Comparison of the EEGs of 27 healthy older adults, 27 individuals with mild Alzheimer's and 22 individuals with moderate cases of Alzheimer’s, has found statistically significant differences across the three groups, using an algorithm that dissects brain waves of varying frequencies.
In particular, delta modulation of the beta frequency band reliably discriminated between healthy controls and mild Alzheimer’s, and disappeared with an increase in disease severity (from mild to moderate). Increase in disease severity was also marked by the appearance of delta modulation of the theta band.
It’s hoped that the algorithm can be used not only to help detect Alzheimer’s disease early, but also to monitor its progression. The algorithm has been shared on the NeuroAccelerator.org online data analysis portal, to enable it to be used by researchers around the world.
 . Characterizing Alzheimer’s Disease Severity via Resting-Awake EEG Amplitude Modulation Analysis. PLoS ONE [Internet]. 2013 ;8(8). Available from: http://dx.doi.org/10.1371/journal.pone.0072240