Author Response: Phenotypic Variability in ALS-FTD and Effect on Survival

We thank Dr. Abe for his interest in our study1 that investigated survival in patients with amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD). Specific comparison of motor and cognitive presentations in ALS-FTD established that patients with a motor onset of their disease had reduced survival—which was associated with increased motor cortex atrophy—suggesting that survival may be mediated by motor function and other critical physiologic aspects.