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Neurology International 2011; volume 3:e15

Obstructive apnea OSA is caused by a physical blockage of the airway; it results from airflow obstruction sec- Correspondence: Steven Brass, MD, MPH ondary to upper airway collapse or anatomic Director of Sleep Medicine Matthew L. Ho, Steven D. Brass airway obstruction, even though the respirato- 4860 Y Street Suite 3700 Sacramento, CA 95817 UC Davis Department of Neurology, ry effort is still present. In the case of CSA, the Tel. +916.734.6785. Davis Medical Center, University airway is not blocked; the brain fails to signal E-mail:[email protected] of California, California, USA the muscles to breathe and is inter- Key words: apnea, , obstructive sleep rupted by a lack of respiratory effort.3 apnea, apnea hypopnea index, respiratory distur- The clinical picture of OSA has long been bance index, respiratory event related arousals. recognized in medical literature. It was first Abstract described in 1918 by William Osler, a 20th cen- Received for publication: 23 August 2011. tury physician who coined the term Accepted for publication: 30 August 2011. Obstructive (OSA) affects mil- Pickwickian syndrome in reference to a char- This work is licensed under a Creative Commons lions of Americans and is estimated to be as acter in Charles Dickens's novel The Pickwick Papers. The character named Joe has all the Attribution NonCommercial 3.0 License (CC BY- prevalent as asthma and diabetes. Given the NC 3.0). fact that obesity is a major risk factor for OSA, classic symptoms of the condition. Joe is con- and given the current global rise in obesity, the stantly hungry, red faced and always falling ©Copyright M.L. Ho and S.D. Brass, 2011 prevalence of OSA will increase in the future. asleep in the middle of doing a task. Licensee PAGEPress, Italy Individuals with sleep apnea are often The object that presented itself to the eyes of Neurology International 2011; 3:e15 unaware of their . It is usually the astonished clerk, was a boy - a wonderfully doi:10.4081/ni.2011.e15 first recognized as a problem by family mem- fat boy - habited as a serving lad, standing bers who witness the apneic episodes or is upright on the mat, with his eyes closed as if in sleep.4 suspected by their primary care doctor because Age is also an important risk factor in the of the individual’s risk factors and symptoms. development of OSA; the prevalence is estimat- The vast majority remain undiagnosed and ed toonly triple in individuals greater than 65 years untreated, despite the fact that this serious Epidemiology of age compared with individuals aged 30-64 disorder can have significant consequences. years.18,19 Regarding gender, the male-to- Individuals with untreated OSA can stop female ratio in community-based studies is OSA affects more than twelve million breathing hundreds of times a night during about 3:1.20 It is theorized that body fat distri- Americans.5 An epidemiological reviewuse by their sleep. These apneic events can lead to bution predispose men to OSA and that sex fragmented sleep that is of poor quality, as the Young et al. estimates that 1 in 5 adults has at hormones play a role in the modulation of brain arouses briefly in order for the body to least mild OSA and 1 in 15 adults has at least upper airway musculature. resume breathing. Untreated, sleep apnea can moderate OSA.6 Sleep apnea can affect anyone As indicated above, the incidence of OSA have dire health consequences and can at any age, even children.7,8 OSA is becoming among male and female are 3:1 prior to increase the risk of hypertension, diabetes, increasingly prevalent. However, because of menopause. However, the incidence of OSA is heart , and . OSA manage- the lack of awareness by the public and health- equal amongst males and females following ment has also become important in a number care professionals, the vast majority remain menopause. There is at least a threefold of comorbid neurological conditions, including undiagnosed and untreated. Data from the , , , and Wisconsin sleep cohort study of patients esti- increase in risk of OSA among post- . Diagnosis typically involves use of mate that 93% of women and 82% of men with menopausal women compared to pre- 21,22 screening questionnaires, physical exam, and moderate-to-severe sleep apnea were undiag- menopausal women. In addition, there is a an overnight or a portable nosed.9 A follow-up publication from the lower prevalence of OSA among post- home study. Treatment options include Wisconsin Cohort Study five years later indi- menopausal women who were on hormone changes in lifestyle, , cated that the prevalence of OSA in people replacement therapy.23 Interestingly, there surgery, and dental appliances. aged 30-60 years was 9-24% for men and 4-9% does not appear to be any difference in preva- for women.10,11 Primary risk factors for OSA lence between males and females prior to Non-commercialinclude the male gender, those over age 40, puberty. overweight persons or recent weight gain, and Structural factors related to craniofacial Introduction persons with a large neck size or small