Sleep Laboratory

Patient Information for Home Sleep Testing | How to use ApneaLink Plus Video | Staff
Resources | Sleep Lap Forms | Sleep Study Terms

Piedmont Sleep at Guilford Neurologic Associates is a comprehensive Sleep Clinic under the direction of Dr. Carmen Dohmeier and Dr. Saima Athar. Our staff of experienced Registered Sleep Technologists and Board Certified Sleep Disorders Specialists (who are also Board Certified Neurologists) are passionate about improving the sleep and quality of life for our patients. We are accredited by the American Academy of Sleep Medicine and we specialize in diagnostic testing, sleep disorders treatment, education, and follow up care.

Our mission is to provide excellence and comfort in each individual’s experience throughout the entire process in order to achieve the best outcomes for our patients. Treatment and testing available for Snoring and Sleep Apnea, Narcolepsy, Restless Leg Syndrome, Periodic Limb movement disorder, Parasomnias, Circadian Rhythm disturbances, and organic Insomnia. We provide Polysomnography, PAP Titration, Split Night studies, Multiple Sleep Latency Testing (MSLT), Maintainence of Wakefulness Testing (MWT), CPAP desensitization and mask fitting sessions, Home Sleep Testing, and clinical follow up care. Please come see us at 912 Third Street, Suite 101 in Greensboro just off of Wendover Ave and Maple Street. Our phone number is (336)275-6380.

Patient Information and Financial Policy for Home Sleep Testing

Welcome to Piedmont Sleep at Guilford Neurologic Associates! We are glad to provide you with information regarding your Home Sleep Test experience. Please call us at (336)275-6380 with any additional questions or concerns. If you were not given the home sleep test unit prior to leaving our office, you will be contacted by a member of our staff to schedule a convenient time to return to receive instructions and the Home Sleep testing device.

What is a Home Sleep Test (HST)?

New technology has given us a way to screen some patients for Obstructive sleep apnea in the comfort and privacy of their own home. The Home Sleep Testing device is worn by the patient for a regular sleep period and then returned to the sleep lab the following morning for interpretation. Home sleep testing is able to detect your breathing (both airflow and effort), oxygen levels, snoring, and heart rate during the time that you are wearing the HST device. HST does not give us information about your sleep quality, limb movements, abnormal behaviors during sleep, heart rhythm, or exhaled carbon dioxide levels. Why has my doctor asked me to do a Home Sleep Study? Your physician has determined that you may be at risk for a sleep disorder known as Sleep Apnea. Some common risk factors include: Obesity, snoring, observed pauses in breathing, and excessive daytime sleepiness. Some Physicians may ask you to be screened for Sleep Apnea prior to having surgery under general anesthesia or if you use certain medications that put you at risk for respiratory depression. For some patients, the health insurance company may require them to have a Home Sleep Test rather than the traditional in lab Sleep Study.

What can I expect?

After a Comprehensive Sleep Consultation with our Board Certified Sleep Specialist, a trained member of our staff at the Sleep Lab will instruct you how to wear the HST unit. You will be given written and picture instructions as well as a hands on demonstration. Prior to your usual night’s sleep, you will apply the sensors to your body over your pajamas. Any medications should be taken as usual unless you are instructed differently by your doctor. Try to follow your usual bedtime routine. If you are awake for extended periods of time while wearing the HST device, try to document the time on a sheet of paper and return it with the device the following day. In order for us to bill your insurance company for the test, you will need to wear the HST device for 6 hours whether you are asleep or not. When you return the HST device to the sleep lab, a Registered Sleep Technologist will manually score and analyze the information and forward the data to our Sleep Medicine Specialist for further analysis and interpretation. Your referring doctor will receive a copy of the results. You may receive a copy of your results if you desire. You will then be contacted to discuss your test results and the Physician’s recommendations.

What if I have questions or concerns during the night? Please call the main number for Guilford Neurologic Associates at (336)273-2511; you will reach the answering service. Let them know you need to reach the Sleep Lab Manager who will help you.

We are here to help you in any way that we can and we hope you enjoy your experience with us!

How to use ApneaLink Plus


Saima Athar, MD, PhD

Dr. Athar graduated from the University of Hamburg in Germany. She completed her Neurology Residency and the Medical University of South Carolina (MUSC) in Charleston. She received fellowship training in both Movement Disorders and Sleep Medicine from Emory University in Atlanta and was on faculty at MUSC for seven years before joining GNA. Dr. Athar is board certified in Neurology and Sleep Medicine.


