Chest ACCP Member Benefits
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Guest Access | Sign In via User Name/Password
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Article Archive
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via ISI Web of Science (2)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Skinner, M. A.
Right arrow Articles by Taylor, D. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Skinner, M. A.
Right arrow Articles by Taylor, D. R.
(Chest. 2004;125:118-126.)
© 2004 American College of Chest Physicians

Lack of Efficacy for a Cervicomandibular Support Collar in the Management of Obstructive Sleep Apnea*

Margot A. Skinner, MPhEd; Ruth N. Kingshott, PhD; David R. Jones, BSc and D. Robin Taylor, MD

* From the Respiratory Research Unit (Ms. Skinner, and Drs. Kingshott and Taylor), Dunedin School of Medicine, University of Otago, Dunedin; and Tom McKendrick Sleep Laboratory (Mr. Jones), Dunedin Hospital, Dunedin, New Zealand.

Correspondence to: Margot A. Skinner, MPhEd, School of Physiotherapy, University of Otago, PO Box 56, Dunedin, New Zealand; e-mail: mskinner{at}gandalf.otago.ac.nz


   Abstract
TOP
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Study objectives: The effect of therapy using a cervicomandibular support collar (CMSC) to manage obstructive sleep apnea (OSA) was compared with standard therapy, nasal continuous positive airway pressure (nCPAP).

Design: Subjects received treatment with CMSC or nCPAP each for 1 month in random order. The study was analyzed on an intention-to-treat basis.

Setting: Tom McKendrick Sleep Laboratory, Dunedin Hospital.

Participants:Ten adult subjects with mild-to-moderate OSA (apnea-hypopnea index [AHI], 24 ± 13/h slept [mean ± SD]) completed the study.

Interventions: The CMSC was designed to prevent mandibular movement and hold the head in slight extension, thus preventing the postural changes that might contribute to OSA. Positioning of the CMSC was confirmed by an externally applied cervical range of motion (CROM) instrument and by cephalometry. Subjects were carefully instructed in the use of each device and completed a symptom diary. After 1 month, subjects underwent polysomnography with each of the allocated devices in situ, and symptom questionnaires were administered.

Measurements and results:Treatment success (AHI <= 10/h slept) with CMSC was achieved in only 2 of 10 subjects, partial success (AHI > 10/h to <= 15/h slept) was achieved in 2 subjects, and in 6 of 10 subjects there was no benefit. In contrast, treatment success was achieved in 7 of 10 subjects receiving nCPAP. Mean AHI was 29.4 ± 13.4/h at baseline, 26.9 ± 17.2/h slept with CMSC, and 9.9 ± 8.0/h slept with nCPAP (p = 0.001). No significant differences in sleep architecture or sleep efficiency were achieved using nCPAP compared to CMSC. The efficacy of the CMSC in maintaining the desired head position was confirmed by cephalometry and the CROM instrument.

Conclusions: Our results, although negative, provide important evidence that control of head and neck posture, perhaps adopted as a second-line treatment, is not helpful in the management of OSA. It appears that other anatomic and physiologic factors have a dynamic overriding influence on upper airway closure compared to simple skeletal relationships.

Key Words: cephalometry • continuous positive airway pressure • neck collar • obstructive sleep apnea • posture


   Introduction
TOP
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
Obstructive sleep apnea (OSA) is characterized by repetitive periods of partial or complete upper airway obstruction during sleep. A number of factors have independent influences on the likelihood and severity of OSA.1 These include obesity,2 neck size,3 skeletal subtype and gender,4 and ethnicity.5 6 Often occurring in combination, these factors result in reduced or altered dimensions of the pharyngeal airway7 and changes in craniocervical relationships and craniofacial morphology.4 8

During sleep, the influence of gravity and loss of muscle tone further enhance narrowing of the upper airway,9 thus increasing the risk of apneic and hypopneic events. Given that the upper airway comprises both rigid and flexible structures, the actual site of obstruction may be multiple and variable.10 Thus the anatomic positions of the hyoid bone, mandible, head, and neck may be critical.11

In awake subjects, airway resistance is higher in patients with OSA than in normal subjects; as the mandible is progressively advanced forward, airway resistance decreases.12 . Similarly, it has been shown that whereas neck flexion significantly increases airway resistance in patients with OSA, maintaining the head in extension preserves airway patency.13 Hiyama et al14 have shown in normal subjects that using a cervical collar, jaw closure and thus airway patency may be maintained during sleep.

