Which of the following is NOT associated with hypnagogic hypersynchrony?

Hypnagogic hypersynchrony refers to the characteristic EEG patterns observed during the transition from wakefulness to sleep, particularly common in children. In this state, delta activity and sleep spindles are typically present. The presence of these patterns indicates the brain's transition into sleep, showcasing a period of synchronous activity among the neurons.

Alpha rhythm, on the other hand, is dominant during relaxed wakefulness and is characterized by oscillations usually in the 8-12 Hz range. It tends to diminish as a person transitions into deeper sleep stages. Therefore, when discussing hypnagogic hypersynchrony, a predominance of alpha rhythm is not a feature since it signifies a state of wakefulness rather than the onset of sleep.

The presence of PSWY, or positive sleep wave activity, is typically coupled with hypnagogic hypersynchrony, making it more associated with these transitional states. Thus, the correct answer highlights that alpha rhythm does not belong to the characteristics associated with hypnagogic hypersynchrony, as it represents a different cerebral state.