New data presented today at the Annual Meeting of the American Academy of Otolaryngology confirm that specialized oral appliances are a viable option to counter the devastating effects of obstructive sleep apnea (OSA) and new FDA-approved technologies for home-based sleep studies are a valuable tool to diagnose and assess the effectiveness of the therapy.
Obstructive sleep apnea syndrome (OSAS) is a disorder characterized by repeated episodes of reductions or cessation in breathing during sleep. Millions of Americans, both men and women, have this medical problem, which is associated with clinical complications such as daytime sleepiness, high blood pressure (hypertension), heart disease, increased risk for stroke, and an increased risk for early death.
The gold-standard method to diagnose and quantify OSA is considered the overnight sleep polysomnography (PSG). With this system, patients spend the night in a sleep lab while hooked to a variety of electrodes, which measure various channels (such as EEG, EOG, EMG, ECK, Flow, Respiratory Effort, Oximetry). The severity of the disorder is expressed as the respiratory disturbance index (RDI), which is the number of sleep disordered breathing events per hour of sleep.
The expense and patient inconvenience of the PSG has lead to the development of a variety of ambulatory sleep study systems performed in the home. These include simple devices such as ambulatory pulse-oximetry, more complex devices that monitor several channels, and even full ambulatory PSG. Recently, the novel Watch-PAT100 ambulatory system, an FDA approved device, has been introduced to diagnose and quantify sleep apnea in the comfort of the patient’s home. The WATCH-PAT100 has been shown to be accurate in diagnosing OSA, and at the same time to be an easy-to-use device; enabling physicians to manage sleep apnea at their own practices.
The most effective treatment for OSA is continuous positive airway pressure delivered via a nasal mask (nCPAP), but it has a very low compliance rate. Weight reduction can greatly alleviate the OSA severity, but it is frequently difficult to achieve or maintain. Surgical procedures benefit some patients but their long-term effectiveness is questionable. Recently, another therapeutic approach has been introduced: the anterior mandibular positioning (AMP) dental device is designed to increase airway caliber and decrease airway resistance by moving the mandible forward during sleep. Previous studies have reported beneficial effects of oral appliances in OSA on mild to moderate cases.
"OSA is significantly under-diagnosed and its consequences are a burden on the healthcare system," noted Professor Giora Pillar. "The PAT is a sensitive indicator of sympathetic activity induced by acute periods of airflow obstruction, such as associated with OSA and the Watch-PAT 100 fills an important void in creating a simple, cost-effective approach to the diagnosis of OSA."
A research team set out to examine whether two different oral appliances were beneficial for various severities of OSA, and whether response can be easily monitored in the dental clinic by the ambulatory Watch-PAT100 sleep diagnosis device. The authors of “Efficacy Assessment of Obstructive Sleep Apnea Treatment: Watch-PAT100 Follow-Up of Patients Treated with Two Oral Appliances,” are Giora Pillar, Sleep laboratory, Rambam Medical Center and Technion – Israel Institute of Technology, Haifa, Israel; Steven Merahn, MD with the Academy of Clinical Sleep Disorders Dentistry , USA; and Edward P. Spiegel, DDS, of Erie, PA. Their findings are being presented at the American Academy of Otolaryngology-Head and Neck Surgery Foundation Annual Meeting & OTO EXPO, being held September 19-22, 2004, at the Jacob Javits Convention Center, New York City, NY.
Twenty patients (four females, 16 males) with a diagnosis of OSA (six with a severe condition) were studied. Patients were overweight (mean BMI 31.7 ± 5.7 Kg/m2), had wide necks (mean neck circumference 17.1 ± 0.9’’), and reported daytime sleepiness (somnolence). They were randomized to use either the EMA2 or the Silencer oral appliance. Both oral appliances are laboratory fabricated and allow three major functions: vertical and anterior positioning, and free lateral movement.
All underwent a pre- and post treatment ambulatory sleep study, using the Watch-PAT100 device. This device detects peripheral arterial tone, sleep state, oxygen saturation, pulse rate and autonomic activation, and has been shown to be accurate at quantifying sleep disordered breathing. The follow-up treatment efficacy study was performed at least three weeks after commencing treatment. Vertical and anterior positioning of the oral appliance was determinate using imaging airway assessment.
Ten patients have been using the EMA2 and ten patients the Silencer device on a nightly basis (reportedly). Age, BMI, neck circumference and pre-treatment OSA severity were similar between the groups. Out of 40 home studies, two were repeated due to technical problems.
On treatment, mean RDI with the EMA2 decreased from 36±17/h to 11±12/h and minimal oxygen saturation increased from 82±6 to 88±4 percent. In 80 percent of the patients, treatment was considered successful (defined as reduction of RDI by at least 50 percent or to less than 10/h). With the Silencer, RDI decreased from 30±20/h to 13±13/h and minimal oxygen saturation increased from 81±12 to 88±4 percent. In 80 percent of the patients, treatment was considered successful. For both appliances, the unsuccessful treatment was in relatively severe patients.
Despite the lack of long-term data, the researchers believe their findings confirm previous reports that oral appliances are beneficial for OSA. While several previous studies concluded that oral appliances should be reserved only for the mild and moderate OSA cases, their results suggest that this treatment may be adequate for severe cases as well (especially for patients non-tolerant to CPAP). In addition, the study offers evidence that the ambulatory monitoring system WATCH-PAT100 is an easy and convenient way to monitor these patients and follow-up on them during treatment.