Repetitive electromyographic activity, spasmorhythmia and spasmophilia.

Spasmorhythmia (SR) can be defined as repetitive electromyographic activity lasting for longer than 4 min under conditions of cuff-induced ischemia. In a study on more than 180 'normal' subjects, this electrical anomaly was found in 21% of men and 30% of women, and was independent of age. Spontaneous variation in SR several hours or weeks apart is relatively slight, an average of 2 min, with the electrical diagnosis being confirmed by a second test in three quarters of cases. Correlations between SR and magnesium metabolism have not been proved as yet. SR has no pathological significance on its own. It assumes diagnostic importance when found in association with various vascular conditions; when found in association with a characteristic symptomatology, it may be used to support a diagnosis of latent tetany.