The effects of visual distraction following traumatic brain injury

INCOG 2.0 Guidelines for Cognitive Rehabilitation Following Traumatic Brain Injury, Part II: Attention and Information Processing Speed

INTRODUCTION

Moderate to severe traumatic brain injury (MS-TBI) commonly causes disruption in aspects of attention due to its diffuse nature and injury to frontotemporal and midbrain reticular activating systems. Attentional impairments are a common focus of cognitive rehabilitation, and increased awareness of evidence is needed to facilitate informed clinical practice.

METHODS

An expert panel of clinicians/researchers (known as INCOG) reviewed evidence published from 2014 and developed updated guidelines for the management of attention in adults, as well as a decision-making algorithm, and an audit tool for review of clinical practice.

RESULTS

This update incorporated 27 studies and made 11 recommendations. Two new recommendations regarding transcranial stimulation and an herbal supplement were made. Five were updated from INCOG 2014 and 4 were unchanged. The team recommends screening for and addressing factors contributing to attentional problems, including hearing, vision, fatigue, sleep-wake disturbance, anxiety, depression, pain, substance use, and medication. Metacognitive strategy training focused on everyday activities is recommended for individuals with mild-moderate attentional impairments. Practice on de-contextualized computer-based attentional tasks is not recommended because of lack of evidence of generalization, but direct training on everyday tasks, including dual tasks or dealing with background noise, may lead to gains for performance of those tasks. Potential usefulness of environmental modifications is also discussed. There is insufficient evidence to support mindfulness-based meditation, periodic alerting, or noninvasive brain stimulation for alleviating attentional impairments. Of pharmacological interventions, methylphenidate is recommended to improve information processing speed. Amantadine may facilitate arousal in comatose or vegetative patients but does not enhance performance on attentional measures over the longer term. The antioxidant Chinese herbal supplement MLC901 (NeuroAiD IITM) may enhance selective attention in individuals with mild-moderate TBI.

CONCLUSION

Evidence for interventions to improve attention after TBI is slowly growing. However, more controlled trials are needed, especially evaluating behavioral or nonpharmacological interventions for attention.

Impact of television on nutritional intake in communal dining room settings among those with acquired brain injury: A pilot study

AIM

Those with acquired brain injury (ABI) experience impairments in executive function, attention and concentration that may contribute to or exacerbate poor nutritional intakes. This is frequently observed in long-stay rehabilitation settings. This investigation aimed to identify the specific impact of the dining room television as a factor that exacerbates poor intake and nutritional status among those with ABI.

METHODS

Routine meal audits were completed (six television on, six television off) over four non-consecutive days. Each individual's protein and energy intake per meal and day were assessed, and the differences were examined through paired t-tests. Dining room decibels were measured, with means, peaks and minimums recorded.

RESULTS

Complete data for 12 meals were collected for seven individuals. Clinically, but not statistically significant increases in 48-hour protein and energy intake occurred with television off compared with on, including those requiring texture modified diets.

CONCLUSIONS

This pilot investigation highlights that television may have a detrimental impact on nutritional intakes among those with ABI. Given the negligible costs and risk, minimising disruptive influences by turning the television off may become a recommendation for ABI in long-care rehabilitation settings.

Advancing the evidence base of rehabilitation treatments: a developmental approach

Translational research refers to the development of new scientific discoveries into evidence-based treatments for human diseases and conditions. This developmental process requires that a number of scientific, as well as social and psychological obstacles, be overcome during a sequence of research stages that address different goals. Rehabilitation, like other biomedical disciplines, requires this kind of developmental process. For a variety of reasons, however, development of rehabilitation treatments is less linear than the familiar phases of pharmaceutical research. In addition, research on treatments intended to address impairments (body structure/function, in terms of the International Classification of Functioning, Disability and Health), faces the challenge of determining the likely impact of an impairment-level treatment on the multifaceted activities and aspects of participation that are the typical goals of rehabilitation treatments. This article describes the application of treatment theory and enablement theory to the development of new impairment-based treatments, and examines similarities and differences between the developmental sequence needed for rehabilitation treatment research versus pharmaceutical research in other areas of medicine.

Can measures of cognitive function predict locomotor behaviour in complex environments following a traumatic brain injury?

