In patients with both amyotrophic lateral sclerosis and frontotemporal dementia (ALS–FTD), the initial presenting symptoms can provide clues as to the future trajectory of the disease, according to new research published in Neurology.

“We wanted to investigate whether disease progression in patients with ALS–FTD differed depending on whether they present first with motor or cognitive symptoms,” explains corresponding author Rebekah Ahmed. “This question has implications for prognostication and also for disentangling fast and slow progressors in clinical trials.”

The study included 59 patients with ALS–FTD who were recruited from clinics at the Brain and Mind Centre, University of Sydney, Australia. Among these individuals, 41 (69%) had initially presented with cognitive symptoms and 18 (31%) had initially presented with motor symptoms.

The researchers found that median survival from the time of symptom onset was considerably shorter in the patients with motor presentation than in those with cognitive presentation (2.7 years versus 4.4 years), despite similar levels of cognitive functioning between the groups at the beginning of the study.

“The main conclusion that can be drawn is that survival in ALS–FTD is not uniformly poor, and that it depends on whether patients develop motor or cognitive symptoms first,” comments Ahmed. “The findings suggest that progression in ALS–FTD is linked to motor and physiological changes rather than to cognitive changes.”

The investigators suggest that future research should focus on the pathological determinants of survival in patients with ALS–FTD, including a potential role for neurodegeneration in the motor cortex.