Kitty dementia?

My Katie is just getting over being sick and is just starting to perk up a little although her appetite has not returned. Shes 18. She has lately taking spells of crying at night. What I thought was going to be a peaceful sleep after working 7 days in row turned out to be just the opposite. She has done this before but just not as frequent. She will stand by the bed and continuously cry (she can't jump) so i pick her up and put her on the bed. She be there for awhile, then get down and a little while later the same thing starts all over again. Then i finally get up for the day and she is sacked out on the bed and I can't arouse her.

Has anyone else had a cat that has done this? And given her age could it be kitty dementia?

I don't know about the dementia, but my cat is also 18 and she cries at night sometimes too.  At first I thought she was trying to tell me something and was in distress.  I finally decided she was calling to our other cat who is her friend and sometimes sleeps with her.  Who knows though...

Yes indeed, cats can get dementia, even Alzheimer's: http://www.veterinarypracticenews.com/vet-dept/feline-practice/cats-can-get-alzheimers.aspx

As for Katie wanting up on the bed, what about getting her some pet steps? She probably also has arthritis at her age and might appreciate not having to jump down.

Something else to consider if you haven't done so recently is to have a vet check with a senior blood panel. Hyperthyroidism is common in older cats and one of the symptoms is yowling.