Question 6: What can we conclude about the differences in psychological test performance between epileptics and controls?
There is no evidence of any difference in vocabulary. The regression lines are virtually identical, so the mean vocabulary score at any age appears to be the same for epileptics and controls.
For verbal learning ability, the lines are parallel but separated by a vertical distance of more than 10 points. There is no evidence that epileptics lose verbal learning ability faster than controls, but their level is lower at each age.
These were the conclusions of the authors (Helmstaedter and Elger 1999).
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