Brain autopsies indicate that Alzheimer disease may be easily misdiagnosed — a concern in light of the large number of dementia cases expected to occur over the next 10 years in the United States.

“It will be increasingly important to correctly recognize, diagnose, prevent, and treat age-related cognitive decline,” affirmed study author Lon White, MD, MPH, in a statement describing the findings, which will be presented at the annual meeting of the American Academy of Neurology this month.

Dr. White’s team autopsied the brains of 426 Japanese-American men who had been residents of Hawaii. Before their deaths at an average age of 87 years, 211 of the men had been diagnosed with dementia, most commonly attributed to Alzheimer disease. However, brain autopsy showed that approximately half of that subgroup did not have sufficient numbers of the characteristic brain lesions to support the diagnosis.

The researchers did find that diagnoses of Lewy body dementia and vascular dementia were more accurate.

Another study focusing on Alzheimer patients added to evidence that people may be more likely to inherit the disease from their mothers than their fathers. Over the course of two years, investigators administered brain scans and cognitive tests to 53 dementia-free people aged 60 years and older —11 with a maternal history of Alzheimer, 10 with a paternal history, and 32 with no parental history of the disease.

The maternal-history participants exhibited twice the amount of gray-matter atrophy as both other sets of subjects, and approximately 1.5 times more whole-brain atrophy per year than the paternal-history patients (Neurology. 2011;76:822-829).