Test for Alzheimer's Disease Directly Measures Synaptic Loss

A study published in JAMA Neurology details a new method for directly quantifying synaptic loss in individuals with Alzheimer's, using positron-emission tomography (PET) imaging to scan for a particular protein in the brain linked to synapses, according to ScienceDaily . The researchers employed a specific radioactive chemical, 11CUCB-J, that adheres to the SV2A protein that nearly all synapses possess. The study involved 21 older adults with either early Alzheimer's or normal cognitive ability. They were each administered 11CUCB-J and then scanned with high-resolution PET technology to visualize "density" in different brain regions. The scans were analyzed, along with results from magnetic resonance imaging and cognitive evaluations for both cohorts. In comparison to individuals with normal cognition, those with Alzheimer's exhibited a 41 percent reduction in the SV2A marker in an area of the brain associated with memory. "We found that in early Alzheimer's disease, there is loss of synaptic density in the region of the hippocampus," says Yale PET Center Professor Ming-Kai Chen. The outcomes reveal the PET scan offers a direct measure of synaptic loss in adults with even mild cognitive impairment. "With this new biomarker, PET imaging for SV2A, we can measure synaptic density in the living human brain," Chen states.