A Preliminary Formula to Predict Timing of Symptom Resolution for Collegiate Athletes Diagnosed With Sport Concussion

CONTEXT

Symptom presentation and recovery after sport concussion (SC) are variable. Empirically based models documenting typical symptom duration would assist health care providers in managing return to play after SC.

OBJECTIVE

To develop a prediction model for SC symptom duration.

DESIGN

Cross-sectional study.

SETTING

Two National Collegiate Athletic Association Division I university laboratories.

PATIENTS OR OTHER PARTICIPANTS

Seventy-six (51 male and 25 female) concussed athletes with an average age of 19.5 ± 1.65 years who were evaluated within 24 hours of diagnosis.

INTERVENTION(S)

Participants completed the Revised Head Injury Scale (HIS-r), Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), and Sensory Organization Test within 24 hours of SC diagnosis.

MAIN OUTCOME MEASURE(S)

A stepwise multivariate regression incorporating ImPACT and Sensory Organization Test composites and HIS-r symptom severity-duration was used to predict the number of days athletes reported symptoms after SC. The resulting regression formula was cross-validated using the Stine cross-validation coefficient.

RESULTS

The final formula consisted of the HIS-r's self-reported neck pain, drowsiness, tingling, and nervousness duration and ImPACT total symptom severity (R = 0.62, R(2) = 39%, R(2)(adj) = 34.2%, P < .001). Approximately 29% (R(2)(cv) = 29%) of the variance associated with total days symptomatic after SC was explained by our preliminary formula when cross-validated. The current formula correctly identified 76% of participants who recovered within 10 days of injury.

CONCLUSIONS

Our results suggest that self-reported duration of 4 symptoms during the initial 24 hours after injury along with total symptom severity as measured by ImPACT accounted for a considerable amount of variance associated with days symptomatic after SC in collegiate athletes. Until the formula is cross-validated in a college-aged sample, caution is warranted in using it clinically.

Amyloid burden and sleep blood pressure in amnestic mild cognitive impairment

OBJECTIVE

To determine whether cortical β-amyloid (Aβ) deposition is associated with circadian blood pressure (BP) profiles and dynamic cerebral blood flow (CBF) regulation in patients with amnestic mild cognitive impairment (aMCI).

METHODS

Forty participants with aMCI were included in this study. Cortical Aβ depositions were measured by (18)F-florbetapir PET and expressed as the standardized uptake value ratio (SUVR) relative to the cerebellum. Circadian BP profiles were measured by 24-hour ambulatory monitoring during awake and sleep periods. The dipping status of sleep BP (i.e., the percent changes from the awake BP) was calculated and dichotomized into the dipper (≥10%) and nondipper (<10%) groups. Dynamic CBF regulation was assessed by a transfer function analysis between beat-to-beat changes in BP and CBF velocity measured from the middle cerebral artery during a repeated sit-stand maneuver.

RESULTS

Age was positively correlated with a greater Aβ deposition in the posterior cingulate, precuneus, and mean cortex. Accounting for the age effect, attenuated reductions in sleep systolic BP were associated with higher levels of posterior cingulate SUVR. Consistently, the nondippers exhibited a higher SUVR in the posterior cingulate than the dippers. Transfer function gain between changes in BP and CBF velocity was diminished in the nondippers, and moreover those individuals with a lower gain exhibited a higher SUVR in the posterior cingulate.

CONCLUSIONS

Attenuated reductions in sleep BP are associated with a greater Aβ burden in the posterior cingulate and altered dynamic CBF regulation in patients with aMCI.

Video Teleconference Administration of the Repeatable Battery for the Assessment of Neuropsychological Status

Teleneuropsychology applications are growing, but a limited number of assessment tools have been studied in this context. The present investigation was designed to determine the feasibility and reliability of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) administration by comparing video teleconference (VTC) with face-to-face (FF) test conditions. Eighteen adult subjects over age 55 with and without cognitive impairment were administered Forms A and B of the RBANS in VTC and FF settings in counterbalanced fashion. Similar RBANS scores were obtained in both test conditions, with generally high correlations between administration methods. Results support the feasibility and reliability of remote administration of the RBANS via VTC.

