Biomedical subjects

David F Tate

Publications and source records attributed to David F Tate.

At least 19 recordsLinked to original sources

PubMed2025

A whole-brain voxel-based analysis of structural abnormalities in PTSD: An ENIGMA-PGC study.

BACKGROUND: Patients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group. METHODS: T1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9). RESULTS: PTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges' g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges' g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (p corrected  = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (p corrected  = .001). CONCLUSIONS: PTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.

Humans↗

PubMed2007

Endothelial function and white matter hyperintensities in older adults with cardiovascular disease.

BACKGROUND AND PURPOSE: The presence of white matter hyperintensities on brain MRI is common among elderly individuals. Previous research suggests that cardiovascular risk factors are associated with increased white matter hyperintensities. Examining the role of direct physiological measures of vascular function will help to clarify the vascular mechanisms related to white matter hyperintensities. The aim of the present study was to examine the association between endothelial-dependent and endothelial-independent vasodilatation and white matter hyperintensity volume. METHODS: Twenty-five older adults with a range of cardiovascular diseases underwent brain MRI and completed assessments of blood vessel integrity using endothelial-dependent and independent flow-mediated dilation of the brachial artery. A semi-automated pixel-based method was used to quantify total brain volume and white matter hyperintensity volume, with white matter hyperintensity volume corrected for total brain volume. The association between measures of flow-mediated dilation and log-transformed white matter hyperintensities was examined. RESULTS: Correlation analysis revealed that endothelial-dependent vasodilatation was significantly and inversely associated with white matter hyperintensity volume. In contrast, endothelial-independent vasodilatation was not associated with white matter hyperintensities. Neither endothelial-dependent nor endothelial-independent vasodilatation was associated with total brain volume. CONCLUSIONS: These data provide preliminary evidence that the integrity of the vascular endothelium is associated with white matter hyperintensities in older adults with cardiovascular disease. Impaired vascular function may be one mechanism that contributes to the development of white matter hyperintensities in the brain. Additional longitudinal research combining measures of vessel function, neuroimaging and cognition will be helpful in clarifying this potential mechanism.

Aged↗

PubMed2006

Elevated body mass index is associated with executive dysfunction in otherwise healthy adults.

There is growing evidence that obesity is linked to adverse neurocognitive outcome, including reduced cognitive functioning and Alzheimer disease. However, no study to date has determined whether the relationship between body mass index (BMI) and cognitive performance varies as a function of age. We examined attention and executive function in a cross-section of 408 healthy persons across the adult life span (20-82 years). Bivariate correlation showed that BMI was inversely related to performance on all cognitive tests. After controlling for possible confounding factors, overweight and obese adults (BMI > 25) exhibited poorer executive function test performance than normal weight adults (BMI, 18.5-24.9). No differences emerged in attention test performance, and there was no evidence of a BMI x age interaction for either cognitive domain. These results provide further evidence for the relationship between elevated BMI and reduced cognitive performance and suggest that this relationship does not vary with age. Further research is needed to identify the etiology of these deficits and whether they resolve after weight loss.

Adolescent↗

PubMed2006

Relation of brain natriuretic peptide levels to cognitive dysfunction in adults > 55 years of age with cardiovascular disease.

Cardiovascular disease (CVD) is associated with cognitive deficits long before the onset of stroke or dementia. Recent work has extended these findings and shown that patients with congestive heart failure also exhibit reduced cognitive performance. Brain natriuretic peptide (BNP) is used to help diagnose heart failure, but no study has examined whether BNP predicts cognitive dysfunction in older patients with CVD. BNP values and performance on the Dementia Rating Scale were assessed in 56 older adults with documented CVD. Forty-eight percent of the participants were women, and their average age was 70 +/- 8 years. All participants had Mini-Mental State Examination scores greater than the cutoff for dementia and no histories of neurologic or severe psychiatric disorders. The average BNP level was 122 +/- 202 pg/ml. Hierarchical regression analyses showed that log-transformed BNP levels predicted Dementia Rating Scale total score after adjusting for possible demographic and medical confounders (DeltaR2 = 0.09, F[1, 44] = 6.14, p = 0.017). Partial correlation analysis adjusting for these possible confounders showed a particularly strong relation to the conceptualization subtest (r = -0.44, p = 0.002), a measure of verbal and nonverbal abstraction abilities. In conclusion, the results of the present study provide the first evidence for an independent relation between BNP and cognitive dysfunction in older adults with CVD.

