The Association of Cognitive Reserve in Chronic-Phase Functional and Neuropsychological Outcomes Following Traumatic Brain Injury.

OBJECTIVE: Examine the association of cognitive reserve (CR) factors (estimated premorbid intelligence quotient [IQ], years of education, and occupational attainment) and traumatic brain injury (TBI) severity with functional and neuropsychological outcomes 1 to 5 years following TBI. PARTICIPANTS: Patients with mild (N = 58), moderate (N = 25), or severe (N = 17) TBI. MAIN MEASURES: Cognitive reserve factors (estimated premorbid IQ, years of education, and occupational attainment); neuropsychological test battery; Glasgow Outcome Scale-Extended; Short Form-36 Health Survey. ANALYSES: Spearman-Brown correlations, linear regression models, and analyses of covariance were used to analyze the relation between CR factors and outcome measures. RESULTS: Analyses revealed significant relations between estimated premorbid IQ and neuropsychological outcomes (P < .004): California Verbal Learning Test, Wechsler Adult Intelligence Scale-Fourth Edition working memory, Booklet Category Test, Trail Making Test B, and Grooved Pegboard Test. There was also a significant correlation between estimated premorbid IQ and Wechsler Adult Intelligence Scale-Fourth Edition processing speed. Years of education had significant relations with California Verbal Learning Test and Wechsler Adult Intelligence Scale-Fourth Edition working memory and processing speed scores. There were significant differences between TBI severity groups and performance on the Trail Making Test A, Grooved Pegboard Test, and Finger Tapping Test. CONCLUSIONS: Cognitive reserve factors may be associated with outcomes following TBI. Additional alternatives to TBI severity are needed to help guide rehabilitative planning postinjury.

Effects of a rapid-resisted elliptical training program on motor, cognitive and neurobehavioral functioning in adults with chronic traumatic brain injury.

This small clinical trial utilized a novel rehabilitation strategy, rapid-resisted elliptical training, in an effort to increase motor, and thereby cognitive, processing speed in ambulatory individuals with traumatic brain injury (TBI). As an initial step, multimodal functional abilities were quantified and compared in 12 ambulatory adults with and 12 without TBI. After the baseline assessment, the group with TBI participated in an intensive 8-week daily exercise program using an elliptical trainer and was reassessed after completion and at an 8-week follow-up. The focus of training was on achieving a fast movement speed, and once the target was reached, resistance to motion was increased in small increments to increase intensity of muscle activation. Primary outcomes were: High-Level Mobility Assessment Tool (HiMAT), instrumented balance tests, dual-task (DT) performance and neurobehavioral questionnaires. The group with TBI had poorer movement excursion during balance tests and poorer dual-task (DT) performance. After training, balance reaction times improved and were correlated with gains in the HiMAT and DT. Sleep quality also improved and was correlated with improved depression and learning. This study illustrates how brain injury can affect multiple linked aspects of functioning and provides preliminary evidence that intensive rapid-resisted training has specific positive effects on dynamic balance and more generalized effects on sleep quality in TBI.

Improved cognitive performance following aerobic exercise training in people with traumatic brain injury.

OBJECTIVE: To examine cognitive function in individuals with traumatic brain injury (TBI) prior to and after participation in an aerobic exercise training program. DESIGN: Pre-post intervention study. SETTING: Medical research center. PARTICIPANTS: Volunteer sample of individuals (N=7) (age, 33.3±7.9y) with chronic nonpenetrating TBI (injury severity: 3=mild, 4=moderate; time since most current injury: 4.0±5.5y) who were ambulatory. INTERVENTION: Twelve weeks of supervised vigorous aerobic exercise training performed 3 times a week for 30 minutes on a treadmill. MAIN OUTCOME MEASURES: Cognitive function was assessed using the Trail Making Test Part A (TMT-A), Trail Making Test Part B (TMT-B), and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Sleep quality and depression were measured with the Pittsburgh Sleep Quality Index (PSQI) and Beck Depression Inventory, version 2 (BDI-II). Indices of cardiorespiratory fitness were used to examine the relation between improvements in cognitive function and cardiorespiratory fitness. RESULTS: After training, improvements in cognitive function were observed with greater scores on the TMT-A (10.3±6.8; P=.007), TMT-B (9.6±7.0; P=.011), and RBANS total scale (13.3±9.3; P=.009). No changes were observed in measures of the PSQI and BDI-II. The magnitude of cognitive improvements was also strongly related to the gains in cardiorespiratory fitness. CONCLUSIONS: These findings suggest that vigorous aerobic exercise training may improve specific aspects of cognitive function in individuals with TBI and cardiorespiratory fitness gains may be a determinant of these improvements.

Estimating premorbid intelligence in persons with traumatic brain injury: an examination of the Test of Premorbid Functioning.

