Donald Trump’s father, Fred Trump Sr., was reported to have “mild senile dementia”, a term commonly used at the time for age-related cognitive decline. Later family accounts and medical reporting have often described it as Alzheimer’s disease / Alzheimer-type dementia.
How old was he when signs first appeared?
The most clearly documented medical record says he was diagnosed in October 1991 at age 86.
However, the physician’s notes from that diagnosis specifically mention “obvious memory decline in recent years”, which means the symptoms had likely started several years earlier, probably in his early 80s (around 82–84).
Some family members said they noticed changes even earlier, during the 1980s, which could place the first noticeable signs in his late 70s to early 80s.
So, in short:
• Type: Alzheimer’s / senile dementia (older terminology)
• Official diagnosis age: 86
• Likely first signs: late 70s to early 80s
• Clear symptoms noted for several years before diagnosis
If you want, I can explain the difference between Alzheimer’s and “senile dementia” in simple terms.