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Rarefied white matter in patients with Alzheimer disease
M Brilliant1, L Hughes, D Anderson
1Center for Alzheimer Disease and Related Disorders, Southern Illinois University School of Medicine, Springfield, USA.
Abstract:
Magnetic resonance head scans of 94 patients with probable Alzheimer disease (AD) and 45 patients with possible AD were examined prospectively to determine the prevalence and significance of rarefied cerebral white matter (leukoaraiosis) in patients with AD. Only 8.7% of patients with probable AD and 11.1% of patients with possible AD exhibited large confluent areas of subcortical leukoaraiosis. The remaining patients had variable degrees of leukoaraiosis surrounding the lateral ventricles. The magnitude of leukoaraiosis correlated with the patient's age but not with the Hachinski Ischemic and Mini Mental Status scores. Postmortem studies of two Alzheimer patients showed that their large confluent areas of subcortical leukoaraiosis consisted of rarefied white matter, gliosis, and arteriosclerotic small arteries. Eight additional Alzheimer patients who underwent autopsy had similar but less pronounced white matter changes limited to the periventricular regions of the cerebral hemispheres. Large confluent areas of rarefied subcortical white matter occur in a small minority of Alzheimer patients and are probably not caused by AD.
Insights
Rarefied cerebral white matter, or leukoaraiosis, is uncommon in Alzheimer disease (AD). When present, it correlates with age, not AD severity, suggesting it
Area of Science:
- Neurology
- Neuroimaging
- Pathology
Background:
- Alzheimer disease (AD) is a progressive neurodegenerative disorder.
- Cerebral white matter changes, including leukoaraiosis, are observed in aging and various neurological conditions.
- The relationship between leukoaraiosis and AD requires further clarification.
Purpose of the Study:
- To determine the prevalence and significance of rarefied cerebral white matter (leukoaraiosis) in patients with probable and possible Alzheimer disease (AD).
Main Methods:
- Prospective examination of magnetic resonance imaging (MRI) head scans from 94 patients with probable AD and 45 patients with possible AD.
- Correlation analysis of leukoaraiosis severity with patient age, Hachinski Ischemic Score, and Mini Mental Status Score.
- Postmortem neuropathological examination of white matter in Alzheimer disease patients with significant leukoaraiosis.
Main Results:
- Only 8.7% of probable AD and 11.1% of possible AD patients showed large confluent subcortical leukoaraiosis.
- Most patients exhibited variable leukoaraiosis around the lateral ventricles.
- Leukoaraiosis magnitude correlated with age but not with Hachinski or Mini Mental Status scores.
- Postmortem findings revealed rarefied white matter, gliosis, and arteriosclerotic arteries in extensive leukoaraiosis areas.
Conclusions:
- Extensive subcortical leukoaraiosis is infrequent in Alzheimer disease patients.
- The observed white matter changes are likely age-related or due to vascular factors, rather than directly caused by Alzheimer disease.
- Leukoaraiosis in AD patients may represent a comorbidity rather than a direct pathological manifestation of AD.