There is no definitive test for FTD, and because symptoms can resemble those of other disorders, or they fully unfold only as the disorder progresses, accurate diagnosis can be delayed. In the case of Bruce Willis, for example, difficulties with words and speech were the earliest symptoms and led to a diagnosis of aphasia. Soon, however, other symptoms emerged.
The most important tools in FTD diagnosis are detailed personal and family history, genetic tests, and brain scans. Diagnosis usually begins with observation of and a detailed history of a person’s symptoms. A personal and family medical history is also important. A family history of related disorders may prompt the need for genetic tests and laboratory tests to rule out other possible causes. Psychiatric tests may be ordered to rule out such conditions as depression and other psychiatric disorders. Neurological tests are conducted to assess memory, cognitive skills, language skills, and motor function. And finally, brain scans may be used to detect patterns of regional brain atrophy as a way to confirm a diagnosis.