The impact of cognitive and behavioral impairment in amyotrophic lateral sclerosis.

Introduction : A spectrum of non-motor manifestations in amyotrophic lateral sclerosis (ALS) patients has been increasingly recognized, with cognitive and behavioural impairments the most prominent. Evidence suggests that ALS overlaps on a pathological, genetic, and clinical level with frontotemporal dementia (FTD), thereby suggesting a frontotemporal spectrum disorder (ALS-FTSD). Cognitive impairment has been reported in up to 75% of ALS patients, whilst the rate of behavioural dysfunction ranges up to 50%. Areas covered : The present review explores the current understanding of cognitive and behavioral changes in ALS with a particular emphasis on its implications on prognosis and survival. Expert opinion : Further longitudinal studies are needed to clarify the evolution of cognitive impairment in ALS and how this may ultimately influence survival. Improving understanding of cognitive changes has important implications towards capacity of patients in making critical medical decisions. There is a need to develop a universally accepted and validated cognitive assessment tool to be administered in a multidisciplinary clinic that is efficient and sensitive, as well as being integrated into the design and analysis of future ALS drug trials. In addition, revision of the ALS diagnostic criteria is critically needed, that should accommodate cognitive and behavioural symptoms in addition to motor manifestations.