title: Examining procedural working memory processing in obsessive-compulsive disorder.
abstract: Previous research has suggested that a deficit in working memory might underlie the difficulty of obsessive-compulsive disorder (OCD) patients to control their thoughts and actions. However, a recent meta-analyses found only small effect sizes for working memory deficits in OCD. Recently, a distinction has been made between declarative and procedural working memory. Working memory in OCD was tested mostly using declarative measurements. However, OCD symptoms typically concerns actions, making procedural working-memory more relevant. Here, we tested the operation of procedural working memory in OCD. Participants with OCD and healthy controls performed a battery of choice reaction tasks under high and low procedural working memory demands. Reaction-times (RT) were estimated using ex-Gaussian distribution fitting, revealing no group differences in the size of the RT distribution tail (i.e., τ parameter), known to be sensitive to procedural working memory manipulations. Group differences, unrelated to working memory manipulations, were found in the leading-edge of the RT distribution and analyzed using a two-stage evidence accumulation model. Modeling results suggested that perceptual difficulties might underlie the current group differences. In conclusion, our results suggest that procedural working-memory processing is most likely intact in OCD, and raise a novel, yet untested assumption regarding perceptual deficits in OCD.
authors.affiliation: Psychology Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel. Electronic address: shahar.nitzan@gmail.com.
authors.forename: Nitzan
authors.initials: N
authors.lastname: Shahar
authors.affiliation: Department of Psychological and Brain Science, Indiana University, Bloomington, IN 47405, USA.
authors.forename: Andrei R
authors.initials: AR
authors.lastname: Teodorescu
authors.affiliation: Psychology Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: Gideon E
authors.initials: GE
authors.lastname: Anholt
authors.affiliation: Psychology Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: Anat
authors.initials: A
authors.lastname: Karmon-Presser
authors.affiliation: Psychology Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: Nachshon
authors.initials: N
authors.lastname: Meiran
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002755:Choice Behavior; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000503:physiopathology / Q000523:psychology*; D008570:Memory, Short-Term / Q000502:physiology*; D009771:Obsessive-Compulsive Disorder / Q000503:physiopathology / Q000523:psychology*; D011930:Reaction Time / Q000502:physiology*; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: Evidence accumulation modeling; Ex-Gaussian distribution; Executive functions; Intra-individual variability; Obsessive compulsive disorder; Working memory