Against this background, therapeutic devices such as the mandibular advancement splint have been designed to protrude the mandible forward, and with it the tongue, as a means of maintaining airway patency during sleep. This results in a significant reduction in the severity of OSA.15 16 17 The success of this approach raises the possibility that other conservative treatments, designed to prevent posteroinferior movement of the mandible and tongue, may have similar beneficial effects.

Taken together, these data suggest that a device such as a cervicomandibular support collar (CMSC) designed to prevent downward displacement of the mandible as well as maintaining the head in slight extension during sleep may be beneficial in OSA. The aim of this cross-over study was to compare the effect of CMSC therapy in mild-to-moderate OSA with standard therapy, nasal continuous positive airway pressure (nCPAP).18


   Materials and Methods
TOP
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Study Population
Ten consecutive subjects referred for suspected OSA who met the inclusion criteria underwent full-night polysomnography. Patients were referred to the Tom McKendrick Sleep Laboratory, the Regional Sleep Centre for the province of Otago, by their general practitioners; ear, nose and throat surgeons; and other hospital physicians. Patients had self-reported symptoms that matched the range of symptoms common to OSA. They were initially assessed at an outpatient clinic, and the decision to conduct a full-night sleep study was based on that assessment. Mild-to-moderately severe OSA was diagnosed,1 and the subjects agreed to participate after giving written informed consent.

Inclusion criteria were mild-to-moderately severe OSA and apnea-hypopnea index (AHI) of 10 to 60/h of total sleep time. Exclusion criteria were a medical history of cardiovascular, neurologic, or psychological disorders affecting sleep; coexisting sleep disorders; and known cervical or temporomandibular joint dysfunction and/or pain.

Study Design
Subjects received treatment with a CMSC or nCPAP each for 1 month in random order. The CMSC device and the nCPAP masks were selected from a range of sizes as appropriate for the individual. Each subject was carefully instructed in the use of each device, and was given a symptom diary at the beginning of each treatment period. At the end of each treatment period, subjects underwent full-night polysomnography with the allocated device in situ, and symptom questionnaires were administered. At the completion of the study, a clinical evaluation of outcomes was undertaken, and each subject was offered long-term therapy depending on results and treatment preference.

CMSC
The CMSC (Fig 1 ) was a modified Headmaster Collar (Symmetric Designs; Salt Spring Island, BC, Canada). The CMSC was designed to retain the head in the natural head position (NHP)19 and prevent jaw opening during sleep. The collar comprised a fabric-covered, semicircular acrylic and latex ring, which was molded to fit under the mandible and rest on the upper third of the manubrium sterni. It was held in place by a fabric-covered foam strap with self-adhesive attachments. A chin piece supported the lower jaw in the closed position with the teeth held in light occlusion, and an anterior support tube was attached between the mandible and sternal portions to provide rigid support and prevent neck flexion beyond the NHP.



View larger version (54K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 1. Subject seated with CMSC in situ and CROM instrument being used to confirm the NHP. Top: Anterior view. Bottom: Lateral view.

