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.
Permanent junctional reciprocating tachycardia (PJRT) is a rare cardiac arrhythmia. It is a supraventricular tachycardia, and a cause of atrioventricular reentrant tachycardia (AVRT). PJRT can cause chronic tachycardia that, untreated, leads to cardiomyopathy. The cause is an accessory pathway in the heart which conducts from the ventricles back to the atria. Unlike the accessory pathway in a more common cause of AVRT, Wolff–Parkinson–White syndrome, the accessory pathway in PJRT conducts slowly. This means that the associated tachycardia may be subclinical and only diagnosed at a late stage, after significant damage to the heart has been caused from prolonged and recurrent episodes of AVRT. Symptoms
Palpitations during exercise or stress may be the presenting symptom. Because the initial symptoms are often mild, there may be significant myocardial damage at the time of diagnosis. It is therefore possible for these patients to present with the symptoms of heart failure, such as shortness of breath, fatigue and  oedema (fluid retention). Cause
In-between episodes there is normal electrical conduction in the heart. During an episode of AVRT caused by PJRT, the accessory pathway conducts electrical activity from the ventricles directly back to the atria at the end of systole, which triggers the atria to contract, and the current to pass back to the ventricles again via the atrioventricular node (AV node); see diagram. Diagnosis
There may be no signs outside of an episode.