Original ResearchIntensified Hypnic Jerks A Polysomnographic and Polymyographic AnalysisChokroverty, Sudhansu; Bhat, Sushanth; Gupta, Divya Author Information Division of Sleep Medicine, New Jersey Neuroscience Institute at JFK Medical Center and Seton Hall University. Address correspondence and reprint requests to Sudhansu Chokroverty, MD, New Jersey Neuroscience Institute at JFK Medical Center, 65 James Street, Edison, NJ 08818, U. S. A.; e-mail: [email protected]. Journal of Clinical Neurophysiology 30(4):p 403-410, August 2013. | DOI: 10.1097/WNP.0b013e31829dde98 Buy Metrics Abstract Purpose: To analyze the nature and propagation of muscle bursts in patients presenting with intensified hypnic jerks and sleep onset insomnia. Methods: We obtained polymyographic recordings from cranially and spinally innervated muscles during polysomnographic study in 10 subjects presenting with repeated jerking movements at sleep onset, anxiety and sleep onset insomnia. One subject also had daytime polymyography during relaxed wakefulness and drowsiness as well as back-averaging of the EEG preceding the muscle bursts. Results: We observed 4 patterns of muscle propagation: synchronous and symmetrical patterned muscle bursts between the two sides and agonist-antagonist muscles similar to those noted in audiogenic startle reflex, reticular reflex myoclonus, dystonic myoclonus, and pyramidal myoclonus with rostrocaudal propagation of muscle bursts. Conclusion: Hypnic jerks are physiological phenomena which may be accentuated and repeated and may be of several physiological subtypes. © 2013 by the American Clinical Neurophysiology Society