Age Factors↗

PubMed2006

C-reactive protein, but not homocysteine, is related to cognitive dysfunction in older adults with cardiovascular disease.

Cardiovascular disease (CVD) is a risk factor for cognitive impairment and dementia. Recent studies implicate homocysteine (HCY) and C-reactive protein (CRP) in this increased risk, as both are associated with cognitive dysfunction in demented and non-demented patients. However, it remains unclear whether they confer added risk in older adults with CVD. A total of 126 older CVD patients underwent blood and neuropsychological evaluation as part of a prospective examination of the neurocognitive consequences of CVD. A subset of these participants (n=37) also underwent neuroimaging to quantify the degree of white matter disease. After adjusting for demographic and medical factors, no significant relationship emerged between HCY and cognitive performance. In contrast, CRP showed significant independent relationships to test performance, including global cognitive performance, attention/psychomotor function, executive function, memory, and visuospatial abilities. Neither HCY nor CRP was related to extent of white matter disease or whole brain volume on magnetic resonance imaging. Further study is needed to identify mechanisms by which inflammatory processes impact on cognitive function and to determine whether reducing circulating levels of inflammatory markers results in improved cognition.

Aged↗

PubMed2006

Regional white matter and neuropsychological functioning across the adult lifespan.

BACKGROUND: The current study utilized magnetic resonance imaging (MRI) to more fully elucidate the relationship among age, regional white matter, and neuropsychological functioning. METHODS: One hundred ninety-nine neurologically healthy adults received MRI and standardized neuropsychological assessment. MR images were spatially normalized and segmented by tissue type; relative white matter values in each of the four cerebral lobes in each hemisphere were computed. Subjects were divided into Younger (ages 21-30), Middle (ages 31-54), and Older (ages 55-79) age groups. RESULTS: The Older group had significantly less overall relative white matter than the Middle group, who had significantly less overall relative white matter than the Younger participants (F (2, 193) = 5.42, p = 0.005). Differences in frontal lobe white matter were of largest magnitude, followed by temporal lobe (F (6, 579) = 3.32, p = 0.003). Age and frontal and temporal lobe white matter were primarily associated with performance on neuropsychological tests of executive functioning and memory. Mediational analysis suggested that frontal lobe white matter mediated the relationship between age and performance on tasks of executive functioning and memory. CONCLUSIONS: The results confirm age-associated decline in frontal and temporal white matter, and age-related cognitive decline in several domains. Decline in neuropsychological functioning is, in part, mediated by a relative age-related reduction in frontal white matter.

Adult↗

PubMed2006

Neurocognitive consequences of HIV in southern India: a preliminary study of clade C virus.

The neurocognitive impact of the clade C viral strain of human immunodeficiency virus (HIV) has not been determined. The purpose of this study was to examine neurocognitive function in southern India among individuals with the clade C virus with advanced HIV. A battery of cognitive tasks sensitive to the effects of HIV on brain function was translated and administered in Tamil and Telegu, two widely spoken languages in southern India. A sample of 30 treatment-naïve HIV-positive individuals with a median CD4 cell count of 97, and 30 age and education matched healthy controls obtained from the same region of India, were included in the study. Results revealed significant differences on most cognitive tests, with lower performances obtained by the HIV-positive individuals. These results suggest that cognitive difficulties are present among individuals with the clade C virus in India, with as many as 56% of the patients with advanced HIV meeting the criterion for impairment in two cognitive domains. Additional study is needed to determine if clade C HIV infection is more or less prone to cause neurocognitive deficit than the clade B virus. Furthermore, the impact of antiretroviral therapy on neurocognitive dysfunction in clade C virual infection needs to be determined.

Adult↗

PubMed2006

The relationship between frontal gray matter volume and cognition varies across the healthy adult lifespan.