Please, see the following resources for additional information regarding sleep disorders and sleep testing:

Sleep Lab Forms

Sleep Study Terms Explained

  • BMI: a numerical index that expresses weight in relation to height.
  • NPSG: Nocturnal Polysomnogram, this is a diagnostic sleep study used to identify if a sleep disorder is present. Patients are prepared or hooked up using electrodes and sensors to monitor EEG, EKG, EMG (leg movements, muscle tone), Respiratory Effort, Respiratory Airflow, Oxygen saturations, Snore, and end tidal CO2 levels. The NPSG generally lasts a minimum of 6 hours.
  • PAP Titration: This is a treatment study in which a patient uses Positive Airway Pressure therapy (CPAP, BiPAP, ASV, iVAPS) for the treatment of Sleep Apnea or other disorders. The goal of this study is to gradually adjust and try different air pressure settings during the night in order to find the custom pressure setting required by an individual patient.
  • Split Night study: First half of the night is the diagnostic study and if significant Sleep Apnea is identified within the first 2-3 hours, then a treatment study (PAP Titration) occurs during the second half of the night. Split Night studies reduce the number of visits for patients.
  • MSLT: Multiple Sleep Latency Test. This is also referred to as a “nap test” and is used to diagnose Narcolepsy, or it can be used to document how quickly someone falls asleep when given the opportunity to nap. This study is for those seeking treatment for excessive daytime sleepiness.
  • TST or Total Sleep Time: The amount of time during the sleep study that a person was actually asleep, usually expressed in total minutes.
  • Lights Out: The actual start of the sleep study which occurs after all equipment and patient calibrations are performed. The actual time the patient is actively trying to sleep.
  • Lights On: The actual end of the sleep study.
  • Total Recording Time: Lights Out to Lights On, usually expressed in total minutes.
  • Sleep Latency: The amount of time it took to fall asleep after Lights Out.
  • Wake after Sleep Onset (WASO): The amount of time spent awake after sleep has been initiated and before final awakening. When WASO is increased, it results in poor sleep efficiency.
  • Sleep Efficiency: The amount of time spent sleeping divided by the time spent in bed – expressed as a percentage (ie.) If a person spends eight hours in bed but only sleeps for four hours, the sleep efficiency would be 50%.
  • Sleep Architecture: Sleep architecture represents the structure of sleep and is generally composed of a somewhat cyclical pattern of the various NREM and REM sleep stages. It is typically summarized by a chart called a Hypnogram.
  • Wake: The physiological state of being awake.
  • NREM Sleep: Comprised of Stages N1, N2, and N3.
  • REM Sleep: Rapid Eye Movement sleep (associated with dreams, lack of muscle tone, REM’s, deep stage of sleep with intense brain activity, it occurs cyclically several times during sleep with more REM occurring during the last 1/3 of the night before awakening). Breathing can become fast, irregular, and shallow. Muscles become immobile. About 20%-25% of sleep in healthy, normal sleepers is made up of REM sleep. The first REM period occurs around 90 minutes after sleep onset.
  • N1: Stage 1 sleep is light sleep or dozing sleep, one is easily awakened from stage 1 sleep, associated with slowing of eye and body movements – sudden jerky movements of legs or other muscles can occur giving the person the sensation of falling. Makes up 5%-10% of normal sleep.
  • N2:Z Stage 2 sleep is characterized by EEG activity called sleep spindles and K-complexes. Makes up about 50% of the total sleep time in healthy, normal sleep.
  • N3: Stage 3 sleep also called slow-wave sleep or delta sleep, this is a deep stage of sleep associated with large slow brain waves called Delta waves – growth hormone is released during this stage of sleep and children generally experience much more Stage 3 sleep than adults. Stage 3 sleep can be difficult to awaken someone from, people usually feel groggy and disoriented when waking from Stage 3. Makes up 10%-20% of normal sleep during the night.
  • Circadian Rhythm: The physician, behavioral, and mental changes that follow a 24 hour cycle, influenced by light and darkness. Also referred to as our “internal clock” that tells us when to sleep, wake, eat, be alert, feel sleepy, etc.
  • Sleep Fragmentation: repetitive short interruptions during sleep which can result in excessive daytime sleepiness - sometimes caused by sleep disordered breathing and period leg movements.
  • Respiratory Events: an observable change in breathing from what was previously established as normal for an individual. Respiratory events usually result in a change in oxygen level, CO2 levels, or sleep disruption. Respiratory events are classified as Obstructive (occurring because of obstruction of the airway), Central (occurring because of a lack of signal coming from the brain), or Mixed (containing both obstruction and central components).
