Survival in frontotemporal dementia.

Abstract

To establish survival in patients with pathologically confirmed frontotemporal dementia (FTD) and to determine whether clinical or pathologic subtype affects prognosis. The authors reviewed the presenting clinical features of 61 patients with dementia and pathologically confirmed FTD studied in Sydney (n = 31) and Cambridge (n = 30) over a 10-year period. Data were available on time of symptom onset, diagnosis, institutionalization, and death. Cases were classified pathologically as tau-positive and tau-negative. Of the 61 patients with FTD, 26 presented with frontal variant (fvFTD), 9 with semantic dementia, 8 with progressive nonfluent aphasia (PNFA), 9 with associated motor neuron disease (FTD-MND), and 9 with corticobasal degeneration features. There was no difference between the groups in age at symptom onset (overall mean 58.5 +/- 7.8 years), but at diagnosis the PNFA (68.3 +/- 2.7) group was significantly older than the fvFTD (59.9 +/- 7.4) and FTD-MND (57.7 +/- 7.9) groups. The median survival from symptom onset and from diagnosis was 6 +/- 1.1 years (95% CI) for fvFTD and 3 +/- 0.4 years for FTD-MND. Survival across subgroups was equivalent except for the FTD-MND group, which had significantly shorter survival. Cases with tau-positive pathology had an older age at onset and a significantly better prognosis: median survival 9.0 +/- 0.9 years vs 5.0 +/- 1.1 years. FTD is a malignant disorder with limited life expectancy. FTD-MND has the shortest duration both before and after diagnosis. Tau-positivity is associated with a more slowly progressive form of FTD.