Imaging Correlates of Memory and Concussion History in Retired National Football League Athletes

IMPORTANCE

To our knowledge, this is the first study to show an association between concussion, cognition, and anatomical structural brain changes across the age spectrum in former National Football League athletes.

OBJECTIVE

To assess the relationship of hippocampal volume, memory performance, and the influence of concussion history in retired National Football League athletes with and without mild cognitive impairment (MCI).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study assessed differences between groups, mean hippocampal volumes, and memory performance by computing age quintiles based on group-specific linear regression models corrected for multiple comparisons for both athletes and control participants. The study was conducted starting in November 2010 and is ongoing at a research center in the northern region of Texas. This current analysis was conducted from October 9, 2013, to August 21, 2014. Participants included 28 retired National Football League athletes, 8 of whom had MCI and a history of concussion, 21 cognitively healthy control participants, and 6 control participants with MCI without concussion.

MAIN OUTCOMES AND MEASURES

Hippocampal volume, age, California Verbal Learning Test scores, and the number of grade 3 (G3) concussions. In addition, the number of games played was examined as an objective variable pertaining to football history.

RESULTS

The mean (SD) age was 58.1 (13) years for the 28 former athletes and 59.0 (12) years for the 27 control participants. Retired athletes with concussion history but without cognitive impairment had normal but significantly lower California Verbal Learning Test scores compared with control participants (mean [SD], 52.5 [8] vs 60.24 [7]; P = .002); those with a concussion history and MCI performed worse (mean [SD], 37 [8.62]) compared with both control participants (P < .001) and athletes without memory impairment (P < .001). Among the athletes, 17 had a G3 concussion and 11 did not. Older retired athletes with at least 1 G3 concussion had significantly smaller bilateral hippocampal volumes compared with control participants at the 40th age percentile (left, P = .04; right, P = .03), 60th percentile (left, P = .009; right, P = .01), and 80th percentile (left, P = .001; right, P = .002) and a smaller right hippocampal volume compared with athletes without a G3 concussion at the 40th percentile (P = .03), 60th percentile (P = .02), and 80th percentile (P = .02). Athletes with a history of G3 concussion were more likely to have MCI (7 of 7) compared with retired athletes without a history of G3 concussion (1 of 5) older than 63 years (P = .01). In addition, the left hippocampal volume in retired athletes with MCI and concussion was significantly smaller compared with control participants with MCI (P = .03).

CONCLUSION AND RELEVANCE

Prior concussion that results in loss of consciousness is a risk factor for increased hippocampal atrophy and the development of MCI. In individuals with MCI, hippocampal volume loss appears greater among those with a history of concussion.

The Brief Cognitive Status Examination (BCSE): Comparing Diagnostic Utility and Equating Scores to the Mini-Mental State Examination (MMSE)

The study purpose was to compare the diagnostic utility of the Brief Cognitive Status Exam (BCSE) to that of the Mini-Mental State Examination (MMSE) and to develop equated scores to facilitate comparisons. One hundred and eighty-two patients underwent cognitive evaluation and were placed into three groups: dementia (DEM), cognitive impairment, no dementia (CIND), and no cognitive impairment (NCI). One hundred and eighty-two healthy controls from the BCSE standardization sample served as a comparison group. On both measures, the DEM group obtained significantly lower scores than the other two groups, and the CIND group scored significantly lower than the NCI group. The BCSE was more sensitive in all clinical groups, although at extremely low scores, the two tests displayed similar sensitivity. Results indicate the BCSE has diagnostic utility as a cognitive screening measure in a mixed clinical sample and is more sensitive at detecting cognitive impairment, particularly milder levels, than the MMSE.

