Short-term incidence dementia can be brought on by any combination of brain structural changes and beta-amyloid deposition, according to research published in Neurology.
Oscar L. Lopez, MD, of the University of Pittsburgh School of Medicine, and colleagues examined the association between structural changes in the brain, beta-amyloid deposition and incidence dementia in 183 elderly patients without dementia.
The researchers used structural MRI and PET scans with 11C-labeled Pittsburgh compound B (PiB) to evaluate brain structure and then clinically evaluated the patients two years later. Of the 183 study participants, 146 were cognitively normal and 37 had mild cognitive impairment. At baseline, 76% were PiB+, had small hippocampal volume or had high white matter lesion volume.
Upon reevaluation, 111 patients were found to be cognitively normal, 51 had mild cognitive impairment, and 21 had dementia. 51% of the cognitively normal (CN) patients and 67.5% of the mild cognitive impairment (MCI) group were PiB+, while 30% of the CN group and 51% of the MCI group had small hippocampi, and 24% of the CN group and 40.5% of the MCI group had abnormal white matter lesions. 20 of the 21 patients with dementia had at least one imaging abnormality, but 14% only were PiB+, 5% had only small hippocampi, 5% had only white matter lesions, 5% was biomarker negative, and the remaining 16 were shown to have various imaging abnormalities. Variables of PiB retention, left and right hippocampal volume and white matter lesion volume all were shown to be independent predictors of dementia in a logistic regression analysis.
The researchers concluded that a combination of any of the three factors could be a strong predictor of short-term incidence dementia since prevalence of beta-amyloid deposition, hippocampal atrophy and white matter lesions was found to be equally high in both cognitively normal patients and those with mild cognitive impairment.
This study examined the association between beta-amyloid deposition and brain structural changes with short-term incidence dementia in elderly people.
Oscar L. Lopez, MD, of the University of Pittsburgh School of Medicine, and colleagues evaluated subjects using structural MRI scan and a PET scan with 11C-labeled Pittsburgh compound B (PiB) in 2009, and reevaluated them clinically in 2011.
The prevalence of β-amyloid deposition, neurodegeneration (i.e., hippocampal atrophy), and small vessel disease (WMLs) is high in CN older individuals and in MCI. A combination of 2 or 3 of these factors is a powerful predictor of short-term incidence of dementia.