An early, accurate diagnosis of AD helps patients and their families plan for the future. It gives them time to discuss care while the patient can still take part in making decisions. Early diagnosis will also offer the best chance to treat the symptoms of the disease.
While the only definite way to diagnose AD is to do a brain biopsy, this is rarely done. Doctors can diagnose AD correctly up to 90 percent of the time in their office.
The first step in diagnosis is to recognize that patients have cognitive impairment such as memory loss or confusion. Family members often bring
these symptoms to the attention of the doctor. The doctor must then determine whether the changes in mental function are enough to
diagnose that the patient has “dementia.” This means that the patient has enough cognitive impairment in multiple areas of thinking to cause impairments in daily living, and that the cognitive impairment is chronic and progressive.
Once a doctor determines that a person suffers from dementia, he then must find out the cause of the dementia. AD is the cause of dementia in about
65% of patients. Other common causes are vascular disease of the brain (multiple strokes leading to vascular dementia), Parkinson’s disease, Lewy Body disease, and some potentially reversible causes such as depression, polypharmacy, vitamin B12 deficiency, thyroid disease, a tumor or hydrocephalus.
To determine the cause of the dementia, doctors do several tests, including:
- Questions about the person’s general health, past medical problems and
ability to carry out daily activities.
- Tests of cognitive function, such as memory, problem solving, attention
and language.
- Medical tests, such as tests of blood, urine, (rarely) spinal fluid
or brain scans.
