title: Does a visual perceptual disturbance characterize trauma-related anxiety syndromes?
abstract: The i-test was developed to assess the visual-perceptual disturbances (VPDs) frequently reported by anxious patients. Persons with the disturbance report a specific abnormal illusion of movement when they maintain a fixed gaze at the i-test stimulus. Base rates for positive responses to the i-test and for reports of a "recurrent specific memory" (RSM) of a fear experience were obtained in psychiatric outpatient (n = 301) and community (n = 128) samples. In each case, approximately one fifth of participants had a positive response to the i-test and one fifth of participants reported an RSM of fear. A positive response to the i-test is observed in women more frequently than in men. Among psychiatric patients, approximately 90% of patients who report one symptom also report the other symptom; among community members, the concordance rate is approximately 33%. When psychiatric patients with both an abnormal illusion of movement response and an RSM of trauma are treated with eye movement desensitization, both symptoms are removed in 70% of cases; when these patients undergo some other form of treatment, both symptoms are removed in 30% of cases. These results indicate that the i-test is an effective way of identifying VPDs associated with psychopathologic conditions; the association between the abnormal illusion of movement and reports of recurrent specific memories of fear experiences suggests that the VPD may be a marker of traumatic stress syndromes.
authors.affiliation: rtympsyc@ozemail.com.au
authors.forename: R
authors.initials: R
authors.lastname: Tym
authors.forename: M J
authors.initials: MJ
authors.lastname: Dyck
authors.forename: G
authors.initials: G
authors.lastname: McGrath
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001008:Anxiety Disorders / Q000209:etiology* / Q000523:psychology; D002648:Child; D003887:Desensitization, Psychologic; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000523:psychology; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology; D009903:Optical Illusions / Q000502:physiology; D010468:Perceptual Disorders / Q000209:etiology* / Q000503:physiopathology* / Q000628:therapy; D012680:Sensitivity and Specificity; D013313:Stress Disorders, Post-Traumatic / Q000523:psychology*; D014796:Visual Perception / Q000502:physiology*