People with Korsakoff Syndrome (KS), a brain disorder usually associated with long-term heavy drinking and thiamine deficiency, often have profound deficits in their "explicit memory" or ability to recall recent events. A study in the April issue of Alcoholism: Clinical & Experimental Research looks at a memory process called visuoperceptual learning, a component of "implicit memory," which does not require conscious recollection. Results suggest that individuals with KS retain the ability to learn information that is presented visually, even without a conscious recollection of that learning.
"'Explicit events' refer to situations that an individual can consciously recall when asked, 'what did you do yesterday?' or 'what did you do over the holidays?,'" explained Edith Sullivan, a professor in the department of psychiatry and behavioral sciences at Stanford University School of Medicine and corresponding author for the study. "Individuals with KS cannot consciously recall what they did or information presented to them earlier in the day."
"Explicit memory is often referred to as 'knowing what' and implicit memory to 'knowing how,'" said Sara Jo Nixon, professor and director of the Neurocognitive Laboratory at the University of Kentucky. "However, the impact of chronic excessive alcohol consumption on implicit memory has been less clear and less frequently studied. Visuoperceptual tasks likely engage a significant component linked to implicit memory functions. Thus, examining implicit memory using such a task in a comparison of Korsakoff alcoholics, non-Korsakoff alcoholics and control