Three approaches to investigating functional compromise to the default mode network after traumatic axonal injury

The default mode network (DMN) is a reliably elicited functional neural network with potential clinical implications. Its discriminant and prognostic utility following traumatic axonal injury (TAI) have not been previously investigated. The present study used three approaches to analyze DMN functional connectedness, including a whole-brain analysis [A1], network-specific analysis [A2], and between-node (edge) analysis [A3]. The purpose was to identify the utility of each method in distinguishing between healthy and brain-injured individuals, and determine whether observed differences have clinical significance. Resting-state fMRI was acquired from 25 patients with TAI and 17 healthy controls. Patients were scanned 6-11 months post-injury, and functional and neurocognitive outcomes were assessed the same day. Using all three approaches, TAI subjects revealed significantly weaker functional connectivity (FC) than controls, and binary logistic regressions demonstrated all three approaches have discriminant value. Clinical outcomes were not correlated with FC using any approach. Results suggest that compromise to the functional connectedness of the DMN after TAI can be identified using resting-state FC; however, the degree of functional compromise to this network, as measured in this study, may not have clinical implications in chronic TAI.

Cognitive and perceptual responses during passive heat stress in younger and older adults

We tested the hypothesis that attention, memory, and executive function are impaired to a greater extent in passively heat-stressed older adults than in passively heat-stressed younger adults. In a randomized, crossover design, 15 older (age: 69 ± 5 yr) and 14 younger (age: 30 ± 4 yr) healthy subjects underwent passive heat stress and time control trials. Cognitive tests (outcomes: accuracy and reaction time) from the CANTAB battery evaluated attention [rapid visual processing (RVP), choice reaction time (CRT)], memory [spatial span (SSP), pattern recognition memory (PRM)], and executive function [one touch stockings of Cambridge (OTS)]. Testing was undertaken on two occasions during each trial, at baseline and after internal temperature had increased by 1.0 ± 0.2°C or after a time control period. For tests that measured attention, reaction time during RVP and CRT was slower (P ≤ 0.01) in the older group. During heat stress, RVP reaction time improved (P < 0.01) in both groups. Heat stress had no effect (P ≥ 0.09) on RVP or CRT accuracy in either group. For tests that measured memory, accuracy on SSP and PRM was lower (P < 0.01) in the older group, but there was no effect of heat stress (P ≥ 0.14). For tests that measured executive function, overall, accuracy on OTS was lower, and reaction time was slower in the older group (P ≤ 0.05). Reaction time generally improved during heat stress, but there was no effect of heat stress on accuracy in either group. These data indicate that moderate increases in body temperature during passive heat stress do not differentially compromise cognitive function in younger and older adults.

An Abbreviated Montreal Cognitive Assessment (MoCA) for Dementia Screening

OBJECTIVE

The Montreal Cognitive Assessment (MoCA) is a cognitive screening instrument growing in popularity, but few studies have conducted psychometric item analyses or attempted to develop abbreviated forms. We sought to derive and validate a short-form MoCA (SF-MoCA) and compare its classification accuracy to the standard MoCA and Mini-Mental State Examination (MMSE) in mild cognitive impairment (MCI), Alzheimer disease (AD), and normal aging.

METHODS

408 subjects (MCI n = 169, AD n = 87, and normal n = 152) were randomly divided into derivation and validation samples. Item analysis in the derivation sample identified most sensitive MoCA items. Receiver Operating Characteristic (ROC) analyses were used to develop cut-off scores and evaluate the classification accuracy of the SF-MoCA, standard MoCA, and MMSE. Net Reclassification Improvement (NRI) analyses and comparison of ROC curves were used to compare classification accuracy of the three measures.

RESULTS

Serial subtraction (Cramer's V = .408), delayed recall (Cramer's V = .702), and orientation items (Cramer's V = .832) were included in the SF-MoCA based on largest effect sizes in item analyses. Results revealed 72.6% classification accuracy of the SF-MoCA, compared with 71.9% for the standard MoCA and 67.4% for the MMSE. Results of NRI analyses and ROC curve comparisons revealed that classification accuracy of the SF-MoCA was comparable to the standard version and generally superior to the MMSE.

