In this article, we will discuss four common questions regarding home sleep testing, an exciting, new diagnostic testing option for sleep disorders.
1) What is a home sleep study?
A home sleep apnea test (HST) is a diagnostic procedure to determine whether you have obstructive sleep apnea. Obstructive sleep apnea (OSA) is by far the most common type of sleep disordered breathing. Tens of millions of people in the United States have OSA, and medical authorities estimate that 80% of OSA sufferers are as yet undiagnosed. OSA correlates very closely with obesity rates, which hover around one third of the U.S. population. Current medical guidelines say that HSTs are appropriate for the vast majority of patients who need sleep diagnostic testing.
An HST is typically worn for one night by the patient. Most HSTs have the capacity to be used for multiple nights in a row if more data is needed. Once the data is acquired, it is typically uploaded for a registered sleep technologist to review. The technologist "scores" the data, marking abnormal breathing events. Then a sleep medicine physician reviews the data, provides a diagnosis, and, if the study shows OSA, gives treatment recommendations.
There are several different manufacturers of HSTs on the market. The three largest brands are:
ARES by Watermark
ApneaLink Air by Resmed
Alice NightOne by Philips (Respironics)
The team at Singular Sleep has tested and compared all of the most popular HST devices on the market, including the three above. Patients often reported to us that the ARES was uncomfortable and sometimes left tell-tale marks on their foreheads. The ApneaLink Air and Alice NightOne are very similar, but Singular Sleep chose the Alice NightOne as our featured device because it provides information on body position during the night, which the ApneaLink does not. This data is important because the degree of sleep apnea can vary in different body positions and this additional information can influence the treatment options that are available to patients, if they test positive for OSA.
The Alice NightOne has only three components:
Nasal pressure transducer: this small cannula fits over your ears and the buds are placed into your nostrils. This sensor measures airflow, or how much air is moving in and out of your body.
Pulse oximeter: this sensor fits on your finger and uses light beams to measure the oxygen level of your blood.
Recording unit with chest belt: the lightweight (3 oz) plastic case contains the device's batteries, a chip that stores the data from the study and an accelerometer that measures body position. The elastic belt measures respiratory effort, or how hard you are trying to breathe.
2) What's the difference between a home sleep test and a laboratory-based polysomnogram?
As you can see below, there's a lot more involved with a sleep study done in a lab:
Sleep Lab Study
Home Sleep Test
In lab-based sleep studies, an abrasive paste is applied to prep the skin for multiple sensors. Compared with HSTs, the additional sensors used in laboratory-based studies are:
- Multiple EEG electrodes on the scalp
- Two electrodes (EOG) applied to the face, above and below the eyes
- Chin EMG electrode
- An additional sensor in the nose called a thermistor
- Snore microphone on the throat
- Two EKG electrodes on the chest
- An additional respiratory effort belt over the abdomen
- EMG electrodes on each leg
Additionally, there is an infrared camera in the room that records video of the patient for the duration of the study.
Both tests have advantages and disadvantages. HSTs have been deemed by the American Academy of Sleep Medicine as being appropriate for most people who are otherwise healthy and at high-risk for obstructive sleep apnea. The standard of care is that patients with certain medical co-morbidities should be evaluated only with an in-lab study. This list includes:
- Moderate to severe pulmonary disease (e.g., COPD)
- Neuromuscular diseases such as ALS or myasthenia gravis
- Recent stroke
- Severe insomnia
- Significant congestive heart failure (NYHA Class III or IV or reduced LVEF)
- Super-obesity (BMI >45)
- Evaluation for other, less common primary sleep disorders such as narcolepsy, parasomnias, periodic limb movement disorder and central sleep apnea
Many people prefer HSTs for the following reasons:
- The study can be done in the comfort of their own home: no unusual noises, uncomfortable, small mattresses or shared bathrooms
- Bedtime and wake time are determined by the patient. In-lab studies often require bedtimes as early as 10 p.m. and rise times of 5-5:30 a.m., which may not fit well with people's normal sleep-wake patterns
- Less obtrusive nature of HST
- No one is watching them sleep
- No interruptions from technologist fixing electrodes during the night, a common scenario during an in-lab sleep study
- Lower cost
- Possible higher degree of accuracy, in some cases, when studying people in their natural environment
3) What are the reasons to get a sleep study?
Indications for a sleep study can be generally divided into two categories: symptoms and co-morbid medical conditions.
Primary symptoms include:
- Habitual snoring
- Witnessed apneas (someone has observed you stop breathing in your sleep)
- Nocturnal choking or gasping
- Non-restorative sleep, i.e., you get adequate amounts of sleep but you still feel tired when you wake up
- Excessive daytime sleepiness (falling asleep easily in sedentary situations such as reading or watching TV)
- Excessive fatigue
Depending on the clinical situation, secondary symptomatic reasons may be:
- Nighttime cough
- Morning headaches
- Nighttime acid reflux
- Night sweats
- Nocturia (excessive nighttime urination)
Co-morbid Medical Conditions
This term refers to other medical problems that have a high association with sleep apnea, meaning that sleep apnea either can cause them or make them worse. These include:
- Hypertension (high blood pressure)
- Type 2 diabetes
- Heart failure
- Myocardial infarction (heart attack)
- Arrhythmias (irregular heart rhythms), including atrial fibrillation or "a fib"
- Pulmonary hypertension
- Cerebrovascular accident (CVA) commonly known as stroke
- Transient ischemic attack (TIA) also known as "mini-stroke"
- Idiopathic intracranial hypertension (IIH) also known as pseudotumor cerebri
4) How should I choose my HST Provider?
There are several important questions to ask before selecting an HST company:
Is the HST company owned and operated by a physician or a non-physician group?
Non-physician groups outsource the processing of their sleep studies and typically look for the lowest cost solution. Unfortunately, many of these firms cut corners by using automated programs to score the sleep study which may decrease the accuracy of the results. The physician who interprets the study may not be properly trained in sleep medicine and may not review the study in its entirety. It is important that your interpreting physician review the entire record to make sure that the proper diagnosis is made. Therefore, choosing a physician-owned company ensures that you get quality results.
Is the interpreting provider a fellowship-trained, board certified sleep physician?
Fellowship-trained, board certified sleep medicine physicians have spent one full year training in sleep medicine and passed a rigorous national examination, thereby demonstrating their expertise in sleep disorders. Only these physicians have the necessary skill-set required to competently read and interpret sleep studies. The average physician only gets one hour of training in sleep disorders during medical school; thus, it is very important to ensure that the doctor in charge of your HST is fellowship trained and board certified. Unfortunately, many physicians who are not fellowship-trained and board certified in sleep medicine have found that attempting to read sleep studies can be a good revenue stream for them. Insist on a fellowship-trained, board certified sleep physician.
What is the turn-around time for results and how is the company's customer service?
Many HST companies can take weeks to months to process your test. Patients commonly feel that they are just a number to these companies and there has been a record of poor customer service in the industry. Make sure to ask how long it will take to get your results before signing up for the study and steer clear of companies that don't provide a first-rate customer experience during this first interaction.