Frequency and duration of inattentive behavior after traumatic brain injury: effects of distraction, task, and practice

Attention and Communication Following TBI: Making the Connection through a Meta-Narrative Systematic Review

BACKGROUND AND AIM

Communication difficulties are one of the hallmark characteristics of adults following traumatic brain injury (TBI), a difficulty that incorporates multiple aspects of cognition and language. One aspect of cognition that impacts communication is attention. This review explores both attention and communication following moderate to severe TBI and aims to connect them through a narrative analysis of the discourse surrounding the terms and how they have evolved over time. This includes exploring and reviewing theories and specific constructs of these two aspects of cognition.

METHOD

A meta-narrative systematic literature review was completed according to RAMESES methodology.

RESULTS

A total of 37 articles were included in the review. The disciplines that populated the articles included, but were not limited to, speech language pathology (SLP) 36.5%, psychology 23.8%, and a collaboration of neuropsychology and SLP 7.9%. Of the papers that were included, 10% explored and supported theories of attention related to executive function affecting communication. Specific levels of attention were mapped onto specific communication skills with the corresponding year and authors to create a timeline and narrative of these concepts.

CONCLUSIONS

The main communication behaviours that are related to attention in the context of post-TBI cognition include discourse, tangential communication, social communication, auditory comprehension, verbal reasoning, topic maintenance, interpretation of social cues and emotions, verbal expression, reading comprehension, verbal response speed, and subvocal rehearsal.

Relationship Between Physiologically Measured Attention and Behavioral Task Engagement in Persons With Chronic Aphasia

Purpose Persons with aphasia (PWAs) have been shown to have impaired attention skills that may interfere with their ability to successfully participate in speech and language therapy. Fluctuations in attention can be detected using physiological measures such as electroencephalography (EEG), but these measures can be impractical for clinical use. The primary purpose of this study was to investigate observable behavioral signs of attention as a means of measuring within-session fluctuations in attention by comparing behavioral ratings to physiological changes. Other aims were to understand the relationship between observable behaviors and task performance and to determine whether syntactic complexity influences behavioral attention. Method Ten PWAs and 10 neurologically healthy adults underwent a sentence-reading task with 45 active and 45 passive sentences while video/audio and EEG data were recorded continuously. EEG data for each trial were classified into one of four levels of attention using a classification algorithm (Berka et al., 2004), and video/audio data were scored for accuracy and behavioral engagement by two trained speech-language pathologist students using a behavioral rating scale of inattention (Whyte et al., 1996). Results Results showed that behavioral engagement was significantly correlated with task performance, with higher engagement scores associated with fewer errors. Behavioral engagement did not differ based on syntactic complexity for either group, but PWAs had significantly lower behavioral engagement scores when they were in lower/distracted states of physiologically measured vigilant attention. Conclusion Behavioral observation may provide an alternative means of detecting clinically significant lapses in attention during aphasia therapy.

The inter-relationship between acquired brain injury, substance use and homelessness; the impact of adverse childhood experiences: an interpretative phenomenological analysis study

PURPOSE

Acquired Brain Injuries, caused by a range of illnesses and injuries, can lead to long-term difficulties for individuals; mental health problems, cognitive and executive impairment and psychosocial problems including relationship breakdown, substance abuse and potentially homelessness. The study aimed to seek and gain a more definitive understanding of the inter-relationship of Acquired Brain Injury, substance abuse and homelessness by identifying key themes associated with the inter-relationship between these variables.

MATERIALS AND METHODS

The study recruited eight participants through homeless organisations and treatment centres. Participants were screened for suitability (Brain Injury Screening Index; Drug Abuse Screening Tool; Alcohol Use Disorders Identification Test and then participated in recorded semi-structured interviews, transcribed and analysed using Interpretative Phenomenological Analysis.

RESULTS

The study identified five master themes: Adverse Childhood Experiences and Trauma; Mental Health; Cognitive Decline and Executive Function; Services; Relationships.