bony anatomy can predispose patients to pha- chin/jaw (Table 1).12 ryngeal collapse during sleep, including retrog- The Greek word apnea means breathless or Epidemiological studies have consistently nathia and micrognathia, mandibular hypopla- loss of breath.1 Sleep-disordered breathing shown that body weight, and in particular BMI, sia, and high-arched palate.24,25 Imaging stud- (SDB) encompasses a heterogeneous group of is the strongest risk factor for OSA. It is esti- ies have demonstrated that patients with OSA sleep-related disorders that are characterized mated that about 70% of those with OSA are have compromised pharyngeal lumens that by abnormal pauses in breathing during sleep. obese and that the prevalence of OSA in obese predispose them to collapse.26 This was inde- There are two major types of SDB: obstructive men and women is about 40%.13,14 Twenty-six pendently confirmed under general anesthesia sleep apnea (OSA) and central sleep apnea percent of patients with a BMI greater than 30 that simulates the total muscle paralysis seen (CSA). Despite the difference in the actual and 33% of those with a BMI greater than 40 during REM sleep.27 Patients with Down syn- cause of each type, in both cases, people with have moderate OSA.15 A large neck circumfer- drome, Marfan syndrome, and Prader-Willi untreated sleep apnea stop breathing repeat- ence is also associated with an increased risk syndrome are particularly at risk due to these edly during their sleep. Of the two types of of OSA. In fact, neck circumference of 15.7 in structural factors. sleep apneas characterized, OSA is the most (40 cm) or greater may have a greater sensitiv- In terms of ethnicity, African American indi- common type, constituting greater than 85% of ity and specificity than BMI in predicting OSA, viduals appear to be more predisposed to OSA all cases of SBD; CSA is far less common.2 regardless of the person’s sex.16,17 than Caucasians, with an odds ratio of 3 in chil-

[page 60] [Neurology International 2011; 3:e15] Review dren younger than 14 and 2 in adults greater increase in tissue pressure, as a product of apnea is usually recognized as a problem by than 25.28 Individuals of Asian descent, particu- extra soft tissue mass (in a normal-sized family members who witness the apneic larly Chinese individuals, have a more crowded enclosure) and/or structural limitations (small episodes or by a primary care doctor because of upper airway and retrognathia compared with maxillary or mandibular compartment) with the individual’s risk factors and symptoms. Caucasians. OSA has a prevalence rate similar normal tissue mass (Figure 1).31 Chronically, Most commonly, patients present with vague in the Asian population sample to those in this dysfunction can cause problems with the complaints. Clinical symptoms can include Caucasians despite a lower obesity rate. Asians regulation of pharayngeal dilator muscle acti- excessive daytime sleepiness (EDS) that usu- have an increased risk of developing OSA, vation (which plays an important role in main- ally begins during quiet activities (eg, reading, regardless of weight or neck circumference, as taining airway patency) in patients with OSA. watching television), daytime fatigue, feeling well as greater disease severity.29 OSA is thus characterized by the partial or tired despite a full night’s sleep, morning total collapse of the pharyngeal airway during , personality and mood changes, dry sleep and the need to arouse to resume venti- or sore throat, gastroesophageal reflux, and lation.32 In adults, the obstruction typically sexual dysfunction. Pathophysiology occurs at the level of the oropharynx Snoring is a common finding in individuals (uvula/soft palate or tongue).33,34 Chronic with OSA. Although not everyone who snores The International Classification of Sleep severe OSA can result in prolonged , is experiencing sleep apnea, snoring in combi- Disorders, second edition (ICSD-2) was pub- sleep deprivation, and other complications. nation with obesity has been found to be high- lished by the American Academy of Sleep With most apneic events, the brain briefly ly predictive of OSA risk.38 The volume of the Medicine to standardize definitions and create arouses in order for the body to resume breath- snoring is not indicative of the severity of a systematic approach to the diagnosis of sleep ing, but consequently, sleep is extremely frag- obstruction. However, snoring with witnessed disorders. The ICSD-2 subdivides sleep disor- mented and of poor quality. apneas has a 94% specificity for OSA. ders into eight major categories, one of which Several additional anatomical factors play a The diagnosis of OSA is based on the evalu- is sleep-disorder breathing (SDB).30 role in OSA. These include the position that the ation of clinical symptoms and risk factors, as The ICSD-2 further classifies SDB into three patient sleeps in, airway reactivity and airway well as a formal sleep study evaluation basic categories: CSA syndromes, OSA syn- secretions. Position can have a strong influence (polysomnography, or a portable home based dromes, and sleep-related hypoventilation/ on