BY CAROLINE SEYDEL
Drinking alcohol has physical effects on the brain and for alcoholics, the brain damage that accompanies alcohol abuse may not heal completely even after the drinking has stopped.
A study of alcoholic men who completed a 28-day rehabilitation program at the Veterans Affairs (VA) Palo Alto Health Care System showed that even after treatment, cognitive ability does not fully recover. Researchers Edith Sullivan, PhD, and Margaret Rosenbloom, at Stanford, and Adolf Pfefferbaum, MD, at SRI International, collected data on 53 alcoholics, testing brain functions such as memory, balance, problem solving and visuospatial ability (like assembling a child's bicycle). The tests were chosen to represent different regions of the brain that might be affected by alcohol consumption.
"We used different types of tests to assess very selective cognitive or motor processes," said Sullivan, associate professor of psychiatry and behavioral sciences.
For instance, in one test patients had to cross out all copies of the letter A interspersed randomly among 400 other letters on a page. Another test involved copying a complex geometrical design. And a test assessing gait and balance required the subjects to walk heel-to-toe for 10 steps, stand on one foot for 30 seconds, and stand with feet placed heel-to-toe with arms folded for 60 seconds -- the same type of tests police officers give suspected drunk drivers.
One of the most striking findings the study turned up was that older alcoholics are at greater risk for problems with balance than younger ones, regardless of lifetime alcohol consumption. A person who becomes an alcoholic at a later age is more likely to have problems.
"Even after you account for the effects of aging in gait and balance, which is really quite dramatic, the alcoholics showed an effect which was over and above that which you would see in normal aging," Sullivan said. "The older people are really worse off for their age than are the younger people, and it's not necessarily because they've drunk more alcohol over their lifetime."
Elderly people are more prone to falls anyway, she said, and elderly recovering alcoholics may have an even higher risk of falling. She said that because gait and balance is a category often overlooked in neuropsychological testing, and was previously thought to fully recover in the absence of alcohol abuse, the finding is particularly significant.
Just as interesting is what the researchers didn't find. Sullivan said she observed no difference between analogous verbal and nonverbal tests, meant to assess differences between the right and left hemispheres of the brain. Previous findings that alcoholics have more trouble processing nonverbal material led to the idea that the right hemisphere is affected to a greater extent. Sullivan's results contradict that hypothesis. "In our hands," she said, "we didn't find any systematic differences in the extent of the deficit of the nonverbal compared with the verbal tests."
The researchers also imaged some patients' brains using magnetic resonance imaging (MRI) to correlate the test results with changes in brain anatomy. They found that although older alcoholics have profound shrinkage in the prefrontal cortex, an area of the brain associated with higher order thinking, their performance on tests to assess such thinking skills was not severely diminished. The researchers note in their paper, "This apparent functional resilience with advancing age occurs despite the increased structural vulnerability to alcohol of the aging brain shown by MRI studies."
They found similar disagreement between the MRI volume measures and test performance in memory function; but in a companion study, they found that decreased volume measures in a brain region called the cerebellar vermis do correspond to problems with gait and balance.
Sullivan hopes the study's findings will help improve rehabilitation efforts. Typical rehab programs last 28 days, and some are even shorter. "These are people that are supposed to be well now," she said of the study subjects. "If a recovering alcoholic had drunk abusively for 10 or 20 or 30 years, why should we expect that he or she could recover after a 3-day or even a 30-day rehabilitation program?" she said. "We don't expect that of a stroke patient. Why should we expect that of an alcoholic who also has sustained demonstrable brain damage?"
She added, "This highlights the importance of prolonged rehabilitation efforts to ensure continued recovery in the newly abstinent alcoholic."
The study was funded by the National
Institute on Alcohol Abuse and Alcoholism. SR