I Googled Senility/Dementia/Alzheimer's hoping to find differentiations. Many of the symptoms are the same. How do you know what it is?

First comes Dementia

Then everything else falls under that umbrella with different symptoms but mostly you are losing your ability to control your normal mind.

Since the brain deals with all cognition whatever is affected has that particular malady named after it.


Dementia is a broad category of brain diseases that cause a long term and often gradual decrease in the ability to think and remember that is great enough to affect a person's daily functioning.[2] Other common symptoms include emotional problems, problems with language, and a decrease in motivation.[2][3] A person's consciousness is usually not affected.[2] A dementia diagnosis requires a change from a person's usual mental functioning and a greater decline than one would expect due to aging.[2][11] These diseases also have a significant effect on a person's caregivers.[2]

The most common type of dementia is Alzheimer's disease, which makes up 50% to 70% of cases. Other common types include vascular dementia (25%), Lewy body dementia (15%), and frontotemporal dementia.[2][3] Less common causes include normal pressure hydrocephalus, Parkinson's disease, syphilis, and Creutzfeldt–Jakob disease among others.[12] More than one type of dementia may exist in the same person.[2] A small proportion of cases run in families.[13] In the DSM-5, dementia was reclassified as a neurocognitive disorder, with various degrees of severity.[14] Diagnosis is usually based on history of the illness and cognitive testing with medical imaging and blood work used to rule out other possible causes.[4] The mini mental state examination is one commonly used cognitive test.[3] Efforts to prevent dementia include trying to decrease risk factors such as high blood pressure, smoking, diabetes, and obesity.[2] Screening the general population for the disorder is not recommended.[15]

There is no cure for dementia.[2] Cholinesterase inhibitors such as donepezil are often used and may be beneficial in mild to moderate disorder.[16][17][7] Overall benefit, however, may be minor.[7][8] There are many measures that can improve the quality of life of people with dementia and their caregivers.[2] Cognitive and behavioral interventions may be appropriate.[2] Educating and providing emotional support to the caregiver is important.[2] Exercise programs may be beneficial with respect to activities of daily living and potentially improve outcomes.[18] Treatment of behavioral problems with antipsychotics is common but not usually recommended due to the little benefit and side effects, including an increased risk of death.[19][20]

Globally, dementia affected about 46 million people in 2015.[9] About 10% of people develop the disorder at some point in their lives.[13] It becomes more common with age.[21] About 3% of people between the ages of 65–74 have dementia, 19% between 75 and 84 and nearly half of those over 85 years of age.[22] In 2013 dementia resulted in about 1.7 million deaths up from 0.8 million in 1990.[23] As more people are living longer, dementia is becoming more common in the population as a whole.[21] For people of a specific age, however, it may be becoming less frequent, at least in the developed world, due to a decrease in risk factors.[21] It is one of the most common causes of disability among the old.[3] It is believed to result in economic costs of 604 billion USD a year.[2] People with dementia are often physically or chemically restrained to a greater degree than necessary, raising issues of human rights.[2] Social stigma against those affected is common.[3] This post was edited by WM BARR . =ABSOLUTE TRASH at September 15, 2017 9:29 AM MDT

I Googled this:  "Senility/Dementia/Alzheimer's"  and it produced a number of links that deal with the differences.  If you haven't done that yet, you might try that.  

At the moment, I am too busy to learn enough about the terms to be able to give you a clear answer---assuming there is one.

Personal experience   Mother had Alzheimer's  She knew nothing about the past or present. She lived in her own world. You could speak to her, she would answer, but she never knew who I was, and did not remember that I was there yesterday (or 5 minutes ago), and she did not care. Her mind was blank save for the imagination. (the worst time was at the beginning, when she had days she was aware of what was happening, and it bothered her so much.  Why is this happening to me?)
  Mother In Law had Dementia..  She slowly lost her short term memory.  Up until the end she knew who I was, but did not remember when I was there last.  Could not tell me what she had for lunch an hour ago, but could tell detailed stories about her youth and childhood. (Names dates etc) Her mind was not a blank, it was only the present that was gone.
  Both were hard for me to accept, but it is something that I had to. You cannot just stick them in a home and forget them.