Brain damage found in cognitively normal people with Alzheimer’s marker

School of Medicine researchers have linked a potential indicator of Alzheimer’s disease to brain damage in humans with no signs of mental impairment.

Although their cognitive and neurological assessments were normal, study participants with lower levels of amyloid beta 42 (A-beta 42) in their cerebrospinal fluid (CSF) had reduced whole brain volumes, suggesting that Alzheimer’s changes might already be damaging their brains. Scientists previously showed that low CSF levels of A-beta 42 mark the presence of amyloid deposition in the brain, a key diagnostic marker of the amyloid plaques that characterize Alzheimer’s disease.

Evidence is mounting that Alzheimer’s harms the brain for many years before symptoms can be detected and is leading to conclusions that successful Alzheimer’s treatments may only be possible if scientists find ways to identify pre-symptomatic sufferers.

The results are an encouraging sign that this search for new indicators may be succeeding, said senior author David M. Holtzman, M.D., the Andrew and Gretchen Jones Professor and chair of Neurology and neurologist-in-chief at Barnes-Jewish Hospital.

“We still need to confirm with long-term follow-up studies that subjects with this biomarker and brain damage go on to develop the cognitive changes characteristic of Alzheimer’s,” Holtzman said. “For now, the evidence we’ve uncovered further proves that identification and treatment prior to the start of the symptoms of Alzheimer’s disease are likely going to be essential to preventing irreversible brain injury.”