OBJECTIVE: Age-associated decline in gray matter brain volume and cognitive function in healthy adults has been reported in the literature. The goal of the current study is to examine the relationship between age-related changes in regional gray matter volumes and cognitive function in a large, cross-sectional sample of healthy adults across the lifespan. METHODS: Magnetic resonance imaging and cognitive assessment were conducted on 148 adults aged 21-76 years. Multiple regression analyses examining the effect of age were performed on magnetic resonance image-derived gray matter brain volumes and standardized cognitive summary scores of attention and executive function. Regression was also performed to test the effect of age, gray matter volumes, and their interaction on the prediction of cognitive performance. RESULTS: Age significantly predicted performance on tests of attention (F [1, 146]=50.97, p <0.01, R2=0.26) and executive function (F [1, 146]=126.19, p <0.01, R2=0.46) and gray matter volumes for frontal subregions (lateral, medial, orbital), hippocampus, amygdala, and putamen (F [2, 145]=45.34-23.96, p <0.01-0.02). Lateral frontal (beta=-1.53, t=-2.16, df=131, p <0.03) and orbital frontal (beta=1.24, t=2.08, df=131, p <0.04) regions significantly predicted performance on tests of attention. Lateral frontal (beta=-1.69, t=-2.83, df=131, p <0.01) and the interaction between age and lateral frontal volume (beta=3.76, t=2.49, df=131, p <0.02) significantly predicted executive function. CONCLUSIONS: The findings confirm age-associated decline in cognitive function and gray matter volumes, particularly in anterior cortical brain regions. Furthermore, the association between lateral frontal gray matter volume and the ability to successfully plan, organize, and execute strategies varies as a function of age across the healthy adult lifespan.

Adult↗

PubMed2005

Neuroimaging and cardiac correlates of cognitive function among patients with cardiac disease.

In the present study, we examined the relationships between whole brain volume (WBV), subcortical hyperintensities (SH), indices of cardiac disease and cognitive function in nondemented cardiac patients with evidence of mild cerebrovascular disease. A total of 27 individuals with evidence of cardiac disease underwent neuropsychological examination, neuroimaging, and cardiac assessment. Cognition was assessed with the Dementia Rating Scale-2 (DRS). WBV and SH were quantified using a semi-automated thresholding program based on MRI. Correlational analyses revealed that WBV predicted performance on the overall DRS score, the attention subscale and the initiation/perseveration scale. SH were significantly associated with performance on the attention subscale, and the initiation/perseveration subscale. Regression analyses revealed that SH accounted for most of the variance in the initiation/perseveration scale, whereas WBV accounted for most of the variance in the attention scale. The only cardiac structural or functional variable related to the neurological indices was aortic diameter, which was strongly related to both neuroimaging variables, as well as performances on the DRS attention and initiation/perseveration subscales. Our results highlight the importance of overall brain parenchyma in determining cognitive status among patients at risk for cognitive decline and suggest that select indices of structural cardiac morphology may be related to the early phases of cerebrovascular disease and cognitive status.

Aged↗

PubMed2005

Category and letter verbal fluency across the adult lifespan: relationship to EEG theta power.

The purpose of this study was to examine the impact of age, sex, and education on category and letter verbal fluency task performance. A secondary goal was to examine whether resting EEG theta power in bilateral frontal and temporal lobes impacts age-associated decline in verbal fluency task performance. A large sample (N = 471) of healthy, normal participants, age 21-82, was assessed for letter fluency (i.e., FAS), and for category fluency (i.e., Animal Naming), and with a 32-channel EEG system for 'eyes-open' resting theta power. The effects of age, sex, and education were examined using analyses of variance. Correlation analyses were used to test the impact of theta power on age and fluency performance by controlling for the effects of theta when examining the relationship between the other two variables. The results indicated that performance on both fluency tests declined linearly with age, but that the rate of decline was greater for category fluency. These age changes were not associated with education level, and there were no sex differences. While theta power was negatively associated with age and positively associated with Animal Naming performance, it did not moderate the relationship between the two. The differential age-associated decline between category and letter fluency suggests separate neurobiological substrates underlying the two domains of performance, which is not related to theta activity.

Adult↗

PubMed2005

Subcortical hyperintensities impact cognitive function among a select subset of healthy elderly.

Previous studies have examined the impact of subcortical hyperintensities (SH), a proxy measure of cerebrovascular disease, on the cognitive abilities of otherwise healthy older adults. However, there remains a limited understanding as to what extent this MRI marker of pathological processes explains the decline in specific cognitive functions that occur nearly ubiquitously with advanced age, especially in relation to other age-related imaging markers. In the present study we compared cognitive abilities between a sample of 53 older healthy adults (age range=50-79) and a sample of 53 younger adults (age range=21-40). As expected, the older group performed significantly worse on most cognitive measures compared to the younger group. Frontal volume and total grey matter volume were also significantly reduced among the older individuals compared to the younger individuals. SH volume was consistently associated with cognitive function in older adults, though, this relationship was evident only for a relatively small subset of older individuals with the most severe SH. These data suggest that the relationship between SH and cognition in the elderly is driven by a subset of individuals who may be in the earliest stages of vascular cognitive impairment. Further, the findings suggest that cognitive aging is largely determined by factors other than SH for most older adults.