airway patency. Because the airway is col- test).only Individuals should be evaluated appro- hypoxic syndromes. OSA involves a complete lapsible, gravitational forces can cause the priately with screening questionnaires, as well cessation or a significant decrease in airflow retropulsion of the tongue and soft palate while as a physical examination. in the presence of breathing effort. CSA is the laying supine, thus generating increased posi- The Epworth sleepiness scale (ESS) has cessation of airflow with an absence of breath- tive tissue pressure and narrowing theuse airway.35 been universally adopted as an effective ing effort. Breathing effort is measured by For this reason, OSA worsens in the supine screening method to monitor for clinical symp- abdominal and/or chest movement. sleeping position for most individuals.36 toms of sleep apnea. This questionnaire is The human airway is composed of soft tis- used to help determine how frequently the sue that can collapse during REM sleep, when patient is likely to doze off in 8 frequently the muscle tone of the body relaxes. Two major encountered situations (e.g., as a passenger in factors likely contribute to OSA pathophysiolo- Evaluation a car, sitting quietly after lunch, etc). A 2003 gy: i) craniofacial structural abnormalities can study showed that an ESS score of 12 or predispose patients to OSA; this has been dis- Individuals with OSA are rarely aware of greater is considered abnormal and would war- cussed previously and has been recognized as their sleep disorder, even upon arousal.37 Sleep rant a more formal evaluation.39 However, the a primary risk factor for OSA; ii) larger soft tis- sue mass or abnormal tissue deposits can also increase extraluminal tissue pressure and lower the threshold for airway collapse (Figure 1). In normal, nonobese individuals without OSA, muscle relaxation during sleep does not completely collapse the airway (normal). However, airway collapse can Non-commercial occur during muscle relaxation when there is a pathological

Table 1. Primary risk factors for obstruc- tive sleep apnea. Primary risk factors for sleep apnea Weight gain or being overweight with a BMI >30 kg/m2 Neck circumference [≥17in (or 43.2 cm) in men; ≥16in or (40.6 cm) in women] Age >40 Male gender Structural factors related to craniofacial anatomy Figure 1. Reprinted with permission of the American Thoracic Society. Copyright (c) 2011 Ethnicity American Thoracic Society. White D. Pathogenesis of obstructive and central sleep apnea. Am J Resp Crit Care Med. 2005; 172: 1363-1370. Official Journal of the American Family history of sleep apnea Thoracic Society.

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ESS is still a subjective self assessment meas- ment of OSA, including hypothyroidism and oximetry, respiratory effort, electrocardio- ure and may be inaccurate for a number of rea- acromegaly. Both are associated with graphic (ECG) tracings, body position, and sons. Therefore, if a patient has multiple risk macroglossia and increased soft tissue mass in snoring are all accumulated. factors for sleep apnea, the individual should the pharyngeal region, and patients should be The portable home-based sleep study has be sent for further evaluation if there is a sus- routinely screened for these conditions as well. recently emerged as an alternative to the PSG. picion of sleep apnea despite a low ESS. Individuals should have a routine evaluation It assesses for oximetry, thoracic and abdomi- Another effective screening tool that has of their upper airway. The Mallampati score nal movements, and body position. The advan- been used in the primary care population is has been used for years to identify patients at tage to this study is that it can be performed the Berlin questionnaire.40 Survey questions risk for difficult tracheal intubation. It is now overnight in the comfort of the individual’s address snoring behavior, EDS/fatigue, and also used commonly by sleep physicians to home and is more cost effective in comparison history of obesity or hypertension. The sensi- evaluate for risk of OSA. The classification pro- to the formal PSG. In one study, normal tivity of the Berlin questionnaire with regards vides a score of 1 thru 4 based on the anatom- overnight oximetry was very sensitive in to high-risk patients having sleep apnea was ic appearance of the airway seen when an indi- excluding OSA.43,44 However, the main limita- 86%. Another screening tool called the STOP vidual opens his mouth (Figure 2). Studies tion of the portable home sleep study is that it BANG questionnaire was developed to screen have shown that for each 1 score increase in does not have the EEG component; it is there- for the most common risk factors seen specifi- the Mallampati score, the number of apneic fore not able to assess an individual’s sleep cally in OSA. The term refers to a mnemonic events increase.42 architecture and will not be able to assess that represents 8 factors: Snoring, Tiredness, The next step in the assessment is a formal arousals based on changes in sleep stages and Observed apneas, elevated blood Pressure, sleep evaluation. An