury,m TBI)患者伤后执行功能(executive function,EF)的动态变化特点。方法对63例m TBI患者(研究组)在伤后1周、1个月、3个月和6个月进行执行功能测查,并与60例健康受试者(对照组)比较。测查工具采用连线测验(trail making test,TMTA)、霍普金斯词语学习测验修订版(Hopkins verbal learning test-revised,HVLT-R)、简易视觉记忆测验—修订版(brief visuospatial memory test-revised,BVMT-R)、Stroop色词测验、持续操作测验(continuous performance test,CPT)。结果伤后1周与对照组比较,TMTA、HVLT-R、BVMT-R、Stroop和CPT-IP分值差异有统计学意义(P0.05);与伤后1周相比,伤后1个月、3个月和6个月时的TMTA分值下降,HVLT-R、BVMT-R、Stroop和CPT-IP分值增加(P0.05)。组内两两比较,伤后1个月与伤后1周比较,TMTA分值下降,BVMT-R、Stroop分值增加(P0.05);伤后3个月与伤后1个月比较,Stroop、BVMT-R和CPT-IP分值增加(P0.05);伤后6个月与伤后3个月比较,Stroop和CPTIP分值增加(P0.05)。结论m TBI患者在注意能力/警觉性、学习与工作记忆、信息处理速度及执行功能上都可能存在一定的损害,伤后不同时间点恢复速度并不一致。     

Longitudinal study of objective and subjective cognitive performance and psychological distress in OEF/OIF Veterans with and without traumatic brain injury

Objective: To describe changes in post-deployment objective and subjective cognitive performance in combat Veterans over 18 months, relative to traumatic brain injury (TBI) status and psychological distress. Method: This prospective cohort study examined 500 Veterans from Upstate New York at four time points, six months apart. TBI status was determined by a structured clinical interview. Neuropsychological instruments focused on attention, memory, and executive functions. Subjective cognitive complaints were assessed with the Neurobehavioral Symptom Inventory (NSI). A psychological distress composite included measures of post-traumatic stress disorder (PTSD), depression, and generalized anxiety. Results: Forty-four percent of the sample was found to have sustained military-related TBI, 97% of which were classified as mild (mTBI), with a mean time since injury of 41 months. Veterans with TBI endorsed moderate cognitive symptoms on the NSI. In contrast to these subjective complaints, mean cognitive test performance was within normal limits at each time point in all domains, regardless of TBI status. Multilevel models examined effects of TBI status, time, and psychological distress. Psychological distress was a strong predictor of all cognitive domains, especially the subjective domain. Substantial proportions of both TBI+ and TBI? groups remained in the clinically significant range at the initial and final assessment for all three distress measures, but the TBI+ group had higher proportions of clinically significant cases. Conclusions: Objective cognitive performance was generally within normal limits for Veterans with mTBI across all assessments. Psychological distress was elevated and significantly related to both objective and subjective cognitive performance.     

Theory of mind following traumatic brain injury: the role of emotion recognition and executive dysfunction

A number of studies have now documented that traumatic brain injury (TBI) is associated with deficits in the recognition of basic emotions, the capacity to infer mental states of others (theory of mind), as well as executive functioning. However, no study to date has investigated the relationship between these three constructs in the context of TBI. In the current study TBI participants (N=16) were compared with demographically matched healthy controls (N=17). It was found that TBI participants' recognition of basic emotions, as well as their capacity for mental state attribution, was significantly reduced relative to controls. Performance on both of these measures was strongly correlated in the healthy control, but not in the TBI sample. In contrast, in the TBI (but not the control) sample, theory of mind was substantially correlated with performance on phonemic fluency, a measure of executive functioning considered to impose particular demands upon cognitive flexibility and self-regulation. These results are consistent with other evidence indicating that deficits in some aspects of executive functioning may at least partially underlie deficits in social cognition following TBI, and thus help explain the prevalence of social dysfunction in TBI.     

