Picking away at frontotemporal dementia

Compared with the knife-edge lobar atrophy that defines the gross pathology of frontotemporal dementia (FTD), the clinical picture of this disorder has less sharp contours.1,2⇓ Articles in this issue of Neurology consider the prevalence of FTD,3 clinical diagnostic criteria for FTD,4 and CSF biomarkers as diagnostic aids.5

Although FTD is uncommon in autopsy series from research centers or from community-based dementia studies,6 the counter-claim is that FTD is underrecognized clinically and accounts for at least 20% of presenile dementia.1 Epidemiologic studies of dementia typically survey people aged 65 and older and may exclude most cases of FTD. Ratnavalli et al.3 determined the prevalence of dementia with onset before age 65 in a geographically defined population. They contacted all primary care, specialty neurology, and psychiatry providers, examined district medical records, and personally evaluated as many patients with suspected FTD as possible, using a detailed clinical and radiologic assessment. They diagnosed FTD according to the consensus criteria of 1998,7 a modification of the earlier set of Manchester–Lund criteria.8 A small retrospective study showed that the consensus criteria had excellent sensitivity and specificity when applied by …