CONCLUSION

Healthcare professionals need to engage with children, their families, and adults, who have been exposed to adverse childhood experiences and should employ routine screening tools for brain injury to ensure their presence is factored into developing appropriate models of intervention.IMPLICATIONS FOR REHABILITATIONNeed person-centred approaches to intervention for those with acquired brain injury who are homeless and have substance abuse issues.Need to screen for the presence of acquired brain injury when engaging with individuals who are homeless or have substance abuse.Need screening of acquired brain injury and adverse childhood experiences to improve access to services post-brain injury.

NIH toolbox cognition tests following traumatic brain injury: Frequency of low scores

PURPOSE/OBJECTIVE

To apply multivariate base rate analyses to the National Institutes of Health Toolbox Cognition Battery (NIHTB-CB) to facilitate the identification of cognitive impairment in individuals with traumatic brain injury (TBI). Research Method/Design: In a multisite cross-sectional design, 158 participants who sustained a complicated mild or moderate TBI (n = 74) or severe TBI (n = 84) at least 1 year earlier were administered the NIHTB-CB. The NIHTB-CB is comprised of 2 crystallized cognition tests (reflecting premorbid ability) and 5 fluid cognition tests, measuring processing speed, memory, and executive functioning. Base rates for obtaining 0 to 5 low fluid cognition scores were calculated across a range of cutoffs for defining a low test score (≤25th to 5th percentiles). Base rates of low scores in the TBI sample were compared to the NIHTB-CB normative sample using diagnostic accuracy statistics.

RESULTS

The proportion of the TBI sample obtaining low scores decreased as the cutoff for defining a low score decreased. Individuals with lower premorbid cognitive ability, as measured by NIHTB-CB Crystallized Composite score, tended to produce more low scores on the NIHTB-CB fluid cognition tests, even when using fully demographically adjusted scores. Certain patterns of low scores were associated with TBI (defined as likelihood ratio >2.0), whereas others were nonspecific, occurring almost as often in participants without TBI.

CONCLUSIONS/IMPLICATIONS

Premorbid ability stratified base rate tables provided in this article can guide researchers and clinicians in the interpretation of NIHTB-CB performance in adults with TBI. (PsycINFO Database Record

Ecologically relevant outcome measure for post-inpatient rehabilitation

BACKGROUND

Transfer of skills learned within the clinic environment to patients' home or community is important in post-inpatient brain injury rehabilitation (PBIR). Outcome measures used in PBIR assess level of independence during functional tasks; however, available functional instruments do not quantitate the environment in which the behaviors occur.

OBJECTIVE

To examine the reliability and validity of an instrument used to assess patients' functional abilities while quantifying the amount of structure and distractions in the environment.

METHODS

2501 patients who sustained a traumatic brain injury (TBI) or cerebrovascular accident (CVA) and participated in a multidisciplinary PBIR program between 2006 and 2014 were identified retrospectively for this study. The PERPOS and MPAI-4 were used to assess functional abilities at admission and at discharge. Construct validity was assessed using a bivariate Spearman rho analysis A subsample of 56 consecutive admissions during 2014 were examined to determine inter-rater reliability. Intra-class correlation coefficient (ICC) and Kappa coefficients assessed inter-rater agreement of the total PERPOS and PERPOS subscales respectively.

RESULTS

The PERPOS and MPAI-4 demonstrated a strong negative association among both TBI and CVA patients. Kappa scores for the three PERPOS scales each demonstrated good to excellent inter-rater agreement. The ICC for overall PERPOS scores fell in the good agreement range.

CONCLUSION

The PERPOS can be used reliably in PBIR to quantify patients' functional abilities within the context of environmental demands.

Inattention, Working Memory, and Goal Neglect in a Community Sample

Executive function deficits have been linked to attention deficit hyperactivity disorder (ADHD), but it has been theorized that the symptom inattention is specifically related to problems with complex verbal working memory (WM). Using the Conners Adult ADHD rating scale, adults aged 18–35 were assessed for ADHD symptoms, and completed tasks designed to tap verbal and spatial aspects of WM (Experiment 1). Results showed that high inattention predicted poor performance on both simple and complex verbal WM measures. Results relating to spatial WM were inconclusive. In a follow up experiment based on the theory that those with inattention have problems receiving verbal instructions, a measure of goal neglect assessing integration of information into a task model in WM was employed (Experiment 2). Results showed that high inattention uniquely predicted performance on this task, representing the first reported association between inattention and the phenomenon of goal neglect. The results from both experiments lend support to the WM theory of inattention.

