Continuum of frontal lobe impairment in amyotrophic lateral sclerosis

Objective: To identify the nature and prevalence of cognitive and behavioral abnormalities in patients with amyotrophic lateral sclerosis (ALS). Design: Survey of clinical characteristics. Setting: Multidisciplinary clinic within a university medical center. Patients: A volunteer sample of 30 new patients with ALS were recruited consecutively. Of those invited, 23 participants (20 with sporadic ALS and 3 with familial ALS) enrolled. Participants ranged in age from 27 to 80 years (mean age, 56.5 years); the education level ranged from 12 to 21 years (mean education level, 3.5 years of college); and 17 participants (74%) were male. Main Outcome Measures: Neuropsychological tests, neurobehavioral interviews, and structured magnetic resonance imaging. Results: Patients were classified into subtypes of frontotemporal lobar degeneration (n = 5), suspected Alzheimer disease (n = 1), and subthreshold variants of cognitive impairment (n = 2), behavioral impairment (n = 4), and cognitively and behaviorally normal (n = 11). Five neuropsychological tests, 2 behavioral abnormalities, and right hemisphere gray matter reductions differentiated patients into normal and abnormal groups. Conclusions: In this sample, a sizable proportion of patients with ALS possess a range of behavioral and cognitive changes that lie on a spectrum of frontotemporal impairment. Right hemisphere atrophy may be a biomarker for cognitive impairment in patients with ALS.