To the Editor.
—In the recently published article by Nelson et al,1 an intriguing P300 amplitude difference between patients with left vs right temporal lobe seizure foci in response to stimulation within the right visual field is reported. Unfortunately, we found that a number of issues critical to the interpretation of this finding were not sufficiently addressed in the article.Nelson et al employed a task that required the patients to respond by button press and mental count to the visual presentation of the word "BAT" or a set of "Chinese characters." They imply that the task demands language processing, but it seems to us that such a task can be accurately performed without relying on language processing beyond what is needed to count. Moreover, although the stimuli were presented either within the left or the right visual fields, it is not clear how it was ensured that