To the Editor.
—The conclusions of the articles by Dr Haley et al1,2 that purport to demonstrate at least 3 distinct Gulf War syndromes are supported by the examination of only 23 patients with self-reported symptoms and exposures. In contrast, studies by the Departments of Defense and Veteran Affairs were based on the evaluations of more than 70 000 veterans.3 We reported the extensive clinical, laboratory, neurophysiological, and histological evaluation (muscle biopsies) of 20 patients with the most severe neuromuscular symptoms and concluded there was no evidence to suggest a neuromuscular disorder unique to the Persian Gulf War or that our veterans' symptoms were related to toxic exposures.4Besides the limitations of their methods,5 there are problems with the neurophysiological data. Evoked potentials have a limited utility in evaluating patients with possible neurologic disorders. The major efficacy of evoked potentials is in looking for paraclinical evidence of demyelination, and