In 1935, Lindsley1 demonstrated electromyographically in patients with myasthenia gravis that the fatigue which accompanies voluntary contraction of muscles is associated with profound fluctuations in the amplitude of the action potentials. Harvey and Masland,2 and more recently Churchill-Davidson and Richardson3 have described more critical electromyographic techniques in the diagnosis of myasthenia gravis, both of which employ repetitive electrical stimulation of peripheral nerve. These procedures have the distinct advantage of eliminating the variability which accompanies voluntary effort, but the extraocular muscles, so frequently involved in myasthenia, cannot be investigated in this fashion.
In recent years action potentials from extraocular muscles have been recorded by numerous investigators, including Björk and Kugelberg,4 Breinin and Moldaver,5 Teasdall and Sears,6 and the characteristic patterns from normal muscle have been clearly defined. Accordingly, it was felt that this procedure might be helpful not only as an aid in the diagnosis
SEARS ML, WALSH FB, TEASDALL RD. The Electromyogram from Ocular Muscles in Myasthenia Gravis. AMA Arch Ophthalmol. 1960;63(5):791-798. doi:10.1001/archopht.1960.00950020793008