Lisa suddenly sat up in bed and started screaming and struggling with the blankets. Although her eyes were open, she didn't seem aware of her surroundings. After a few minutes, she fell back asleep. In the morning she remembered nothing of the incident. Lisa was probably in __________ sleep and incident. Lisa was probably in experiencing a ____________ . a. stage 4 NREM; sleep terror b. stage 1 NREM; hypnagogic hallucination c. REM; nightmare d. REM; sleep terror

Lisa was showing the following signs and symptoms during the incident: 1. She suddenly sat up in bed 2. She started screaming 3. She struggled with her blankets 4. Her eyes were open 5. She didn't seem aware of her surroundings 6. She fell back asleep after a few minutes 7. Lisa didn't remember the incident in the morning

- Stage 4 NREM (Non-Rapid Eye Movement) Sleep: This is the deepest stage of NREM sleep, where one would experience slow brain waves and complete relaxation. It's also known as slow-wave sleep. - Sleep terror: An intense fear episode characterized by extreme panic, screams, and rapid breathing. They generally occur during deep NREM sleep, i.e., stage 3 or stage 4. - Stage 1 NREM Sleep: This is a light sleep stage, where one might experience muscle jerks or hypnagogic hallucinations. - Hypnagogic hallucination: These are vivid dreaming-like experiences that typically occur during stage 1 NREM sleep. - REM sleep (Rapid Eye Movement): This is the sleep stage where one experiences dreams and nightmares. The body is typically paralyzed during this stage.

- Based on the symptoms that Lisa was experiencing, the most suitable explanation is that she went through a sleep terror. This matches her screaming and struggling behavior, lack of awareness, and not remembering the incident in the morning. - Sleep terrors typically occur during deep NREM sleep, specifically stage 3 or stage 4. We conclude that Lisa was in stage 4 NREM sleep.

According to our analysis, Lisa experienced sleep terror while being in stage 4 NREM sleep. We can now conclude that the correct option is: a. stage 4 NREM; sleep terror