Table 4.

Trained observer rating.

Level	Phenomenon
1	Do not look sleepy at all; gaze moves quickly and frequently, blink at a constant rate of about 2 times every 2 s, and body movements are active.
2	Slightly sleepy, open lips, slow eye movement.
3	Looks somewhat sleepy, blinks slowly and frequently, mouth moves, sits up straight, and puts hands on face.
4	Looks quite sleepy and blinks as if conscious. Unnecessary movements of the entire body, such as shaking the head or moving the shoulders up and down. Frequent yawning and deep breathing. Slow blinking or eye movements.
5	Looks very sleepy, eyelids closed, head tilted forward or back.