Alzheimers and Presenile dementia

Alzheimers noun - A progressive form of presenile dementia that is similar to senile dementia except that it usually starts in the 40s or 50s; first symptoms are impaired memory which is followed by impaired thought and speech and finally complete helplessness.

Presenile dementia and Alzheimers are semantically related. In some cases you can use "Presenile dementia" instead a noun "Alzheimers".

Presenile dementia noun - Dementia with onset before the age of 65.

Alzheimers and presenile dementia are semantically related. Sometimes you can replace term "Alzheimers" with "Presenile dementia", this terms are similar.