What is the required duration for EEG arousals to be counted?

Arousal events in the context of EEG monitoring during sleep are defined specifically to capture significant disturbances in the brain's electrical activity that can impact sleep quality. To be considered an arousal, an event must last at least 3 seconds. This duration is critical because it allows for a consistent and standardized measurement across various sleep studies, ensuring that the arousals identified are not merely transient fluctuations but are instead substantial enough to disrupt the normal sleep architecture. This definition is crucial for diagnosing sleep disorders and assessing the overall quality of sleep. Understanding this standard aids practitioners in interpreting sleep data and making informed clinical decisions.