From:  Hyperbaric oxygen therapy—a new hope for Alzheimer’s patients: a case report and literature review

Cognitive and neurophysiological investigations. Clock drawing item: ACE-III 77/100 in 2020 (a); mini-ACE 20/30 one year later (2021) (b); power spectrum analysis of the whole brain is shown for the left hemisphere in (c) and the right hemisphere in (d). Each color-coded line represents an electrode. The black line and the grey area are the mean and standard deviation, respectively. An enhancement in slow waves, indicated by the peak at 2 Hz, was observed in both hemispheres. This was most pronounced in temporal and parietal electrodes. dB: decibel