May 29, 2024

Understanding Polysomnography: What is a Sleep Study?

A sleep study, or polysomnography, is a diagnostic tool that monitors multiple physiological functions during sleep to evaluate various sleep disorders. It provides a detailed view of sleep patterns, helping to detect abnormalities and guide effective treatment for issues like insomnia, sleep apnea, and excessive daytime sleepiness.

What is a Sleep Study?

A polysomnography sleep study (pronounced “poly-som-no-graphy”), is a diagnostic tool used to diagnose various sleep disorders. By monitoring multiple body systems and physiological functions during sleep, it provides a comprehensive view of your sleep patterns and detects any abnormalities.

When Should I Consider a Sleep Study?

Consider polysomnography to diagnose and evaluate sleep disorders in several situations. Here are specific scenarios where you might need a sleep study:

Chronic Insomnia

Difficulty falling asleep, staying asleep, or waking up too early for over three months despite having the opportunity to sleep. A sleep study might help identify underlying issues.

Obstructive Sleep Apnea (OSA)

Experiencing loud snoring, choking, gasping, or pauses in breathing during sleep, along with daytime fatigue. A sleep study can diagnose the severity of OSA.

Excessive Daytime Sleepiness (EDS)

Feeling excessively sleepy during the day, even after a full night's sleep. A sleep study can determine if you have a sleep disorder like narcolepsy or idiopathic hypersomnia.

Monitoring Sleep-related Breathing Disorders

Conditions like chronic obstructive pulmonary disease (COPD) or congestive heart failure that affect breathing during sleep might necessitate a sleep study.

Unexplained Fatigue

Persistent fatigue not improved by sleep or rest might indicate an underlying sleep disorder.

Periodic Limb Movement Disorder (PLMD) or Restless Legs Syndrome (RLS)

An irresistible urge to move your legs, often accompanied by uncomfortable sensations or involuntary limb movements during sleep. A sleep study can be helpful.

REM Sleep Behavior Disorder (RBD)

Acting out dreams or making violent movements during REM sleep. A sleep study can diagnose RBD.

Sleepwalking or Other Parasomnias

Engaging in abnormal behaviors during sleep, such as sleepwalking, talking, or eating. A sleep study can help identify the cause.

Circadian Rhythm Disorders

If your sleep-wake cycle consistently misaligns with the natural day-night cycle, causing sleep problems. A sleep study can help assess your condition.

Evaluation of Treatment Effectiveness

If you have a diagnosed sleep disorder and are undergoing treatment (e.g., CPAP therapy for sleep apnea), a follow-up sleep study can assess the treatment's effectiveness.

If you experience any of these symptoms or conditions, True Sleep Therapy can help you determine if polysomnography is appropriate and guide you through the process.

When and Where is a Sleep Study Performed?

A sleep study typically takes place either in your home or at a sleep center during your normal sleeping hours, generally at night. If you work nights, a sleep study can be performed during daytime hours to match your regular sleep schedule.

Types of Sleep Studies

At-Home Sleep Study

  • Home Sleep Apnea Testing (HSAT): Conducted with a portable monitoring device at home.
  • Focuses on fewer parameters than in-lab studies, primarily monitoring breathing patterns, oxygen levels, and heart rate to diagnose sleep apnea.

Sleep Center Sleep Study

  • In-Lab Polysomnography (PSG): Conducted overnight at a sleep center or hospital.
  • Monitors brain activity (EEG), eye movements (EOG), muscle activity (EMG), heart rate (ECG), breathing patterns, blood oxygen levels (pulse oximetry), and body movements.

Sleep Apnea vs. Sleep Apnoea

Sleep Apnea and Sleep Apnoea refer to the same condition. "Sleep Apnoea" is often used in Europe and the UK, while the US drops the "O".


Elsbeth Fast, sleep therapist, sitting on a couch discussing sleep therapy with a patient.

Are you ready to finally get better sleep?

Take the first step and fill out our contact form today.

What Does a Sleep Study Measure?

Electroencephalogram (EEG)

Measures muscle activity, particularly useful for detecting conditions like REM sleep behavior disorder (RBD).