overnight polysomnogra- can therefore underestimate the prevalence of BMI (greater than 35 kg/m2), Age (greater phy (PSG) is recorded during the normal sleep- OSA. It is thus indicated for use as an alterna- than 50), Neck circumference (greater than 40 ing hours of a patient. Patients sleep 6 to 8 tive to PSG for the diagnosis of OSA in patients cm), and Gender (male). Patients receive a hours before either awakening spontaneously with a high pretest probability of moderate to point for each positive risk factor, and those or being awokened. The goal of the PSG is to severe OSA and no other comorbid sleep disor- whose scores are equal to or greater than 3 quantify the amount of time spent in various ders or major comorbid medical disorders.45 have a higher likelihood of having OSA. The stages of sleep during the night and to docu- Patients should be excluded if they have con- sensitivities of the STOP BANG questionnaire ment clinically relevant events such as car- gestiveonly heart failure, chronic obstructive pul- for mild, moderate, and severe sleep apnea diopulmonary abnormalities and/or changes in monary disease, neuromuscular disease, use were 83.6%, 92.9%, and 100%, respectively. sleep stages. The standard PSG includes limit- certain medications (potent narcotics), or may The physical examination is frequently nor- ed multi-channel recording of an individual’s have another suspected causes for sleepiness. mal in patients with OSA, other than the pres- electroencephalography (EEG) to assessuse for ence of obesity, an enlarged neck circumfer- sleep architecture, sleep stages and arousals. ence, and/or structural craniofacial bony In addition, surface electromyography of the abnormalities. There are other medical condi- chin and all four limbs (to assess for move- Diagnosis tions that may be associated with the develop- ment), electro-oculogram, airflow, pulse The American Academy of Sleep Medicine (AASM) defines an apnea as a cessation in air- flow lasting at least 10 sec; apneic episodes can last anywhere from 10 sec to min, and may occur multiple times per hour.46 Hypopnea is Figure 2. Mallampati defined as a recognizable transient reduction score. Author Jmarchn. (but not complete cessation) of breathing for January 29, 2011. at least10 sec. This differs from apnea in that Permission is granted to copy, distribute and/or there remains some flow of air. In the context modify this document of sleep disorders, a hypopnea event is only under the terms of the considered to be clinically significant if there GNU Free Documenta - is a 30% or more reduction in flow with an Non-commercialtion License, Version 1.2 associated 4% or greater desaturation in O2 or any later version pub- lished by the Free Software level, lasting for 10 seconds or longer, or if it is Foundation. [online] associated with an arousal or fragmentation of Available from: http://en. sleep. Apneas and are both consid- wikipedia.org/wiki/Malla ered in assessing the severity of a person’s mpati_score. sleep disorder.47 The Apnea-Hypopnea Index (AHI) is an index used to assess the severity of sleep apnea based on the total number of apneas and hypopneas occurring per hour of sleep. In gen- eral, an individual is considered to have an OSA syndrome if they demonstrate an AHI of at least 5 with the presence of daytime symptoms or AHI of 15 or more independent of symptoms. The AHI can also be used to stratify the sever- ity of the disease; an AHI of 5-15 is classified as mild, 15-30 is considered moderate, and greater than 30 is considered severe.48

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Another measure that is often used is the direct neural injury or cause extension of vas- Table 2. Long term health problems associ- Respiratory Disturbance Index (RDI). Like the cular penumbra via and ischemia in ated with untreated obstructive sleep AHI, RDI measures respiratory events; howev- stroke.68 apnea. er, it also includes respiratory event related There appears to be a higher incidence of Health problems associated with sleep arousals (RERAs). RERAs are arousals from OSA in the multiple sclerosis (MS) population, apnea sleep that do not technically meet the defini- but this has been poorly studied in small Hypertension tions of apneas or hypopneas, but do disrupt prospective series. It is unclear at this time if Stroke sleep. Some research studies have found that this comorbidity association is due to MS Diabetes 30% of symptomatic patients would have been lesions, symptomatic medications used for left untreated if the AHI were used rather the pain and spasticity, etc.69 Chronic and morning Heart failure RDI.49 Please see Figure 5 for a simplified headaches are a relatively common symptom Cardiac guideline for the evaluation, diagnosis and in OSA, and OSA may aggravate the frequency appropriate treatment options for OSA man- and severity of .70 OSA treatment has Obesity agement. been shown to reduce fre- Depression quency in patients with OSA and comorbid Worsening of Attention Defficit Hyperactivity cluster headaches.71 The conclusion regarding Disorder (ADHD) OSA as a comorbid condition in some neuro- Complications