[The staircase phenomenon in myasthenia gravis and other neuromuscular disorders (author's transl)]

The isometric contractions with repetitive stimulation of 2/sec during 90 sec have been recorded in 39 patients with neuromuscular disorders other than myasthenia gravis. Seven patients had falling amplitudes of the contractions, in 14 cases the increase was below 12 per cent and 21 patients had a normal staircase phenomenon. It is recommended to take only a falling of the contraction amplitudes as an important indication for myasthenia gravis. This finding, however, is not specific and in the indivisual case it has to be considered in combination with the other clinical, electro-physiological and histological findings.