Catherine Willmott

Factors influencing outcome following mild traumatic brain injury in adults

This study aimed to investigate outcome in adults with mild traumatic brain injury (TBI) at 1 week and 3 months postinjury and to identify factors associated with persisting problems. A total of 84 adults with mild TBI were compared with 53 adults with other minor injuries as controls in terms of postconcussional symptomatology, behavior, and cognitive performance at 1 week and 3 months postinjury. At 1 week postinjury, adults with mild TBI were reporting symptoms, particularly headaches, dizziness, fatigue, visual disturbance, and memory difficulties. They exhibited slowing of information processing on neuropsychological measures, namely the WAIS-R Digit Symbol subtest and the Speed of Comprehension Test. By 3 months postinjury, the symptoms reported at 1 week had largely resolved, and no impairments were evident on neuropsychological measures. However, there was a subgroup of 24% of participants who were still suffering many symptoms, who were highly distressed, and whose lives were still significantly disrupted. These individuals did not have longer posttraumatic amnesia (PTA) duration. They were more likely to have a history of previous head injury, neurological or psychiatric problems, to be students, females, and to have been injured in a motor vehicle accident. The majority were showing significant levels of psychopathology. A range of factors, other than those directly reflecting the severity of injury, appear to be associated with outcome following mild TBI.

Impact of early intervention on outcome following mild head injury in adults

Background: The impact of mild head injury is variable and determinants of outcome remain poorly understood. Results of previous intervention studies have been mixed. Objectives: To evaluate the impact on outcome of the provision of information, measured in terms of reported symptoms, cognitive performance, and psychological adjustment three months postinjury. Methods: 202 adults with mild head injury were studied: 79 were assigned to an intervention group and were assessed one week and three months after injury; 123 were assigned to a non-intervention control group and were seen at three months only. Participants completed measures of preinjury psychological adjustment, concurrent life stresses, post-concussion symptoms, and tests of attention, speed of information processing, and memory. Subjects seen at one week were given an information booklet outlining the symptoms associated with mild head injury and suggested coping strategies. Those seen only at three months after injury did not receive this booklet. Results: Patients in the intervention group who were seen at one week and given the information booklet reported fewer symptoms overall and were significantly less stressed at three months after the injury. Conclusions: The provision of an information booklet reduces anxiety and reporting of ongoing problems.

Self-awareness following traumatic brain injury and implications for rehabilitation.

Primary objective : Many studies investigating self-awareness following traumatic brain injury (TBI) have been conducted more than 2 years post-injury, thereby providing limited information regarding the implications of insight for rehabilitation. The present study aimed to investigate awareness of deficits in a group of patients who were less than 2 years post-injury and still involved in rehabilitation. Research design : Thirty patients with a history of moderate or severe TBI and their significant other (SO) were studied in a cross-sectional analysis. A sub-group also participated in an interdisciplinary Memory Group at the Bethesda Rehabilitation Centre. Methods and procedures : Level of insight was measured by the degree of agreement between self and significant other (SO) report on the Awareness of Deficit questionnaire (ADQ), assessing various domains of daily functioning. Results : There was substantial agreement between patients and their SO, although the patients with TBI were less likely to acknowledge executive problems. Interestingly, both groups reported only low-to-moderate levels of difficulty. Conclusions : The data indicate that SOs awareness may also be limited in the early recovery stages. A sub-group of the patients obtained benefit from participation in the Memory Group in a rehabilitation setting.

Efficacy of methylphenidate in the rehabilitation of attention following traumatic brain injury: a randomised, crossover, double blind, placebo controlled inpatient trial

Objectives: Most previous studies evaluating the use of methylphenidate following traumatic brain injury (TBI) have been conducted many years post-injury. This study evaluated the efficacy of methylphenidate in facilitating cognitive function in the inpatient rehabilitation phase. Methods: 40 participants with moderate–severe TBI (mean 68 days post-injury) were recruited into a randomised, crossover, double blind, placebo controlled trial. Methylphenidate was administered at a dose of 0.3 mg/kg twice daily and lactose in identical capsules served as placebo. Methylphenidate and placebo administration was randomised in a crossover design across six sessions over a 2 week period. Primary efficacy outcomes were neuropsychological tests of attention. Results: No participants were withdrawn because of side effects or adverse events. Methylphenidate significantly increased speed of information processing on the Symbol Digit Modalities Test (95% CI 0.30 to 2.95, Cohen’s d = 0.39, p = 0.02), Ruff 2 and 7 Test—Automatic Condition (95% CI 1.38 to 6.12, Cohen’s d = 0.51, p = 0.003), Simple Selective Attention Task (95% CI −58.35 to −17.43, Cohen’s d = 0.59, p = 0.001) and Dissimilar Compatible (95% CI −70.13 to −15.38, Cohen’s d = 0.51, p = 0.003) and Similar Compatible (95% CI −74.82 to −19.06, Cohen’s d = 0.55, p = 0.002) conditions of the Four Choice Reaction Time Task. Those with more severe injuries and slower baseline information processing speed demonstrated a greater drug response. Conclusions: Methylphenidate enhances information processing speed in the inpatient rehabilitation phase following TBI. This trial is registered with the Australian New Zealand Clinical Trials Registry (12607000503426).

