I think iwfal was asking a rhetorical question, but beyond multi-infarct or stroke-related dementia, there's vascular dementia, parkinsonian dementia without overt parkinsonian features, lewy body dementia, progressive supranuclear palsy, cortical-basal degeneration, infectious dementias (eg, caused by cryptococci) and of course everyone's favorite, Creutzfeld-Jacob disease and Kuru, or the "laughing death." Etc.
Speaking of which, I wonder if Avanir's Zenvia works for emotional lability associated with Kuru. Might be a bigger market.