What is the recommended pause time between the end of a Polysomnography (PSG) and the start of a Multiple Sleep Latency Test (MSLT)?

Pause Time Between PSG and MSLT

The MSLT must be performed the morning immediately following the PSG with no discharge of the patient between tests, meaning there is no extended "pause time" - the MSLT begins 1.5 to 3 hours after the PSG ends to allow for morning awakening and preparation. 1

Key Timing Requirements

No Patient Discharge Between Tests

• Patients must remain in the sleep laboratory continuously from PSG through MSLT completion - they cannot be discharged home between the overnight PSG and the daytime MSLT 1
• The MSLT is conducted the morning immediately following the overnight PSG as part of a continuous evaluation protocol 1

Practical Morning Transition

• After the PSG ends (typically around 6-7 AM), patients are awakened and given time for morning routine activities
• The first MSLT nap trial typically begins 1.5 to 3 hours after the final awakening from the PSG
• This brief interval allows for:
  • Morning hygiene and breakfast
  • Medication administration if needed
  • Patient preparation for daytime testing

Critical Pre-Test Requirements

Minimum Sleep Duration on PSG Night

• A minimum of 6 hours of total sleep time must be documented on the overnight PSG before proceeding with the MSLT 1
• This requirement ensures adequate sleep opportunity and distinguishes organic hypersomnolence from insufficient sleep syndrome 1
• If the patient fails to achieve 6 hours of sleep, the MSLT may yield false-positive results and should be rescheduled 1

Pre-Admission Sleep Documentation

• Wrist actigraphy should be performed for 7-14 days prior to the PSG/MSLT to objectively document habitual sleep-wake patterns 1, 2, 3
• This pre-test monitoring is essential because chronic sleep debt cannot be fully resolved with just one night of adequate sleep 4
• Research demonstrates that patients with accumulated sleep debt showed mean sleep latency of 5.8 minutes on standard 1-night protocol versus 13.9 minutes after extended hospitalization (p < 0.001), with 5 of 12 cases changing from abnormal to normal results 4

Common Pitfalls to Avoid

Insufficient Sleep Debt Resolution

• The single biggest pitfall is performing MSLT after only one night of adequate sleep when the patient has chronic sleep debt 4
• Even if patients achieve adequate nocturnal sleep during the PSG, pre-existing sleep debt may not be fully resolved, leading to false-positive shortened sleep latencies 4
• Consider extending hospitalization for multiple nights (≥3 nights) before PSG/MSLT in patients with documented chronic insufficient sleep on actigraphy 4

Medication Interference

• Stimulants (amphetamines, methylphenidate, modafinil) must be discontinued before MSLT as they mask sleepiness 2
• Sedating medications (benzodiazepines, hypnotics, antihistamines) must also be stopped before testing 2