Dual Task Performance after Severe Diffuse Traumatic Brain Injury or Vascular Prefrontal Damage

The ability to perform two tasks simultaneously is a key function of the central executive of working memory (Baddeley, 1986). This study addressed dual-task performance after diffuse very severe traumatic brain injury (TBI) (mean coma duration = 21 days, mean post-traumatic amnesia = 70 days) or prefrontal damage due to a ruptured aneurysm of the anterior communicating artery (AACA). Mean time since injury was 8 and 16 months in the TBI and the AACA group respectively. A simple visual reaction time and random number generation were used as single and dual tasks. Randomization was self-paced, to control for individual differences in speed. Both patient groups had greater reaction time decrements than controls under the dual-task condition, suggesting a divided attention deficit. In addition, patients with AACA performed significantly poorer in random generation. These results suggest that patients with AACA and with severe TBI suffer from an impairment of the central executive system.     

Executive function as a predictor of inattentive behavior after traumatic brain injury.

Emerging evidence from recent studies using laboratory and naturalistic attention tasks suggests that individuals with traumatic brain injury (TBI) may have a deficit mainly in strategic control of attention. In the present study, we tested the hypothesis that inattentive behavior after TBI could be predicted by performance on psychometric measures of executive function. A group of 37 individuals with moderate to severe TBI were assessed with previously validated naturalistic measures of attention. A battery of neuropsychological tests was also administered to assess various aspects of executive function. Seven measures of executive function and 10 variables reflecting inattentive behavior were combined to form 1 executive and 3 inattentive behavior (IB) composite scores. Three predictors (executive composite, current disability scores, and age) were associated, at the univariate level, with one of the IB composites reflecting frequency and duration of off-task episodes. A stepwise multiple regression procedure indicated that the executive composite was the only significant predictor of the IB composite. Additional post-hoc regression analyses suggested that the relationship was not likely to be mediated by processing speed. The current study supports the hypothesis that executive function, measured by commonly used neuropsychological tests, significantly predicts certain aspects of inattentive behavior in real-world tasks after TBI.     

Dual task performance after severe diffuse traumatic brain injury or vascular prefrontal damage

The ability to perform two tasks simultaneously is a key function of the central executive of working memory (Baddeley, 1986). This study addressed dual-task performance after diffuse very severe traumatic brain injury (TBI) (mean coma duration = 21 days, mean post-traumatic amnesia = 70 days) or prefrontal damage due to a ruptured aneurysm of the anterior communicating artery (AACA). Mean time since injury was 8 and 16 months in the TBI and the AACA group respectively. A simple visual reaction time and random number generation were used as single and dual tasks. Randomization was self-paced, to control for individual differences in speed. Both patient groups had greater reaction time decrements than controls under the dual-task condition, suggesting a divided attention deficit. In addition, patients with AACA performed significantly poorer in random generation. These results suggest that patients with AACA and with severe TBI suffer from an impairment of the central executive system.     

Long-term attention problems in children with traumatic brain injury

OBJECTIVE: To examine long-term attention problems and their cognitive correlates after childhood traumatic brain injury (TBI). METHOD: Data were drawn from a prospective, longitudinal study conducted between 1992 and 2002. Participants included 41 children with severe TBI, 41 with moderate TBI, and 50 with orthopedic injury (OI), who were all between 6 and 12 years of age at the time of injury. Parent ratings of attention problems were obtained at a long-term follow-up on average 4 years post-injury and compared with ratings of premorbid attention problems obtained shortly after injury. At the long-term follow-up, children also completed several cognitive tests of attention and executive functions. RESULTS: Hierarchical linear and logistic regression analyses indicated that the severe TBI group displayed significantly more attention problems than the OI group at 4 years post-injury, both behaviorally and cognitively, after controlling for race, socioeconomic status, and premorbid attention problems. At long-term follow-up, 46% of the severe TBI group displayed significant attention problems on the Child Behavior Checklist, as opposed to 26% of the OI group (odds ratio=3.38; 95% confidence interval, 1.15-9.94). On the Attention-Deficit/Hyperactivity Disorder Rating Scale, 20% of the severe TBI group displayed clinically significant attention problems compared with 4% in the OI group (odds ratio=9.59; 95% confidence interval, 1.24-73.99). However, group differences in behavioral symptoms were significantly larger for children with more premorbid symptoms than for children with fewer premorbid problems. Measures of executive functions were significantly related to behavioral attention problems, after controlling for group membership, race, and socioeconomic status. CONCLUSIONS:Childhood TBI exacerbates premorbid attention problems. Long-term behavioral symptoms of attention problems are related to the cognitive deficits in attention and executive functions that often occur in association with childhood TBI.     

