Sleep Study / PSG Test

What Is a Sleep Study?

A sleep study, also called polysomnography or PSG, is an overnight test that records what happens in the body during sleep.

It can measure:

• Brain activity and sleep stages
• Eye movements
• Muscle activity
• Breathing pattern
• Oxygen levels
• Heart rhythm
• Snoring
• Body position
• Leg movements
• Awakenings and sleep fragmentation

A sleep study is most commonly used to evaluate suspected sleep apnea, but it can also help assess other sleep-related problems depending on the clinical question.

At JHN, a sleep study is not treated as just a test. We first clarify what question the test needs to answer, then connect the result to a clear treatment plan.

Quick Check: When Might a Sleep Study Be Needed?

A doctor may advise a sleep study if you have:

• Loud snoring
• Choking or gasping during sleep
• Witnessed breathing pauses
• Excessive daytime sleepiness
• Morning headaches
• Unrefreshing sleep
• Resistant hypertension
• Obesity, diabetes, heart disease, or stroke risk
• Restless legs or abnormal movements during sleep
• Nighttime behaviors, shouting, or dream enactment
• Suspected parasomnia
• Need for CPAP/BiPAP titration
• Persistent fatigue where sleep apnea is suspected

Key Point

A sleep study is most useful when it is guided by a clinical question.
The goal is not just to collect data. The goal is to understand what is disturbing sleep and what treatment should follow.

Types of Sleep Studies

Diagnostic PSG

This is an overnight in-lab sleep study used to diagnose sleep apnea and other sleep-related abnormalities.

Split-Night Study

In selected patients, the first part of the night may be used for diagnosis, and the second part may be used for CPAP titration if sleep apnea is clearly present and criteria are met.

CPAP / BiPAP Titration Study

This study is used to determine appropriate pressure settings and mask setup for patients who need PAP therapy.

Home Sleep Apnea Testing

Home testing may be appropriate for selected patients with high suspicion of uncomplicated obstructive sleep apnea. It is not ideal for every patient, especially if symptoms are complex or other sleep disorders are suspected.

What to Expect Before Your Sleep Study

Before scheduling a sleep study, we first clarify what question the test needs to answer. This helps avoid unnecessary testing and makes the final report more useful.

Your first consultation may include review of:

• Main sleep complaint
• Snoring, choking, gasping, and breathing history
• Daytime sleepiness and fatigue
• Morning headaches
• BP, diabetes, weight, and cardiometabolic risk (Cardiometabolic risk means risk affecting the heart, blood pressure, blood sugar, cholesterol, and metabolism.)
• Medications, sedatives, alcohol, and stimulants
• Restless legs or abnormal sleep movements
• Anxiety, insomnia, and work schedule
• Whether the test will change treatment

How to Prepare for a Sleep Study

Unless your doctor gives different instructions:

• Wash your hair before the study.
• Avoid hair oil, gel, spray, or heavy hair products.
• Avoid caffeine after lunch on the day of the study.
• Avoid alcohol before the study.
• Bring comfortable sleepwear.
• Bring your regular medicines and prescriptions.
• Take your usual medicines unless your doctor specifically tells you otherwise.
• Inform the clinic if you use CPAP/BiPAP, oxygen, sleeping pills, sedatives, or nighttime medicines.
• Arrive at the instructed time so sensors can be placed calmly before sleep.
• Bring previous sleep reports, ECG, prescriptions, and relevant medical records if available.
• Tell the team if you have skin sensitivity, mobility difficulty, severe anxiety, or special comfort needs.

What Happens During the Study?

Sensors are placed on the scalp, face, chest, abdomen, legs, and finger. These sensors record sleep and body signals. The test is non-invasive.

Some patients sleep less than usual because the environment is new. Usually, enough information can still be collected to guide diagnosis.

What Happens After the Study?

After the test:

• The sleep data is reviewed
• The report is interpreted in clinical context
• The patient receives an explanation of the findings
• Treatment options are discussed
• CPAP/BiPAP titration may be recommended if needed
• Mask fitting and CPAP support may be arranged
• Follow-up is scheduled to track symptoms and adherence

A sleep study is not just a report. It should lead to a clear treatment plan.

JHN Support After the Sleep Study

Depending on results, JHN may help with:

• Sleep apnea explanation
• CPAP/BiPAP titration planning
• Mask fitting and comfort troubleshooting
• Insomnia guidance
• Restless legs or movement-related sleep treatment
• Medication review
• On-site pharmacy support for prescribed medicines and sleep-care items when available
• Follow-up to review whether symptoms are improving

Patient-Friendly Summary

A sleep study helps turn vague symptoms like snoring, fatigue, poor sleep, and daytime sleepiness into measurable information. It is most useful when guided by a proper sleep consultation and followed by treatment planning.