Absence of central functional cholinergic deficits in myasthenia gravis.

Sporadic reports have suggested central involvement in myasthenia gravis, a disorder in which there is an antibody-mediated loss of peripheral nicotinic acetylcholine receptors. Five patients with symptomatic myasthenia gravis performed an auditory vigilance test of ability to direct and sustain attention, presumed to reflect central cholinergic function. No deficits were found, either in comparison with the same subject's performance when muscle strength had improved after plasma exchange, or compared with that of healthy controls. The results thus failed to substantiate reports of functionally significant central cholinergic deficits in myasthenia gravis.