No abstract

The effect of local cooling was studied in 28 patients with myastenia gravis. We stimulated the ulnar nerve with single stimuli and trains at 3/s for 2s and at 50/s for 1.5 s. The compound muscle action potential (MAP), the muscle twitch and the isometric tetanic force of the adductor pollicis were registered. 1. At 3/s stimulation the pathological decrement of the MAP decreased after slight cooling. 2. The amplitude of the single MAP was higher at lower temperature when compared to normal temperature. The same increase is however to be found in healthy subjects. 3. After slight cooling, the maximum tetanic force was higher. However, the decrement of the force was higher also, therefore ruling out a practicable application of cooling for the patient. 4. After severe cooling (18-22 degrees C) the tetanic force was much lower and in many cases a complete failure of the neuromuscular transmission occured.

The compound muscle action potential (MAP) and the isometric twitch force of the adductor pollicis of 25 normal subjects were registered after local cooling. Intramuscular temperature ranged from 36.6 to 18.0 degrees C. The amplitude of the MAP increased while the twitch force decreased at lower temperatures. The increase of the MAP could be caused by the effect of cooling directly at the muscle cell membrane. The decreased twitch force probably is due to an affect on the contractile apparatus.

No abstract

4 patients are described with ophthalmoplegia (Figs. 1 and 2) and ataxia with acute onset. Three of them showed only very slight symptoms of generalized polyneuritis. Measurement of sensory nerve conduction velocity (Fig. 4, Table 2) and determination of vibration sense by an electrical vibrator (Fig. 3) proved to be helpful for diagnosis. The ocular EMG revealed signs of peripheral denervation in 3 cases. Pathological changes of the somatosensory evoked potential (Fig. 5) which has been registered in one case, might give some speculation as to whether or not central nervous pathways are affected.