For this study, researchers compared two groups of children: 11 (10 male, 1 female) with confirmed prenatal alcohol exposure, and 14 nonexposed children (13 males, 1 female). All of the children completed 20 trials of both SRT and CRT tasks. Muscle activity was recorded from the bicep brachii muscle of each arm using electromyography to measure reaction times.
"Our study showed that for SRT tasks, when the information-processing load is relatively small," said Simmons, "there was no significant difference in reaction time between the children with prenatal alcohol exposure and the control children. However, when the information load increased during CRT tasks, alcohol-exposed children had slower reaction times. This is consistent with the notion that alcohol exposure results in brain damage, which, in turn, impairs information processing and produces a slower CRT."
"It is significant that these findings persisted after the investigators controlled for IQ deficits," noted Sandra W. Jacobson, professor and director of Therapy Research and Resident Training at Wayne State University School of Medicine. "Otherwise, it could be argued that the processing speed deficit was merely another manifestation of the children's poorer IQ. Instead, what is shown here is that even when you control for IQ, the children who are heavily exposed process information and react more slowly." These deficits, she added, likely reflect damage to numerous regions of the brain.
"Another significant and innovative aspect of this report," said Jacobson, "is that the investigators used a state-of-the-art paradigm, one in which they were able to further separate premotor from motor reaction times in children known to have been heavily exposed to alcohol during pregnancy and compare their performance to that of matched controls."
Premotor reaction time re
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16-Sep-2002