title: Let's inhibit our excitement: the relationships between Stroop, behavioral disinhibition, and the frontal lobes.
abstract: OBJECTIVE
  The Stroop (Stroop, 1935) is a frequently used neuropsychological test, with poor performance typically interpreted as indicative of disinhibition and frontal lobe damage. This study tested those interpretations by examining relationships between Stroop performance, behavioral disinhibition, and frontal lobe atrophy.
  
  
  METHODS
  Participants were 112 patients with mild cognitive impairment or dementia, recruited through UCSF's Memory and Aging Center. Participants received comprehensive dementia evaluations including structural MRI, neuropsychological testing, and informant interviews. Freesurfer, a semiautomated parcellation program, was used to analyze 1.5T MRI scans. Behavioral disinhibition was measured using the Neuropsychiatric Inventory (Cummings, 1997; Cummings et al., 1994) Disinhibition Scale. The sample (n = 112) mean age was 65.40 (SD = 8.60) years, education was 16.64 (SD = 2.54) years, and Mini-Mental State Examination (MMSE; Folstein et al., 1975) was 26.63 (SD = 3.32). Hierarchical linear regressions were used for data analysis.
  
  
  RESULTS
  Controlling for age, MMSE, and color naming, Stroop performance was not significantly associated with disinhibition (β = 0.01, ΔR² = 0.01, p = .29). Hierarchical regressions controlling for age, MMSE, color naming, intracranial volume, and temporal and parietal lobes, examined whether left or right hemisphere regions predict Stroop performance. Bilaterally, parietal lobe atrophy best predicted poorer Stroop (left: β = 0.0004, ΔR² = 0.02, p = .002; right: β = 0.0004, ΔR² = 0.02, p = .002). Of frontal regions, only dorsolateral prefrontal cortex atrophy predicted poorer Stroop (β = 0.001, ΔR² = 0.01, p = .03); left and right anterior cingulate cortex atrophy predicted better Stroop (left: β = -0.003, ΔR² = 0.01, p = .02; right: β = -0.004, ΔR² = 0.01, p = .02).
  
  
  CONCLUSIONS
  These findings suggest Stroop performance is a poor measure of behavioral disinhibition and frontal lobe atrophy even among a relatively high-risk population.
authors.affiliation: Department of Neurology, Memory and Aging Center, University of California, San Francisco Medical Center, USA. lara.heflin@va.gov
authors.forename: Lara H
authors.initials: LH
authors.lastname: Heflin
authors.forename: Victor
authors.initials: V
authors.lastname: Laluz
authors.forename: Jung
authors.initials: J
authors.lastname: Jang
authors.forename: Robin
authors.initials: R
authors.lastname: Ketelle
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Miller
authors.forename: Joel H
authors.initials: JH
authors.lastname: Kramer
mesh_terms: D000368:Aged; D001931:Brain Mapping; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology; D003704:Dementia / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009483:Neuropsychological Tests; D009929:Organ Size; D011859:Radiography; D011930:Reaction Time; D057190:Stroop Test