PRIMARY OBJECTIVE

To determine the relationships between clinical measures of executive function and attention, and laboratory measures of anticipatory locomotor adaptations with dual tasks following a TBI.

METHODS AND PROCEDURES

Ten people with moderate or severe TBI were compared to 10 healthy subjects for neuropsychological measures in the clinic, as well as locomotor patterns and reading time in the laboratory for adapted Stroop tasks (Bar and Word) during unobstructed and obstructed walking.

MAIN OUTCOMES AND RESULTS

As previously found 1 (Vallee M, McFadyen BJ, Swaine B, Doyon J, Cantin JF, Dumas D. Effects of environmental demands on locomotion after traumatic brain injury. Archives of Physical Medicine Rehabilitation 2006;87:806--813) during the locomotor activities, subjects with TBI walked slower, had higher clearance margins and took longer to read during the Stroop tasks than healthy subjects. In general, subjects with TBI also showed deficits in executive functions and attention. Significant relationships were specifically observed between scores on Trail Making B and clearance margins for subjects with TBI, but not for healthy subjects. Alternatively, significant relationships between clinical scores on Stroop and dual task Stroop reading times were obtained for healthy subjects but not for subjects with TBI.

CONCLUSIONS

These results suggest that measures of executive functioning and attention may be associated to locomotor behaviour in complex environments following a moderate to severe TBI.

Increased inattentional blindness in severe traumatic brain injury: Evidence for reduced distractibility?

PRIMARY OBJECTIVE

To examine the role of selective attention and visual perception in medicating inattentional blindness in a severe traumatic brain injured sample.

RESEARCH DESIGN

Cross-sectional design with age and education matched control sample.

METHODS AND PROCEDURES

Twenty participants with severe traumatic brain injury (n = 10) and matched controls (n = 10) completed a series of tests of focused attention (Stroop test), divided attention (Trail Making Test), visual perception (Visual Object and Space Perception Battery) and two tasks of inattentional blindness.

MAIN OUTCOMES AND RESULTS

The group with severe TBI were significantly slower on the Stroop test and TMT and displayed significantly elevated Stroop interference and TMT ratio scores. On the inattentional blindness tasks, fewer TBI participants identified a distracting stimulus.

CONCLUSION

The results indicate severe TBI is associated with deficits to focused and divided attention with the finding of a potentially more debilitating impairment arising from reduced distractibility following severe TBI.

UFOV performance and driving ability following traumatic brain injury

PRIMARY OBJECTIVE

To investigate the relationship between performance on the Useful Field of View Test (UFOV) and driving performance following traumatic brain injury (TBI).

PARTICIPANTS

Sixty people with TBI referred for driving evaluation.

MEASURES

Useful Field of View Test, Global Rating Scale and Driver Assessment Scale.

RESULTS

Subject performance diminished as the complexity of the UFOV sub-tests increased. There was a significant relationship between UFOV performance, particularly on the second sub-test, and on-road driving performance. Subject age and Trail Making Test, Part B were also predictive of driving performance.

CONCLUSIONS

The UFOV can be used as a screening measure to determine readiness to participate in an on-road driving assessment.

Impulsivity, neural deficits, and the addictions: the "oops" factor in relapse

Impulsive behaviors are observed in a wide range of psychiatric disorders, including substance use, bipolar, attention-deficit hyperactivity, antisocial and borderline personality, gambling, and eating disorders. The shared phenotype of impulsivity is thought to significantly contribute to both the etiology and perpetuation of these disorders. In this review, we focus upon the relevance of impulsivity to the addictive disorders, particularly substance use disorders. First, the literature supporting the presence of impulsive behaviors prior to the onset of drug use and addiction is discussed. The relevance of impulsivity to relapse is then presented, with a focus on three distinct neurocognitive constructs: automaticity, response inhibition, and decision making. Automaticity is a quickly occurring relapse process resulting from the learned habits induced by persistent drug use. Addicted persons with response inhibition deficits are unable to suppress these previously reinforced behaviors. Decision-making deficits contribute to relapse through a poorly considered assessment of the consequences of drug use. The brain regions associated with each model of impulsive behavior are described, and relevant neurobiologic disruptions in addicted subjects are discussed in the context of their specific neurocognitive deficit(s). Descriptive confusions in the terminology and confounds inherent in the study of impulsivity are described. Empirical investigations documenting the hypothesized relationship between specific deficits in impulsive behaviors, coupled with their neurobiological correlates, and relapse should be the focus of future studies.

