Getting jerk, hiccups, movement one makes before exactly the sleep starts and spasms one gets during anxiety or stress are examples of myoclonus originating from physical problem.
Essential Type :
Myoclonus of this type develops on its own, without any reason. Hence no apparent cause is available for this type. It is believed to be of hereditary origin.
Epileptic Type :
Epilepsy is the cause of this type of myoclonus exhibiting muscle jerk.
Secondary Type :