Atropine effect by cognitive group. NC: Normal Control; CI: Cognitive Impairment; AD: Alzheimer’s disease. Box & whiskers plots showing the median as a line and the boxes representing the inter-quartile range (25%-75%). Whiskers indicate 5-95 percentile. In terms of the atropine effect score, impaired study participants were much more like those with clinically diagnosed Alzheimer’s disease than controls, however there was broad overlap. AE < 0 was present in 9/29 (31%) NC, 12/13 (92%) with CI and 12/14 (86%) with AD. The rates of AE < 0 in the normal controls and individuals with AD in this study are very similar to the rates of underlying AD at autopsy reported in the literature in comparable clinical groups.