Visual scan paths are abnormal in deluded schizophrenics.
One explanation for delusion formation is that they result from distorted appreciation of complex stimuli. The study investigated delusions in schizophrenia using a physiological marker of visual attention and information processing, the visual scan path-a map tracing the direction and duration of gaze when an individual views a stimulus. The aim was to demonstrate the presence of a specific deficit in processing meaningful stimuli (e.g. human faces) in deluded schizophrenics (DS) by relating this to abnormal viewing strategies. Visual scan paths were measured in acutely-deluded (n = 7) and non-deluded (n = 7) schizophrenics matched for medication, illness duration and negative symptoms, plus 10 age-matched normal controls. DS employed abnormal strategies for viewing single faces and face pairs in a recognition task, staring at fewer points and fixating non-feature areas to a significantly greater extent than both control groups (P < 0.05). The results indicate that DS direct their attention to less salient visual information when viewing faces. Future paradigms employing more complex stimuli and testing DS when less-deluded will allow further clarification of the relationship between viewing strategies and delusions.
Phillips
M L
ML
Department of Psychological Medicine, Institute of Psychiatry, London, U.K.
David
A S
AS
D000328:Adult; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology; D003702:Delusions / Q000523:psychology*; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D008606:Mental Processes; D011569:Psychiatric Status Rating Scales; D012565:Schizophrenic Psychology; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*