CONCLUSIONS

Findings suggest the SF-MoCA could be an effective brief tool in detecting cognitive impairment.

Subclinical atherosclerosis and subsequent cognitive function

OBJECTIVE

To examine the relationship between measures of subclinical atherosclerosis and subsequent cognitive function.

METHOD

Participants from the Dallas Heart Study (DHS), a population-based multiethnic study of cardiovascular disease pathogenesis, were re-examined 8 years later (DHS-2) with the Montreal Cognitive Assessment (MoCA); N = 1904, mean age = 42.9, range 8-65. Associations of baseline measures of subclinical atherosclerosis (coronary artery calcium, abdominal aortic plaque, and abdominal aortic wall thickness) with MoCA scores measured at follow-up were examined in the group as a whole and in relation to age and ApoE4 status.

RESULTS

A significant linear trend of successively lower MoCA scores with increasing numbers of atherosclerotic indicators was observed (F(3, 1150) = 5.918, p = .001). CAC was weakly correlated with MoCA scores (p = .047) and MoCA scores were significantly different between participants with and without CAC (M = 22.35 vs 23.69, p = 0.038). With the exception of a small association between abdominal AWT and MoCA in subjects over age 50, abdominal AWT and abdominal aortic plaque did not correlate with MoCA total score (p ≥ .052). Cognitive scores and atherosclerosis measures were not impacted by ApoE4 status (p ≥ .455).

CONCLUSION

In this ethnically diverse population-based sample, subclinical atherosclerosis was minimally associated with later cognitive function in middle-aged adults.

Video teleconference-based neurocognitive screening in geropsychiatry

Validation of remote video teleconference (VTC)-based procedures for geropsychiatry applications is essential to ensure validity and reliability of diagnostic procedures. The current study demonstrates the similarity of scores obtained from several brief neurocognitive screening measures in an outpatient VA geropsychiatry clinic population when participants were tested in-person and via VTC. Results revealed similar mean scores and moderate to good consistency among our mixed geropsychiatric sample on brief measures of global cognition, attention, and visuospatial function.

Central artery stiffness, baroreflex sensitivity, and brain white matter neuronal fiber integrity in older adults

Cerebral hypoperfusion elevates the risk of brain white matter (WM) lesions and cognitive impairment. Central artery stiffness impairs baroreflex, which controls systemic arterial perfusion, and may deteriorate neuronal fiber integrity of brain WM. The purpose of this study was to examine the associations among brain WM neuronal fiber integrity, baroreflex sensitivity (BRS), and central artery stiffness in older adults. Fifty-four adults (65 ± 6 years) with normal cognitive function or mild cognitive impairment (MCI) were tested. The neuronal fiber integrity of brain WM was assessed from diffusion metrics acquired by diffusion tensor imaging. BRS was measured in response to acute changes in blood pressure induced by bolus injections of vasoactive drugs. Central artery stiffness was measured by carotid-femoral pulse wave velocity (cfPWV). The WM diffusion metrics including fractional anisotropy (FA) and radial (RD) and axial (AD) diffusivities, BRS, and cfPWV were not different between the control and MCI groups. Thus, the data from both groups were combined for subsequent analyses. Across WM, fiber tracts with decreased FA and increased RD were associated with lower BRS and higher cfPWV, with many of the areas presenting spatial overlap. In particular, the BRS assessed during hypotension was strongly correlated with FA and RD when compared with hypertension. Executive function performance was associated with FA and RD in the areas that correlated with cfPWV and BRS. These findings suggest that baroreflex-mediated control of systemic arterial perfusion, especially during hypotension, may play a crucial role in maintaining neuronal fiber integrity of brain WM in older adults.

