consistent during both waking and sleeping states. symptoms of os include: genetic defects mitochondrial disease mitochondrial respiratory chain defects inborn errors of metabolism glycine encephalopathy cortical malformations cerebral asymmetry posterior fossa anomalies agenesis of mammillary bodies frequent minor generalized seizures severe and continuous epileptic eeg abnormality severe psychomotor prognosis spike-and-wave pattern during sleep in continuous spike-and-wave syndrome (csws), a rare form of age-related epilepsy, children between the ages of three and seven exhibit continuous spike-and-wave discharges during slow-sleep. this disorder is found in 0.2–0.5% of all child epilepsy cases. this disorder's discharges rarely result in absence seizures, but motor impairment and neurophysiological regression have been found in csws. spike-and-wave activity occupies about 85% of the non-rapid eye movement sleep. this continuous pattern during sleep, like other aspects of spike-and-wave activity, are not completely understood either. however, what is hypothesized is that corticothalamic neuronal network that is involved in oscillating sleep patterns may begin to function as a pathologic discharging source. clinical relevance reoccurrence after a solitary unprovoked seizure in children is about 50%, so the use of anti-epileptic drugs (aeds) is very prevalent. aeds aim to slow down the excess firing, associated with spike-and-wave discharges, at the beginning of seizures. they can bring about serious adverse drug reactions so physicians need to be aware of the safety and admissibility for each drug. these adverse effects are a major source of disability, morbidity, and mortality. some of the adverse effects, such as serious cutaneous, haematological and hepatic events, usually require withdrawal in children and place a heavy burden on the costs of healthcare. bromide was introduced as the first anti-epileptic drug 150 years ago. because of the adverse effects mentioned above, bromide is not currently in use as an aed. early treatment discontinuation was occurring far too frequently and eventually resulted in negative effects on several patients. current treatment options include phenytoin, valproic acid, ethosuximide, and the new anti-epileptic drugs. over the past 20 years, 15 new anti-epileptic drugs with positive outcomes have been introduced to the public. these new aeds are aimed at improving the cost-benefit balance in aed therapy, improving tolerability profiles and reducing potential for drug interaction. despite these major advances, there is always room for improvement, especially regarding the tailored treatment of individuals who have suffered adverse effects from older aeds.