title: Deficits in concept formation in amyotrophic lateral sclerosis.
abstract: OBJECTIVE
  Amyotrophic Lateral Sclerosis (ALS) is associated with impaired executive control. The aim of the current research was to test the hypothesis that concept formation deficits associated with an extramotor neurocognitive network involving executive and semantic resources can be found in some ALS patients.
  
  
  METHODS
  Forty-one patients with clinically definite ALS were assessed with Delis Kaplan Executive Function System Sorting Test (D-KEFS), a measure of concept formation requiring patients to manipulate verbal and visual semantic information and neuropsychological tests measuring naming, semantic memory, and executive control. Using D-KEFS scale scores, a k-mean cluster analysis specifying a 3-group solution was able to classify ALS patients into groups presenting with mildly impaired, average, and above average sorting test performance. High-resolution T1 structural MRI was used to examine cortical thickness in a subset of 16 ALS patients.
  
  
  RESULTS
  Stepwise regression analyses related free and recognition sorting test performance to measures of action naming, single word semantic knowledge, and mental search/working memory. MRI studies found widespread cortical thinning involving bilateral frontal, temporal, and parietal regions. Regression analyses related recognition sorting performance to reduced MRI cortical thickness involving the left prefrontal and left parietal cortex.
  
  
  CONCLUSIONS
  An extramotor cognitive network is associated with impaired concept formation in ALS.
authors.affiliation: Department of Neurology, Drexel University College of Medicine, New College Building, 245 North 15th Street, Philadelphia, PA 19102, USA. dlibon@drexelmed.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Libon
authors.forename: Corey
authors.initials: C
authors.lastname: McMillan
authors.forename: Brian
authors.initials: B
authors.lastname: Avants
authors.forename: Ashley
authors.initials: A
authors.lastname: Boller
authors.forename: Brianna
authors.initials: B
authors.lastname: Morgan
authors.forename: Lisa
authors.initials: L
authors.lastname: Burkholder
authors.forename: Keerthi
authors.initials: K
authors.lastname: Chandrasekaran
authors.forename: Lauren
authors.initials: L
authors.lastname: Elman
authors.forename: Leo
authors.initials: L
authors.lastname: McCluskey
authors.forename: Murray
authors.initials: M
authors.lastname: Grossman
mesh_terms: D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications* / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D016000:Cluster Analysis; D003072:Cognition Disorders / Q000209:etiology*; D003210:Concept Formation / Q000502:physiology*; D004185:Disability Evaluation; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012372:ROC Curve; D012044:Regression Analysis; D012660:Semantics