Single neuropsychological test scores associated with rate of cognitive decline in early Alzheimer disease

Alzheimer disease (AD) characteristically begins with episodic memory impairment followed by other cognitive deficits; however, the course of illness varies, with substantial differences in the rate of cognitive decline. For research and clinical purposes it would be useful to distinguish between persons who will progress slowly from persons who will progress at an average or faster rate. Our objective was to use neurocognitive performance features and disease-specific and health information to determine a predictive model for the rate of cognitive decline in participants with mild AD. We reviewed the records of a series of 96 consecutive participants with mild AD from 1995 to 2011 who had been administered selected neurocognitive tests and clinical measures. Based on Clinical Dementia Rating (CDR) of functional and cognitive decline over 2 years, participants were classified as Faster (n = 45) or Slower (n = 51) Progressors. Stepwise logistic regression analyses using neurocognitive performance features, disease-specific, health, and demographic variables were performed. Neuropsychological scores that distinguished Faster from Slower Progressors included Trail Making Test - A, Digit Symbol, and California Verbal Learning Test (CVLT) Total Learned and Primacy Recall. No disease-specific, health, or demographic variable predicted rate of progression; however, history of heart disease showed a trend. Among the neuropsychological variables, Trail Making Test - A best distinguished Faster from Slower Progressors, with an overall accuracy of 68%. In an omnibus model including neuropsychological, disease-specific, health, and demographic variables, only Trail Making Test - A distinguished between groups. Several neuropsychological performance features were associated with the rate of cognitive decline in mild AD, with baseline Trail Making Test - A performance best separating those who declined at an average or faster rate from those who showed slower progression.

Optimal neurocognitive, personality and behavioral measures for assessing impulsivity in cocaine dependence

BACKGROUND

Impulsivity may underlie the poor treatment retention and high relapse rates observed in cocaine-dependent persons. However, observed differences in measures of impulsivity between cocaine-dependent and healthy control participants often do not reach clinical significance, suggesting that the clinical relevance of these differences may be limited.

OBJECTIVES

To examine which measures of impulsivity (i.e. self-report impulsivity, self-report personality, neurocognitive testing) best distinguish cocaine-dependent and healthy control participants (i.e. showing differences at least 1.5 standard deviations [SD] from controls). Optimal measures were considered to demonstrate sufficient classification accuracy.

METHODS

Sixty-five recently abstinent cocaine-dependent and 25 healthy control participants were assessed using select neurocognitive tests and self-report questionnaires including the NEO Personality Inventory-Revised (NEO-PI-R), Temperament and Character Inventory (TCI), Barratt Impulsiveness Scale (BIS-11a), and the Frontal Systems Behavior Scale (FrSBe).

RESULTS

When corrected for years of education and gender, neurocognitive measures did not demonstrate clinically significant differences between cocaine-dependent and control participants. The personality measures TCI Purposefulness and Congruent Second Nature and NEO-PI-R Impulsiveness, and the self-rating measures FrSBe Disinhibition and BIS-11 Motor Impulsivity and Total successfully identified clinically meaningful elevations in impulsivity within cocaine-dependent participants (>1.5 SDs from controls). Furthermore, these measures achieved 84-93% accuracy in discriminating cocaine-dependent from control participants.

CONCLUSION

Clinically significant neurocognitive impairment in cocaine-dependent participants was not observed in this sample. As the BIS-11 or FrSBe are brief to administer, accurate, and have been shown to predict treatment retention and relapse, these measures appear to be optimal, relative to the personality measures, for examining trait impulsivity in cocaine dependence.

Global brain hypoperfusion and oxygenation in amnestic mild cognitive impairment

BACKGROUND

To determine if global brain hypoperfusion and oxygen hypometabolism occur in patients with amnestic mild cognitive impairment (aMCI).