Cognitive rehabilitation interventions for executive function: moving from bench to bedside in patients with traumatic brain injury

Executive function mediated by prefrontally driven distributed networks is frequently impaired by traumatic brain injury (TBI) as a result of diffuse axonal injury and focal lesions. In addition to executive cognitive functions such as planning and working memory, the effects of TBI impact social cognition and motivation processes. To encourage application of cognitive neuroscience methods to studying recovery from TBI, associated reorganization of function, and development of interventions, this article reviews the pathophysiology of TBI, critiques currently employed methods of assessing executive function, and evaluates promising interventions that reflect advances in cognitive neuroscience. Brain imaging to identify neural mechanisms mediating executive dysfunction and response to interventions following TBI is also discussed.     

Effects of divided attention on episodic memory in chronic traumatic brain injury: a function of severity and strategy

Eleven patients with mild traumatic brain injury (MTBI) and 13 patients with moderate-to-severe TBI (STBI) were compared to 10 matched controls on episodic memory for pictorial scene–object associations (e.g. kitchen–bread) and a range of standardized neuropsychological tests of memory and frontal-lobe functions. We tested the hypothesis that deficits in episodic memory result from impaired attentional resources and/or strategic control by manipulating attentional load at encoding (focused versus divided attention) and environmental support at retrieval (free recall and recalled cued by scene versus recognition of object and scene). Patients with TBI were disproportionately affected by the divided attention manipulation, but this effect was modulated by injury severity and encoding strategy. Overall, MTBI patients were impaired only when items were encoded under divided attention, indicating memory deficits that were secondary to deficits in the executive control. STBI patients could be differentiated into two distinct functional subgroups based on whether they favored a strategy of attending to the encoding or digit-monitoring task. The subgroup favoring the digit-monitoring task demonstrated deficits in the focused attention condition, and disproportionate memory deficits in the divided attention condition. In contrast, the subgroup favoring the encoding task demonstrated intact performance across all memory measures, regardless of attentional load, and despite remarkable similarity to the other STBI subgroup on demographic, neuropsychological, and acute injury severity measures. We discuss these outcome differences in terms of the relationship between strategy and executive control and highlight the need for more sensitive anatomical and behavioral measurement at both acute and chronic stages of injury.     

Effects of interactive strategy modelling training on problem‐solving by persons with traumatic brain injury

Background: Problem‐solving skills may be affected by traumatic brain injury (TBI). Because the ability to solve problems is integral to the social, educational, and vocational reintegration of persons who have sustained a TBI, interventions to improve this executive function have become an important part of rehabilitation. Aims: This Phase I study examined the effects of a behavioural intervention, interactive strategy modelling training (ISMT), on problem solving by individuals who had incurred a TBI. Methods & Procedures: Study participants were 20 individuals recruited from TBI support groups. All lived at home and were several months post‐injury. Participants received a period of ISMT intended to train them to use meta‐cognitive strategies to solve 20‐questions problems. RAPS (Rapid Assessment of Problem Solving), a clinical test of problem solving was used to assess the effects of ISMT (Marshall, Karow, Morelli, Iden, & Dixon, 2003a). RAPS was administered before (Pre‐training), after (Post‐training), and 1‐month after training (Follow‐up). Outcomes & Results: Participants improved in problem solving significantly on RAPS from the Pre‐ to the Post‐training tests. Specifically, they (a) solved problems with fewer questions, (b) asked more constraint‐seeking questions, and (c) increased their question‐asking efficiency scores. These improvements were maintained on the Follow‐up test. Conclusions: Improved problem solving on RAPS was associated with better planning and strategy use, less impulsivity, and strategy shifting. Results suggest that IMST had a therapeutic effect and indicate a need to develop further hypotheses for testing ISMT in functional contexts.     

