Brain perfusion during rapid-eye-movement sleep successfully identifies amnestic mild cognitive impairment

Prodromal markers of Alzheimer's disease (AD) have been derived from wakefulness. However, brain perfusion during rapid-eye movement (REM) sleep could be a sensitive marker of amnestic mild cognitive impairment (aMCI), as activation of REM sleep relies more on the cholinergic system.

Eight subjects with aMCI, and 16 controls, underwent two single-photon emission computed tomography (SPECT) scans with tracer injected during REM sleep then wakefulness.

Perfusion in the anterior cingulate cortex was significantly decreased in aMCI cases compared to controls for both conditions. That defect was much larger and more severe in REM sleep (1795 voxels) compared to wakefulness (398 voxels), and extended to the middle cingulate cortex and the olfactory cortex. Hypoperfusion in the anterior cingulate cortex during REM sleep allowed better classification than hypoperfusion found in wakefulness (93.8 vs 81.3%).

REM sleep imaging is a valuable tool with which to identify individuals at risk of developing AD.