 
Before fitting the CMSC, each subject sat in the upright position and was instructed to assume their NHP using the orthoposition method.20 The NHP was confirmed using a cervical range of motion (CROM) instrument [Performance Attainment Associates; St Paul, MN] by means of the zero points on the sagittal plane and lateral flexion gravity meters of the CROM instrument (Fig 1) . The CROM instrument is considered to be a reliable external measure of range of movement in the neck.21 22 Active cervical movements (flexion, extension, right and left lateral flexion, and right and left rotation) were recorded using the CROM instrument. The CMSC was then adjusted to ensure the subject’s head was in 5° of extension. The CROM instrument remained in situ to confirm the extended position. Each subject was then asked to attempt active neck flexion, and the CROM was used to confirm that the CMSC did not permit active flexion beyond the NHP. Inability of the subject to open the lower jaw against the chin support confirmed that it prevented downward rotation of the mandible.

nCPAP
At the commencement of the nCPAP treatment arm, each subject was allocated an autotitrating machine (Autoset T, Sullivan; ResMed Ltd; North Ryde, NSW, Australia) and an Ultra Mirage nasal mask. Minimum CPAP pressure was set at 4 cm H2O, and maximum CPAP pressure was set at 20 cm H2O. The Autoset T permits automatic titration of the continuous positive airway pressure (CPAP) required to maintain airway patency while asleep. After 3 to 5 nights of monitoring, data were downloaded from the Autoset T to a computer in the sleep laboratory. The 95th percentile pressure was then used to set the pressure on a ResMed S6 Elite (ResMed Ltd) CPAP machine, which was then given to each subject for the remainder of the trial period.

Cephalometric Radiographs
Cephalograms were obtained at the commencement of the CMSC study arm with and without the CMSC in situ, with each subject lying supine as for the NHP,19 using the orthoposition method.20 A fluid level was used to register the head posture, and care was taken to limit changes in cervical position during the introduction of the cephalostats. A chain suspended from the film cassette registered the true vertical plane. Subjects were instructed to hold the teeth in light occlusion, and cephalograms were obtained at the end of expiration.

All supine lateral cephalometric landmarks were coordinated with the true horizontal and vertical lines. Conventional bony landmarks (Fig 2 , top) were marked on cephalometric tracing film and digitized with a reflex metrograph. Reference lines and angles (Fig 2 , bottom) were measured to the nearest 0.01 mm or degree.



View larger version (20K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 2. Top: Key landmarks identified on cephalometric radiographs and digitized with a reflex metrograph. Bottom: Key reference lines and angles measured on the cephalometric radiographs. VER = true vertical; HOR = true horizontal; N = nasion, most anterior point of the frontonasal suture; S = centre of sella turcica, centre of the pituitary fossa of the sphenoid bone; Ba = basion, most posteroanterior point on the anterior margin of the foramen magnum; ANS = spinal point, apex of the anterior nasal spine; gn = gnathion, most inferior point of the symphysis formed by bisecting the angle formed by the facial and mandibular planes; Hy = most superior and anterior point on the body of the hyoid bone; PNS: pterygomaxillary point, intersection between the nasal floor and posterior contour of the maxilla; pt = intersection point between the contour of the tongue and the upper occlusal line; pw = intersection point between the posterior pharyngeal wall and the upper occlusal line; tgol = point at which the tangent from gn meets the lower contour of the mandible; C2a = anteroinferior point of the second cervical vertebra; C3a = anteroinferior point of the third cervical vertebra; C4a = anteroinferior point of the fourth cervical vertebra; C2ps = posterosuperior point of the second cervical vertebra; C2pi = posteroinferior point of the second cervical vertebra; C3pi = posteroinferior point of the third cervical vertebra; C4pi = posteroinferior point of the fourth cervical vertebra; NSL = line connecting S and N; OPT = occipital tangent line drawn from C2ps through C2pi; CVT = cervical vertebrae tangent line drawn from C2ps through C4pi.

 
Polysomnography
Polysomnography was conducted using a 16-channel polysomnograph system (Compumedics; Abbotsford, VIC, Australia). Standard scoring criteria were used to define OSA.1 Sleep was scored according to the guidelines of Rechtschaffen and Kales.23 Arousals were defined as a shift in EEG frequency for a minimum of 3 s with a concurrent rise in electromyogram if they occurred in rapid eye movement sleep.24 All studies were manually scored in 30-s epochs for sleep stage, apnea type and duration, and arousals, by one scorer, and were confirmed by a second independent scorer. In addition, an integrating sound-level meter (NL-05; Rion; Tokyo, Japan) monitored sound levels in decibels (dB). The calibrated sound meter was situated at the side of the bed, with the microphone attached 4 cm from the wall at the head of the bed and 20 cm above the pillow. The snore parameters were as follows: the background baseline value was set at 40 dB in each bedroom, a minimum deviation of 5 dB from the sound baseline was required before a snore was detected, and the minimum time between snores was 1 s. Each peak snoring sound was then automatically counted and placed into a range of decibel bins using an automated program (Compumedics S; Compumedics) and divided by total sleep time to give a snore index for each decibel range.