Adolescent↗

PubMed2005

Anoxic versus traumatic brain injury: amount of tissue loss, not etiology, alters cognitive and emotional function.

Research in neuropsychology suggests that the etiology of a neurologic injury determines the neuropathological and neuropsychological changes. This study compared neuropsychological outcome in subjects who had traumatic brain injury (TBI) with subjects who had anoxic brain injury (ABI), who were matched for age, gender, and ventricle-to-brain ratio. There were no group differences for morphologic or neuropsychological measures. Both groups exhibited impaired memory, attention, and executive function, as well as slowed mental processing speed. Intelligence correlated with whole brain volume, and measures of memory correlated with hippocampal atrophy. There was no unique contribution of hippocampal atrophy on neuropsychological outcome between the groups. In the absence of localized lesions, the amount of neural tissue loss, rather than etiology, may be the critical factor in neuropsychological outcome.

Adult↗

PubMed2005

Blood pressure variability and white matter hyperintensities in older adults with cardiovascular disease.

The present study examined the relationship between multiple blood pressure (BP) indices and white matter hyperintensities (WMH) in a sample of 39 older adults with cardiovascular disease (CVD). Resting BP was measured using an automated monitor every 10 min for 2 h. WMH were quantified on FLAIR images and separate indices were generated for neocortical, periventricular and subcortical brain regions. Correlation analyses revealed systolic BP variability was related to neocortical and total WMH. A function of systolic BP variability and average diastolic pressure showed the strongest relationships, including significant correlation to neocortical, subcortical and total WMH. No BP index was related to WMH in periventricular regions. Exploratory analyses showed only the function of systolic BP variability and average diastolic pressure predicted total WMH, whereas as age, CVD conditions and psychosocial factors did not. These findings demonstrate BP variability is an important contributor to WMH in older adults with CVD and suggests it may have differential relationships to WMH in different brain regions. Additional studies are needed to examine the role of autoregulatory systems in the development of WMH, particularly those using beat-to-beat measures of BP.

Aged↗

PubMed2005

Apathy is associated with volume of the nucleus accumbens in patients infected with HIV.

Apathy refers to a reduction in self-initiated behavior, and it is commonly reported by patients infected with human immunodeficiency virus (HIV). It remains unclear whether apathy among HIV patients reflects a direct effect of the virus on subcortical brain circuits or a secondary neuropsychiatric symptom. In the present study we examined the relationship between ratings of apathy and quantitative analysis of the nucleus accumbens (NA), a subcortical brain structure that regulates initiation of behavioral activation. Twelve HIV-positive individuals without dementia were administered the Marin Apathy Scale and underwent neuroimaging. Voxel-based quantification of the nucleus accumbens was completed using a segmentation protocol. Results of our study revealed that increased ratings of apathy were significantly correlated with lower volume of the nucleus accumbens. By contrast, ratings of depression were unrelated to either apathy or nucleus accumbens volume. These findings provide preliminary evidence that apathy reflects direct involvement of the central nervous system in patients with HIV.

Adult↗

PubMed2005

Macrocephaly, corpus callosum morphology, and autism.

Although the cause of autism is undetermined, a general consensus has been that some type of early aberrant neural development underlies the disorder. Given the increased prevalence of macrocephaly in autism, one theory of abnormal neural development implicates early brain growth resulting in larger brain and head size in autism. Surface area measurements of the midsagittal section of the corpus callosum can be used as an index of neural development and white-matter integrity because the corpus callosum is the major white-matter structure that interconnects the two cerebral hemispheres. The purpose of this study was to obtain corpus callosum surface area, shape, and contour in a sample of non-mentally retarded autistic subjects with macrocephaly (n = 12) and compare them with those of matched (n = 8), typically developing control subjects with benign macrocephaly. No significant differences were found in surface area, shape, or contour between groups, nor did corpus callosum surface area relate to measures of IQ or picture vocabulary. These findings suggest no unique difference in overall regional corpus callosum surface area in autism with macrocephaly.

