The diagnostic term for a disease characterized by early senility, confusion, loss of recognition of persons or familiar surroundings, and restlessness is:

Alzheimer's Disease

Explanation:

There are seven stages of changes occurring in an individual with Alzheimer's disease.  

In the first stage, the brain works normally and only through PET scan Alzheimer's disease can be detected.  

In the second stage, a person starts forgetting small things such as spelling, words etc.  

In the third stage, forgetfulness reaches the second level and a person can forget things which he/she has just seen or read. She/he questions the same thing again and again and also forgets name of people he/she meet regularly.  

In the fourth stage, a patient forgets his/her own detail and by the fifth stage he/she become unable to do daily course work such as dressing etc. due to forgetfulness.  

In the sixth stage, delusions occur and in the last stage a person can even forget about eating, bathing, swallowing etc.