The definitions of apnea and hypopnea used in our study to calculate the respiratory disturbance index/AHI followed the American Association of Sleep Medicine guidelines.1 A thermistor was used to define airflow characteristics. An apnea was defined as cessation of airflow lasting at least 10 s. Changes in thoracoabdominal movements were used to score hypopneas, given that the thermistor is unable to quantify the reduction in airflow, or to distinguish between obstructive and central events. A reduction in any of these signals by >= 50% from a rolling baseline, and persisting for >= 10 s, or a reduction in thoracoabdominal movement with an accompanying oxygen desaturation of at least 3% and/or associated with an arousal, defined the significant respiratory events.

Outcome Measures
Sleep habits, daytime sleepiness, snore symptoms, exercise capacity, general health, and medication use at presentation were recorded using standardized questionnaires: a general health questionnaire, the Medical Outcomes Study Short-Form 36 (SF-36),25 the Functional Outcomes of Sleep Questionnaire (FOSQ),26 the Scottish National Sleep Laboratory symptom questionnaire (SQ),27 and the Epworth sleepiness scale (ESS).28 Throughout the study, sleep habits, the period of time wearing the device at night, subjective levels of sleepiness/alertness on waking, daytime hypersomnolence, side effects, and any other relevant symptoms were recorded in the self-reported diary. At the end of each period, subjects completed an adverse effects questionnaire, which comprised 19 adverse effects commonly associated with nCPAP therapy such as a dry mouth, sore jaw, and poor mask fit. These were also applied to the CMSC therapy. Each effect was ranked on a scale of 0 to 3 (0 = no effect, 1 = mild effect but did not disturb sleep, 2 = sleep disturbed, 3 = could not use device) At the end of the study, subjects were asked to rate the overall benefit of each therapy on a 10-point linear scale (1 = no benefit, to 10 = maximum benefit).

Anthropometric data including body height and weight, neck circumference (at the fourth cervical vertebra), and abdominal circumference (mid point between the tenth rib and iliac crest) were measured at baseline and at the end of each treatment period. Objective CPAP compliance time was downloaded from the Autoset T and the ResMed S6 Elite into a computer in the laboratory.

Analysis of Results
The primary outcome for treatment success was defined as an AHI <= 10/h of total sleep time. Partial success was defined as an AHI in the range > 10/h to <= 15/h slept. An AHI > 15/h slept was defined as treatment failure.

Results were analyzed on an intention-to-treat basis. Paired t tests were undertaken for the mean differences between the changes from baseline for each of the two treatments. Paired cephalometric data with and without the CMSC were compared using t tests. Stepwise linear regression analysis was undertaken to examine the relationship between cephalometric variables and changes in AHI. Multivariate analysis was used to determine any order effect. Because multiple comparisons were made, a significance level of 0.01 was used. The study protocol was approved by the Otago Ethics Committee, and all subjects gave written informed consent.


   Results
TOP
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Study Population
Ten consecutive subjects (2 women) who met the study criteria agreed to participate in the study. Demographic and anthropometric data are shown in Table 1 . All subjects completed both arms of the study.


