[Electromyographic recording of the Strümpell phenomenon applied to pyramidal syndrome diagnosis]

After some years of empirical observation which pointed to the possibility of using the Strümpell phenomenon (SPh) electromyographic register (EMG) as a helpful tool in pyramidal syndrome diagnosis, the author began to study the SPh systematically, from March 1987 on, during the EMG examination of the anterior tibial muscles. The EMG was always effected with a needle concentric electrode and a calibration of 0.05 to 0.2mV and 1s per division. The patient, lying on the back, is asked to slowly and completely stretch his thigh, and a positive SPh displays an EMG which shows involuntary tonic contractions of growing amplitude on the anterior tibial muscle during its extension. In order to establish an EMG systematic schedule of this synkinesia and to be able to evaluate its relevance for pyramidal syndrome diagnosis, the author revised all 579 EMG registers he had established from March-1987 on. 26 reports (4.49%) belonged to SPh-positive patients, and it was possible to detect or to confirm that they presented a pyramidal syndrome. 20 patients of similar age who showed no pyramidal sign presented EMG silence (90%) or some clonic contractions (10%) on the tibial muscle during SPh research. The author suggests, therefore, the inclusion of SPh research into the conventional EMG examination of the anterior tibial muscles, specially in cases of amyotrophic lateral sclerosis and in cases presenting myeloradicular or spinal cord syndromes.