What kind of seizure would cause a 6 yo to violently shake his hand in his sleep around 7am for a min or so? his arm was bent and tense. he seemed fine upon waking. we have a neuro appt on the 22nd. please help me start learning so i can be informed?

See below: It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. It is good that you have an appointment. Wish you and your child good health!

"seizure": Your description does fit a focal seizure, which is generated from the opposite side of the brain. You are proceeding in the correct direction and a neurologist will likely order imaging and an EEG. Would anticipate interventions will likely control or stop these events.