Many research groups have begun using techniques such as magnetic resonance spectroscopy, functional imaging and cortical thickness measurements in an attempt to offer an earlier diagnosis to the FTD patient. Fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) scans classically show frontal and/or anterior temporal hypometabolism, which helps differentiate the disease from Alzheimers disease. The PET scan in Alzheimers disease classically shows biparietal hypometabolism. Meta-analyses based on imaging methods have shown that frontotemporal dementia mainly affects a frontomedial network discussed in the context of social cognition or theory of mind. This is entirely in keeping with the notion that on the basis of cognitive neuropsychological evidence, the ventromedial prefrontal cortex is a major locus of dysfunction early on in the course of the behavioural variant of frontotemporal degeneration. The language subtypes of frontotemporal lobar degeneration (semantic dementia and progressive nonfluent aphasia) can be regionally dissociated by imaging approaches in vivo.The confusion between Alzheimers and FTD is justifiable due to the similarities between their initial symptoms. Patients do not have difficulty with movement and other motor tasks. As FTD symptoms appear, it is difficult to differentiate between a diagnosis of Alzheimers disease and FTD. There are distinct differences in the behavioral and emotional symptoms of the two dementias, notably, the blunting of emotions seen in FTD patients. In the early stages of FTD, anxiety and depression are common, which may result in an ambiguous diagnosis.
However, over time, these ambiguities fade away as this dementia progresses and defining symptoms of apathy, unique to FTD, start to appear.Recent studies over several years have developed new criteria for the diagnosis of behavioral variant frontotemporal dementia (bvFTD).The confirmatory diagnosis is made by brain biopsy, but other tests can be used to help, such as MRI, EEG, CT, and physical examination and history. Six distinct clinical features have been identified as symptoms of bvFTD. Disinhibition
Apathy/Inertia
Loss of Sympathy/Empathy
Perseverative/compulsive behaviors
Hyperorality
Dysexecutive neuropsychological profileOf the six features, three must be present in a patient to diagnose one with possible bvFTD. Similar to standard FTD, the primary diagnosis stems from clinical trials that identify the associated symptoms, instead of imaging studies. The above criteria are used to distinguish bvFTD from disorders such as Alzheimers and other causes of dementia. In addition, the new criteria allow for a diagnostic hierarchy distinguished possible, probable, and definite bvFTD based on the number of symptoms present.A 2021 study, led by researchers at the University of Pennsylvania, determined that using cerebrospinal fluid (CSF) biomarkers of pathologic amyloid plaques, tangles, and neurodegeneration, collectively called ATN, can be useful in diagnosing FTD. Neuropsychological tests
The progression of the degeneration caused by bvFTD may follow a predictable course. The degeneration begins in the orbitofrontal cortex and medial aspects such as ventromedial cortex. In later stages, it gradually expands its area to the dorsolateral cortex and the temporal lobe. Thus, the detection of dysfunction of the orbitofrontal cortex and ventromedial cortex is important in the detection of early stage bvFTD.