Atonic seizure true http://www.case.edu/EpSO.owl#AtonicSeizure Drop seizures Atonic seizures UMLS:C0270846 SNOMEDCT_US:42365007 Drop attacks 2010-07-10T03:13:06Z Atonic seizure is a type of motor seizure characterized by a sudden loss or diminution of muscle tone without apparent preceding myoclonic or tonic event lasting about 1 to 2 seconds, involving head, trunk, jaw, or limb musculature. Sudden loss of muscle tone HP:0010819 SNOMEDCT_US:189198006 Hypotonic seizure Astatic seizures Astatic seizure This term describes the initial semiology of the seizure without specifying whether the onset is focal or generalized. Thus it can be used for coding atonic seizures when the onset is not known. Hypotonic seizures human_phenotype UMLS:C1836509 peter HP:0002124 https://www.epilepsydiagnosis.org/seizure/atonic-overview.html generalized motor onset seizure