A perfusion fMRI study of the neural correlates of sustained-attention and working-memory deficits in chronic traumatic brain injury

BACKGROUND

Given that traumatic brain injury (TBI) results in chronic alteration of baseline cerebral perfusion, a perfusion functional MRI (fMRI) method that dissociates resting- and task-related cerebral blood flow (CBF) changes can be useful in noninvasively investigating the neural correlates of cognitive dysfunction and recovery in TBI.

OBJECTIVE

The authors used continuous arterial spin-labeled (ASL) perfusion fMRI to characterize CBF at rest and during sustained-attention and working-memory tasks.

METHODS

A total of 18 to 21 individuals with moderate to severe TBI and 14 to 18 demographically matched healthy controls completed 3 continuous 6-minute perfusion fMRI scans (resting, visual sustained attention, and 2-back working memory).

RESULTS

For both tasks, TBI participants showed worse behavioral performance than controls. Voxelwise neuroimaging analysis of the 2-back task found that group differences in task-induced CBF changes were localized to bilateral superior occipital cortices and the left superior temporal cortex. Whereas controls deactivated these areas during task performance, TBI participants tended to activate these same areas. These regions were among those found to be disproportionately hypoperfused at rest after TBI. For both tasks, the control and TBI groups showed different patterns of correlation between performance and task-related CBF changes.

CONCLUSIONS

ASL perfusion fMRI demonstrated differences between individuals with TBI and healthy controls in resting perfusion and in task-evoked CBF changes as well as different patterns of performance-activation correlation. These results are consistent with the notion that sensory/attentional modulation deficits contribute to higher cognitive dysfunction in TBI.

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.

Alpha-2 adrenergic challenge with guanfacine one month after mild traumatic brain injury: altered working memory and BOLD response

Alterations in working memory (WM) are common after traumatic brain injury (TBI). Frontal catecholaminergic systems, including the alpha-2 adrenergic system, modulate WM function and may be affected in TBI. We hypothesized that administration of an alpha-2 adrenergic agonist might improve WM after mild TBI (MTBI). Thirteen individuals with MTBI 1month after injury and 14 healthy controls (HC) were challenged with guanfacine and placebo prior to administration of a verbal WM functional MRI task. Guanfacine was associated with improved WM performance in the MTBI but not the HC group. On guanfacine the MTBI group showed increased activation within a WM task-specific region of interest. Findings are consistent with the hypothesis that alterations in WM after MTBI may be improved with the alpha-2 agonist guanfacine.

Dopaminergic challenge with bromocriptine one month after mild traumatic brain injury: altered working memory and BOLD response

Catecholamines, particularly dopamine, modulate working memory (WM). Altered sensitivity to dopamine might play a role in WM changes observed after traumatic brain injury (TBI). Thirty-one healthy controls (HC) and 26 individuals with mild TBI (MTBI) 1 month after injury were challenged with bromocriptine versus placebo before administration of a verbal WM functional MRI task. Bromocriptine was associated with improved WM performance in the HC but not the MTBI group. On bromocriptine, the MTBI group showed increased activation outside of a task-specific region of interest. Findings are consistent with the hypothesis that individuals with MTBI have altered responsivity to dopamine.

Neuropsychological assessment in traumatic brain injury

Traumatic brain injury (TBI) is a neurological injury that can affect the cognitive, emotional, psychological, and physical functioning of an individual. The clinical neuropsychologist working with TBI patients must take a holistic approach when assessing and treating the patient and consider the patient in total, including premorbid and post-incident factors, to formulate a comprehensive and accurate picture of the patient. This approach will guide the clinician regarding multiple types of treatment the patient may require.

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.

