Sleep disorders

Nancy Foldvary-Schaefer, DO, MS, on OSA Diagnosis and Treatment

Sleep disordered breathing is an umbrella term used for several chronic sleep conditions, including obstructive sleep apnea (OSA)—the most common sleep-related breathing disorder. Recent research presented at the American Academy of Neurology’s 2019 Annual Meeting highlighted a new potential treatment for daytime sleepiness associated with narcolepsy or OSA,1 insomnia in epilepsy,2 and the results of upper airway stimulation as a treatment for OSA.3

Another important session about OSA, “Sleep-Disordered Breathing in Neurology Populations: From Lab to Clinic,”4 was presented by Nancy Foldvary-Schaefer, DO, MS, who is director of the Sleep Disorders Center at Cleveland Clinic, a neurologist at Cleveland Clinic Neurological Institute; a professor of neurology at Cleveland Clinic Lerner College of Medicine; and a staff member of the Epilepsy Center.

Neurology Consultant caught up with Dr Foldvary-Schaefer after her session.

NEUROLOGY CONSULTANT: How is OSA diagnosed? What screening methods are used?

Nancy Foldvary-Schaefer: At least 27% of men and 11% of women are affected by OSA, based on older studies when obesity rates were not as high as they are today. In just the past 15 to 20 years, OSA diagnoses have increased by 10% to 50%. Though many people may not know about it, it is more prevalent than chronic diseases like diabetes or Alzheimer disease. Approximately 17% of middle-aged men and 9% of middle-aged women have moderate to severe OSA, the range that contributes to other health conditions such as heart disease and stroke. While most people think of men as being more at risk, after menopause women are just as likely to develop OSA. At least 80% of cases in the United States are undiagnosed. 

The International Classification of Sleep Disorders 3rd Edition (ICSD-3) diagnostic criteria for OSA requires diagnostic testing with either an overnight in-lab polysomnogram (PSG) or a Home Sleep Apnea Test (HSAT). For individuals with a lower severity on the diagnostic test (apnea-hypopnea index [AHI] 5-<15 on PSG or respiratory event index [REI] 5-<15 on HSAT), symptoms such as excessive daytime sleepiness, snoring, or witnessed apneas are required for the diagnosis. The presence of associated medical comorbidities such as hypertension, congestive heart failure, coronary heart disease, diabetes mellitus, atrial fibrillation, or history of stroke can meet the diagnostic criteria of symptoms in the setting of lower severity on diagnostic testing.

The STOP-BANG instrument is a simple way to screen for OSA. Three or more of the following suggest a high risk of OSA:

  • Do you SNORE loudly (louder than talking or loud enough to be heard through closed doors)?
  • Do you often feel TIRED, fatigued or sleepy during the daytime?
  • Has anyone OBSERVED you stop breathing during your sleep?
  • Do you have or are you being treated for high blood PRESSURE?
  • Is your BODY mass index more than 35 kg/m2?
  • Is your AGE over 50 years old?
  • Is your NECK circumference more than 40 cm (15.75 in)?
  • Are you of male GENDER?

 

NEURO CON: What is the relationship between sleep disordered breathing and other prevalent neurological disorders?

NFS: Beyond the symptoms of OSA mentioned previously, recurrent upper airway collapse in sleep leads to a state of chronic partial sleep deprivation—the effects of which have vast implications on brain health including psychological, physical, social, occupational well-being, and driving safety. Attention is the cognitive ability most easily influenced by sleep deprivation.  As the day wears on, deficits in attention increase, and the ability to focus on tasks becomes erratic. Memory behaves in a similar manner, as does the brain’s reward system that controls motivational behaviors like risk taking and impulsivity. Sleep loss impairs rational decision making when challenged with making difficult choices. The neurophysiological underpinnings of impairments in cognition, alertness, and mood associated with sleep loss are becoming increasingly elucidated. Sleep deprivation produces changes in neuronal connectivity, including in the hippocampus that plays a crucial role in memory consolidation. Disturbed sleep seems to be a precursor to memory loss in Alzheimer disease, and sleep duration has been shown to be inversely correlated with β-amyloid plaque burden.

