title: Levels-of-processing effect on internal source monitoring in schizophrenia.
abstract: BACKGROUND
  Recognition can be normalized in schizophrenia by providing patients with semantic organizational strategies through a levels-of-processing (LOP) framework. However, patients may rely primarily on familiarity effects, making recognition less sensitive than source monitoring to the strength of the episodic memory trace. The current study investigates whether providing semantic organizational strategies can also normalize patients' internal source-monitoring performance.
  
  
  METHODS
  Sixteen clinically stable medicated patients with schizophrenia and 15 demographically matched healthy controls were asked to identify the source of remembered words following an LOP-encoding paradigm in which they alternated between processing words on a 'shallow' perceptual versus a 'deep' semantic level. A multinomial analysis provided orthogonal measures of item recognition and source discrimination, and bootstrapping generated variance to allow for parametric analyses. LOP and group effects were tested by contrasting recognition and source-monitoring parameters for words that had been encoded during deep versus shallow processing conditions.
  
  
  RESULTS
  As in a previous study there were no group differences in LOP effects on recognition performance, with patients and controls benefiting equally from deep versus shallow processing. Although there were no group differences in internal source monitoring, only controls had significantly better performance for words processed during the deep encoding condition. Patient performance did not correlate with clinical symptoms or medication dose.
  
  
  CONCLUSIONS
  Providing a deep processing semantic encoding strategy significantly improved patients' recognition performance only. The lack of a significant LOP effect on internal source monitoring in patients may reflect subtle problems in the relational binding of semantic information that are independent of strategic memory processes.
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA. ragland@bbl.med.upenn.edu
authors.forename: J Daniel
authors.initials: JD
authors.lastname: Ragland
authors.forename: Erin
authors.initials: E
authors.lastname: McCarthy
authors.forename: Warren B
authors.initials: WB
authors.lastname: Bilker
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Brensinger
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Valdez
authors.forename: Christian
authors.initials: C
authors.lastname: Kohler
authors.forename: Raquel E
authors.initials: RE
authors.lastname: Gur
authors.forename: Ruben C
authors.initials: RC
authors.lastname: Gur
mesh_terms: D000328:Adult; D001244:Association; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000523:psychology*; D008606:Mental Processes; D011939:Mental Recall; D010414:Pennsylvania; D021641:Recognition, Psychology; D012565:Schizophrenic Psychology; D012660:Semantics