In patients with frontotemporal dementia (FTD) and frontotemporal lobar degeneration (FTLD), symptoms are more likely to occur later in life, which could aid in antemortem neuropathologic predictions, according to study findings presented in Neurology.
A total of 2 consecutive cohorts of patients who were evaluated and diagnosed at the UCSF Memory and Aging Center were included in this study. The cohorts were comprised of autopsied patients with a diagnosis of FTD spectrum clinical syndrome (n=190) and patients with a primary neuropathologic FTLD diagnosis irrespective of clinical syndromic diagnosis (n=201). Using a cut-off of 65 years, the series were divided by age at symptom onset.
Among patients included in cohort 1 and cohort 2, a total of 48 (25.3%) and 57 (28.4%) patients experienced the onset of symptoms by ≥65 years (late onset), respectively. In cohort 1, overall FTLD-tau and progressive supranuclear palsy (PSP) were more frequent in late-onset FTD vs early-onset FTD (P =.014 and P <.001, respectively). A post-hoc analysis demonstrated a significantly higher frequency of pathologic diagnosis of PSP than of corticobasal degeneration in late-onset vs early-onset corticobasal syndrome (CBS) (P =.002), whereas early-onset CBS demonstrated a significantly higher rate of Alzheimer disease pathologic diagnosis than PSP when compared with late-onset CBS (P =.002).
In the second cohort, FTLD with transactive response DNA-binding protein (43 kDa) was more frequent in early-onset FTLD (44.4%) than in late-onset FTLD. Conversely, FTLD-tau was more common in late-onset FTLD than in early-onset FTLD (58.3%). In addition, the antemortem diagnosis of a non-FTD syndrome (eg, Alzheimer disease-type dementia) was more common among patients experiencing late-onset FTLD vs early-onset FTLD in cohort 2 (19.3% vs 7.7%, respectively; P =.017).
In addition, patients with late-onset FTLD often had pathologically diagnosed FTLD that coexisted with other neuropathologic changes. Compared with early-onset FTLD, the investigators observed more frequent cerebral amyloid angiopathy (16.1% vs 37.2%, respectively; P =.004), vascular brain injury (18.7% vs 35.9%, respectively; P =.026), arteriosclerosis (65.9% vs 93.8%, respectively; P =.002), argyrophilic grain disease (28.9% vs 58.6%, respectively; P =.005), and hippocampal sclerosis (0.0% vs 10.5%, respectively; P <.001) in late-onset FTLD.
The small sample sizes within each cohort represents the study’s primary limitation. Additionally, archived patient data were not evaluated to the level of completion that newer cases were, which may limit the power of the findings.
Findings from this study may assist in raising “awareness of FTD in the geriatric population and help improve antemortem prediction of pathology.”
Seo SW, Thibodeau MP, Perry DC, et al. Early vs late age at onset frontotemporal dementia and frontotemporal lobar degeneration [published online February 16, 2018]. Neurology. doi:10.1212/WNL.0000000000005163