Occupational attainment influences survival in autopsy-confirmed frontotemporal degeneration

Abstract

Objective: To examine the influence of occupational attainment and education on survival in autopsyconfirmed cases of frontotemporal lobar degeneration (FTLD) and Alzheimer disease (AD).Methods: We performed a retrospective chart review of 83 demographically matched, autopsyconfirmed FTLD (n 5 34) and AD (n 5 49) cases. Each patient's primary occupation was classified and ranked. Level of education was recorded in years. Survival was defined as time from symptom onset until death. Linear regression was used to test for associations among occupational attainment, education, and patient survival.Results: Median survival was 81 months for FTLD and 95 months for AD. Years of education and occupational attainment were similar for both groups. We found that higher occupational attainment was associated with longer survival in FTLD but not AD. Cognitive reserve (CR) posits that a person develops cognitive strategies and neural connections over the course of a lifetime through experiences such as education, occupation, and mental engagement. Conclusions:

Cognitive reserve in frontotemporal degeneration

“…These findings are consistent with a reserve model linking preserved frontal anatomic integrity and superior strategic processing to the prolonged survival of patients with FTLD who have higher education and occupational attainment. 13 Our findings are consistent with other evidence suggesting that CR is an environmental factor influencing the spectrum of disease in FTLD. Prior neuroimaging studies of patients with bvFTD with unconfirmed FTLD pathology indicate CR may counteract the onset of dementia, [10][11][12] while a recent survival analysis in patients with autopsy-confirmed FTLD pathology by our group indicates that higher occupational attainment is associated with prolonged survival from symptom onset.…”

“…Prior neuroimaging studies of patients with bvFTD with unconfirmed FTLD pathology indicate CR may counteract the onset of dementia, [10][11][12] while a recent survival analysis in patients with autopsy-confirmed FTLD pathology by our group indicates that higher occupational attainment is associated with prolonged survival from symptom onset. 13 These studies suggest that, despite the commonality of frontotemporal-predominant neurodegeneration, patients with FTLD appear to exhibit heterogeneous disease course that is determined in part by environmental factors related to CR. It is imperative to identify and understand potential environmental contributors to the rate of decline in FTLD, as these may serve as prognostic markers and eventual therapeutic targets.…”

“…13 From this perspective, patients with FTLD with higher occupational attainment may detect dementia symptoms earlier than lower occupational attainment patients due to increased frontally mediated work demands, therefore giving the impression that they are surviving longer. This is in contrast with traditional CR accounts based on Alzheimer disease (AD) that suggest that higher CR factors such as education and occupational attainment are associated with shorter survival.…”

Tuberculous optochiasmatic arachnoiditis and vision loss

“…Our work, 4 associating higher CR with early frontal atrophy and prolonged survival in autopsy-proven FTD, contrasts with observations in AD that show shorter survival in patients with higher CR and later frontal atrophy. 5 While our imaging methods account for interindividual differences in intracranial volume, 6 and control for differences in disease duration and age, we cannot rule out the possibility that individuals with higher CR are able to sustain cognitive function due to greater neuronal richness or frontal brain connectivity.…”

“…These 2 mechanisms may help reconcile apparently contradictory findings in dementia, whereby higher CR is associated with shorter disease duration in Alzheimer disease (AD), 3 but longer duration in frontotemporal dementia. 4 It is plausible that, in AD, compensatory mechanisms can delay symptomatology, whereas, in frontotemporal dementia, brain reserve may be more important. Longitudinal studies that combine behavioral and neuroimaging data are likely to shed light on this important issue.…”