Objective: To compare the clinical features at presentation in patients with frontotemporal dementia (FTD) who develop amyotrophic lateral sclerosis (ALS) with those of patients with behavioral variant FTD (bvFTD) who do not develop ALS.
Design: Archival data analysis on 61 deceased patients with FTD. We reviewed the clinical features at presentation (behavioral changes, psychotic symptoms, language, and executive and memory problems) and survival.
Setting: Early Onset Dementia Clinic, Cambridge, England. Patients From a total of 156 patients with a clinical diagnosis of behavioral FTD, we selected 61 deceased patients with comprehensive medical records, including 43 with bvFTD and 18 with FTD/ALS.
Main outcome measures: Clinical features and survival.
Results: There was a significant association between the presence of delusions (50%; odds ratio, 4.4; 95% confidence interval, 1.3-14.5) and diagnosis of FTD/ALS (n = 18), whereas the behavioral features were identical in both groups. The interval between the onset of behavioral changes and diagnosis of ALS was less than 2 years in 12 (67%) of the patients with FTD/ALS. The median survival from symptom onset was significantly shorter for the FTD/ALS group (2.4 years; 95% confidence interval, 1.8-3.0 years) than for the bvFTD group (6.6 years; 5.6-7.6 years).
Conclusions: Delusions are particularly common in patients who develop FTD/ALS. The occurrence of delusions in the context of behavioral FTD should lead to an early search for ALS features.