Use of the Westmead PTA scale to monitor recovery of memory after mild head injury

Study objective: Duration of post-traumatic amnesia (PTA) is an important index of severity of head injury. Retrospective assessment of PTA duration is arguably unreliable. Existing objective measures of PTA duration are designed for use over a 24-hour timeframe and, therefore, are not useful for assessing PTA following mild head injury (MHI). A revised version of the Westmead PTA scale was developed for assessing patients with MHI in the Emergency Department (ED) at hourly intervals. The objective of this study was the field testing of this scale in EDs and assessment of validity and reliability of test items. Methods: The scale contained 12 items, assessing orientation, memory for a face and name in a photograph and three pictures of objects. This revised scale, administered by nursing staff, was completed at least four times at hourly intervals by 147 adults with MHI in the ED and again at follow-up 1 week later. It was also completed by 109 demographically similar controls. Results were compared with Glasgow Coma scores and retrospective estimates of PTA duration based on patient report and medical records. Results: Thirty-six per cent of MHI participants made errors on the scale in the ED, a significantly greater proportion than in MHI or controls at follow-up. Removal of the items 5 (day of week) and 9 (recall of name of face in photograph) improved the validity of the measure significantly. Scores correlated significantly with Glasgow Coma Scale scores and estimated duration of PTA. Conclusion: The Westmead Scale (minus items 5 and 9) is a valid measure of PTA duration in adult patients with MHI in ED. Its use will allow for more appropriate timing of discharge and accurate prognostic information.

Factors contributing to attentional impairments after traumatic brain injury.

The aim of the present study was to investigate the contribution of impaired information processing speed and strategic control of attention to performance on attentional tasks after traumatic brain injury (TBI). Forty moderately to severely injured rehabilitation inpatients and 40 healthy controls completed a selection of attentional tasks. Slowed processing speed in the TBI group was identified on the Symbol Digit Modalities Test (SDMT), 2&7 Selective Attention Test (2&7), Selective Attention (SAT), and Four Choice Reaction Time (4CRT) tasks. Impaired working memory was evident on the Letter Number Sequencing (LNS) task. Structural equation modeling revealed that the group difference in RT on the complex SAT was accounted for by slowed speed of processing on the simple SAT, and not working memory. TBI participants made more errors and missed responses on the complex version of the SAT, suggesting impairment in some aspects of strategic control of attention, and appeared unable to benefit from the automatic condition of the 2&7 Test. There was little evidence of deficit on the Sustained Attention to Response Task (SART). The present study provides evidence for a significant contribution of slowed processing speed to impaired performance on attentional tasks after TBI.

Higher levels of mobility are associated with greater societal participation and better quality-of-life

Introduction: Participation rates and quality-of-life (QoL) have been a major focus of rehabilitation programmes and outcome studies following traumatic brain injury (TBI). The extent to which mobility limitations impact on participation rates and QoL has not been thoroughly explored. The main aim of this study was to investigate the relationship between mobility limitations, participation rates and QoL following TBI. Methods: Thirty-nine people who had sustained an extremely severe TBI were recruited from a major rehabilitation facility. Mobility was quantified using the high-level mobility assessment tool (HiMAT). The Brain Injury Community Rehabilitation Outcome (BICRO-39) and Community Integration Questionnaire (CIQ) were used to measure participation rates and the shorter version of the World Health Organization Quality of Life (WHOQoL-BREF) and Assessment of Quality-of-Life (AQoL-2) were used to measure QoL. Results: Mobility was most strongly correlated with the total BICRO-39 score (r = −0.60, p < 0.001) and the mobility domain (r = −0.59, p < 0.001) of the BICRO-39. Although mobility had a significant relationship with health-related QoL, AQoL-2 (r = 0.60, p < 0.001), it was most strongly related to the AQoL-2 independent living domain (r = 0.79, p < 0.001). Conclusion: Greater capacity to mobilize was associated with higher participation rates and better QoL.

Hand-hemispace spatial compatibility, precueing, and stimulus-onset asynchrony.

