Behavioural variant frontotemporal dementia: not all it seems?
BACKGROUND
The diagnosis of the behavioural variant of frontotemporal dementia (bvFTD) can be challenging. At present there is a paucity of prospective work addressing the specificity of current diagnostic criteria for bvFTD with respect to long-term outcome (i.e., false positives versus true positives).


METHODS
Here we report two individuals who met current clinical criteria for bvFTD and who underwent detailed long-term clinical and neuropsychological follow-up. In addition, both had serial volumetric MRI and functional metabolic (FDG-PET) imaging separated by 5 years.


RESULTS
One case had a slow clinical decline as well as both progressive atrophy and hypometabolism in a frontotemporal distribution, consistent with a neurodegenerative FTD syndrome. However, the second developed neither atrophy nor hypometabolism and remained clinically stable, a decade from symptom onset.


CONCLUSIONS
We propose that these cases illustrate that while there may be a slow evolution in bvFTD, it is possible that some cases who meet current criteria may not have a neurodegenerative syndrome. If correct, this hypothesis has important implications for the current diagnostic criteria. A potential hierarchy for diagnostic certainty in bvFTD is suggested.
Kipps
C M
CM
Department of Clinical Neurosciences, Addenbrooke's Hospital, Cambridge, UK.
Nestor
P J
PJ
Fryer
T D
TD
Hodges
J R
JR
D001519:Behavior / Q000502:physiology*; D001931:Brain Mapping; D003704:Dementia / Q000000981:diagnostic imaging / Q000523:psychology*; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography