Biomedical subjects

Omar Haque

Publications and source records attributed to Omar Haque.

3 recordsLinked to original sources

PubMed2005

Progressive morphometric and cognitive changes in vascular dementia.

Evidence for progressive cognitive decline in vascular dementia (VaD) is mixed, with some studies showing little or no decline over time. One possible explanation for these inconsistent findings is the heterogeneity of pathology encompassed by the VaD diagnosis. It is possible that subtypes of VaD (i.e. those resulting from different lesion distributions) show different patterns of cognitive decline. In the present study, a heterogeneous VaD group demonstrated cognitive decline from baseline to 12-month follow-up. Although this decline was coincident to morphometric changes (i.e. increased subcortical hyperintensities (SH), decreased whole brain volume (WBV)), no relationship emerged between cognitive decline and morphometric changes. Preliminary examination of VaD subtypes revealed patients with subcortical infarct or SH-only exhibited greater decline than VaD patients with cortical lesions. Further research is needed to determine whether this observed decline is attributable to differential lesion distribution or statistical artifact.

Aged↗

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↗

PubMed2004

Computer-mediated measurement and subjective ratings of white matter hyperintensities in vascular dementia: relationships to neuropsychological performance.

White matter hyperintensities (WMHs) are frequently found on MRI studies of vascular dementia (VaD) patients. As several studies have demonstrated that WMHs are often associated with severity of illness, cognitive impairment, and functional decline, the accurate and reliable measurement of WMHs on MRI is an important, yet often overlooked, prerequisite for accurate interpretation of neuroimaging studies. Using a sample of 39 VaD patients, we evaluated the reliability and validity of a visual ordinal rating scale and a computer-mediated thresholding technique to evaluate WMHs. Results indicated the computer-mediated technique had slightly stronger inter-rater reliability than the visual ordinal rating scale. Furthermore, the computer-mediated thresholding technique was correlated with measures of neuropsychological functioning believed to be compromised in VaD (i.e., psychomotor speed, executive functioning) while the visual rating scale was not. Results suggest that this computer-mediated thresholding technique is superior to visual ratings of WMHs.

Aged↗