“…With regard to confounding factors, eight of 33 studies (24.2%) excluded patients with dementia [35,43,49,52,59,64,65]; six (18.2%) included subjects with dementia and studied differences in EEG between patients with delirium, with dementia, and with both conditions [41, 60-62, 66, 71]; four (12.1%) included subjects with dementia but did not take this into account in their analyses [42,50,56,57]; 15 (45.5%) did not mention whether subjects with dementia were included [44, 46-48, 51, 53-55, 58, 63, 67-70, 72]. Furthermore, six studies (18.2%) did not include patients with alcohol/substance abuse [41,49,59,62,67,71]; three (9.1%) included patients with alcohol/substance abuse and took this into account in their analysis [46,58,66]; six (18.2%) included patients with alcohol/substance abuse but did not consider this in the [50,[54][55][56][57]69]; 18 (54.5%) did not mention whether patients with alcohol/substance abuse were included [35, 42-45, 47, 48, 51-53, 60, 61, 63-65, 68, 70, 72].…”