Adolescent↗

PubMed2004

Cerebral volume loss, cognitive deficit and neuropsychological performance: comparative measures of brain atrophy: I. Dementia.

There are several magnetic resonance (MR) imaging methods to measure brain volume and cerebral atrophy; however, the best measure for examining potential relationships between such measures and neuropsychological performance has not been established. Relationships between seven measures of MR derived brain volume or indices of atrophy and neuropsychological performance in the elderly subjects of the population-based Cache County, Utah Study of Aging and Memory (n = 195) were evaluated. The seven MR measures included uncorrected total brain volume (TBV), TBV corrected by total intracranial volume (TICV), TBV corrected by the ratio of the individuals TICV by group TICV (TBVC), a ventricle-to-brain ratio (VBR), total ventricular volume (TVV), TVV corrected by TICV, and a measure of parenchymal volume loss. The cases from the Cache County Study were comprised of elderly individuals classified into one of four subject groups based on a consensus diagnostic process, independent of quantitative MR imaging findings. The groups included subjects with Alzheimer's disease (AD, n = 85), no dementia but mild/ambiguous (M/A) deficits (n = 30), a group of subjects with non-AD dementia or neuropsychiatric disorder including vascular dementia (n = 60), and control subjects (n = 20). Neuropsychological performance was based on the Mini-Mental Status Exam (MMSE) and an expanded neuropsychological test battery (consortium to establish a registry for Alzheimer's disease (CERAD). The results demonstrated that the various quantitative MR measures were highly interrelated and no single measure was statistically superior. However, TBVC, TBV/TICV and VBR consistently exhibited the more robust relationships with neuropsychological performance. These results suggest that a single corrected brain volume measure or index is sufficient in studies examining global MR indicators of cerebral atrophy in relation to cognitive function and recommends use of either TBVC, TBV/TICV, or VBR.

Aged↗

PubMed2004

Clinical rating of cortical atrophy and cognitive correlates following traumatic brain injury.

We report on the utility of using a rapid, easy-to-use, visually based semi-quantitative neuroimaging atrophy rating scale in individuals with traumatic brain injury (TBI) and normal control subjects. Magnetic resonance (MR) scans were rated using a standardized semi-quantitative MR rating method. A four-point scale was used to rate each scan for atrophy in frontal, temporal, and parietal areas. Seventy-five TBI subjects (50 males, 25 females) and 75 age- and gender-matched control subjects were compared for atrophy ratings. Clinical atrophy ratings were also compared to a quantitative measure of atrophy, the ventricle-to-brain ratio, and with the TBI subjects' scores on standard neuropsychological tests. TBI patients had significantly higher clinical atrophy ratings in frontal and temporal lobe areas compared to controls. The clinical atrophy ratings significantly correlated with the ventricle-to-brain ratio, a quantitative measure of atrophy in the same TBI subjects. Higher clinical ratings of frontal and temporal atrophy correlated with deficits in memory and executive function. These findings indicate that clinical ratings of trauma-induced atrophy can be reliably performed and are associated with neuropsychological outcome and quantitative measures of cerebral atrophy.

Adolescent↗

PubMed2003

Role of white matter lesions, cerebral atrophy, and APOE on cognition in older persons with and without dementia: the Cache County, Utah, study of memory and aging.

Neuropsychological, qualitative, and quantitative magnetic resonance imaging findings were examined in subjects with Alzheimer's disease (AD), non-AD dementia or mixed neuropsychiatric disorder, subjects characterized as mild/ambiguous, and controls, all with known apolipoprotein E (APOE) genotype. Neuropsychological tasks included an expanded Consortium to Establish a Registery for Alzheimer's Disease (J. T. Tschanz et al., 2000; K. A. Welsh, J. M. Hoffman, N. L. Earl, & M. W. Hanson 1994) battery and the Mini-Mental Status Examination (M. F. Folstein, S. E. Folstein, & P. R. McHugh, 1975). Periventricular white matter lesions were the most clinically salient, and generalized measures of cerebral atrophy were the most significant quantitative indicators. APOE genotype was unrelated to imaging or neuropsychological performance. Neuropsychological relationships with neuroimaging findings depend on the qualitative or quantitative method used.

Aged↗