Head-Mounted Displays for Clinical Virtual Reality Applications: Pitfalls in Understanding User Behavior while Using Technology

The use of virtual environments with head-mounted displays (HMDs) offers unique assets to the evaluation and therapy of clinical populations. However, research examining the effects of this technology on clinical populations is sparse. Understanding how wearers interact with the HMD is vital. Discomfort leads to altered use of the HMD that could confound performance measures; the very measures which might be used as tools for clinical decision making. The current study is a post-hoc analysis of the relationship between HMD use and HMD comfort. The analysis was conducted to examine contributing factors for a high incidence of simulator sickness observed in an HMD-based driving simulator. Pearson correlation analysis was used to evaluate objective and subjective measures of HMD performance and self-reported user comfort ratings. The results indicated weak correlations between these variables, indicating the complexity of quantifying user discomfort and HMD performance. Comparison of two case studies detailing user behavior in the virtual environment demonstrates that selected variables may not capture how individuals use the HMD. The validity and usefulness of the HMD-based virtual environments must be understood to fully reap the benefits of virtual reality (VR) in rehabilitation medicine.

Dimensions of disordered attention in traumatic brain injury: further validation of the Moss Attention Rating Scale

OBJECTIVES

To investigate the factor structure of disordered attention in moderate to severe, acute traumatic brain injury (TBI) and to use factor analysis and item response theory to further validate and refine an observational rating scale of attention for clinical and research purposes.

DESIGN

Multicenter inception cohort.

SETTING

Inpatient rehabilitation units.

PARTICIPANTS

Patients with TBI (N=372) consecutively admitted to 8 Traumatic Brain Injury Model System centers within 2 weeks prior to observation, who consistently followed commands and who were on stable doses of all psychotropic medications for a 3-day rating period.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Participants were rated independently by treating occupational and physical therapists at an average of 1 month postinjury on the Moss Attention Rating Scale (MARS), a 45-item, Likert-type scale of attention-related behavior.

RESULTS

Exploratory and confirmatory factor analyses revealed 3 correlated factors of disordered attention, interpreted as restlessness/distractibility, initiation, and sustained/consistent attention. Item response (Rasch) analysis was used to eliminate redundant items and to fill gaps in item difficulty. The resulting MARS consists of 22 items that can produce 3 factor scores and a total score that covers the broad construct of disordered attention.

CONCLUSIONS

The factor-scored MARS has potential utility as a quantitative observational method with which to assess and study different dimensions of disordered attention in acute TBI, and to monitor change over time and treatment response within these dimensions.

Effects of Environmental Demands on Locomotion After Traumatic Brain Injury

OBJECTIVE

To determine the effects of increasingly demanding environments related to simultaneous visual tasks and physical obstructions on the locomotor ability of people with traumatic brain injury (TBI).

DESIGN

Group comparison study.

SETTING

Gait analysis laboratory within a postacute rehabilitation facility.

PARTICIPANTS

Volunteer sample of 9 people (8 men, 1 woman; age, 39.3+/-13.0y) with moderate to severe TBI and a comparison group of 9 subjects without neurologic problems matched for age and sex (8 men, 1 woman; age, 39.7+/-12.3y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Reading times for the Stroop bar and Stroop word tasks, walking speeds, stride lengths, and obstacle clearance margin.

RESULTS

The TBI group was slower than the control group in performing the Stroop bar task during sitting (P=.002), and while avoiding the narrow obstacle (P=.05), and in performing the Stroop word task while avoiding the wide obstacle (P=.019). Despite their relatively normal gait speeds on level ground, subjects with TBI walked more slowly than control subjects for the narrow (P=.024) and the wide (P=.019) obstacle conditions and for the most complex dual task (P=.042). Greater lead-limb clearance margins were observed for the TBI group than for control subjects for all conditions whereas no differences were found for the trail limb except at the far end of the wide obstacle.

CONCLUSIONS

Despite their good recovery of locomotor function, with respect to normal level walking speeds and ability to avoid obstacles, subjects with moderate and severe TBI showed residual deficits in relation to greater difficulties in dealing with environments that challenge their locomotor and attentional abilities. The use of such naturally based dual tasks may help identify some of the environmental obstructions to social participation after TBI.

