title: Is there a hypersensitive visual alarm system in panic disorder?
abstract: Agoraphobia in panic disorder (PD) has been related to abnormal balance system function. Vision influences balance and behavioural adaptations; peripheral vision influences orienting and fast defensive reactions whereas central vision analyzes details of objects. We have hypothesized that the abnormal balance function in PD could be mainly related to peripheral vision as part of a defensive alarm system in the brain. In 25 patients with PD and agoraphobia and 31 healthy controls we assessed, by posturography, balance system reactivity to video-films projected in peripheral and central visual fields (randomized sequence). Length, velocity and surface of body sway were calculated. Patients increased their body sway during peripheral stimulation, whereas controls did not; the two groups showed a similar increase of body sway during central stimulation. Anxiety levels during peripheral stimulation significantly influenced the postural response in the group of patients. These preliminary results suggest that the higher visual sensitivity to peripheral stimulation in patients with PD and agoraphobia may be linked to a more active "visual alarm system" involving visual, vestibular and limbic areas that might influence the development of agoraphobia in situations where environmental stimuli are uncertain.
authors.affiliation: Department of Clinical Neuroscience, San Benedetto Hospital, Hermanas Hospitalarias, Albese con Cassano, Italy. caldiroladaniela@gmail.com
authors.forename: Daniela
authors.initials: D
authors.lastname: Caldirola
authors.forename: Roberto
authors.initials: R
authors.lastname: Teggi
authors.forename: Stefano
authors.initials: S
authors.lastname: Bondi
authors.forename: Fabiana Leao
authors.initials: FL
authors.lastname: Lopes
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Grassi
authors.forename: Mario
authors.initials: M
authors.lastname: Bussi
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Perna
mesh_terms: D000328:Adult; D000379:Agoraphobia / Q000503:physiopathology*; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D016584:Panic Disorder / Q000503:physiopathology*; D010775:Photic Stimulation; D004856:Postural Balance / Q000502:physiology*; D011569:Psychiatric Status Rating Scales; D012678:Sensation Disorders / Q000175:diagnosis / Q000209:etiology*; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception; D055815:Young Adult