Knowledge of intelligence is essential for interpreting cognitive performance following traumatic brain injury (TBI). The Test of Premorbid Functioning (ToPF), a word reading test co-normed with the Wechsler Adult Intelligence Scale 4th Edition (WAIS-IV), was examined as a tool for estimating premorbid intelligence in persons with a history of TBI. Fifty-two participants with mild, moderate, or severe TBI were administered the ToPF and WAIS-IV between two weeks and 19 months post-injury. The independent ability of the ToPF/demographic score and the Verbal Comprehension Index (VCI) to predict WAIS-IV Full Scale IQ (FSIQ) was examined, as were discrepancies between ToPF and WAIS-IV scores within and between participants. The ToPF/demographic predicted FSIQ accounted for a significant proportion of variability in actual FSIQ, above and beyond that accounted for by education or time since injury. ToPF and WAIS-IV scores did not differ by injury severity. In our sample, the ToPF/demographic predicted FSIQ underestimated intelligence in a substantial portion of our participants (31%), particularly in those with high average to superior intelligence. Finally, VCI scores were more predictive of actual FSIQ than the ToPF/demographic predicted FSIQ. The ToPF frequently underestimated post-injury intelligence and is therefore not accurately measuring premorbid intelligence in our sample, particularly in those with above average to superior intelligence. Clinicians are encouraged to administer the entire WAIS-IV, or at minimum the VCI subtests, for a more accurate measure of intelligence in those with above average intelligence and history of TBI.

The Impact of Affective States on Postconcussive Symptoms in a TBI Population.

The occurrence of persistent postconcussive symptoms (PCS) associated with traumatic brain injury (TBI) is an increasing cause of disability and lost productivity. The reasons for these persistent symptoms in a percentage of even mild TBI are poorly understood. The existence of comorbid conditions such as post-traumatic stress disorder or other traumatic injuries may be factors that impact the presence of PCS. We expect that greater levels of affective symptoms will be associated with increases in PCS assessed on the Neurobehavioral Symptom Inventory (NSI). TBI subjects (N = 69) who were seen 1 year post-injury were recruited from a larger cohort study of TBI. Subjects were administered the NSI, Brief Symptom Inventory-18 (BSI-18) and the Post Traumatic Stress Disorder Checklist (PCL). Data were analyzed using Spearman's rho correlations and analysis of variances. We found significant correlations between the four NSI factors and the three BSI factors and the PCL total score. Mild TBI subjects were found to have the highest correlations between affective and somatic symptoms. These findings support our hypothesis that affective states are associated with higher PCS reporting and that early identification and treatment may decrease PCS.

Rey Tangled Line Test: A measure of processing speed in TBI.

OBJECTIVE: Neuropsychological assessment plays a key role in characterizing and detecting cognitive impairment after traumatic brain injury (TBI). The Rey Tangled Line Test (RTLT), an understudied neuropsychological assessment thought to be capable of detecting visual processing deficits, was examined to determine which cognitive abilities may contribute to performance on the test in participants with a history of TBI. METHOD: One-hundred participants with a history of mild to severe TBI were administered a battery of neuropsychological tests assessing attention, executive functioning, memory, visual construction, motor functioning, and processing speed between 30 days and 5 years postinjury. An exploratory principal components analysis (PCA) was performed to determine which cognitive tests the RTLT was most highly associated with. RESULTS: No difference in RTLT latency was present between mild and moderate/severe TBI. The PCA resulted in 5 factors. RTLT latency had a significant primary factor loading on the "processing speed" factor, and a secondary loading on the "motor" factor. Forty-two percent of participants had an impaired latency score. CONCLUSIONS: RTLT latency appears to measure processing speed, and likely aspects of motor functioning, in our sample. The RTLT may be useful as a rapid assessment in individuals with a history of TBI to detect cognitive deficit before initiating further cognitive testing or rehabilitation efforts. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Brain Volume, Connectivity, and Neuropsychological Performance in Mild Traumatic Brain Injury: The Impact of Post-Traumatic Stress Disorder Symptoms.