View this table:
[in this window]
[in a new window]

  		Table 1. Demographic Details of Study Participants (n = 10; 8 Men and 2 Women)

 
Clinical Outcomes
With the CMSC, mean AHI (± SD) was 26.9 ± 17.2/h slept. There was minimal overall reduction in the AHI compared to baseline (29.4 ± 13.4/h slept) [Table 2 ]. Treatment success with CMSC (AHI <= 10/h slept) was achieved in 2 of 10 subjects, partial success (AHI > 10 to <= 15/h slept) was achieved in a further 2 subjects, and in the remaining 6 subjects there was no significant benefit, given that the AHI remained > 15/h slept with treatment. In three subjects, the AHI with CMSC was higher than the AHI at baseline. The mean adherence to CMSC therapy was 89 ± 23% of the total available study nights. Mean nightly duration of use of the CMSC was 5.2 ± 1.2 h (Table 3 ).


View this table:
[in this window]
[in a new window]

  		Table 2. AHI Scores per Hour Slept for Each Subject

 

View this table:
[in this window]
[in a new window]

  		Table 3. Values for Subjective Reporting by Subjects Recorded at Baseline*

 
In contrast, the mean AHI with nCPAP was significantly lower (9.9 ± 8.0/h slept) compared to baseline (29.4 ± 13.4/h slept) [p < 0.001]. Treatment success with nCPAP was achieved in seven subjects, partial success was achieved in one subject, and in two subjects nCPAP was deemed to be a treatment failure (Table 2) . The mean adherence with nCPAP was 68 ± 24% of the total available study nights. Mean nightly duration of nCPAP usage was 4.4 ± 1.2 h (Table 3) .

The difference in the mean change from baseline AHI to AHI with the nCPAP was therefore significantly greater than the mean change from baseline AHI to AHI with the CMSC (p = 0.001). The mean difference in the change from baseline in the total number of snores per hour using nCPAP was also significantly greater compared to the mean difference in the change from baseline to the total number of snores per hour using CMSC (p = 0.009) [Table 4 ]. No significant differences in the mean changes in sleep architecture or sleep efficiency were achieved using nCPAP compared to the CMSC (Table 4) . There was no treatment order effect.


View this table:
[in this window]
[in a new window]

  		Table 4. Values for Polysomnographic Data Recorded at Baseline*

 
Cephalometric Outcomes
A comprehensive range of cephalometric variables was measured with and without the CMSC. Cephalometric measures revealed that with the CMSC the head was held in 10° of extension from the NHP (Table 5 ). This confirmed the efficacy of the CMSC in maintaining the desired amount of extension from the NHP. With the CMSC in situ, there was an increase in the mean linear distance between the hyoid bone and the anteroinferior point of the fourth cervical vertebra (HyC4a) [p = 0.002] and the distance between the anterior pharyngeal wall (APW) and posterior pharyngeal wall (PPW) within the lower airway space, along the line through the base of the third cervical vertebra (p = 0.003). No other significant differences in anatomic relationships were identified for airway or craniocervical measures and angles.


View this table:
[in this window]
[in a new window]

  		Table 5. Values for Cephalometric Variables*

 
Linear regression analysis was used to examine the relationship between supine cephalometric variables with and without the CMSC, and changes in polysomnographic outcome. No significant relationships were found.

Subjective Outcomes
Results obtained from patient questionnaires and diary entries are summarized in Table 3 . Despite the differences between nCPAP and the CMSC for objective outcome measures, the subjective outcomes were comparable for both devices. There was a trend toward a lower mean ESS score using the CMSC, but the results were not significant (Table 3 , Fig 3 ). Results for other measures of daytime symptoms and sleep symptoms (SF-36, FOSQ, SQ) compared to baseline were similar with each of the two therapies. There were fewer adverse effects reported with the CMSC than with nCPAP, but there was no preference demonstrated for one therapy over the other (Table 3) .



View larger version (18K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 3. ESS for each subject (n = 10) at baseline, with the CMSC and with nCPAP (p = 0.215). Closed circles indicate mean ESS value.

 

   Discussion
TOP
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
In this study, we compared the effectiveness of a CMSC with standard nCPAP therapy in the management of OSA. AHI (<= 10/h slept) was used as the primary outcome measure to define treatment success. We failed to demonstrate that the CMSC was an effective treatment. Only 2 of 10 patients responded successfully with the CMSC, and the mean AHI for this group did not change (mean AHI at baseline, 29.4 ± 13.4/h slept; mean AHI with CMSC, 26.9 ± 17.2/h slept). These results contrasted strongly with the mean decrease in AHI obtained using nCPAP (9.9 ± 8.0/h slept).

