Steps Involved in an In-lab Polysomnography Session

If you've been referred for an in-lab polysomnography, it's natural to feel a bit uncertain about what the process involves. While the idea of sleeping in a clinic under observation might sound intimidating, the procedure is safe, painless, and designed to give your healthcare team valuable insights into your sleep patterns. Understanding each step in the process can help ease anxiety and ensure a smooth experience.

Step 1: Pre-study Preparation

Before your sleep study appointment, your clinic will give you specific instructions, which usually include:

• Avoiding caffeine or alcohol for at least 24 hours prior
  
  

• Washing your hair and avoiding conditioners or styling products
  
  

• Bringing comfortable pyjamas, toiletries, and perhaps a book or something to relax with
  
  

You may also be asked to maintain a sleep diary for a few days beforehand. This helps the clinician understand your usual sleep habits and determine the best time to begin monitoring.

Step 2: Arrival and Check-In

You’ll typically arrive at the sleep centre in the evening, usually around 7–8 PM. A sleep technologist will welcome you, guide you to your private room, and explain what the night will entail.

Each room is designed to resemble a quiet hotel room — with a bed, nightstand, and sometimes a television — to make you feel at ease.

Step 3: Electrode Setup and Sensor Placement

This stage is the most technical part of the study and takes around 30–45 minutes. The technologist will attach multiple sensors to various parts of your body:

• Scalp and forehead – EEG electrodes to monitor brain activity
  
  

• Sides of eyes – EOG sensors to track eye movements
  
  

• Chin and legs – EMG sensors to detect muscle activity
  
  

• Chest and abdomen – belts to measure breathing effort
  
  

• Nose and mouth – nasal cannula and/or thermistor for airflow
  
  

• Finger – pulse oximeter to monitor oxygen saturation
  
  

A small microphone may also be placed near your throat to record snoring or vocalisations. Wires are bundled and connected to a device, allowing you to move and sleep relatively freely.

Step 4:  Lights Out – The Sleep Monitoring Process

Once everything is in place, the technologist will leave the room and monitor your signals from a separate control room. Communication is available via intercom.

The recording typically lasts for a full night’s sleep — around 6 to 8 hours — and includes:

• Sleep onset latency (how long it takes you to fall asleep)
  
  

• Sleep stages (light, deep, and REM sleep)
  
  

• Arousals or awakenings
  
  

• Apnoea events, breathing effort, oxygen drops
  
  

• Abnormal movements or behaviours during sleep
  
  

The technologist will note anything unusual, such as leg twitches, talking in sleep, or pauses in breathing.

Step 5: CPAP Titration (If Required)

If you're suspected of having sleep apnoea, and it’s confirmed early in the study, the second half of the night may involve CPAP titration.

This means you'll be fitted with a CPAP (Continuous Positive Airway Pressure) mask, and the technician will adjust air pressure levels to find the right setting that prevents airway collapse. This step helps streamline diagnosis and treatment planning.

Step 6: Morning Wake-Up and Sensor Removal

You’ll usually be woken around 6–7 AM. The sensors will be gently removed, and any adhesive cleaned off. Some slight redness may remain but will fade quickly. You can shower and dress normally after the session.

Most patients are free to go about their day and can drive themselves home unless instructed otherwise.

Step 7: Data Analysis and Follow-Up

The data from your study — often thousands of data points — are analysed by a sleep physician. This detailed review can take a few days. A follow-up appointment is then scheduled to:

• Review your results
  
  

• Confirm or rule out sleep disorders
  
  

• Discuss treatment options, such as CPAP, medications, or behavioural therapies
  
  

Conclusion

An in-lab polysomnography may seem complex, but it’s a carefully coordinated process focused on your comfort and the accurate detection of sleep disorders. Knowing what to expect — from sensor placement to waking up the next day — can help reduce anxiety and improve cooperation. For many, this overnight test is the first major step toward reclaiming restful, restorative sleep and improving overall health.

Source: In Lab Polysomnography: Precise Sleep Disorder Diagnosis (CLM Sleep) https://www.clmsleep.com/in-lab-polysomnography/