Reduced binocular depth inversion in patients with alcoholism.

Binocular depth inversion represents an illusion of visual perception, serving to invert the perception of implausible hollow objects, e.g. a hollow face into a normal face. Such inversion occurs frequently, especially when objects with a higher degree of familiarity (e.g. photographs of faces) are displayed. Cognitive factors are assumed to override the binocular disparity cues of stereopsis. The hypothesis was tested that during mild and moderate alcohol withdrawal, and severe and mild alcohol intoxication, the central nervous system is unable to correct implausible perceptual hypotheses. Measurements of binocular depth inversion in perception of three-dimensional objects were performed in 10 patients with severe alcohol intoxication, in 10 subjects with mild alcohol intoxication, in nine patients with moderate alcohol withdrawal treated with carbamazepine, in 10 patients with moderate alcohol withdrawal without any pharmacological treatment, in 11 patients with mild alcohol withdrawal and in 10 healthy volunteers. The binocular depth inversion scores were highly elevated in the severely intoxicated patients group and in the group with moderate withdrawal symptoms without carbamazepine treatment, in comparison to the healthy volunteers. The data demonstrate a strong impairment of binocular depth inversion in moderate alcohol withdrawal and during severe alcohol intoxication. This supports the view that these states may be accompanied by a disorganization of the interaction between sensory input and top-down component. The effects of carbamazepine are discussed.