This outcome was disappointing, given the need to provide effective alternative therapy to nCPAP in a significant number of patients.29 Our study was based on evidence that during sleep, downward movement of the mandible has an influence on airway patency2 14 30 and that airway resistance increases with neck flexion.13 31 32 The CMSC was designed to prevent mandibular movement, and to hold the head in slight extension, thus preventing the postural changes that might contribute to OSA. Both CROM and cephalometric measures demonstrated that these two objectives were adequately achieved and retained throughout the CMSC treatment period.

Previously, Choi et al13 demonstrated in awake subjects that there is a significant difference in the mechanical resistance to airflow caused by changes in jaw and neck position, notably flexion, and that neck flexion is greater in OSA subjects. Studies undertaken by Kushida et al31 32 provided further support for our working hypothesis. These authors showed a significant improvement in AHI in subjects with OSA using a specially designed pillow to encourage neck extension. However, the results for individual subjects were inconsistent, and the clinical relevance of very simple posture control in the management of OSA remained unclear. For this reason, we adopted a more rigorous approach.

In our study, careful attention was paid to maintaining appropriate head and neck posture. The CMSC was fitted with the head in slight extension, measured using the external CROM instrument. Thus, cephalometric measurements for craniohorizontal variables obtained in supine position (Table 5) demonstrated that the position of the head in relation to the true horizontal and in relation to the cervical column remained in 10° of extension, and was significantly different to the baseline angles measured. The CMSC prevented head flexion beyond the NHP when subjects attempted to do so. Further, the chin piece of the CMSC supported the lower jaw and prevented downward rotation of the mandible. Theoretically, this ought also to have contributed positively to the maintenance of airway patency during sleep. Despite these features of the CMSC design, our results strongly suggest that maintaining the postural relationships of the cranium, mandible, and cervical spine during sleep is insufficient to maintain airway patency. Clearly, other anatomic and physiologic factors must have a dynamic overriding influence compared to simple skeletal relationships.

It is interesting to note that there was a very positive subjective response to this form of treatment. Our subjects completed a number of questionnaires relating to quality of life and sleep habits. Despite the striking differences between the CMSC and nCPAP in controlling OSA, there was a nonsignificant trend toward reduced daytime hypersomnolence, as measured by the ESS, with the collar. Also fewer adverse side effects were reported by subjects when using the CMSC. Clearly, a strong placebo effect was obtained, and our findings confirm the results of a previous study33 that have showed there are no clear-cut relationships between objective polysomnographic improvements and daytime function in patients with OSA. These outcomes highlight the importance of rigorous controlled crossover studies to assess the value of more conservative treatments to manage OSA.

Initially, our study was designed to include a sample size of 20 adults. However, the study was terminated prematurely after the results for 10 subjects were analyzed and confirmed that the CMSC was failing to achieve clinically important reductions in the AHI, despite subjective benefit. There was no "washout" period between the two study arms. It is unlikely that this would have altered the outcomes given the complete lack of objective benefit from the CMSC: no carry-over benefit was occurring.

Our results, although negative, provide important evidence that control of head and neck posture, perhaps adopted as a second-line treatment in the management of OSA, is unhelpful. Although nCPAP is clearly effective, its use is often restricted by the frequency of poor patient acceptance, or cost. Mandibular advancement splints are often recommended as an alternative to nCPAP, but their long-term efficacy is uncertain. As a consequence, sleep physicians and patients alike are seeking new, innovative therapies that are cost-effective and are well tolerated. There may yet be a role for the CMSC as an alternative to the chin strap in assisting jaw closure during nCPAP therapy. However, our data suggest that while elimination of postural abnormalities may have some subjective impact, they are in themselves insufficient to control OSA.


