Propriospinal myoclonus: diagnostic value of polymyography and video polysomnography

Propriospinal myoclonus is a hyperkinetic movement disorder characterized by painless jerks of the axial muscles, mainly in the trunk and hips. A 53-year-old woman was referred to the Sleep Unit with trunk flexion movements in the supine position during the wake-sleep transition and during sleep, with premonitory sensation. We performed 2 video polysomnographic recordings. In the first video polysomnogram, the recording showed jerks of the trunk and abdomen that appeared when the posterior dominant alpha rhythm disappeared; during these jerks the patient stayed at stage 1 or stage 2 of non-rapid eye movement sleep. The second video polysomnogram included several electromyogram electrodes located at the masseter, deltoid, rectus abdominis (T9-T0 level), vastus lateralis, and tibialis anterior muscles. This polysomnogram revealed 123 repetitive arrhythmic jerks with variable duration, usually lasting 500-1,900 ms each (906 ± 0.4 ms). In our patient, propriospinal myoclonus was detected up to stage 2 of non-rapid eye movement sleep and even at rapid eye movement sleep.

Ramos RW, Viñas LL, Martín ER, Cárdenas CL, Pereda AF, Manzanares LL. Propriospinal myoclonus: diagnostic value of polymyography and video polysomnography. J Clin Sleep Med. 2023;19(5):995-998.