and comorbidities logical disorders is that neurologists should be mindful of the fact that OSA is more prevalent However, noncompliance is common and may Untreated, OSA can have a profound effect in their patient population and that practition- be as high as 40%, due mainly to discom- 82,83 on the body and can contribute to multiple ers should routinely screen for OSA in their fort. health problems (Table 2). It is associated with patients. Newer models of CPAP devices humidify the cardiovascular disease,50,51 hypertension,52-54 air, which decreases dry mouth and makes 84 stroke,55 , and insulin resistance. usage more comfortable. In addition, newer Patients with OSA have a 30% higher risk of models have automatic positive airway pres- sure options. This modality automatically heart attack or death than those unaffected.58 Treatment options only Hypertension that is primarily caused by OSA titrates the amount of pressure delivered to the patient to the minimum required to maintain (in contrast to essential hypertension) is dis- The most common first step in the treat- an unobstructed airway on a breath-by-breath tinctive in that the blood pressure does not ment of mild OSA is behavioral or lifestyle basis by measuring the resistance in the drop significantly when the individual is sleep- modification, including losing weight,use avoid- patient's breathing, thereby giving the patient ing.59 OSA that remains untreated can also ing alcohol, sleep aids or muscle relaxants, and the precise pressure required at a given have a negative effect on memory. Research quitting smoking.72 Weight loss in overweight time.85 has recently shown that individuals with OSA patients has been shown to decrease apneic BiPAP (variable/bilevel positive airway pres- have mammillary bodies that were nearly 20 episodes,72,73 both directly and by reducing sure) provides two levels of pressure: a higher percent smaller on MRI.60 This decreased tis- neck fat and nasopharyngeal crowding.75,76 inspiratory positive airway pressure (IPAP) sue mass may be related to the memory prob- If an individual’s apneic episodes are mild and a lower expiratory positive airway pres- lems seen in chronic OSA. and occur mainly during supine sleep, then sure (EPAP) for easier exhalation. This modal- OSA can have broader cognitive impair- patients are advised to take measures to avoid ity appears to be better tolerated and individu- ments, including sustained attention, working sleeping supine.77,78 The most common posi- als may find it easier to use; it is used in cases memory, visuospatial learning, motor perform- tion that apneic and hypopnic episodes are when patients cannot tolerate CPAP, for ance, and executive functioning.61,62 In partic- observed during sleep is in the supine posi- patients with chronic CO retention as well as ular, patients with OSA have been shown to tion. These patients may also benefit from 2 have impaired judgment, prolonged reaction sleeping at a 30-degree incline.79 Both these sleep apnea, and for patients with neuromus- time and vision problems, all of which can steps may help prevent the tongue and palate cular disease who need some assistance with nocturnal ventilation. BiPAP may also be more compromise work and driving ability.63 OSA from falling backwards and prevents the gravi- useful in CSA.86 increases motor vehicle accident risk by 2- to tational collapse of the airway. 3-fold, independent of EDS or Non-commercial AHI score.64 Along with lifestyle modifications, there are Behavior and mood can also be profoundly other treatment options of OSA. Dental appliances affected by a lack of the adequate restful sleep Dentists specializing in sleep dentistry can seen in sleep apnea, including irritability, Positive airway pressure make a custom-made mouthpiece that shifts aggressiveness, lack of attentiveness, as well For moderate to severe sleep apnea, the use the lower jaw forward, thereby maintaining an as depression.65 of a continuous positive airway pressure open airway (in theory). This approach can be There has been increasing recognition of (CPAP) is the first line therapy.80 CPAP uses successful in individuals with mild to moder- OSA as a comorbid condition in a number of continuous pressurized air flow to keep the ate OSA but has been proven less effective for neurological disorders, including epilepsy, individual’s airway open during sleep. The severe cases.87 In one study comparing CPAP stroke, multiple sclerosis, and headache. OSA amount of pressure used is initially titrated to dental appliance in mild to moderate OSA, appears to be more prevalent in patients with during the PSG (split test) based on the dental appliances decreased AHI from 21 epilepsy than in the general population and patient’s comfort and lowest pressure required (baseline) to 14, compared to a decreased AHI untreated OSA may theoretically worsen to decrease apneic and hypopneic episodes. of 5 in patients using CPAP.88 control by increasing seizure burden CPAP therapy is the most effective treatment through sleep disruption/deprivation.66 OSA option in reducing apneas in OSA.81 It has Surgery also increases the risk of stroke and appears to been shown to improve AHI, RDI, sleep archi- Surgical treatment for OSA needs to be indi- compromise rehabilitation following .67 tecture, EDS, neurobehavioral performance vidualized in order to address all anatomical It is theorized that OSA may directly cause and cardiovascular morbidity (hypertension). areas of obstruction. The most frequently uti-

