Pelvic thrusting may be a feature of seizures of frontal lobe origin; occasionally it may occur in temporal lobe seizures. Pelvic thrusting also occurs in pseudoseizures, particularly those of the "thrashing" variety.
Choreiform disorders may involve the pelvic region causing thrusting or rocking movements.
Geyer JD, Payne TA, Drury I. The value of pelvic thrusting in the diagnosis of seizures and pseudoseizures. Neurology 2000; 54: 227-229