SummaryThe role of attention and the resolution of coding conflicts in hand-hemispace spatial-compatibility effects was examined in a precueing experiment in which visual and vibrotactile precues, with various stimulus-onset asynchronies (SOAs), were presented in blocked and random order. It was expected that precues at the shorter SOAs would fail to facilitate the shifting of attention, as they occur too close to the imperative stimulus to be informative. The task would therefore approximate one of choice reaction time (RT), resulting in a hand-hemispace spatial-compatibility effect. Conversely, the longer SOAs would provide the subject with sufficient time in which to shift attention fully, and would therefore result in a task more like that of simple reaction time (SRT). It was expected that the hand-hemispace spatial-compatibility effect would then be absent. As was expected, this effect was present at the shorter SOAs, and absent at the longer SOAs. In Experiments 2 and 3, provision of a visual precue further facilitated attentional deployment, as did blocking the presentation of various SOAs in Experiment 3. Vibrotactile and visual precues did not differ in their ability to direct attention, implying that these modalities orient attention and precue location in essentially similar ways. These findings are discussed within the context of the mechanisms thought to underlie the time course of spatial compatibility and the dissipation of a fading trace of interfering spatial codes.

SAFETY OF METHYLPHENIDATE FOLLOWING TRAUMATIC BRAIN INJURY: IMPACT ON VITAL SIGNS AND SIDE-EFFECTS DURING INPATIENT REHABILITATION

OBJECTIVE The aim of the present study was to evaluate the safety of methylphenidate administered during inpatient rehabilitation following traumatic brain injury. METHODS Forty inpatients with moderate-severe traumatic brain injury (mean 68.4 days post-injury) participated in a randomized, cross-over, double-blind, placebo-controlled trial of methylphenidate administered at a dose of 0.3 mg/kg body weight twice daily. RESULTS Methylphenidate administration resulted in a statistically significant increase in pulse of 12.3 beats/min (95% confidence interval (CI) 9.25-15.36), diastolic blood pressure of 4.1 mmHg (95% CI 2.11-6.10), and mean arterial pressure of 3.75 mmHg (95% CI 1.79-5.72). These changes did not, however, appear to be symptomatic, as no participants were withdrawn due to adverse events, and there was no significant self-report of increased heart rate with methylphenidate. Blinding was successful. Significantly greater reporting of irritability of 0.14 points (95% CI 0.02-0.26), difficulty sleeping of 0.17 points (95% CI 0.02-0.31) and total side-effects of 0.68 points (95% CI 0.06-1.30) was associated with methylphenidate compared with placebo. CONCLUSION Methylphenidate given at 0.3 mg/kg body weight appears to be safe in the inpatient rehabilitation phase. This trial is registered with the Australian New Zealand Clinical Trials Registry (12607000503426).

Speed of processing and strategic control of attention after traumatic brain injury

Introduction: Slowed information processing speed has consistently been documented after traumatic brain injury (TBI). Debate continues as to whether deficits in strategic control are proportionate to, or remain after controlling for, reduced speed of processing. The study aim was to investigate the association of speed of processing and strategic control of attention with working memory, selective attention, response inhibition, and mental flexibility task performance after TBI using traditional and novel clinical measures. Method: Twenty-five individuals with complicated mild to severe TBI (post-traumatic amnesia duration, M = 39.52 days, SD = 38.34; worst Glasgow Coma Scale score, M = 7.33, SD = 4.35; time post-injury, M = 392.64 days, SD = 537.19) and 25 matched healthy controls completed assessment of attentional and executive functioning. Measures included the Symbol Digit Modalities Test (SDMT), the computerized Selective Attention Task (SAT), the Ruff 2&7 Selective Attention Test (2&7), the visual n-back, Digit Span, Hayling Test, and Trail Making Test (TMT). Results: t tests revealed that individuals with TBI demonstrated reduced processing speed on the SDMT, n-back, SAT, 2&7, Hayling Test, and TMT-A (p ≤ .002 for all). Digit Span performance did not differ between groups. Mixed-model ANOVAs revealed that individuals with TBI demonstrated a disproportionate increase in reaction time with complexity, which was accounted for by speed on the SAT but remained on the Hayling Inhibition Test after controlling for speed in ANCOVAs. Mann-Whitney U tests revealed that individuals with TBI also made more errors on the Hayling Test, missed responses on the n-back and were unable to benefit from the automatic condition of the 2&7. Conclusions: While slowed speed of information processing was pervasive across tasks after TBI, residual difficulties in response inhibition remained after controlling for slowness, which suggests impaired strategic control. These findings support targeted intervention for slowed speed of thinking and inhibition following TBI.