Why Do I Need a Second Sleep Study?

Common Reasons Why Further Sleep Testing Is Necessary

Sleep study.
Credit: BSIP / Contributor / Getty Images

If you have gone through the ordeal of an overnight sleep study once, you might wonder: Why do I need a second sleep study? Learn why a sleep specialist may consider repeating a study and in what situations it may help the management of your sleep disorder.

Lost or Inadequate Prior Records

One of the most common reasons that a sleep specialist will order a repeat sleep study is because records of the initial study are simply inaccessible. Unfortunately, patients and physicians alike have not always been great record-keepers. This is more common if a change in your sleep doctor has occurred. If the study was completed years ago, there is a high likelihood that the reports and associated data of the study have been lost. In order to establish the diagnosis, a sleep study is universally required for insurance to pay for CPAP equipment.

Moreover, there have been recent changes in insurance requirements, especially for those who use Medicare in the United States. Strict rules are now in place that demands detailed clinic notes, sleep study reports interpreted by board-certified sleep specialists, and documentation of compliance with therapy in the first 90 days of use. When this paperwork is not in order, as it often is not due to less stringent requirements from years ago, a new sleep study is often required to resume or continue CPAP therapy, including to qualify for new supplies such as masks and tubing.

Changes in Your Health

If a sleep study was performed some years ago, there may be significant changes in your health that necessitate a reassessment of your sleep. A relatively modest change in weight, either gaining or losing 10% of your body weight, may be a reason to repeat a study. Weight gain will often worsen the degree of sleep apnea while losing it might improve or even fully alleviate the condition.

Symptoms that you have developed that were not present at the time of your initial diagnosis may also prompt a repeat sleep assessment. For example, if you newly have restless legs syndrome or are noted to have frequent leg movements at night, this may require evaluation. In addition, abnormal sleep behaviors such as REM behavior disorder may develop later in life and should be assessed with a formal sleep study.

Finally, even more significant health changes could necessitate a second look. Heart failure, stroke, or the introduction of narcotic medications may all be reasons to ensure changes in breathing during sleep have not occurred. Each of these conditions can be associated with central sleep apnea, a disorder that often requires bilevel therapy.

Assessment of the Success of Alternative Treatments

Many people choose alternative therapies to treat sleep apnea, including the use of an oral appliance from a dentist or surgical treatments. How do you know if the treatment works? CPAP machines are able to track nightly response to therapy, but these alternative treatments do not provide this continuous feedback on treatment effectiveness. As a result, a second sleep study can be a useful way to check on how your appliance works or whether the surgery was a success.

The oral appliance can be worn while a standard sleep study is performed to evaluate your breathing. A study can also be done postoperatively, and will typically occur 2 months or longer after the surgery was performed. It is important to compare apples to apples and orange to oranges: have the same type of study (and at the same location) as your prior testing to ensure that other variables do not undermine the comparisons. If sleep apnea persists despite these treatments, it is often necessary to reconsider other therapy options.

Unresolved Symptoms and Optimizing CPAP Therapy

Sometimes a sleep study is repeated to address unresolved symptoms. If you are still too sleepy, this may be an indication to dig a little deeper. These repeat studies also allow for optimization of treatments, including the titration of CPAP therapy.

Persistent excessive daytime sleepiness may require reassessment as other conditions may be occurring. The Epworth Sleepiness Scale is a screening tool used in clinics to identify someone who may be too sleepy. More intensive evaluation often proves necessary to sort out the underlying cause of the state. It may occur due to sleep deprivation, undertreated sleep apnea, narcolepsy, or other factors. A diagnostic polysomnogram followed by multiple sleep latency testing (MSLT) may provide evidence as to the cause.

The most common indication for the second night of sleep study is to initiate and optimize positive airway pressure treatment to remedy sleep apnea. It sometimes proves impossible to find the most effective pressure settings either as part of an initial split night study or with a trial of therapy at home. Instead, a second titration study can be used to ensure proper mask fitting, improve acclimatization to the therapy, and identify the necessary pressures to maintain the airway during sleep. In some cases, alternative therapies can be explored including CPAP, bilevel, and even auto or adaptive servo-ventilation (ASV). The sleep technician can work with you to optimize the therapy experience.

If you believe you may benefit from a second sleep study, speak with a sleep specialist about the options available to you. Depending on your needs, you may even explore the possibility of having a home sleep test. Fortunately, these sophisticated studies can help you to get the quality sleep that you need to improve your overall health and well-being.