Hypsarrhythmia is a pattern most often associated with which condition?

Hypsarrhythmia is a specific EEG pattern characterized by chaotic, high-amplitude slow waves with asynchronous spikes, and it is most commonly linked to infantile spasms. This condition is a type of epilepsy that typically appears in infancy and involves brief, sudden movements known as spasms. The distinct EEG findings of hypsarrhythmia are crucial for the diagnosis of infantile spasms, as they reflect the underlying abnormalities in brain function associated with this condition.

In contrast, the other conditions listed, such as febrile seizures, grand mal seizures, and absence seizures, each present with different EEG patterns and clinical characteristics. Febrile seizures occur in the context of fever and generally show a more organized EEG pattern. Grand mal seizures, or generalized tonic-clonic seizures, exhibit a different type of EEG activity characterized by generalized spike-and-wave discharges. Absence seizures typically present with a pattern of 3 Hz spike-and-wave discharges on an EEG. Therefore, the association of hypsarrhythmia specifically with infantile spasms underscores its importance in clinical neurology and in the appropriate management of the condition.