PubMed Health⌕ Search

Biomedical subjects

R Shankle

Publications and source records attributed to R Shankle.

5 recordsLinked to original sources
PubMed1996

Gender comparisons of cognitive performances among vascular dementia, Alzheimer disease, and older adults without dementia.

BACKGROUND: We hypothesized that women with Alzheimer disease (AD) would perform worse on a test of semantic memory but not on tests of other cognitive domains. We did not expect that women without dementia would perform more poorly than men without dementia on the same task. OBJECTIVE: To explore the specificity of a semantic memory deficit among women with AD by exploring gender differences among a group of subjects with vascular dementia (VD). DESIGN: A case-control study in which differences between men and women were explored using regression models to control for the potentially confounding effects of age, education, duration of dementia, and severity of dementia. SETTING: Alzheimer's Disease Research Center Consortium of Los Angeles and Orange Counties, California. SUBJECTS: Volunteers, recruited from the community or clinic referrals, who met clinical criteria for AD (n = 159) or VD (n = 117) or met criteria for control status without dementia (n = 134). MAIN OUTCOME MEASURES: Five neuropsychological measures, commonly used in the diagnosis and assessment of dementia. RESULTS: Women with VD scored lower than men with VD on 3 tests. However, when controlling for potential confounds, the gender difference was maintained only for the semantic memory task. Women with AD showed a strong trend to perform worse than men with AD on the test of semantic memory only. No gender differences were found among subjects without dementia. CONCLUSIONS: Findings support the existence of a semantic memory deficit for women with AD and suggest that a similar deficit may exist among women with VD.

Aged↗
PubMed1996

Vision in dementia: contrast effects.

Contrast sensitivity has been shown to be affected in Alzheimer's disease (Ad). We investigated low contrast acuity and contrast sensitivity using clinical test charts in this patient population. Additionally, we tested patients with vascular dementia (vd) and mixed dementia (md), (Alzheimer' with vascular dementia). Contrast sensitivity was assessed using the Vistech VCTS 6500 test chart. Low contrast acuity was measured using the Regan charts at four contrast levels (96%, 50%, 25% and 11%). The patient population consisted of 19 Ad patients, 9 vd patients and 10 md patients. Reduction in acuity was found with contrast level in all cases. Regression lines were fit to the data and statistical analysis was performed. We did not find a statistically significant difference between the Ad and vd or md groups. We did, however, find a difference between the vd and md groups. We did find reduction in contrast sensitivity at all spatial frequencies when compared to the elderly normal. Correspondingly, we found a significant difference in acuity when compared with normal data at the four contrast levels tested. Acuity is reduced with contrast in all patient groups. Our contrast sensitivity results are similar to those reported in the literature. This study points out the importance of using simple clinical test charts and further underscores the idea that there is a primary visual deficit in Ad.

Aged↗
PubMed1992

Criteria for the diagnosis of ischemic vascular dementia proposed by the State of California Alzheimer's Disease Diagnostic and Treatment Centers.

Accurate diagnosis of vascular dementia is important for the recognition of underlying pathophysiology and the institution of appropriate therapy. It is also important for the determination of the incidence and prevalence of not only vascular dementia but also Alzheimer's disease (AD), since differentiating between these two entities is often problematic. The State of California Alzheimer's Disease Diagnostic and Treatment Centers (ADDTC) herein propose criteria for the diagnosis of ischemic vascular dementia (IVD). These criteria broaden the conceptualization of vascular dementia, include the results of neuroimaging studies, emphasize the importance of neuropathologic confirmation, refine nosology, and identify areas that require further research. Parallel use of the proposed definitions of "possible" and "mixed" categories in the diagnosis of both AD and IVD would ensure compatibility between the National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) criteria for AD and the ADDTC criteria for IVD. Uniform classification of subtypes of IVD will improve the generalizability of individual studies and aid in multicenter collaborations.

Brain Ischemia↗
PubMedDate not supplied

Beta-amyloid deposition and other measures of neuropathology predict cognitive status in Alzheimer's disease.

The relationship between progressive cognitive decline and underlying neuropathology associated with Alzheimer s disease (AD) is a key issue in defining the mechanisms responsible for functional loss. This has been a subject of much controversy, with separate studies comparing various clinical and neuropathological indices in AD. Further, it is difficult to compare studies with differences in histochemical staining protocols, brain regions examined, and data quantification criteria. There are many difficulties in designing a clinical-pathological correlative study involving AD patients. It is necessary to control for several key parameters. For example, a broad range of cognitively impaired subjects is needed, as well as short postmortem delays, brief intervals between cognitive testing and death, and the most sensitive detection and quantification techniques. In this study, we carefully controlled for each of these parameters to determine if there is a relationship between global cognitive dysfunction and multiple neuropathological indices. We selected 20 individuals representing a broad range of cognitive ability from normal to severely impaired based on the MMSE, Blessed IMC, and CDR. We counted plaque number, NFT number, dystrophic neurite number, and the relative extent of thioflavine positive plaques and neuritic involvement within plaques. We also quantified cortical area occupied by beta-amyloid immunoreactivity (A beta Load) and PHF-1 positive neuropil threads and tangles (PHF Load) using computer-based image analysis. Interestingly, we found that most pathologic measures correlated highly with the severity of dementia. However, the strongest predictor of premortem cognitive dysfunction on all three cognitive measures was the relative area of entorhinal cortex occupied by beta-amyloid deposition. In conclusion, our data show that in a carefully controlled correlative study, a variety of neuropathological variables are strongly correlated with cognitive impairment. Plaque related variables may be as strongly related to cognitive dysfunction as other established measures, including synapse loss, cell death and tau hyperphosphorylation, although no correlative study can demonstrate causality.

Aged↗