Effects of auditory distraction on cognitive processing of young adults

OBJECTIVE

The effects of interference, competition, and distraction on cognitive processing are unclearly understood, particularly regarding type and intensity of auditory distraction across a variety of cognitive processing tasks.

METHOD

The purpose of this investigation was to report two experiments that sought to explore the effects of types of distraction (4-talker babble; word repetition; combined 4-talker babble with word repetition) when compared to a control condition of quiet on a range of computerized measures (simple reaction time; choice reaction time; serial pattern matching; lexical decision-making; visual selective attention; response reversal and rapid visual scanning; and form discrimination) in 40 young adults (Experiment 1).

RESULTS

Few distraction effects were found on cognitive processing at the comfortable loudness level (40dB SL). In Experiment 2, statistically significant differences for choice reaction time and serial pattern matching (working memory) were found in both speed and accuracy when distractions were presented at perceived uncomfortable loudness levels (ULL) and compared with conditions of quiet and comfortable loudness level (40dB SL).

CONCLUSION

Cognitive resource allocation models may be useful in interpreting the effects of auditory distraction on cognitive-linguistic processing, and this model may help to explain differential distraction effects in clinical populations with attention deficits.

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.

Response Inhibition After Traumatic Brain Injury (TBI) in Children: Impairment and Recovery

Children who experience traumatic brain injury (TBI) often show cognitive impairments postinjury, some of which recover over time. We examined the recovery of motor response inhibition immediately following TBI and over 2 years. We assessed the role of injury severity, age at injury, and lesion characteristics on initial impairment and recovery while considering the role of pre-injury psychiatric disorder. Participants were 136 children with TBI aged 5-16 years. Latency of motor response inhibition was measured with the stop-signal task within 1 month of the injury and again at 3, 6, 12, and 24 months. The performance of the TBI participants at each measurement occasion was standardized with 117 children of similar age, but without injury. Residualized latency scores were calculated. Growth curve analyses showed an initial impairment in response inhibition and improvement over the 2 years following injury. Younger TBI patients were initially more impaired although they exhibited greater recovery of response inhibition than did older TBI patients. Longer duration of coma, but not reactivity of pupils or Glasgow Coma Scale score, predicted initial deficit. Lesion characteristics or pre-injury attention deficit hyperactivity disorder did not predict initial impairment or recovery. Replication with longitudinal testing of a comparison group of children sustaining extracranial injury is necessary to confirm our findings.

Closed head injury and perceptual processing in dual-task situations

Using a classical psychological refractory period (PRP) paradigm we investigated whether increased interference between dual-task input processes is one possible source of dual-task deficits in patients with closed-head injury (CHI). Patients and age-matched controls were asked to give speeded motor reactions to an auditory and a visual stimulus. The perceptual difficulty of the visual stimulus was manipulated by varying its intensity. The results of Experiment 1 showed that CHI patients suffer from increased interference between dual-task input processes, which is related to the salience of the visual stimulus. A second experiment indicated that this input interference may be specific to brain damage following CHI. It is not evident in other groups of neurological patients like Parkinson's disease patients. We conclude that the non-interfering processing of input stages in dual-tasks requires cognitive control. A decline in the control of input processes should be considered as one source of dual-task deficits in CHI patients.

Effects of ambient stimuli on measures of behavioral state and microswitch use in adults with profound multiple impairments

The effects of different types and amounts of environmental stimuli (visual and auditory) on microswitch use and behavioral states of three individuals with profound multiple impairments were examined. The individual's switch use and behavioral states were measured under three setting conditions: natural stimuli (typical visual and auditory stimuli in a recreational situation), reduced visual stimuli, and reduced visual and auditory stimuli. Results demonstrated differential switch use in all participants with the varying environmental setting conditions. No consistent effects were observed in behavioral state related to environmental condition. Predominant behavioral state scores and switch use did not systematically covary with any participant. Results suggest the importance of considering environmental stimuli in relationship to switch use when working with individuals with profound multiple impairments.

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.

Traumatic brain injury research: a review of clinical studies

There is a growing volume of research on trauma brain injury (TBI) as evidenced by a recent Medline search that reported over 6000 articles published on TBI in the past 5 years.