Rodney D. Vanderploeg

Factors moderating neuropsychological outcomes following mild traumatic brain injury: A meta-analysis

There continues to be debate about the long-term neuropsychological impact of mild traumatic brain injury (MTBI). A meta-analysis of the relevant literature was conducted to determine the impact of MTBI across nine cognitive domains. The analysis was based on 39 studies involving 1463 cases of MTBI and 1191 control cases. The overall effect of MTBI on neuropsychological functioning was moderate (d = .54). However, findings were moderated by cognitive domain, time since injury, patient characteristics, and sampling methods. Acute effects (less than 3 months postinjury) of MTBI were greatest for delayed memory and fluency (d = 1.03 and .89, respectively). In unselected or prospective samples, the overall analysis revealed no residual neuropsychological impairment by 3 months postinjury (d = .04). In contrast, clinic-based samples and samples including participants in litigation were associated with greater cognitive sequelae of MTBI (d = .74 and .78, respectively at 3 months or greater). Indeed, litigation was associated with stable or worsening of cognitive functioning over time. The implications and limitations of these findings are discussed.

The neuropsychological impact of sports-related concussion: A meta-analysis

There is increasing interest in the potential neuropsychological impact of sports-related concussion. A meta-analysis of the relevant literature was conducted to determine the impact of sports-related concussion across six cognitive domains. The analysis was based on 21 studies involving 790 cases of concussion and 2014 control cases. The overall effect of concussion (d = 0.49) was comparable to the effect found in the non-sports-related mild traumatic brain injury population (d = 0.54; Belanger et al., 2005). Using sports-concussed participants with a history of prior head injury appears to inflate the effect sizes associated with the current sports-related concussion. Acute effects (within 24 hr of injury) of concussion were greatest for delayed memory, memory acquisition, and global cognitive functioning (d = 1.00, 1.03, and 1.42, respectively). However, no residual neuropsychological impairments were found when testing was completed beyond 7 days postinjury. These findings were moderated by cognitive domain and comparison group (control group versus preconcussion self-control). Specifically, delayed memory in studies utilizing a control group remained problematic at 7 days. The implications and limitations of these findings are discussed.

Long-term neuropsychological outcomes following mild traumatic brain injury.

Mild traumatic brain injury (MTBI) is common, yet few studies have examined neuropsychological outcomes more than 1 year postinjury. Studies of nonreferred individuals with MTBI or studies with appropriate control groups are lacking, but necessary to draw conclusions regarding natural recovery from MTBI. We examined the long-term neuropsychological outcomes of a self-reported MTBI an average of 8 years postinjury in a nonreferred community-dwelling sample of male veterans. This was a cross-sectional cohort study derived from the Vietnam Experience Study. Three groups matched on premorbid cognitive ability were examined, those who (1) had not been injured in a MVA nor had a head injury (Normal Control; n = 3214), (2) had been injured in a motor vehicle accident (MVA) but did not have a head injury (MVA Control; n = 539), and (3) had a head injury with altered consciousness (MTBI; n = 254). A MANOVA found no group differences on a standard neuropsychological test battery of 15 measures. Across 15 measures, the average neuropsychological effect size of MTBI compared with either control group was -.03. Subtle aspects of attention and working memory also were examined by comparing groups on Paced Auditory Serial Addition Test (PASAT) continuation rate and California Verbal Learning Test (CVLT) proactive interference (PI). Compared with normal controls, the MTBI group evidenced attention problems in their lower rate of continuation to completion on the PASAT (odds ratio = 1.32, CI = 1.0-1.73) and in excessive PI (odds ratio = 1.66, CI = 1.11-2.47). Unique to the MTBI group, PASAT continuation problems were associated with left-sided visual imperceptions and excessive PI was associated with impaired tandem gait. These results show that MTBI can have adverse long-term neuropsychological outcomes on subtle aspects of complex attention and working memory.

Long-term morbidities following self-reported mild traumatic brain injury.

The objective of this study was to examine the prevalence of long-term psychiatric, neurologic, and psychosocial morbidities of self-reported mild traumatic brain injury (MTBI). A cross-sectional cohort sample of three groups was examined: those who had not been injured in a motor vehicle accident nor had a MTBI (n = 3,214); those who had been injured in an accident but did not have a MTBI (n = 539); and those who had a MTBI with altered consciousness (n = 254). Logistic regression analyses were used to model odds ratios for the association between group and outcome variables while controlling demographic characteristics, comorbid medical conditions, and early-life psychiatric problems. Compared with uninjured controls, MTBI increased the likelihood of depression and postconcussion syndrome. MTBI also was associated with peripheral visual imperceptions and impaired tandem gait. Similarly, the MTBI group had poorer psychosocial outcomes including an increased likelihood of self-reported disability, underemployment, low income, and marital problems. Results suggest that MTBI can have adverse long-term psychiatric, neurologic, and psychosocial morbidities.

