Examining procedural working memory processing in obsessive-compulsive disorder. (July 2017)

• Record Type: Journal Article
• Authors: Shahar, Nitzan; Teodorescu, Andrei R.; Anholt, Gideon E.; Karmon-Presser, Anat; Meiran, Nachshon
• Is Part Of: Psychiatry research. Volume 253(2017)
• Page Start: 197
• Page End: 204
• Publication Date: 2017-07
• Subjects: Obsessive compulsive disorder -- Ex-Gaussian distribution -- Intra-individual variability -- Evidence accumulation modeling -- Working memory -- Executive functions; Psychiatry -- Periodicals; Psychiatry -- periodicals; Psychiatrie -- Périodiques; 616.89
• DOI: 10.1016/j.psychres.2017.03.048
• Languages: English
• ISSNs: 0165-1781

Abstract

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. Highlights: Working memory deficits were suggested to underlie obsessive-compulsive symptoms. Recent meta-analysis found only small-effect sizes for working memory deficits in OCD. This might be due to the strict use of declarative working memory measurements. We show that procedural working memory is also intact in OCD. Decision modeling raise a novel assumption regarding perceptual deficits in OCD.