Electrooculogram (EOG)

Monitors heart rate and rhythm.

Respiratory Monitors

Measure airflow and breathing effort, which is crucial for diagnosing sleep apnea.

Monitors heart rate and rhythm.

Pulse Oximetry

Measures blood oxygen levels to detect drops during apneas or hypopneas.

Snore Microphone

Records snoring sounds.

Video & Audio Recording

Sometimes captures any unusual behaviors or movements during sleep.

Gray-haired man on the diagnosis of EEG - electroencephalography, sensors are attached to his head during a sleep study.

What Should I Expect During a Sleep Study?

Sleep Study Consultation:

  • Initial Appointment: Meet with a sleep specialist to discuss your symptoms, medical history, and the need for a sleep study.
  • Instructions: Receive specific instructions on how to prepare, such as avoiding caffeine and alcohol on the day of the study and maintaining a regular sleep schedule.

Packing for a Sleep Study:

  • Comfortable Clothing: Bring pajamas or other comfortable sleepwear.
  • Personal Items: Pack toiletries, medications, and anything else you need for your nighttime routine.
  • Entertainment: Bring a book or other non-electronic entertainment, as you may have some waiting time before the study begins.

Arrival at the Sleep Center:

  • Check-In:
    • Evening Arrival: Typically, check-in during the evening.
    • Paperwork: Complete any necessary paperwork and provide insurance information.
  • Room Setup:
    • Private Room: Stay in a private room designed to be comfortable and mimic a typical bedroom.
    • Atmosphere: The room will be equipped with monitoring equipment but arranged to help you relax and sleep.

During a Sleep Study:

  • Sensor Attachment:
    • Technician Assistance: A sleep technician will attach various sensors to your body using adhesive patches. These sensors monitor brain waves (EEG), eye movements (EOG), muscle activity (EMG), heart rate (ECG), breathing patterns, blood oxygen levels, and snoring.
    • Minimal Discomfort: The process is generally painless, although some people might find the sensors slightly uncomfortable at first.
  • Monitoring:
    • All-Night Monitoring: Once you are ready for bed, the technician will start the monitoring equipment.
    • Observation: You will be observed via video and audio to capture any unusual behaviors or movements.
  • Sleep:
    • Natural Sleep: Try to sleep as naturally as possible. The environment is controlled to minimize disturbances.
    • Assistance: If you need to use the restroom or require assistance during the night, you can call the technician.

Waking Up from a Sleep Study:

  • Morning Wake-Up: The study usually ends in the early morning.
  • Sensor Removal: The technician will remove the sensors, which might leave slight marks or adhesive residue on your skin.

Sleep Study Follow-Up:

  • Initial Discussion: The technician may provide a brief overview of the night's data, but detailed results will come later.
  • Reviewing Data: A sleep specialist reviews the recorded data to identify any abnormalities or patterns indicative of sleep disorders.
  • Report: You'll receive a detailed report outlining the findings, such as sleep stages, number of apneas or hypopneas, oxygen levels, and any detected movements or behaviors.
  • Diagnosis and Treatment: Based on the results, the sleep specialist will diagnose any sleep disorders and recommend treatment options, which may include lifestyle changes, medical devices (e.g., CPAP for sleep apnea), medications, or other therapies like Cognitive Behavioral Therapy for Insomnia.

A sleep study is essential for diagnosing and understanding sleep disorders and improving sleep quality and overall health. If you suspect you have a sleep disorder, True Sleep Therapy can help!

With expert guidance and unwavering support from Elsbeth, a revitalized sleep experience awaits. Take the first step today towards a brighter, more energized tomorrow. Contact Elsbeth today.

A sleep study, or polysomnography, is a diagnostic tool that monitors multiple physiological functions during sleep to evaluate various sleep disorders. It provides a detailed view of sleep patterns, helping to detect abnormalities and guide effective treatment for issues like insomnia, sleep apnea, and excessive daytime sleepiness.

What is a Sleep Study?