Post-traumatic stress disorder (PTSD) is commonly associated with mild traumatic brain injury (mTBI). To better understand their relationship, we examined neuroanatomical structures and neuropsychological performance in a sample of individuals with mTBI, with and without PTSD symptoms. Thirty-nine subjects with mTBI were dichotomized into those with (n = 12) and without (n = 27) significant PTSD symptoms based on scores on the PTSD Checklist. Using a region-of-interest approach, fronto-temporal volumes, fiber bundles obtained by diffusion tensor imaging, and neuropsychological scores were compared between the two groups. After controlling for total intracranial volume and age, subjects with mTBI and PTSD symptoms exhibited volumetric differences in the entorhinal cortex, an area associated with memory networks, relative to mTBI-only patients (F = 4.28; p = 0.046). Additionally, subjects with PTSD symptoms showed reduced white matter integrity in the right cingulum bundle (axial diffusivity, F = 6.04; p = 0.020). Accompanying these structural alterations, mTBI and PTSD subjects also showed impaired performance in encoding (F = 5.98; p = 0.019) and retrieval (F = 7.32; p = 0.010) phases of list learning and in tests of processing speed (Wechsler Adult Intelligence Scale Processing Speed Index, F = 12.23; p = 0.001; Trail Making Test A, F = 5.56; p = 0.024). Increased volume and white matter disruptions in these areas, commonly associated with memory functions, may be related to functional disturbances during cognitively demanding tasks. Differences in brain volume and white matter integrity between mTBI subjects and those with mTBI and co-morbid PTSD symptoms point to neuroanatomical differences that may underlie poorer recovery of mTBI subjects who experience PTSD symptoms. These findings support theoretical models of PTSD and its relationship to learning deficits.

Concurrent Validity of New Subscale Scores for the Booklet Category Test.

The Booklet Category Test (BCT) is a neuropsychological test of cognitive dysfunction that provides only one overall error score indicative of global impairment. It does not, however, delineate specific domains that might be impaired. The aim of this study is to concurrently validate 13 new BCT subscales using legacy instruments in patients with nonpenetrating traumatic brain injury (TBI). Eighty-nine patients with mild, moderate, and severe TBI completed a battery of neuropsychology tests. Partial correlations controlling for age were performed and there were significant correlations between the a priori selected scores from legacy measures of major cognitive domains and both BCT total errors and subscale scores. Additional analysis showed that several subscales were able to differentiate between performance levels on the legacy measures. Overall, our results showed that the subscales measured cognitive skills beyond global impairment, supporting the use of the BCT subscales in a population with TBI.

Sleep extension improves neurocognitive functions in chronically sleep-deprived obese individuals.

BACKGROUND: Sleep deprivation and obesity, are associated with neurocognitive impairments. Effects of sleep deprivation and obesity on cognition are unknown, and the cognitive long-term effects of improvement of sleep have not been prospectively assessed in short sleeping, obese individuals. OBJECTIVE: To characterize neurocognitive functions and assess its reversibility. DESIGN: Prospective cohort study. SETTING: Tertiary Referral Research Clinical Center. PATIENTS: A cohort of 121 short-sleeping (<6.5 h/night) obese (BMI 30-55 kg/m(2)) men and pre-menopausal women. INTERVENTION: Sleep extension (468±88 days) with life-style modifications. MEASUREMENTS: Neurocognitive functions, sleep quality and sleep duration. RESULTS: At baseline, 44% of the individuals had an impaired global deficit score (t-score 0-39). Impaired global deficit score was associated with worse subjective sleep quality (p = 0.02), and lower urinary dopamine levels (p = 0.001). Memory was impaired in 33%; attention in 35%; motor skills in 42%; and executive function in 51% of individuals. At the final evaluation (N = 74), subjective sleep quality improved by 24% (p<0.001), self-reported sleep duration increased by 11% by questionnaires (p<0.001) and by 4% by diaries (p = 0.04), and daytime sleepiness tended to improve (p = 0.10). Global cognitive function and attention improved by 7% and 10%, respectively (both p = 0.001), and memory and executive functions tended to improve (p = 0.07 and p = 0.06). Serum cortisol increased by 17% (p = 0.02). In a multivariate mixed model, subjective sleep quality and sleep efficiency, urinary free cortisol and dopamine and plasma total ghrelin accounted for 1/5 of the variability in global cognitive function. LIMITATIONS: Drop-out rate. CONCLUSIONS: Chronically sleep-deprived obese individuals exhibit substantial neurocognitive deficits that are partially reversible upon improvement of sleep in a non-pharmacological way. These findings have clinical implications for large segments of the US population. TRAIL REGISTRATION: www.ClinicalTrials.gov NCT00261898. NIDDK protocol 06-DK-0036.

The neurometric-quantitative electroencephalogram as a predictor for psychopharmacological treatment: an investigation of clinical utility.

A retrospective validation study of the Neurometric method of the Quantitative Electroencephalogram (QEEG) in predicting response to psychotropic medication was conducted. The clinical outcomes of 2 groups of patients were compared: those patients prescribed medication regimens that were concordant with the QEEG predictors vs. those whose medication regimens were discordant with the QEEG predictors. Participants included 70 adolescent inpatients who were administered the QEEG upon admission. The results indicated no significant difference in clinical outcome between the 2 groups. The failure of this study to find significant differences in patient outcomes brings into question this particular use of the QEEG. The existing literature and future directions for research and clinical use of this method are discussed.