[Neurology International 2011; 3:e15] [page 63] Review lized surgery treatment is the uvu- effective surgery for OSA patients, because it Armodafinil, the R-enantiomer of modafinil, is lopalatopharyngoplasty (UPPP or UP3). These increases the posterior airway space.92 In a now FDA approved for use as well. The surgeries aim to address pharyngeal obstruc- study in 2008, it was noted that MMA surgery American Academy of Sleep Medicine (AASM), tion by removing tissue in the back of the led to a significant increase in general produc- in a clinical review of medical therapies for throat, including part of the uvula, the soft tivity, social outcome, activity level and sex.93 OSA, recommended Modafinil as a standard palate, the tonsils, the adenoids and pharynx In addition, there are specialized tech- treatment of residual excessive daytime (Figure 3). In a retrospective review compar- niques that are available for correction of spe- sleepiness in patients with OSA despite maxi- ing CPAP to surgery, there appeared to be cific regions or obstruction, including the mal management of CPAP. Protriptyline was superior results with CPAP compared to nasal passages (septoplasty and turbinate sur- not recommended as a primary treatment for UPPP.89 Further studies have not been conclu- gery), the soft palate (implantation of Dacron OSA, although it was acknowledged that it may sive that this surgery has been effective at pillars) and the tongue. However, there have induce moderate improvement in the AHI in treating severe OSA.90 not been clinical trials or current evidence to patients with OSA and may be used as a second Maxillomandibular advancement (MMA) is support the use of these techniques in the line treatment option. Aminophylline, theo- another type of surgery that has been used to treatment of OSA. phylline, SSRIs and estrogen were not recom- treat OSA. This procedure aims to advance the mended for treatment of patients with OSA maxilla and mandible, thereby pulling forward Pharmacological management given that there was no consistent evidence of the anterior pharyngeal tissues attached to the Medications are generally not a part of the their effectiveness.94 maxilla, mandible and hyoid to structurally primary treatment of OSA. Modafinil is enlarge the retrolingual and retropalatal approved by the FDA for use in patients with spaces (Figure 4).91 It is considered the most OSA who have residual daytime sleepiness. Conclusions

In the context of the current epidemic of obesity, the prevalence and consequences of OSA will likely increase in the coming years. Givenonly the aging population, the number of neurological patients with OSA and comorbid stroke, epilepsy, headache, and cognitive decline will also likely rise. OSA can signifi- usecantly affect physical health, mental health and emotional well-being. Fortunately, screening methods for sleep apnea have improved, and there are now very effective means of diagno- sis and treatment. Treatment can lead to a ben- eficial impact on a patient’s health and quality of life. Several treatment options exist, and research into additional options continues. The medical community faces many hurdles Figure 3. Reprinted with permission of the American Thoracic Society. Copyright (c) regarding the development of adequate early 2011 American Thoracic Society. Won C, Li K, Guilleminault C. Surgical treatment of screening and appropriate treatment of OSA. : upper airway and maxillomandibular surgery. Proc Am Thorac An important next steps in understanding and Soc. 2008; 5: 193–199. Official Journal of the American Thoracic Society. treating OSA is to be proactive and develop bet- ter screening methods and properly treat patients at risk (Figure 5). It is imperative that the medical communi- ty understand that the effects of OSA is far- Non-commercial reaching, and early detection/treatment will be beneficial to individual patients, as well as a cost-effective public health measure to reduce morbidity and mortality. Physicians of all specialties should screen for the presence of sleep disturbances and consider referral to a sleep specialist when indicated. Neurologists, in particular, should be mindful of comorbid OSA in their patient population, since prompt identification and treatment of OSA may reduce health risk and improve neu- rological functioning.

Figure 4. Reprinted with permission of the American Thoracic Society. Copyright (c) 2011 American Thoracic Society. Won C, Li K, Guilleminault C. Surgical treatment of References obstructive sleep apnea: upper airway and maxillomandibular surgery. Proc Am Thorac Soc. 2008; 5: 193–199. Official Journal of the American Thoracic Society. 1. Oxford English Dictionary. Oxford

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