A polysomnography sleep study (pronounced “poly-som-no-graphy”), is a diagnostic tool used to diagnose various sleep disorders. By monitoring multiple body systems and physiological functions during sleep, it provides a comprehensive view of your sleep patterns and detects any abnormalities.

When Should I Consider a Sleep Study?

Consider polysomnography to diagnose and evaluate sleep disorders in several situations. Here are specific scenarios where you might need a sleep study:

Chronic Insomnia

Difficulty falling asleep, staying asleep, or waking up too early for over three months despite having the opportunity to sleep. A sleep study might help identify underlying issues.

Obstructive Sleep Apnea (OSA)

Experiencing loud snoring, choking, gasping, or pauses in breathing during sleep, along with daytime fatigue. A sleep study can diagnose the severity of OSA.

Excessive Daytime Sleepiness (EDS)

Feeling excessively sleepy during the day, even after a full night's sleep. A sleep study can determine if you have a sleep disorder like narcolepsy or idiopathic hypersomnia.

Monitoring Sleep-related Breathing Disorders

Conditions like chronic obstructive pulmonary disease (COPD) or congestive heart failure that affect breathing during sleep might necessitate a sleep study.

Unexplained Fatigue

Persistent fatigue not improved by sleep or rest might indicate an underlying sleep disorder.

Periodic Limb Movement Disorder (PLMD) or Restless Legs Syndrome (RLS)

An irresistible urge to move your legs, often accompanied by uncomfortable sensations or involuntary limb movements during sleep. A sleep study can be helpful.

REM Sleep Behavior Disorder (RBD)

Acting out dreams or making violent movements during REM sleep. A sleep study can diagnose RBD.

Sleepwalking or Other Parasomnias

Engaging in abnormal behaviors during sleep, such as sleepwalking, talking, or eating. A sleep study can help identify the cause.

Circadian Rhythm Disorders

If your sleep-wake cycle consistently misaligns with the natural day-night cycle, causing sleep problems. A sleep study can help assess your condition.

Evaluation of Treatment Effectiveness

If you have a diagnosed sleep disorder and are undergoing treatment (e.g., CPAP therapy for sleep apnea), a follow-up sleep study can assess the treatment's effectiveness.

If you experience any of these symptoms or conditions, True Sleep Therapy can help you determine if polysomnography is appropriate and guide you through the process.

When and Where is a Sleep Study Performed?

A sleep study typically takes place either in your home or at a sleep center during your normal sleeping hours, generally at night. If you work nights, a sleep study can be performed during daytime hours to match your regular sleep schedule.

Types of Sleep Studies

At-Home Sleep Study

  • Home Sleep Apnea Testing (HSAT): Conducted with a portable monitoring device at home.
  • Focuses on fewer parameters than in-lab studies, primarily monitoring breathing patterns, oxygen levels, and heart rate to diagnose sleep apnea.

Sleep Center Sleep Study

  • In-Lab Polysomnography (PSG): Conducted overnight at a sleep center or hospital.
  • Monitors brain activity (EEG), eye movements (EOG), muscle activity (EMG), heart rate (ECG), breathing patterns, blood oxygen levels (pulse oximetry), and body movements.

Sleep Apnea vs. Sleep Apnoea

Sleep Apnea and Sleep Apnoea refer to the same condition. "Sleep Apnoea" is often used in Europe and the UK, while the US drops the "O".


Elsbeth Fast, sleep therapist, sitting on a couch discussing sleep therapy with a patient.

Are you ready to finally get better sleep?

Take the first step and fill out our contact form today.

What Does a Sleep Study Measure?

Electroencephalogram (EEG)

Measures muscle activity, particularly useful for detecting conditions like REM sleep behavior disorder (RBD).

Electrooculogram (EOG)

Monitors heart rate and rhythm.

Respiratory Monitors

Measure airflow and breathing effort, which is crucial for diagnosing sleep apnea.

Monitors heart rate and rhythm.

Pulse Oximetry

Measures blood oxygen levels to detect drops during apneas or hypopneas.

Snore Microphone

Records snoring sounds.

