Characteristics and classification MMPSI is characterized by seizures that onset between the 1st week of life and 7 months of age, with average age of onset being 3 months. These seizures are nearly continuous, without interposed periods of remission, and involve independent areas of either side of the brain. These seizures result in psychomotor delay, which is a child failing to meet developmental milestones on time, ultimately resulting in intellectual disability. The International League Against Epilepsy (ILAE) classifies MMPSI as an 'electroclinical syndrome.' Each electroclinical syndrome is a disease that is distinguishable from others on the basis of age of onset of seizures, seizure types, electroencephalogram (EEG) findings, and various other clinical features. Electroclinical syndromes are primarily classified by age of onset, in which MMPSI is preceded by Ohtahara syndrome and succeeded by West syndrome, which onset in the neonatal and<unk>  periods, respectively. It may also be considered an 'epileptic encephalopathy,' diseases in which unremitting epileptic activity leads to severe cognitive and behavioral impairments. When categorized based on age of onset, it is grouped together with early infantile epileptic encephalopathy (EIEE, same as Ohtahara syndrome), early myoclonic encephalopathy (EME), and infantile spasms (IS, same West syndrome). Disease phases + Age of onset of each phase Phase Age range first 1 week and 7 months second 3 weeks and 10 months third shortly before 1 year and 5 years MMPSI has been described to have three phases. In the first phase, seizures are sporadic and typically only affect motor function. The second phase is termed the "stormy phase." Seizures become very frequent and polymorphous, meaning that seizures affect different parts of the body each time. Seizures can be so frequent that they appear to be continuous for weeks at a time. In the third phase, seizures are characteristically absent. However, recurrent seizures and status epilepticus can still occur.
Malignant migrating partial seizures in infancy
Childhood absence epilepsy
Benign familial neonatal seizures
Benign infantile epilepsy
Benign familial infantile epilepsy
Autosomal dominant nocturnal frontal lobe epilepsy
Generalized epilepsy with febrile seizures plus
Benign neonatal seizures