The effects of depression and anxiety on memory performance

The effects of depression and anxiety, as assessed by MMPI D and Pt scales, on memory performance was examined in 3999 veterans who completed the California Verbal Learning Test (CVLT). Depressive symptoms (without anxiety) had an adverse effect on immediate recall of new information and the total amount (but not rate) of acquisition; however, retrieval and retention were unaffected. On the other hand, high levels of anxiety did not have significant detrimental effects on any aspect of memory functioning assessed including immediate recall, total amount acquired, retention, and retrieval of novel information. However, when depression was compounded by anxiety, there was not only an adverse effect on immediate recall and amount (but not rate) of acquisition, but also on the retrieval of newly learned information. We conclude that the presence of comorbid anxiety may, in part, account for the variability in previous research findings regarding the effects of depression on memory functioning.

Program development and defining characteristics of returning military in a VA Polytrauma Network Site

The conflicts in Iraq and Afghanistan have resulted in a new generation of combat survivors with complex physical injuries and emotional trauma. This article reports the initial implementation of the Polytrauma Network Site (PNS) clinic, which is a key component of the Department of Veterans Affairs (VA) Polytrauma System of Care and serves military personnel returning from combat. The PNS clinic in Palo Alto, California, is described to demonstrate the VA healthcare systems evolving effort to meet the clinical needs of this population. We summarize the following features of this interdisciplinary program: (1) sequential assessment, from initial traumatic brain injury screening throughout our catchment area to evaluation by the PNS clinic team, and (2) clinical evaluation results for the first 62 clinic patients. In summary, this population shows a high prevalence of postconcussion symptoms, posttraumatic stress, poor cognitive performance, head and back pain, auditory and visual symptoms, and problems with dizziness or balance. An anonymous patient feedback survey, which we used to fine-tune the clinic process, reflected high satisfaction with this new program. We hope that the lessons learned at one site will enhance the identification and treatment of veterans with polytrauma across the country.

Neuropsychological performance following a history of multiple self-reported concussions: a meta-analysis.

Debate continues about the long-term neuropsychological impact of multiple mild traumatic brain injuries (MTBI). A meta-analysis of the relevant literature was conducted to determine the impact of having a history of more than one self-reported MTBI (versus just one MTBI) across seven cognitive domains, as well as symptom complaints. The analysis was based on 8 studies, all conducted with athletes, involving 614 cases of multiple MTBI and 926 control cases of a single MTBI. The overall effect of multiple MTBI on neuropsychological functioning was minimal and not significant (d = 0.06). However, follow-up analyses revealed that multiple self-reported MTBI was associated with poorer performance on measures of delayed memory and executive functioning. The implications and limitations of these findings are discussed.

Assessment and diagnosis of mild traumatic brain injury, posttraumatic stress disorder, and other polytrauma conditions: burden of adversity hypothesis.

OBJECTIVE/METHOD Military personnel returning from Iraq and Afghanistan have been exposed to physical and emotional trauma. Challenges related to assessment and intervention for those with posttraumatic stress disorder (PTSD) and/or history of mild traumatic brain injury (TBI) with sequelae are discussed, with an emphasis on complicating factors if conditions are co-occurring. Existing literature regarding cumulative disadvantage is offered as a means of increasing understanding regarding the complex symptom patterns reported by those with a history of mild TBI with enduring symptoms and PTSD. IMPLICATIONS The importance of early screening for both conditions is highlighted. In addition, the authors suggest that current best practices include treating symptoms regardless of etiology to decrease military personnel and veteran burden of adversity.

Symptom Complaints Following Combat-Related Traumatic Brain Injury: Relationship to Traumatic Brain Injury Severity and Posttraumatic Stress Disorder

Patients with a history of mild (n = 134) or moderate-to-severe (n = 91) TBI were asked to complete the Neurobehavioral Symptom Inventory (NSI) and the Posttraumatic Stress Disorder Checklist. Consistent with prior research, significantly more postconcussion symptoms were endorsed by the mild group. After controlling for age, time since injury, and mechanism of injury, TBI severity continued to be significantly related to postconcussion complaints on the NSI. However, after controlling for these same variables, along with posttraumatic stress disorder symptom severity, there no longer were differences between the TBI severity groups. That is, patients with mild TBI did not endorse significantly more complaints (adjusted mean = 22.4) than the moderate-to-severe group (adjusted mean = 21.8). These findings suggest that much of the symptom complaints in mildly injured patients may be due to emotional distress.

Judgements of emotion in words and faces: ERP correlates

Visual event-related potentials (ERPs) to two types of stimuli (faces and words) were analyzed to determine the effects of the perceived emotional connotations of the stimuli (positive, neutral, or negative) in 10 right-handed normal functioning adult males. Principal component analysis (PCA) of the ERPs reveals 5 factors accounting for over 90% of the ERP waveform variance for both faces and words. In the facial data, two ERP components varied in amplitude according to the perceived emotional connotation of the stimulus. For the P3 component, neutrally rated stimuli produced significantly larger amplitudes than stimuli rated as positive or negative. This effect was lateralized to the left hemisphere. A later positive component, the slow wave (448-616 ms), manifested complementary effects, i.e. faces perceived as positive and negative produced larger amplitudes than those perceived as neutral over the right hemisphere. The verbal stimuli did not result in significant main effects for perceived emotional connotation, but produced subtle connotation-related differences in slow wave topography. Hemispheric asymmetries, unrelated to affective connotation, were evident in the verbal data, manifesting different patterns of lateralization depending on the ERP component. The results suggest that differential processing of emotional connotation affects ERP waveforms and that the effects can be understood in terms of ERP components known to be associated with more general aspects of cognitive processing.