Selective attention deficits following severe closed head injury: the role of inhibitory processes

Heightened distractibility following severe closed head injury (sCHI) may result from a deficit in selective attention. The integrity of inhibitory processes involved in selective attention was assessed through use of a negative priming paradigm, allowing dissociation of inhibitory and episodic retrieval processes. In this task, inhibitory processes are elicited under intact stimulus conditions, whereas episodic retrieval is elicited when target stimuli are degraded. Despite inconsistent evidence of inhibitory deficits following sCHI in the literature, long-term survivors of sCHI showed no negative priming under intact stimulus conditions, providing evidence of compromised inhibitory processing. The sCHI participants' demonstration of negative priming when target stimuli were degraded provides evidence that automatic retrieval processes are intact following sCHI, results that are consistent with prior findings.

Effects of Methylphenidate on Attention Deficits After Traumatic Brain Injury

OBJECTIVE

To evaluate the effects of methylphenidate on a variety of aspects of attention, ranging from laboratory-based impairment measures to caregiver ratings and work productivity, in individuals after traumatic brain injury.

DESIGN

A total of 34 adults with moderate to severe traumatic brain injury and attention complaints in the postacute phase of recovery were enrolled in a 6-wk, double-blind, placebo-controlled, repeated crossover study of methylphenidate, administered in a dose of 0.3 mg/kg/dose, twice a day. A wide range of attentional measures was gathered weekly, including computerized and paper-and-pencil tests of attention, videotaped records of individual work in a distracting environment, real-time observational scoring of attentiveness in a classroom environment, and caregiver and clinician rating scales of attentiveness. Participants also attempted to guess their drug condition each week. Data from the first ten participants were used for pilot purposes, to develop attentional factors for composite scoring, and to identify attentional dimensions suggestive of a treatment effect for independent replication. The remaining 24 participants' results were used to confirm potential treatment effects seen in the pilot sample, using Wilcoxon's signed-ranks test on composite factor scores and individual variables.

RESULTS

A total of 54 dependent variables were reduced to 13 composite factors and 13 remaining individual variables. Of the 13 attentional factors, five showed suggestive treatment effects in the pilot sample. Of these, three showed statistically significant treatment effects in the replication sample: speed of information processing (effect sizes, -0.06 to 0.48; P < 0.001), attentiveness during individual work tasks (effect sizes, 0.15-0.62; P = 0.01), and caregiver ratings of attention (effect sizes, 0.44-0.50; P = 0.01). Of the individual variables, four showed suggestive treatment effects in the pilot sample, but only one showed significant treatment effects in the replication sample: reaction time before errors in the Sustained Attention to Response Task (effect size, 0.20; P = 0.03). No treatment-related improvement was seen in divided attention, sustained attention, or susceptibility to distraction. None of the variables showed suggestive or definite negative treatment effects. Effect sizes for those performance measures positively affected by methylphenidate were in the small to medium range and included both impairment and activity level measures. Improvements in processing speed did not seem to come at the expense of accuracy.

CONCLUSIONS

Methylphenidate, at 0.3 mg/kg/dose, given twice a day to individuals with attentional complaints after traumatic brain injury, seems to have clinically significant positive effects on speed of processing, caregiver ratings of attention, and some aspects of on-task behavior in naturalistic tasks. Further research is needed to identify the optimal dose and to extend these findings to less carefully selected individuals.

Effects of practice and unpredictable distractors on planning and executing aiming after stroke

The primary purpose of this study was to examine practice effects on the planning and execution of an aiming movement after right versus left stroke. A secondary purpose was to investigate the effects of a distractor that appeared randomly on motor performance after stroke. Right-hand dominant individuals, 15 with right stroke (right-sided brain damage), 16 with left stroke, and 30 without stroke, performed aiming movements to targets. Those with stroke used the ipsilesional upper extremity (UE). Right and left comparison groups used the right and left UE, respectively. Reaction time (RT) and movement time (MT) were collected to represent movement planning and execution, respectively. Individuals with right stroke improved RT with practice. Individuals with left stroke did not improve RT with practice and made more errors than their comparison group. Those with left stroke achieved faster MT with practice, but MT remained slower than their comparison group. There were no effects of the distractor on RT or MT. Adults with left stroke have persistent deficits in movement planning and execution. Further studies are needed to determine how the performance of older adults, with or without stroke, is affected by an unpredictable visual distractor.

