What is required for a NREM arousal according to polysomnography protocols?

The requirement for a NREM arousal, as outlined in polysomnography protocols, is that an EEG change must be present. During NREM sleep, the brain exhibits distinct EEG patterns that can be observed in different sleep stages. An arousal from NREM sleep is indicated by a shift in the EEG pattern, typically toward a more awake state, which may include the presence of theta or alpha waves as the individual transitions toward wakefulness.

This EEG change is essential for determining that an arousal has indeed occurred, as it reflects alterations in brain activity that occur with arousal from sleep. While other physiological parameters, such as heart rate and muscle tone, may also change, the EEG is the primary determinant for identifying the specific event of arousal during NREM sleep according to standardized protocols.

Other factors like chin EMG might show changes, but they are not the primary criteria for defining an arousal. This reinforces the central role of the EEG in sleep studies for identifying and categorizing arousals.