  • Obstructive Apnea: Cessation in breathing for 10 seconds or longer due the closure or obstruction of the upper airway during sleep. (For adults - pediatric patients have different criteria for both Apneas and Hypopneas)
  • Central Apnea: Cessation in breathing for 10 seconds or longer because the brain doesn’t send proper signals to the muscles that control your breathing.
  • Mixed Apnea: Cessation in breathing for 10 seconds or longer in which part of the apnea meets the obstructive apnea definition and part meets the central apnea definition.
  • Hypopnea: Reduction of airflow by at least 30% that lasts 10 seconds or longer and is followed by a decrease in oxygen levels by at least 3%-4% or causes disruption from sleep (arousal).
  • Apnea-Hypopnea Index: Also referred to as the AHI. This number represents how many times per hour of sleep that an Apnea or Hypopnea occurred. The AHI helps determine if Sleep Apnea is mild, moderate or severe.
    • normal = AHI < 5
    • mild = AHI 5-15/hr
    • moderate = AHI 15-30/hr
    • severe = AHI 30/hr or greater
  • Respiratory Disturbance Index: A number that represents the number of respiratory events per hour of recording (Apneas, Hypopneas, and also Respiratory event related arousals)
  • Index: Whenever the word Index is used in the report, it is describing how many times per hour something occurred.
  • Respiratory Event Related Arousal (RERA): Changes in breathing where airflow is diminishing over a period of 10 seconds or longer, while the effort to breathe increases (the brain is trying to get more air), and these breathing changes result in sleep disruption (arousal).
  • Periodic Limb Movement Disorder (PLMD): A Sleep disorder which involves rhythmic, involuntary movement of the arms or legs during sleep which can contribute to sleep disruption and arousals.
  • Oxygen Saturation: determined via pulse oximetry generally worn on the finger. Normal values should stay above 90%, some brief drops during REM sleep can be considered normal due to the normal variations of respiration during REM sleep.
  • Oxygen Desaturation: a drop in the blood oxygen level from previously established baseline levels (usually a 3% or 4% minimum is required to be considered significant).
  • CPAP Therapy: The gold standard treatment for OSA in which the patient uses a CPAP machine and mask during sleep to help prevent the airway changes that contribute to sleep apnea by using a small amount of air pressure to hold the airway open.
  • CPAP: Continuous Positive Airway Pressure, one air pressure setting to keep the airway open
  • EPR or C-flex: A comfort setting which allows the pressure to briefly drop when the patient starts to exhale.
  • BiPAP (BPAP): Bi-level positive airway pressure, the Inspiratory Positive Airway Pressure is set higher than the Expiratory Positive Airway Pressure, or simply, two air pressure settings to keep the airway open. Some patients find BiPAP more comfortable, some conditions also benefit from BiPAP therapy over regular CPAP such as CO2 retention.
  • ASV: Adaptive Servo Ventilation, designed to treat central sleep apnea in all its forms, including complex and mixed sleep apnea.
  • iVAPS: Intelligent Volume Assured Pressure Support
  • Arousal: An abrupt change from sleep to wakefulness, or from a deeper stage or sleep to a lighter sleep. Frequent arousals contribute to non-restorative sleep and excessive daytime sleepiness.
  • Positional Therapy: avoiding sleeping in a certain position because it makes sleep apnea worse, this is usually for those who have worsened sleep apnea when sleeping on their back.
  • Nocturia: getting up during the night to use the restroom
  • Alpha intrusion: brief occurrence of alpha activity during sleep. “Alpha” refers to alpha waves, which are brain waves that are present when you are awake and relaxed. When alpha intrusion occurs, alpha waves intrude into deep sleep.
  • ENT Evaluation: A referral to an Ear, Nose, Throat Physician to evaluate the airway in order to treat snoring, sleep apnea, or sinus issues or to improve nasal breathing issues which complicate the use of CPAP therapy.
  • Sleep Psychology Referral: A referral to a specially trained Psychologist or Psychiatrist who helps the individual determine possible causes of insomnia and then works with them to resolve causes and create a relaxing night routine in order to help alleviate chronic insomnia. This is therapy to change behaviors in order to achieve better sleep.
  • Mandibular Advancement or Oral Appliance Device, also referred to as a Dental Device: A device composed of wire and plastic that is inserted in the mouth of patients with obstructive sleep apnea before going to sleep at night. The device moves the bottom jaw forward 4-6 mm and can be an effective treatment for mild-moderate sleep apnea especially when CPAP therapy is not an option.
  • Hypnogram: A graphical summary of the sleep stages as they occur during a single night’s sleep. The Hypnogram can also include Respiratory data, limb movement data, CPAP, and Oxygen data, etc. A visual depiction of the Polysomnogram.