title: Fragmented perception: slower space-based but faster object-based attention in recent-onset psychosis with and without Schizophrenia.
abstract: BACKGROUND
  Schizophrenia is associated with impairments of the perception of objects, but how this affects higher cognitive functions, whether this impairment is already present after recent onset of psychosis, and whether it is specific for schizophrenia related psychosis, is not clear. We therefore tested the hypothesis that because schizophrenia is associated with impaired object perception, schizophrenia patients should differ in shifting attention between objects compared to healthy controls. To test this hypothesis, a task was used that allowed us to separately observe space-based and object-based covert orienting of attention. To examine whether impairment of object-based visual attention is related to higher order cognitive functions, standard neuropsychological tests were also administered.
  
  
  METHODS
  Patients with recent onset psychosis and normal controls performed the attention task, in which space- and object-based attention shifts were induced by cue-target sequences that required reorienting of attention within an object, or reorienting attention between objects.
  
  
  RESULTS
  Patients with and without schizophrenia showed slower than normal spatial attention shifts, but the object-based component of attention shifts in patients was smaller than normal. Schizophrenia was specifically associated with slowed right-to-left attention shifts. Reorienting speed was significantly correlated with verbal memory scores in controls, and with visual attention scores in patients, but not with speed-of-processing scores in either group.
  
  
  CONCLUSIONS
  deficits of object-perception and spatial attention shifting are not only associated with schizophrenia, but are common to all psychosis patients. Schizophrenia patients only differed by having abnormally slow right-to-left visual field reorienting. Deficits of object-perception and spatial attention shifting are already present after recent onset of psychosis. Studies investigating visual spatial attention should take into account the separable effects of space-based and object-based shifting of attention. Impaired reorienting in patients was related to impaired visual attention, but not to deficits of processing speed and verbal memory.
authors.affiliation: University Center of Psychiatry, University Medical Center Groningen, Groningen, The Netherlands. H.G.O.M.Smid@umcg.nl
authors.forename: Henderikus G O M
authors.initials: HG
authors.lastname: Smid
authors.forename: Richard
authors.initials: R
authors.lastname: Bruggeman
authors.forename: Sander
authors.initials: S
authors.lastname: Martens
mesh_terms: D000328:Adult; D001288:Attention; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010465:Perception; D011618:Psychotic Disorders / Q000523:psychology*; D011930:Reaction Time; D012559:Schizophrenia; D012565:Schizophrenic Psychology; D013028:Space Perception; D014796:Visual Perception; D055815:Young Adult
references.citation: Am J Psychiatry. 1999 Sep;156(9):1358-66
references.pmid: 10484945
references.citation: Psychol Med. 1998 Sep;28(5):1091-100
references.pmid: 9794016
references.citation: Schizophr Res. 2004 Dec 15;72(1):29-39
references.pmid: 15531405
references.citation: Vision Res. 2004 Jun;44(12):1351-65
references.pmid: 15066395
references.citation: Schizophr Bull. 2010 Mar;36(2):400-9
references.pmid: 18682375
references.citation: Psychiatry Res. 1991 May;37(2):139-46
references.pmid: 1876627
references.citation: J Exp Psychol Gen. 1994 Jun;123(2):161-77
references.pmid: 8014611
references.citation: J Psychiatr Res. 1993 Jan-Mar;27(1):119-30
references.pmid: 8515384
references.citation: Biol Psychiatry. 2008 Jul 1;64(1):40-7
references.pmid: 18549875
references.citation: Schizophr Res. 2006 Jul;85(1-3):174-95
references.pmid: 16713184
references.citation: Schizophr Res. 1999 Nov 9;40(1):75-80
references.pmid: 10541010
references.citation: Am J Psychiatry. 2010 Jul;167(7):828-35
references.pmid: 20439390
references.citation: J Abnorm Psychol. 1980 Jun;89(3):409-18
references.pmid: 7410708
references.citation: Arch Gen Psychiatry. 2010 Aug;67(8):772-82
references.pmid: 20679585
references.citation: Schizophr Bull. 2011 Jul;37(4):690-9
references.pmid: 21700589
references.citation: Arch Gen Psychiatry. 2002 Nov;59(11):1011-20
references.pmid: 12418934
references.citation: J Neurosci. 2003 Oct 29;23(30):9812-6
references.pmid: 14586009
references.citation: Science. 1996 Feb 2;271(5249):651-3
references.pmid: 8571128
references.citation: Am J Psychiatry. 1997 May;154(5):647-54
references.pmid: 9137120
references.citation: Neuropsychologia. 1997 Dec;35(12):1519-25
references.pmid: 9460721
references.citation: Brain Cogn. 2005 Feb;57(1):30-4
references.pmid: 15629211
references.citation: Biol Psychiatry. 2010 Feb 1;67(3):255-62
references.pmid: 19897178
references.citation: Psychol Bull. 2005 Jul;131(4):618-632
references.pmid: 16060805
references.citation: Arch Gen Psychiatry. 1988 Sep;45(9):814-21
references.pmid: 3415424
references.citation: J Abnorm Psychol. 1992 Nov;101(4):682-9
references.pmid: 1430608
references.citation: J Exp Psychol Gen. 1994 Jun;123(2):146-60
references.pmid: 8014610
references.citation: Schizophr Bull. 2000;26(1):167-77
references.pmid: 10755679
references.citation: Neuropsychologia. 1995 Oct;33(10):1205-23
references.pmid: 8552225
references.citation: Annu Rev Neurosci. 1990;13:25-42
references.pmid: 2183676
references.citation: Q J Exp Psychol. 1980 Feb;32(1):3-25
references.pmid: 7367577
references.citation: J Exp Psychol Gen. 1984 Dec;113(4):501-17
references.pmid: 6240521
references.citation: Schizophr Bull. 2007 Jan;33(1):142-56
references.pmid: 17118973
references.citation: Neuropsychol Rev. 2003 Jun;13(2):43-77
references.pmid: 12887039
references.citation: Schizophr Res. 2000 Dec 15;46(2-3):209-15
references.pmid: 11120433
references.citation: Psychol Bull. 1992 Jul;112(1):155-9
references.pmid: 19565683
references.citation: Schizophr Res. 2006 Jul;85(1-3):280-7
references.pmid: 16730429
references.citation: Biol Psychiatry. 1992 Oct 1;32(7):617-20
references.pmid: 1450288