In the second Neuropsychology study, an established psychological test has picked up early-warning signs of Alzheimer's disease. A new study in the September issue of Neuropsychology explains how the dichotic listening task, which measures how well people process information when they hear one thing in the left ear and another in the right ear, confirms that very early in the disease, people have problems with selective attention. This problem, although not as obvious as memory loss, may also explain why early-stage patients start to struggle with everyday tasks that call for processing a lot of information such as driving.
At the Alzheimer's Disease Research Center at Washington University in St. Louis, Janet Duchek, PhD and David Balota, PhD, studied 94 participants in their early to mid-70s with healthy, very mild, or mild dementia of the Alzheimer's type. They looked for information-processing breakdowns suspected to happen early in the disease, before the appearance of language and visuospatial problems. Problems with attention, the authors say, could "underlie the difficulty with daily activities often seen in the early stages of the disease."
Duchek and Balota used a dichotic listening task, presenting information to participants via headphones. One stream of information computer-generated speech naming three digits (such as 4, 3, 1) went to the left ear; a different stream (such as 9, 2, 5) went to the right ear. The psychologists measured how well participants recalled the digits presented to each ear.
As predicted, people with early dementia remembered the digits presented to the right ear far better than they recalled the digits presented to the left ear. When the researchers controlled for overall recall performance, the mild dementia group recalled 21.7% more information from their right ear vs. left ear, and even the very mildly affected group recalled 11.3% more from the
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Contact: Pam Willenz
pwillenz@apa.org
American Psychological Association
25-Sep-2005