Biomedical subjects

David F Tate

Publications and source records attributed to David F Tate.

23 records · Page 2Linked to original sources

PubMed2003

Reduced hippocampal volume in alcohol and substance naïve Vietnam combat veterans with posttraumatic stress disorder.

OBJECTIVE: This pilot study was undertaken to exclude the effects of alcohol and other substances on brain morphology in posttraumatic stress disorder. BACKGROUND: Posttraumatic stress disorder and alcohol use are among the conditions associated with decreased hippocampal volume. The possible confounding contribution of alcohol and other substances of abuse to decreased hippocampal volume in posttraumatic stress disorder has not been previously explored directly. METHOD: In this pilot study, magnetic resonance imaging scans of 4 substance naive subjects with combat-related posttraumatic stress disorder and of 4 controls were quantified. RESULTS: Bilateral hippocampal volumes were significantly smaller in posttraumatic stress disorder subjects. No significant differences were found between posttraumatic stress disorder subjects and the comparison group for total brain, gray and white matter, and ventricular volumes. CONCLUSIONS: These findings suggest that posttraumatic stress disorder in the absence of alcohol and other substance abuse may be associated with reduced hippocampal volume. The significance of reduced hippocampal volume in posttraumatic stress disorder is discussed.

Atrophy↗

PubMed2002

Dementia, asymmetry of temporal lobe structures, and apolipoprotein E genotype: relationships to cerebral atrophy and neuropsychological impairment.

We examined asymmetry of hippocampal volume as well as other temporal lobe structures (temporal lobe, temporal horn of the lateral ventricular system, parahippocampal and fusiform gyri) in 194 subjects from the Cache County, Utah study, with varying disorders [85 with Alzheimer's disease (AD), 59 with some cognitive or neuropsychiatric disorder-referenced as a Mixed Neuropsychiatric group, 30 with mild ambiguous/mild cognitive impairment (MA/MCI) and 20 controls] and APOE genotypes. Asymmetry was determined by subtracting left-side volume from the right corrected by total intracranial volume. No significant asymmetry was observed to be associated with presence of the epsilon4 allele. Since the AD-epsilon4 allele risk effect may be expressed early in the course of the disorder, we also examined asymmetry indices in AD, MA/MCI and Mixed Neuropsychiatric subjects early in the course of their disorder (2 years or less) to those with longer duration illness (greater than 2 years). We observed a leftward asymmetry (i.e., left side larger) regardless of APOE genotype in hippocampal volume where both AD and MCI subjects demonstrated a leftward shift in hippocampal size when length of disease (LOD) was less but not more than 2 years. Leftward asymmetry was not associated with LOD in the Mixed Neuropsychiatric group. These findings do not support an association between epsilon4 and hippocampal asymmetry in dementia. We also examined whether asymmetry influenced neuropsychological performance, but minimal effects were observed. Where significance or strong trends were observed, better neuropsychological performance was associated with larger parenchymal volume of temporal lobe structures. These findings were interpreted as representing cognitive reserve effects where larger volume was protective against impairment. The role of asymmetry research in understanding neuropsychological performance in dementia is discussed.

Aged↗

PubMed2002

Traumatic brain injury and atrophy of the cingulate gyrus.

The medial surface areas of the cingulate gyrus (CG) and other midline structures (corpus callosum, thalamus, lateral ventricle) were examined in 27 traumatically brain injured (TBI) and 12 age- and gender-matched control subjects from an established TBI data base. Significant atrophy, primarily in the posterior CG, was found in TBI patients. Degree of atrophy was related to severity of injury. TBI subjects also had significantly reduced corpus callosum and thalamic cross-sectional surface areas with associated increased lateral ventricular volume, as well as reduced brain volume and increased ventricle-to-brain ratio. Despite significant atrophy of the posterior CG, neuropsychological performance was not related to changes in CG cross-sectional surface area in the TBI subjects. This apparent discrepancy is discussed.

Adolescent↗

PubMedDate not supplied

White matter lesions, quantitative magnetic resonance imaging, and dementia.

The authors performed quantitative and qualitative image analysis on a sample of the elderly population of Cache County, Utah, relating neuroimaging findings to Mini-Mental Status Examination (MMSE) scores and the presence of the apolipoprotein E epsilon4 allele. Neuroimaging measures included white, gray, and hippocampal volumes; a ventricle-to-brain ratio (VBR); and qualitative ratings of white matter lesions (WMLs) in the periventricular (PV) and centrum semiovale (CS) regions. Subjects included 85 persons with possible and probable Alzheimer disease (AD), 21 with vascular dementia (VaD), 30 with cognitive symptoms classified as mild/ambiguous (M/A), a heterogenous group of 39 non-AD or VaD subjects but diagnosed with some form of neuropsychiatric disorder ("Mixed Neuropsychiatric" group), and 20 normal control subjects aged 65 years or older. Controlling for age, sex, and length of disease, the authors found that AD and VaD subjects differed significantly from control subjects on WMLs, but only the VaD subjects significantly differed from M/A subjects. The two dementia groups also displayed, as expected, significant cerebral atrophy. The WMLs generally increased with age and severity of dementia. PV WMLs were significantly but only modestly associated with white matter volume loss and greater impairment on the MMSE. Modest correlations were also present between the quantitative measures of cerebral structure and MMSE performance. However, when degree of cerebral atrophy was controlled by using the VBR measure, WML effects on MMSE performance became nonsignificant, with the only significant relationship remaining being that between hippocampal volume and MMSE performance. There were no significant qualitative or quantitative findings related to presence of the epsilon4 allele and MMSE performance. The role of WMLs in aging and dementia is discussed.

Aged↗

PubMedDate not supplied

Temporal lobe, autism, and macrocephaly.

BACKGROUND AND PURPOSE: Because of increased prevalence of macrocephaly in autism, head size must be controlled for in studies that examine volumetric findings of the temporal lobe in autistic subjects. We prospectively examined temporal lobe structures in individuals with autism who were normocephalic or macrocephalic (head circumference > 97th percentile) and in control subjects who were normocephalic or macrocephalic or who had a reading disorder (unselected for head size). The rationale for the reading disorder group was to have control subjects with potential temporal lobe anomalies, but who were not autistic. METHODS: In individuals aged 7-31 years, autism was diagnosed on the basis of standardized interview and diagnostic criteria. Control subjects ranged in age from 7 to 22 years. All subjects were male. MR morphometrics of the major temporal lobe structures were based on ANALYZE segmentation routines, in which total brain volume and total intracranial volume (TICV) were calculated. Both group comparisons and developmental analyses were performed. RESULTS: No distinct temporal lobe abnormalities of volume were observed once head size (TICV) was controlled for. In autistic and control subjects, robust growth patterns were observed in white and gray matter that differed little between the groups. Although subtle differences were observed in some structures (ie, less white matter volume in the region of the temporal stem and overall temporal lobe), none was statistically significant. CONCLUSION: No major volumetric anomalies of the temporal lobe were found in cases of autism when IQ, TICV, and age were controlled. Temporal lobe abnormalities that may be associated with autism are likely to be more related to functional organization within the temporal lobe than to any gross volumetric difference.

Adolescent↗