Frontal-lobe mediated behavioral dysfunction in amyotrophic lateral sclerosis

Eur J Neurol. 2010 Jan;17(1):103-10. doi: 10.1111/j.1468-1331.2009.02801.x. Epub 2009 Oct 29.


Background: Cognitive impairment secondary to frontal lobe atrophy exists in 40-60% of Amyotrophic Lateral Sclerosis (ALS) cases. We aimed to determine the prevalence of frontal-lobe mediated behavioral impairment in (ALS) and to ascertain its relationship to cognitive impairment.

Methods: Two-hundred and twenty five patients diagnosed with sporadic ALS were evaluated for behavioral dysfunction using the Frontal Systems Behavior Scale (FrSBe), a validated measure used to examine frontal-lobe mediated behaviors, specifically apathy, executive dysfunction and disinhibition; a total behavior score is also provided. Additionally, a subset of patients also underwent a comprehensive neuropsychological evaluation.

Results: Changes in the total FrSBe scores were observed in 24.4% of the patients and 39.6% of the patients had impairment in at least one behavioral domain with symptoms of Apathy being the most common (31.1%). Cognitively impaired ALS patients had worse total (P = 0.05) and apathy scores (P < 0.01); however, behavioral dysfunction was also present in 16% of the cognitively intact patients. Half of the behaviorally intact patients exhibited cognitive impairment. Significant correlations were observed for performance on certain neuropsychological tests (Animal fluency, Block Design, Logical Memory I and Verbal Series Attention Test) and severity of behavioral dysfunction on certain FrSBe sub scores.

Conclusions: Frontal-lobe mediated behavioral dysfunction appears to be common in ALS. Cognitively impaired ALS patients had greater behavioral dysfunction. Recognition of behavioral and cognitive dysfunction may assist health-care providers and care-givers recognize changes in decision-making capacity and treatment compliance of patients with ALS.

MeSH terms

  • Adult
  • Aged
  • Amyotrophic Lateral Sclerosis / epidemiology*
  • Amyotrophic Lateral Sclerosis / psychology*
  • Cognition Disorders / diagnosis*
  • Cognition Disorders / epidemiology*
  • Comorbidity
  • Decision Making / physiology
  • Disability Evaluation
  • Female
  • Frontal Lobe / physiopathology*
  • Humans
  • Male
  • Mental Disorders / diagnosis
  • Mental Disorders / epidemiology
  • Middle Aged
  • Neuropsychological Tests
  • Predictive Value of Tests
  • Prevalence
  • Severity of Illness Index