Multisensory integration after traumatic brain injury: a reaction time study between pairings of vision, touch and audition

Traumatic brain injury (TBI) frequently results in deficits in attention and speed of information processing. In order to disentangle the influence of sensory-specific factors and the role of cross-modal integration from the supra-modal aspects of cognitive slowing, the present reaction time (RT) study was designed. Simple and choice RT to pairings of visual, auditory and tactile stimuli were measured in 35 TBI patients and 35 matched controls. Results proved a strong influence of sensory-specific and cross-modal factors in the RTs. The tactile modality was more difficult to integrate with the visual and the auditory modality, rather than the visual and the auditory modalities between them. TBI patients showed prolonged simple and choice RTs throughout all tasks, but their difficulty with integrating the tactile modality was disproportionately higher in comparison to controls.

Fatigue and Attention Following Traumatic Brain Injury

Abstract: Numerous outcome studies have indicated that fatigue is one of the most universal and persistent problems reported following traumatic brain injury (TBI). The present study will examine fatigue following TBI, as reported subjectively, its relationship with demographic and injury-related factors, depression and anxiety, as well as its relationship with measures of attention and mental speed. In a group of 28 TBI participants and 28 controls, TBI participants reported significantly greater fatigue on the Fatigue Severity Scale. Fatigue was greater in those who were older, more educated and a longer time post-injury. Depression was also associated with high fatigue, but not in all cases. The relationship of subjective fatigue with mental speed and attention will be the next focus of this study.

Dissociations within the anterior attentional system: effects of task complexity and irrelevant information on reaction time speed and accuracy

Patients with focal frontal or nonfrontal lesions were compared with control participants on 4 reaction time (RT) tasks varying in levels of complexity based on a feature-integration model of detection. Superior medial lesions affected simple RT speed. Increasing the demands of feature detection did not differentially affect speed of correct responses among the groups. Frontal structures appear to play little role in correct integration of features during detection. The analysis of error types within the complex task revealed a frontal lobe hemispheric distinction between sensitivity and bias: right dorsolateral-decreased sensitivity; left dorsolateral-altered response bias. The frontal lobes, particularly right dorsolateral, were required to inhibit an incorrect response. There are at least 3 functionally and anatomically separable anterior attentional processes.

Useful field of view after traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) survivors often have sensory and cognitive impairments that may interfere with driving ability. The Useful Field of View (UFOV) is a measure of visual information processing that is a good predictor of vehicle crash risk in older adults.

OBJECTIVE

The objective of this study was to explore the possibility that UFOV is compromised after TBI.

DESIGN

UFOV performance of 23 TBI survivors and 18 young adults without neurological impairment were compared.

CONCLUSION

TBI survivors had higher UFOV scores than young adults, which indicated a greater functional loss of peripheral vision. The results suggest that the UFOV may be a valuable instrument for assessing driving readiness in TBI survivors.

Electrophysiological correlates of visual impairments after traumatic brain injury

Our aims were to investigate: (i) the VEP correlates of functional visual impairments following traumatic brain injury (TBI), in particular of the reduced spatial form perception; and (ii) the VEP correlates of visual sustained arousal in TBI patients. We used two approaches: (i) the analysis of latency and amplitude of the peaks; and (ii) the study of the correlations among the latencies of the peaks as a label of temporal synchronization. Thirty-five severe TBI outcome inpatients and 35 matching controls were studied. Pattern-reversal VEPs were recorded at Oz-Fz and Cz-A1, first without counting, then with counting of the reversals. Seven peaks of the waveform at Oz and eight peaks at Cz were measured. We found several differences in amplitude and latency between patients and controls, and between nocount/count. The temporal binding of the peaks within each channel and between the two channels was calculated by correlation matrices, and tested by factor analysis. Results indicated that the synchronization of the peaks within each channel did not differ between patients and controls. The temporal covariation between peaks occurring at Oz and Cz, however, was highly significantly altered in patients. This suggests that visual impairments in TBI patients may be due to a deranged synchronization of the activity of different brain regions.