Individuals with this type of seizures have epileptic activity in both hemispheres of the brain which is evident in the EEG. The signs can include body stiffening, jerky movements and loss of consciousness for a brief period of time.
Idiopathic generalized epilepsies
Idiopathic generalized epilepsies are usually genetically determined and manifest as typical absences, myoclonic jerks and generalized tonic-clonic seizures. Most often this may develop among the children, particularly before the age of 10 or adolescence but can also affect the adults. This is a life-long condition and in some cases, it can be age-related. EEG can record the abnormality that is triggered by the hyperventilation, sleep deprivation or photic stimulation. Generally, the idiopathic generalized epilepsy cannot be associated with any underlying condition as most seizures are caused by a stroke, brain tumor or other disorders. Some of the types of generalized epilepsy syndromes include the childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy and generalized epilepsies with febrile seizures plus.
Some of the types of generalized epilepsy seizures include the following;
Tonic-clonic seizures
This occurs in two phases, the tonic phase followed by the clonic phase. The tonic phase presents a loss of consciousness and stiffness of the body. The clonic phase may present jerky movements of the limbs, loss of bladder control, clenching of the teeth and difficulty with breathing. After the seizure, individuals may experience tiredness, headaches, memory problems and confusion.
Atonic seizures
This presents the loss of all muscle tone and the individual tends to drop on the floor. This may only last for a very brief period and most often the individual is able to get up straight away but can get hurt with the fall.
Myoclonic seizures
This can occur as brief contractions of body muscles which can begin in both the sides of the body. It may also involve one arm or the foot that can suddenly jerk during sleep. This can either be mild or very forceful.
Absence seizures
This type lasts for a few seconds that involves blank staring that start and end abruptly. This commonly occurs in children between the age of 4 and 12 years who may experience as much as 100 attacks per day. In some cases, it may be accompanied with brief myoclonic jerking of the eyelids or facial muscles.
Secondarily generalized seizure
This occurs after the initial event, which can be a partial seizure. It develops when an abnormal electrical activity in a part of the brain tends to spread throughout. The seizures during this phase don’t last more than a few minutes. The secondary generalized seizure can be quite dramatic in a sudden and forceful form. This can occur as the partial seizure or complex partial seizure that can continue into the secondary generalized seizure which begins with the stiffening of the muscles. The additional signs include loss of consciousness, biting of the tongue or the cheek and may turn blue in the face. After the tonic phase continues the clonic phase with jerky movements of the legs along with the flexing of the elbows, knees and the hips can continue for a few minutes. The bladder control is lost and the individual may feel confused or agitated after regaining consciousness. Typically these seizures last for up to 3 minutes and those that continue beyond 5 minutes usually require medical intervention. Most of the seizures of this kind are treated with medication, devices and diet therapy.
References
http://epilepsychicago.org/epilepsy/seizure-types/generalized-seizures/
http://www.epilepsy.com/learn/types-seizures/secondarily-generalized-seizures