Is senile dementia reversible?

No, unfortunately, it's not. :(

The disease will only progress as the dog gets older and eventually she won't be able to coordinate herself, or function normally. I hope before then, you decide to have her placed down, so that her suffering isn't prolonged and so that she dies in a humane and comfortable fashion. I know this is going to be the hardest if not one of the hardest moments of your life because you've had this girl for a long time and she's probably been your guardian, little tiny guardian for years, but understand, that you'll be doing her a HUGE favor, by having her die peacefully, rather then suffering in agony, and pain, and trauma.

If it is senile dementia then no it cannot be reversed, Did the vet see her since the spleen was removed you might want to consult him about what you are presuming is senile dementia. There is some chance that a chemical imbalance related to the surgery is causing the odd behavior. Though at 15 senile dementia would not be unexpected.

No., Canine Cognative Dysfunction aka doggie dementia is not reversible. There are prescription drugs, that your vet can give you a prescription for, that can help slow the disease.

A couple of years ago, the drug was Anipryl. I'm not sure if their still using it for CCD or if something better has come along. As your vet.

The correct answer is possibly to some degree. The drug Anipryl can sometimes restore some function, in addition to slowing the progression of the disease. While nothing will make it go away entirely, this drug, along with lifestyle changes, can help.

Sorry, no. Dementia is not reversible. At 15, she's lived a long and presumably happy life. Just try to keep her comfortable.

No. she is coming to the end of her life ad you will have to enjoy her until life is no longer pleasurable for her and then let her go.

No, brain cells can not regenerate sorry but she is coming to the end of her life.