By Dr Ananya Mandal, MD
There are several different types of epilepsy and each type has a different unique combination of symptoms, age of onset, type and frequency of convulsions or seizures, EEG appearance, treatment and possible response to therapy. Several of these are syndromes that encompass a combination of features.
Some of the epilepsy syndromes include:
Benign centrotemporal lobe epilepsy of childhood or Benign rolandic epilepsy
This is an epilepsy that is idiopathic and typically begins in children between 3 and 13 years of age. Most commonly it starts before onset of puberty. There are simple partial seizures that involve facial muscles and are frequently associated with excessive salivation and drooling. There may be secondary generalization of the partial seizures. Seizures typically occur at night during sleep. The EEG shows spike discharges that occur over the centrotemporal scalp over the central sulcus of the brain. This is called the Rolandic sulcus. Seizures may require anticonvulsant treatment but may cease to occur beyond puberty.
Benign occipital epilepsy of childhood (BOEC)
This is an idiopathic epilepsy with an evolving group of syndromes. There are two subtypes. One of them is early and occurs between 3–5 years of age and another late onset that occurs between 7–10 years. The seizures have visual symptoms such as appearance of brightly colored spots or lines (scotoma) or blindness (amaurosis). Seizures usually may affect half of the body with eye deviation or head turning. In the early onset type the symptoms are similar to migraine with headache and nausea. Older patients develop visual symptoms. The EEG in BOEC shows spikes recorded from the back of head or occipital regions. There is a genetic component in inheritance and it is inherited as an autosomal dominant trait. Panayiotopoulos syndrome is a group of epileysy syndromes that share some clinical features of BOEC.
Temporal lobe epilepsy
This is another symptomatic epilepsy and is most common in adults. In most cases the region of problem region is found in the midline (mesial) temporal structures like hippocampus, amygdala, and parahippocampal gyrus. There are complex partial seizures sometimes preceded by an aura and sometimes secondary generalization of seizures.
Frontal lobe epilepsy
This is a cryptogenic epilepsy. It appears from lesions causing seizures that occur in the frontal lobes of the brain.
This is a syndrome of epilepsy that affects women around their menstrual cycle.
Childhood absence epilepsy
This is also called idiopathic generalized epilepsy that affects children between the ages of 4 and 12 years of age. The absence seizures are brief episodes of unresponsive staring with features such as blinking or chewing. The child appears to freeze at what he or she is doing. If unaware, the care givers may feel he or she is day dreaming. Once the episode passes the child goes back to what they were doing. The typical EEG feature is 3 Hz spike and wave discharges. Sometimes the seizure may be generalized. There is usually no risk of cognitive decline with this type.
Juvenile absence epilepsy
This is another idiopathic generalized epilepsy with later onset that childhood absence epilepsy. The features are similar.
This is characterized by severe myoclonic seizures and is called Severe myoclonic epilepsy of infancy (SMEI). This is a generalized epilepsy. It starts in the first year of life. There may be fetal hemiclonic epilepsy with clonic seizures of one half of the body. Sometimes there may be generalized status epilepticus. Males are affected more than females. Prognosis is poor and there is presence of a family history of epilepsy in a quarter of all cases.
Juvenile myoclonic epilepsy (JME)
This occurs in patients aged 8 to 20 years. Patients have normal cognition. There are myoclonic jerks along with some episodes of generalized tonic-clonic seizures, absence seizures etc. Myoclonic jerks usually cluster in the early morning. The EEG reveals generalized 4–6 Hz spike wave discharges.
Lennox-Gastaut syndrome (LGS)
There are three features of this epilepsy syndrome - developmental delay with childhood dementia, mixed generalized seizures, and EEG demonstrating 2 Hz slow spike-wave pattern. It is an idiopathic, symptomatic, or cryptogenic epilepsy. There may be different types of seizures with common occurrence of astatic seizures (drop attacks), tonic seizures, tonic-clonic seizures, atypical absence seizures and complex partial seizures.
This is a rare form of epilepsy that occurs with cerebral palsy. There are frequent seizures which typically start in the first few days of life. There is severe disability and low chances of survival till adulthood.
Progressive myoclonic epilepsies
These include groups of symptomatic generalized epilepsies with progressive dementia and myoclonic seizures. This includes Unverricht-Lundborg disease, Lafora disease, neuronal ceroid lipofucinosis, and sialdosis.
This is another localization-related epilepsy which occurs due to a progressive, inflammatory lesion in children below 10. Seizures start as simple partial or complex partial seizures and may go on to become epilepsia partialis continuata (simple partial status epilepticus). On scans of the brain inflammatory encephalitis on one side of the brain is seen. Dementia and weakness of one side of the body are other problems.
This has three features of developmental delay, seizures termed infantile spasms, and EEG demonstrating a pattern termed hypsarrhythmia. It starts between 3 months and 2 years of age. There may be idiopathic or cryptogenic causes. The most common cause is tuberous sclerosis.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)