Hypsarrhythmia is abnormal interictal high amplitude waves and a background of irregular spikes seen on an EEG. It is very common in infants who have been diagnosed with infantile spasms. Both waves and Spikes vary in duration and size, have no rhythm or pattern and can alternate between focal (partial seizures) and multi focal (epileptic seizures).

Brookelyn has been diagnosed as having Hypsarrhythmia after her first EEG. There is not much that can be done to treat this type of seizure.