Anipryl, aka selegiline or L-deprenyl, is more often used in dogs (for either Cushing's or cognitive disfunction), much rarer to use it in cats. Here is an extremely thorough discussion of feline CDS: http://www.vetstreamfelis.com/ACI/De...2/dis60684.asp
Definitely make sure Quincy has his T4 levels checked when he goes in to see the vet, as hyperthyroidism can often look like the onset of dementia.
Something else you might want to look into is Cholodin: http://www.vetinfo.com/cholodin-feli...e-effects.html
A good multi-vitamin wouldn't hurt either. NuCat Senior is the best one, IMO.