This document discusses myoclonus, which are sudden, brief involuntary muscle jerks. It describes the different types of myoclonus including positive vs negative and cortical vs subcortical. Various potential causes are outlined such as neurological disorders, metabolic conditions, infections, and medications. Treatment options mentioned include anticonvulsant medications and deep brain stimulation.
2. Introduction
• Sudden, brief, shock-like involuntary movements, associated
with bursts of muscular activity (positive myoclonus) or
silencing of muscular activity (negative myoclonus)
• It may be present at rest, during voluntary movement (action-
induced) or due to provoking stimuli such as sensory, visual,
auditory or emotional cues
• Typically, myoclonus presents as short (10–50 ms, rarely more
than 100 ms), non-rhythmic jerks, often without any
discernible pattern
Caviness, J.N. Myoclonus. Mayo Clin. Proc. 1996, 71, 679–688.
Shibasaki, H. Neurophysiological classification of myoclonus. Neurophysiol. Clin. 2006, 36, 267–269
3. Epidemiology
• The average annual incidence: 1 per 100,000 person-years
• Lifetime prevalence: less than 10 cases per 100,000 population
• The rate increased with advancing age and was consistently
higher in men
• Neurodegenerative and dementing diseases were the most
common cause of symptomatic myoclonus (about 70%)
Caviness, J.N.; Alving, L.I.; Maraganore, D.M.; Black, R.A.; McDonnell, S.K.; Rocca, W.A. The incidence and prevalence of myoclonus in olmsted county, minnesota. Mayo Clin. Proc. 1999, 74, 565–569.
Caviness, J.N.; Brown, P. Myoclonus: Current concepts and recent advances. Lancet Neurol. 2004, 3, 598–607.