People with frontotemporal dementia (FTD) are often misdiagnosed with Alzheimer’s disease (AD), psychiatric disorders, vascular dementia or Parkinson’s disease. The early symptoms and the brain image are often the most helpful tools to reach the right diagnosis.
Frontotemporal Dementia versus Alzheimer’s Disease
AD is the most common dementia in older people. Therefore, it is often one of the first diseases a doctor considers. But Alzheimer’s disease usually begins with memory loss, while FTD is typically a behavior or language disorder.
- The probability of AD is strongly affected by the age of the person showing the symptoms. The odds of having Alzheimer’s disease increase markedly the older you get, while the odds for FTD may decrease with age.
- FTD often begins with distinct behavioral changes (socially inappropriate, apathetic, impulsive, etc.) while people with Alzheimer’s disease in the early stages tend to remain socially skillful despite their memory problems (they may even become adept at covering up their difficulties). In advanced AD, people generally have trouble managing their finances, show poor judgment and irritability, and may become equally difficult to manage as people with FTD.
- Apathy in AD patients is milder, whereas apathy in FTD patients is more pervasive and more often reflects a lack of concern for others or lack of initiative.
- People with AD usually have early and profound difficulty learning and retaining new information. As the disease progresses, memory for new and old information is lost. These memory problems may lead to language problems as well, but the root is a problem remembering. In contrast, most mildly impaired FTD patients generally know the day or time and their location, and they are able to keep track of recent events. They may not test well, but that may be due to a lack of concern or effort in the testing situation.
Frontotemporal Dementia versus Psychiatric Disorders
When behavioral symptoms predominate, people with FTD who become ill in mid-life may be confused with patients who have late-life depression. When the onset is in younger persons, the FTD may be confused with schizophrenia or bipolar disorder. Repetitive compulsive behaviors are very common in bvFTD, and some patients may initially be given the diagnosis of obsessive-compulsive disorder. Since the history and exam of a person with a psychiatric disorder and a person with FTD may look very similar, neuropsychological testing and a brain image may help clarify the picture. MRI can help rule out other diseases and support a diagnosis of FTD.
Frontotemporal Dementia Diagnosis
Once other likely explanations have been ruled out, an FTD diagnosis is made by looking at the data from a neurological exam and personal history (which may come from the patient, family, or another caregiver); neuropsychological tests that help quantify memory, language, and other cognitive skills; and a brain image – usually an MRI (magnetic resonance imaging) scan but perhaps a functional scan like PET (positron emission tomography), which can show increased or lowered brain activity in the frontal and anterior temporal areas.