METHODS

Thirty-two aMCI and 21 normal subjects participated. Total cerebral blood flow (TCBF), cerebral metabolic rate of oxygen (CMRO2), and brain tissue volume were measured using color-coded duplex ultrasonography (CDUS), near-infrared spectroscopy (NIRS), and MRI. TCBF was normalized by total brain tissue volume (TBV) for group comparisons (nTCBF). Cerebrovascular resistance (CVR) was calculated as mean arterial pressure divided by TCBF.

RESULTS

Reductions in nTCBF by 9%, CMRO2 by 11%, and an increase in CVR by 13% were observed in aMCI relative to normal subjects. No group differences in TBV were observed. nTCBF was correlated with CMRO2 in normal controls, but not in aMCI.

CONCLUSIONS

Global brain hypoperfusion, oxygen hypometabolism, and neurovascular decoupling observed in aMCI suggest that changes in cerebral hemodynamics occur early at a prodromal stage of Alzheimer's disease, which can be assessed using low-cost and bedside-available CDUS and NIRS technology.

Depressive symptoms and white matter dysfunction in retired NFL players with concussion history

OBJECTIVE

To determine whether correlates of white matter integrity can provide general as well as specific insight into the chronic effects of head injury coupled with depression symptom expression in professional football players.

METHOD

We studied 26 retired National Football League (NFL) athletes who underwent diffusion tensor imaging (DTI) scanning. Depressive symptom severity was measured using the Beck Depression Inventory II (BDI-II) including affective, cognitive, and somatic subfactor scores (Buckley 3-factor model). Fractional anisotropy (FA) maps were processed using tract-based spatial statistics from FSL. Correlations between FA and BDI-II scores were assessed using both voxel-wise and region of interest (ROI) techniques, with ROIs that corresponded to white matter tracts. Tracts demonstrating significant correlations were further evaluated using a receiver operating characteristic curve that utilized the mean FA to distinguish depressed from nondepressed subjects.

RESULTS

Voxel-wise analysis identified widely distributed voxels that negatively correlated with total BDI-II and cognitive and somatic subfactors, with voxels correlating with the affective component (p < 0.05 corrected) localized to frontal regions. Four tract ROIs negatively correlated (p < 0.01) with total BDI-II: forceps minor, right frontal aslant tract, right uncinate fasciculus, and left superior longitudinal fasciculus. FA of the forceps minor differentiated depressed from nondepressed athletes with 100% sensitivity and 95% specificity.

CONCLUSION

Depressive symptoms in retired NFL athletes correlate negatively with FA using either an unbiased voxel-wise or an ROI-based, tract-wise approach. DTI is a promising biomarker for depression in this population.

Depressive symptoms and concussions in aging retired NFL players

We examined the relationship between a remote history of concussions with current symptoms of depression in retired professional athletes. Thirty retired National Football League (NFL) athletes with a history of concussion and 29 age- and IQ-matched controls without a history of concussion were recruited. We found a significant correlation between the number of lifetime concussions and depressive symptom severity using the Beck Depression Inventory II. Upon investigating a three-factor model of depressive symptoms (affective, cognitive, and somatic; Buckley et al., 2001) from the BDI-II, the cognitive factor was the only factor that was significantly related to concussions. In general, NFL players endorsed more symptoms of depression on all three Buckley factors compared with matched controls. Findings suggest that the number of self-reported concussions may be related to later depressive symptomology (particularly cognitive symptoms of depression).

Neuroimaging of cognitive dysfunction and depression in aging retired National Football League players: a cross-sectional study