OSA has been more extensively studied in patients with epilepsy than any other neurological disorder. The largest study assessing the prevalence and predictors for OSA in adults with epilepsy found that 30% of 134 consecutive adults unselected for sleep disorder symptoms or epilepsy severity were affected. And 16% had moderate to severe disease. Predictors of OSA included age and standardized antiepileptic drug dose, a measure of drug burden. Male gender, age older than 50 years, obesity, and hypertension were associated with higher AHI. Self-reported daytime sleepiness was not helpful in predicting OSA. In turn, the effect of positive airway pressure (PAP) therapy on seizure outcomes at 1 year in 132 adults with epilepsy showed significant improvement in seizure control in 84% of PAP-treated patients vs. 40% of untreated OSA patients and 54% of those without OSA. In the absence of clinical trials, observational studies support routine screening and treatment of OSA in adults with epilepsy.

Various types of sleep disordered breathing are common in patients with stroke, neuromuscular disease, and neurodegenerative diseases. Patients with certain neurodegenerative disorders are also commonly affected with restless legs syndrome, hypersomnia disorders, and parasomnias like REM sleep behavior disorder.

 

NEURO CON: What are the latest advancements in therapies for sleep disordered breathing? What’s on the horizon?

NFS: There are many innovations in for sleep apnea evolving. Hypoglossal nerve stimulation (HNS) is the newest high-impact innovation for patients with moderate to severe OSA. Eligibility requires the absence of concentric collapse of the soft palate on drug-induced sleep endoscopy and a history of PAP intolerance or failure. The development of HNS as a therapeutic option for OSA stems from evidence that stimulation of the genioglossus muscle, the primary pharyngeal dilator of the hypoglossal nerve, reverses inspiratory flow limitation in sleep.

HNS is an implanted system consisting of a thoracic respiratory sensing lead, a pulse generator, and an electrode cuff. In the multicenter STAR trial, stimulation led to significant improvements in objective and subjective measurements of OSA severity, including a reduction in median AHI of 68%, improved quality of life, and average nightly compliance exceeding 80%, with few unanticipated adverse events. At 5 years, success persisted in 75%, and 44% of participants had normalization of AHI.

NEURO CON: What is the role of neuromodulation in the treatment plan?

NFS: Current eligibility for HNS requires a patient have failure PAP there or proves to be intolerant. Also, patients cannot have a body mass index more than 32 kg/m2, which precludes consideration for many patients given that many OSA patients are typically obese.

NEURO CON: What other knowledge gaps exist among neurologists in this area?

NFS: Few neurologists have formal training in sleep medicine, yet common sleep disorders are highly prevalent in neurologic populations, and their treatment improves neurologic outcomes in some cases. Therefore, neurologists should understand the basics regarding recognition and treatment of common disorders like OSA.

References:

  1. Foldvary-Schaefer N, Shapiro C, Schwab R, et al. A Long-term study of the safety and maintenance of efficacy of solriamfetol (JZP-110) for treatment of excessive daytime sleepiness associated with narcolepsy or obstructive sleep apnea. Paper presented at: American Academy of Neurology’s 2019 Annual Meeting; May 4-10, 2019; Philadelphia, PA. http://indexsmart.mirasmart.com/AAN2019/PDFfiles/AAN2019-000555.pdf. Accessed May 20, 2019.
  2. Somboon T, Pascoe M, Eippert M, et al. Insomnia in epilepsy: association between insomnia symptom severity and disease-related characteristics. Paper presented at: American Academy of Neurology’s 2019 Annual Meeting; May 4-10, 2019; Philadelphia, PA. http://indexsmart.mirasmart.com/AAN2019/PDFfiles/AAN2019-001358.pdf. Accessed May 20, 2019.
  3. Waters T, Kominsky A, Wang L, et al. Impact of upper airway stimulation treatment for obstructive sleep apnea on comorbid insomnia, depression and sleepiness patient reported outcome measures. Paper presented at: American Academy of Neurology’s 2019 Annual Meeting; May 4-10, 2019; Philadelphia, PA. http://indexsmart.mirasmart.com/AAN2019/PDFfiles/AAN2019-004253.pdf. Accessed May 20, 2019.
  4. Foldvary-Schaefer N. Sleep-disordered breathing in neurology populations: from lab to clinic. Paper presented at: American Academy of Neurology’s 2019 Annual Meeting; May 4-10, 2019; Philadelphia, PA. http://tools.aan.com/annualmeeting/search/index.cfm?fuseaction=home.detail&id=7036&keyword=&topic=&type=all. Accessed May 20, 2019.