Patterns of association between performance in a natural environment and measures of executive function in people with schizophrenia

This study examined the relationships between a set of real-world performance measures and a set of executive function measures with a sample of community based individuals with schizophrenia (N=80). Participants were given a battery of cognitive tests and were evaluated with a real-world performance measure, the Test of Grocery Shopping Skills (TOGSS). Using canonical correlation analysis, executive functions of planning, problem solving, working memory, and task persistence were significantly related to grocery shopping efficiency and accuracy. Two canonical variates with moderate correlations (0.547 and 0.519) explain that 30% of the variance in the executive function and grocery shopping measures was shared. These results identify patterns of association between executive function performance and the independent living skill of grocery shopping indicating the Test of Grocery Shopping Skills may be considered a sensitive measure of executive function performance in a real-world setting.     

Persistent cognitive deficits after whiplash injury: a comparative study with mild traumatic brain injury patients and healthy volunteers

In this study, we evaluated persistent cognitive deficits in whiplash injury (WI) patients and compared these to cognitive functioning in mild traumatic brain injury (MTBI) patients and healthy controls (HC). Sixty-one patients suffering from a WI were compared with 57 patients suffering from a MTBI and with 30 HC. They were examined with an extensive neuropsychological test battery assessing attention, memory, and visuospatial and executive functions. In both patient groups, participants showed persistent cognitive symptoms (more than 6 months post-injury). The two patient groups did not differ significantly with regard to measurements of attention, memory, and visuospatial and executive functions. The WI group, as compared to the HC group, was found to be significantly more deficient in speed of performance during sustained and divided attention, focused attention, alternating attention, the storage of new auditory-verbal unrelated information into memory, the long-term delayed recall of stored auditory-verbal related information from memory, abstract reasoning and accuracy of performance during planning and problem solving. No differences could be found between both groups concerning speed of information processing, visuospatial abilities and verbal fluency.     

Pre-injury assessment of everyday executive function in moderate to severe traumatic brain injury

Executive dysfunction is frequently observed in moderate to severe traumatic brain injury (TBI) and is commonly assessed with objective measures or subjective rating scales. Given the variability in executive function in the normal population, a reliable measure of pre-injury executive function would be of considerable value. In this study we examined pre-injury self and collateral (relative or friend) ratings on the Frontal Systems Behavior Rating Scale (FrSBe). Fifty-one persons with moderate to severe TBI and their collaterals provided before- and after-TBI ratings at 3 months post injury. A subset of 36 dyads were retested at 6 and 12 months; 26 neurologically intact controls and their collaterals also provided FrSBe ratings. At 3 months post injury, the difference between patient and collateral ratings of current status was larger than the difference relating to premorbid status, suggesting that patients were able to rate themselves from a pre-injury perspective. However, pre-injury ratings from collaterals were more reliable over time compared with patients’ self-ratings. For all sets of ratings – before injury, after injury, and status of healthy controls – collateral ratings indicated more abnormality, overall, than comparable self-ratings. Evaluating one’s own executive behaviour may be a difficult task even without TBI, with the difficulty exacerbated by the effects of injury.     

Association between cognitive impairments and obsessive-compulsive spectrum presentations following traumatic brain injury

This study examined the association between self-reported obsessive-compulsive spectrum symptomatology and cognitive performance in a sample of patients with traumatic brain injury (TBI). Twenty-four adults with a moderate-severe TBI accessing a community brain injury rehabilitation service were recruited. Age ranged between 19 and 69 years. Participants completed a battery of neuropsychological tasks assessing memory, executive functioning, and speed of information processing. Self-report questionnaires assessing obsessive-compulsive (OC) symptoms and obsessive-compulsive personality disorder (OCPD) traits were also completed. Correlational analyses revealed that deficits in cognitive flexibility were associated with greater self-reported OC symptomatology and severity. Greater OC symptom severity was significantly related to poorer performance on a visual memory task. Verbal memory and speed of information processing impairments were unrelated to OC symptoms. Performance on tasks of memory, executive functioning, and speed of information processing were not associated with OCPD traits. Overall, results indicate that greater OC symptomatology and severity were associated with specific neuropsychological functions (i.e., cognitive flexibility, visual memory). OCPD personality traits were unrelated to cognitive performance. Further research is needed to examine the potential causal relationship and longer-term interactions between cognitive sequelae and obsessive-compulsive spectrum presentations post-TBI.