One of the problems with AChEI's is the fact that they cause
gastrointestinal side-effects that many people cannot tolerate.  While
this study poses a concern, it was only performed on 29 otherwise
healthy men (18-35 y.o.); the impaired acetylcholinergic nervous
system in AD and other dementias may lead to a different result.  At
the very least, switching to a daytime regimen should be closely
monitored by a physician.

For the curious, here is the entire discussion by the authors, with
respect to acetylcholine levels at sleep time, in sufferers of AD:

"This finding also implies that the administration of cholinesterase
inhibitors before sleep in patients with AD should be reconsidered."

Darryl.