Accurate, early FTD diagnosis is crucial – for appropriate care, improved quality of life and disease management, adequate support for caregivers, better informed decisions around family planning, and access to clinical trial participation. But because FTD comprises a group of disorders, many of whose symptoms overlap with other neuropsychiatric and neurodegenerative conditions, FTD can be challenging to recognize and diagnose, even for experienced medical professionals.

The multistep FTD diagnostic process adds further complexity. Currently, in the absence of validated biomarkers, a probable FTD diagnosis can only be made following a comprehensive clinical evaluation, neuropsychological testing, speech-language assessment, neuroimaging, and, in some cases, genetic testing. (A definitive diagnosis can only be made through genetic testing – or, if one’s FTD is not genetic in nature, upon autopsy.)

The FTD diagnostic process begins with a thorough clinical history and physical examination. Clinicians gather detailed information from the patient and – because insight into one’s own behavioral or cognitive changes can be limited in FTD – from close family members or caregivers as well.

The FTD disorders primarily affect the brain’s frontal and temporal lobes, which are responsible for one’s behavior, personality, communication, and movement. Symptoms include:

Diagnosing a person’s specific clinical subtype of FTD requires identifying the most prominent symptoms, along with neuroimaging. Differentiating these subtypes from similar conditions, including Alzheimer’s disease or Parkinson’s disease, is essential to ensure proper care planning.

A full neuropsychological evaluation should be included to better assess the pattern of cognitive loss in an individual suspected of having FTD, and to help rule out psychiatric etiologies for their symptoms. Neuropsychological assessments can characterize cognitive deficits, which helps distinguish FTD from other dementias and provide supportive evidence for an FTD diagnosis. Note, however, that some patients can perform within normal limits during this assessment, particularly when their symptoms are mild. Full neuropsychological screenings are conducted by a neuropsychologist and can take several hours.

Speech-language assessments play a critical role in diagnosing primary progressive aphasia (PPA), an FTD subtype characterized by difficulty producing and understanding language, both written and spoken. They can also help identify which of the three PPA variants (nonfluent/agrammatic, semantic, and logopenic) a person has, allowing clinicians to develop personalized therapy strategies for both the patient and their family members.

Structural and functional brain imaging is a cornerstone of FTD diagnosis. MRI typically reveals atrophy in the frontal and/or temporal lobes, with patterns corresponding to a specific FTD subtypes. Meanwhile, functional imaging (e.g., FDG-PET or SPECT) can detect hypometabolism in affected regions before structural changes are obvious on MRI. These modalities are especially helpful in differentiating FTD from Alzheimer’s, which tends to show parietal and medial temporal involvement.

Approximately 40% of FTD cases have a family history. In a subset of those cases – roughly 15-20% – a genetic variant can be identified as the cause of FTD; these variants can then be passed along to the next generation. Many current clinical trials evaluating FTD treatments focus on genetic forms of the disease, giving families and clinicians an additional reason to consider genetic counseling and testing.

Genetic testing – preceded by genetic counseling, which AFTD strongly recommends – should be considered for patients with a family history of dementia, psychiatric conditions, Parkinson’s, or ALS. Identifying an FTD-causing genetic mutation can aid in confirming the diagnosis, informing prognosis, opening opportunities for clinical trials, and guiding family counseling.

Several conditions can mimic FTD. Part of the diagnostic process involves ruling out other conditions, including:

Therefore, laboratory workups including blood tests, thyroid function, vitamin levels (especially B12), and sometimes infectious or autoimmune panels may be part of the diagnostic process.

Diagnosing FTD is a multifaceted process that requires careful integration of clinical assessment, neuropsychological testing, neuroimaging, and sometimes genetic testing. The variable presentation and overlapping symptoms with psychiatric and other neurological disorders make early and accurate diagnosis challenging but vital for patient care, prognosis, and planning. As research advances, particularly in the areas of biomarkers and genetics, the hope is to improve diagnostic precision and develop targeted treatments for this complex and heterogeneous disease.

Visit AFTD’s website for a list of medical diagnostic centers with experience in diagnosing FTD.