OBJECTIVES To assess cognitive impairment and depression in aging former professional football (National Football League [NFL]) players and to identify neuroimaging correlates of these dysfunctions. DESIGN We compared former NFL players with cognitive impairment and depression, cognitively normal retired players who were not depressed, and matched healthy control subjects. SETTING Research center in the North Texas region of the United States. PATIENTS Cross-sectional sample of former NFL players with and without a history of concussion recruited from the North Texas region and age-, education-, and IQ-matched controls. Thirty-four retired NFL players (mean age, 61.8 years) underwent neurological and neuropsychological assessment. A subset of 26 players also underwent detailed neuroimaging; imaging data in this subset were compared with imaging data acquired in 26 healthy matched controls. MAIN OUTCOME MEASURES Neuropsychological measures, clinical diagnoses of depression, neuroimaging mea-sures of white matter pathology, and a measure of cerebral blood flow. RESULTS Of the 34 former NFL players, 20 were cognitively normal. Four were diagnosed as having a fixed cognitive deficit; 8, mild cognitive impairment; 2, dementia; and 8, depression. Of the subgroup in whom neuroimaging data were acquired, cognitively impaired participants showed the greatest deficits on tests of naming, word finding, and visual/verbal episodic memory. We found significant differences in white matter abnormalities in cognitively impaired and depressed retired players compared with their respective controls. Regional blood flow differences in the cognitively impaired group (left temporal pole, inferior parietal lobule, and superior temporal gyrus) corresponded to regions associated with impaired neurocognitive performance (problems with memory, naming, and word finding). CONCLUSIONS Cognitive deficits and depression appear to be more common in aging former NFL players compared with healthy controls. These deficits are correlated with white matter abnormalities and changes in regional cerebral blood flow.

Consumer acceptability of brief videoconference-based neuropsychological assessment in older individuals with and without cognitive impairment

Growing evidence suggests that neuropsychological assessment via videoconference shows good agreement with traditional in-person assessment. However, there are few published studies regarding patient acceptability of this methodology, particularly in individuals with cognitive impairment. In this study we sought to evaluate patient preferences and acceptability of teleneuropsychology to further shed light on the viability of this cognitive assessment medium. We examined acceptability of videoconference-based neuropsychological assessment among healthy aging individuals and in subjects with mild cognitive impairment or early stage Alzheimer disease. We found that teleneuropsychology appears to be well accepted by consumers. Our results reflected 98% satisfaction, and roughly two-thirds of participants indicated no preference between traditional face-to-face testing and examination by teleneuropsychology. Furthermore, even participants with cognitive impairment showed good acceptability of teleneuropsychological assessment. In conjunction with the preliminary data on reliability and validity from this growing literature, these results support teleneuropsychology as a viable and acceptable method for assessing cognitive functioning, and show promise for the implementation and utilization of this cognitive assessment medium in clinical and research settings.

Masters athletes exhibit larger regional brain volume and better cognitive performance than sedentary older adults

PURPOSE

To investigate differences in the age-related decline in brain tissue concentration between Masters athletes and sedentary older adults.

MATERIALS AND METHODS

Twelve Masters athletes (MA) (three females, age = 72.4 ± 5.6 years, endurance training >15 years), 12 sedentary elderly (SE) similar in age and educational level (four females, age = 74.6 ± 4.3 years), and nine young controls (YC) (four females, age = 27.2 ± 3.6 years) participated. T1-weighted high-resolution (1 × 1 × 1mm(3) ) images were acquired. Voxel-based analysis was conducted to identify clusters showing tissue concentration differences with t-tests. Cognitive function was assessed using a standard clinical battery focused on executive function and memory.

RESULTS

Two MA and two SE were unable to complete the magnetic resonance imaging (MRI) study. Both SE and MA showed lower gray matter (GM) concentrations than YC in the superior, inferior and middle frontal gyrus, superior temporal gyrus, postcentral gyrus, and the cingulate gyrus (PFDR-corrected < 0.001) and lower white matter (WM) concentrations in the inferior frontal gyrus and precentral gyrus (PFDR-corrected < 0.005). Notably, MA showed higher GM and WM concentrations than SE in the subgyral, cuneus, and precuneus regions related to visuospatial function, motor control, and working memory (PFDR-corrected < 0.005). After controlling for estimated intelligence, MA outperformed SE on tasks of letter (P < 0.01) and category (P < 0.05) fluency.

CONCLUSION

Life-long exercise may confer benefits to some aspects of executive function and age-related brain tissue loss in the regions related to visuospatial function, motor control, and working memory in older adults.