Video & Audio Recording

Sometimes captures any unusual behaviors or movements during sleep.

Gray-haired man on the diagnosis of EEG - electroencephalography, sensors are attached to his head during a sleep study.

What Should I Expect During a Sleep Study?

Sleep Study Consultation:

  • Initial Appointment: Meet with a sleep specialist to discuss your symptoms, medical history, and the need for a sleep study.
  • Instructions: Receive specific instructions on how to prepare, such as avoiding caffeine and alcohol on the day of the study and maintaining a regular sleep schedule.

Packing for a Sleep Study:

  • Comfortable Clothing: Bring pajamas or other comfortable sleepwear.
  • Personal Items: Pack toiletries, medications, and anything else you need for your nighttime routine.
  • Entertainment: Bring a book or other non-electronic entertainment, as you may have some waiting time before the study begins.

Arrival at the Sleep Center:

  • Check-In:
    • Evening Arrival: Typically, check-in during the evening.
    • Paperwork: Complete any necessary paperwork and provide insurance information.
  • Room Setup:
    • Private Room: Stay in a private room designed to be comfortable and mimic a typical bedroom.
    • Atmosphere: The room will be equipped with monitoring equipment but arranged to help you relax and sleep.

During a Sleep Study:

  • Sensor Attachment:
    • Technician Assistance: A sleep technician will attach various sensors to your body using adhesive patches. These sensors monitor brain waves (EEG), eye movements (EOG), muscle activity (EMG), heart rate (ECG), breathing patterns, blood oxygen levels, and snoring.
    • Minimal Discomfort: The process is generally painless, although some people might find the sensors slightly uncomfortable at first.
  • Monitoring:
    • All-Night Monitoring: Once you are ready for bed, the technician will start the monitoring equipment.
    • Observation: You will be observed via video and audio to capture any unusual behaviors or movements.
  • Sleep:
    • Natural Sleep: Try to sleep as naturally as possible. The environment is controlled to minimize disturbances.
    • Assistance: If you need to use the restroom or require assistance during the night, you can call the technician.

Waking Up from a Sleep Study:

  • Morning Wake-Up: The study usually ends in the early morning.
  • Sensor Removal: The technician will remove the sensors, which might leave slight marks or adhesive residue on your skin.

Sleep Study Follow-Up:

  • Initial Discussion: The technician may provide a brief overview of the night's data, but detailed results will come later.
  • Reviewing Data: A sleep specialist reviews the recorded data to identify any abnormalities or patterns indicative of sleep disorders.
  • Report: You'll receive a detailed report outlining the findings, such as sleep stages, number of apneas or hypopneas, oxygen levels, and any detected movements or behaviors.
  • Diagnosis and Treatment: Based on the results, the sleep specialist will diagnose any sleep disorders and recommend treatment options, which may include lifestyle changes, medical devices (e.g., CPAP for sleep apnea), medications, or other therapies like Cognitive Behavioral Therapy for Insomnia.

A sleep study is essential for diagnosing and understanding sleep disorders and improving sleep quality and overall health. If you suspect you have a sleep disorder, True Sleep Therapy can help!

With expert guidance and unwavering support from Elsbeth, a revitalized sleep experience awaits. Take the first step today towards a brighter, more energized tomorrow. Contact Elsbeth today.

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Your Partner for Better Sleep

I love helping my clients reclaim restful sleep through cognitive behavioral therapy for insomnia.

True Sleep Therapy is all about transforming your relationship with sleep so that you can regain confidence in your body’s innate, natural ability to rest. It fills me with great joy and gratitude to partner with my clients and to play in their life-changing sleep journey.

True Sleep is possible. You deserve it. I’d love to help you discover the promise of True Sleep.

Elsbeth Fast 

Elsbeth Fast
Licensed Clinical Social Worker LCSW
Specialized in Cognitive Behavioral Therapy for Insomnia with deep expertise in treating Insomnia with co-occurring PTSD, Depression, Anxiety Disorder, or Chronic Pain.

Better sleep is within reach.

You deserve restful sleep, and I can guide you there. 
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