Seizures are caused by temporary disturbances in the braincells. The way an attac of epilepsy appears depends on the location of the initial disturbance and to what extent the disturbances spread throughout the brain. Persons with mild epilepsy may have a couple of attacs during a lifetime, persons with severe epilepsy may have several different types of seizures and daily attacs, despite of medication.
Epilepsy is caused by a permanent or a temporary damage of the brain, more or less severe. The greater the braindamage, the greater the risk of seizures. Therefore epilepsy is far more common among persons with diagnosed dagamges of the brain, like CP, than among the population in general. These persons will also probably have a more severe type of epilepsy than other persons with epilepsy.
Epilepsy is statistically a bit more common among persons with Down syndrome than in the general population, because epilepsy is quite common as a complication to dementia, which is overrepresented among persons with Down syndrome. Children with Down syndrome are not diagnosed with epilepsy more than children in general, but if they do get diagnosed, it is generally with the more serious types of epilepsy.
Infantile spasm, also called West Syndrome or BNS-seizures, is a rare, severe form of epilepsy that is overrepresented among children with Down syndrome. Most children with Down syndrome who have epilepsy have infantile spasm.
BNS means blitz (lightning)-nick (nod)-salaam, which is a very accurate description of the seizure: seizure comes quick like lightning, the upper body nods forward and arms fling out like in an arabic "salaam-greeting".
Infantile spasm always appears before 18 months of age and is diagnosed with EEG; the infantile spasm EEG is very characteristic. It is most important to start treatment immediately as infantile spasm causes a strong disturbance in the whole brain and the progress of the child is affected.
If you have a child with Down syndrome and you see something that just vagely reminds of infantile spasm you should see to it that the child immediately is taken to an expert, a neurologist specialized in children!
Infantile spasm-seizures might be difficult to spot as they only last a second, but they often come in series and are thus possible to notice.
Some children reacts positively at medication and are soon free of seizures, others have attacs that are more difficult to control, which, sadly, leads to slower psycho-motoric progress. Often infantile spasm in those children progress into other forms of severe and hard-to-control-epilepsy, like Lennox-Gastaut syndrome, myoclonic epilepsy, astatic-myoclonic epilepsy or epilepsy with tonic-clonic seizures ("grand mal") or a combination of some or all the above.
Read Katarina's history of epilepsy.
General information about epilepsy can be found at Svenska Epilepsiförbundet (also in English).