Sleep Stages

Question 1

Characteristics of stage 1 sleep are:

Answer 1

EEG shows alpha waves (8-25Hz), mixed frequency, low voltage,

• Last 1-7 minute (initial cycle)
• Easily interrupted by noise!

Question 2

Characteristics of stage 2 sleep are:

Answer 2

• 10-25 mins (initial cycle)
• Gets longer with each successive cycle
• EEG shows low voltage mixed frequency, sleep spindles and k-complexes are present
• Eye movement stops
• Sleep spindles are occasional burst of rapid waves

Question 3

Describe the characteristics of the third sleep stage (stage3).

Answer 3

Stage 3

• occurs in the first 1/3 of the sleep-
• aka deep sleep
• EEG SHOWS high voltage and slow wave activity (delta wave)
• frequency-<2Hz
• no eye movement or muscle activity

Question 4

Describe the characteristics of REM sleep (stage4)

Answer 4

20-25% of tsts, usually occurs 60-90 mins after sleep onset
-low voltage, mixed frequency waves seen on EEG (1-2 Hz)
slower than Wake Alpha), Often with saw tooth waves
- Bursts of rapid eye movements in various directions.

Question 5

When wouldn’t the EEG show alpha waves of 8-25Hz in stage 1 sleep

Answer 5

New borns

Narcolepsy

Question 6

Give the physiological differences between REM and NREM

Answer 6

DURING REM SLEEP:
• Penile erections
• Respiration – more rapid, irregular and shallow
• Cardiovascular – HR increases, BP rises
• If awoken – describe “dreams”
• Loss of ability to regulate body temperature
Abnormally low/high temperatures can disrupt REM sleep