It would be fair to say many of us believe the stand-out sign of Alzheimer's is memory loss.
But a new study warns that isn't the case.
In fact, it claims there are numerous symptoms of the degenerative disease which often go unnoticed, meaning many people are not diagnosed until much later than they could be.
The latest research from Northwestern University's Cognitive Neurology and Alzheimer's Disease Centre seeks to change our preconceptions.
"We wanted to describe these individuals to raise awareness about the early clinical and brain features of PPA [primary progressive aphasia] to develop metrics which would advocate for their inclusion in clinical trials targeting Alzheimer's disease," Dr Emily Rogalski told the Daily Mail.
"These individuals are often excluded because they don't have memory deficits, but they share the same disease [Alzheimer's] that's causing their symptoms."
According to Dr Rogalski, your symptoms and type of Alzheimer's will depend on what part of the brain is affected.
And a doctor cannot know for sure where a person's disease is rooted until after their death during a post-mortem examination.
However, there are some key markers of PPA that we may not immediately recognise as symptoms.
1. Unusual confidence
Lack of inhibitions can be the case for many types of Alzheimer's, including PPA.
"Someone who was very shy may go up to a grocery store clerk - who is a stranger - and try to give her a hug or a kiss," Dr Rogalski said.
2. Language issues
This symptom presents most clearly in patients with PPA.
Primary progressive aphasia is a form of dementia that impacts our ability to process speech and articulate words.
Patients may have delayed or halting speech, decreased vocabulary, and misuse of words.
3. Writing difficulties
A person who may have had no problems with spelling words may begin to struggle.
They may also struggle with simple writing tasks, like a cheque or signing a birthday card.
4. Struggling to read
It can become problematic to follow sentences through to the end, or to digest a full paragraph.