The significance of medial temporal lobe atrophy

Background: Medial temporal lobe atrophy ( MTA) is a sensitive radiologic marker for Alzheimer disease ( AD) and associated with cognitive impairment. The value of MTA in the oldest old ( > 85 years old) is largely unknown. Methods: A total of 132 formalin-fixed brains from the Vantaa 85 + community-based study were subjected to postmortem MRI. Visual ratings of MTA were determined in a blinded fashion and compared with neuropathologic findings and clinical assessment ( dementia according to Diagnostic and Statistical Manual of Mental Disorders-III-R). Results: A strong relationship was found between MTA scores and Alzheimer pathology ( p < 0.001). The previously proposed cutoff MTA score > 2 correctly excluded subjects with no or borderline Alzheimer-type pathology ( 45/48), but was not very sensitive for AD ( modified National Institute on Aging-Reagan Institute criteria). MTA scores > 2 were also found in subjects with other primary neurodegenerative hippocampal pathology including hippocampal sclerosis, Lewy-related pathology, and argyrophilic grain disease, either alone or in combination with Alzheimer-type pathology. High MTA scores were associated with clinical dementia-in this subgroup, sensitivity was 63% and specificity 69% for AD. Conclusion: Medial temporal lobe atrophy ( MTA) on postmortem MRI is sensitive to primary degenerative hippocampal pathology in the very old, but not specific for Alzheimer-type pathology. MTA scores of 2 or less are not frequently associated with dementia.