Hypsarrhythmia
![Awake EEG showing hypsarrhythmia in a 4-month old girl with cryptogenic West syndrome. High amplitude waves and spikes are present, randomly appearing and with no topographical distribution identified; also, there is no frequency nor amplitude gradient, indicating a highly disorganized brain activity. Although having this seemingly chaotic EEG, the patient doesn't show any clinical seizures when recorded.](/Images/godic/202501/19/Hypsarrhythmia0004.png")
Hypsarrhythmia is an abnormal interictal pattern, consisting of high amplitude and irregular waves and spikes in a background of chaotic and disorganized activity seen on electroencephalogram (EEG), and frequently encountered in an infant diagnosed with infantile spasms, although it can be found in other conditions. In simpler terms, it is very chaotic and disorganized brain electrical activity with no recognizable pattern, whereas a normal EEG shows clear separation between each signal and visible pattern.