11 Key Differences Between Dementia And Alzheimer's Disease

7. How Diagnosis Is Made

Diagnosing dementia involves identifying a pattern of cognitive decline, but pinpointing which type—such as Alzheimer’s—requires a deeper evaluation. Doctors use memory and cognitive tests, blood work, brain scans (like MRI or CT), and sometimes PET scans to detect patterns of brain atrophy or plaque buildup. Alzheimer’s is often diagnosed by ruling out other causes of dementia, combined with a detailed review of symptoms and progression. In contrast, other dementias might be diagnosed based on the presence of movement issues, hallucinations, or sudden cognitive decline. A neurologist may also perform spinal fluid tests or genetic screenings in certain cases. Accurate diagnosis is crucial for choosing the right therapies and planning for future care.

8. Age of Onset and Early Signs

While most people with Alzheimer’s are over the age of 65, early-onset cases can appear as young as 40 or 50. These cases may be misdiagnosed initially due to the patient’s age and often begin with subtle memory lapses or difficulty concentrating. Other types of dementia can appear even earlier, particularly frontotemporal dementia, which commonly affects people in their 40s and 50s and tends to show up first as changes in personality, judgment, or language—not memory. Lewy body dementia may begin with visual hallucinations or sleep disturbances. Noticing the nature and timing of early signs can help steer patients toward a more accurate diagnosis sooner.