Visual performance and recovery in recently detoxified alcoholics

In order to assess the impact of chronic alcohol misuse on basic Visual fun ctions. we investigated motion perception. visual short-term memory, and vi sual divided attention in recently detoxified patients and matched controls by means of visual psychophysical tasks, subjects were tested twice within the first 3 weeks of detoxification in order to assess the potential recov ery of visual performance. Patients demonstrated significant impairments in visual perception of coherent motion for slow, but not faster. speeds, and in speed discrimination as assessed by random dot kinematograms. Visual sh ort-term memory tested with a delayed vernier discrimination task. on the o ther hand, was not significantly affected in patients. When processing hier archical letters. a divided attention task, detoxified patients showed neit her impairments in overall attentional capacity nor attentional allocation, bur slightly enhanced interference of global information on local target p rocessing. The results of the visual divided attention task contradict the predictions of the 'right hemisphere' hypothesis of alcoholism: global targ et information - mediated by the right hemisphere - was not only accessible to detoxified patients, hut seemed to exert an even greater influence on l ocal processing during early detoxification. than in matched controls. Limi ted recovery within the first 3 weeks was seen only in visual speed discrim ination. Recently detoxified patients revealed deficits similar to intoxica ted social drinkers in identical tests of visual perception of motion, hut not visual short-term memory.