Donepezil effects on hippocampal and prefrontal functional connectivity in Alzheimer's disease: preliminary report

We used functional connectivity magnetic resonance imaging (fcMRI) to investigate changes in interhemispheric brain connectivity in 11 patients with mild Alzheimer's disease (AD) following eight weeks of treatment with the cholinesterase inhibitor donepezil. We examined functional connectivity between four homologous temporal, frontal, and occipital regions. These regions were selected to represent sites of AD neuropathology, sites of donepezil-related brain activation change in prior studies, and sites that are minimally affected by the pathologic changes of AD. Based on previous findings of selective, localized frontal responses to donepezil, we predicted that frontal connectivity would be most strongly impacted by treatment. Of the areas examined, we found that treatment had a significant effect only on functional connectivity between right and left dorsolateral prefrontal cortices. Implications for understanding the impact of donepezil treatment on brain functioning and behavior in patients with AD are discussed. This preliminary report suggests that fcMRI may provide a useful index of treatment outcome in diseases affecting brain connectivity. Future research should investigate these treatment-related changes in larger samples of patients and age-matched controls.

Molecular neuropsychology: creation of test-specific blood biomarker algorithms

BACKGROUND

Prior work on the link between blood-based biomarkers and cognitive status has largely been based on dichotomous classifications rather than detailed neuropsychological functioning. The current project was designed to create serum-based biomarker algorithms that predict neuropsychological test performance.

METHODS

A battery of neuropsychological measures was administered. Random forest analyses were utilized to create neuropsychological test-specific biomarker risk scores in a training set that were entered into linear regression models predicting the respective test scores in the test set. Serum multiplex biomarker data were analyzed on 108 proteins from 395 participants (197 Alzheimer patients and 198 controls) from the Texas Alzheimer's Research and Care Consortium.

RESULTS

The biomarker risk scores were significant predictors (p < 0.05) of scores on all neuropsychological tests. With the exception of premorbid intellectual status (6.6%), the biomarker risk scores alone accounted for a minimum of 12.9% of the variance in neuropsychological scores. Biomarker algorithms (biomarker risk scores and demographics) accounted for substantially more variance in scores. Review of the variable importance plots indicated differential patterns of biomarker significance for each test, suggesting the possibility of domain-specific biomarker algorithms.

CONCLUSIONS

Our findings provide proof of concept for a novel area of scientific discovery, which we term 'molecular neuropsychology'.

Predictive pursuit association with deficits in working memory in psychosis

BACKGROUND

Deficits in smooth pursuit eye movements are an established phenotype for schizophrenia (SZ) and are being investigated as a potential liability marker for bipolar disorder. Although the molecular determinants of this deficit are still unclear, research has verified deficits in predictive pursuit mechanisms in SZ. Because predictive pursuit might depend on the working memory system, we have hypothesized a relationship between the two in healthy control subjects (HC) and SZ and here examine whether it extends to psychotic bipolar disorder (BDP).

METHODS

Volunteers with SZ (n = 38), BDP (n = 31), and HC (n = 32) performed a novel eye movement task to assess predictive pursuit as well as a standard visuospatial measure of working memory.

RESULTS

Individuals with SZ and BDP both showed reduced predictive pursuit gain compared with HC (p < .05). Moreover, each patient group showed worse performance in visuospatial working memory compared with control subjects (p < .05). A strong correlation (r = .53, p = .007) was found between predictive pursuit gain and working memory in HC, a relationship that showed a trend correlation within the BDP group but not among SZ.

CONCLUSIONS

Individuals with SZ and BDP showed similar deficits in predictive pursuit, suggesting that this alteration could be a characteristic trait of the psychosis domain. The correlation between predictive pursuit and working memory in HC supports the assumption that working memory is related to predictive pursuit eye movements; however, the degradation of working memory in people with psychosis disrupts its association with eye-tracking behavior.