   Footnotes
 
Abbreviations: AHI = apnea hypopnea index; APW = anterior pharyngeal wall; CMSC = cervicomandibular support collar; CPAP = continuous positive airway pressure; CROM = cervical range of movement instrument; dB = decibels; ESS = Epworth sleepiness scale; FOSQ = functional outcomes of sleep questionnaire; nCPAP = nasal continuous positive airway pressure; NHP = natural head position; OSA = obstructive sleep apnea; PPW = posterior pharyngeal wall; SF-36 = Medical Outcomes Study Short-Form 36; SQ = Scottish National Sleep Laboratory symptom questionnaire

This work was performed at the Respiratory Research Unit, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.

The study was funded by the University of Otago School of Physiotherapy and the Otago Respiratory Research Trust.

Received for publication December 3, 2002. Accepted for publication August 15, 2003.


   References
TOP
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. . American Academy of Sleep Medicine. (1999) Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research; the Report of an American Academy of Sleep Medicine Task Force. Sleep 22,667-689[ISI][Medline]
  2. Ferguson, KA, Ono, T, Lowe, AA, et al The relationship between obesity and craniofacial structure in obstructive sleep apnea. Chest 1995;108,375-381[Abstract/Free Full Text]
  3. Davies, RJ, Stradling, JR The relationship between neck circumference, radiographic pharyngeal anatomy, and the obstructive sleep apnea syndrome. Eur Respir J 1990;3,509-514[Abstract]
  4. Lowe, AA, Ono, T, Ferguson, KA, et al Cephalometric comparisons of craniofacial and upper airway structure by skeletal subtype and gender in patients with obstructive sleep apnea. Am J Orthod Dentofacial Orthop 1996;110,653-664[CrossRef][ISI][Medline]
  5. Redline, S, Kump, K, Tishler, PV, et al Gender differences in sleep disordered breathing in a community-based sample. Am J Respir Crit Care Med 1994;149,722-726[Abstract]
  6. Coltman, R, Taylor, DR, Whyte, K, et al Craniofacial form and obstructive sleep apnea in Polynesian and Caucasian men. Sleep 2000;23,943-950[ISI][Medline]
  7. Rivlin, J, Hoffstein, V, Kalbfleisch, J, et al Upper airway morphology in patients with idiopathic obstructive sleep apnea. Am Rev Respir Dis 1984;129,355-360[ISI][Medline]
  8. Jamieson, A, Guilleminault, C, Partinen, M, et al Obstructive sleep apneic patients have craniomandibular abnormalities. Sleep 1986;9,469-477[ISI][Medline]
  9. Remmers, JE, de Groot, WJ, Sauerland, EK, et al Pathogenesis of upper airway occlusion during sleep. J Appl Physiol 1978;44,931-938[Free Full Text]
  10. Hudgel, DW Variable site of airway narrowing among obstructive sleep apnea patients. J Appl Physiol 1986;61,1403-1409[Abstract/Free Full Text]
  11. Isono, S, Remmers, JE, Tanaka, A, et al Static properties of the passive pharynx in sleep apnea. Sleep 1996;19,S175-S177[ISI][Medline]
  12. Masumi, S, Nishigawa, K, Williams, AJ, et al Effect of jaw position and posture on forced inspiratory airflow in normal subjects and patients with obstructive sleep apnea. Chest 1996;109,1484-1489[Abstract/Free Full Text]
  13. Choi, J-K, Goldman, M, Koyal, S, et al Effect of jaw and head position on airway resistance in obstructive sleep apnea. Sleep Breath 2000;4,163-168[CrossRef][Medline]
  14. Hiyama, S, Ono, T, Ishiwata, Y, et al Changes in mandibular position and upper airway dimension by wearing cervical headgear during sleep. Am J Orthod Dentofacial Orthop 2001;120,160-168[CrossRef][ISI][Medline]
  15. Ferguson, KA, Ono, T, Lowe, AA, et al A randomized crossover study of an oral appliance vs nasal-continuous positive airway pressure in the treatment of mild-moderate obstructive sleep apnea. Chest 1996;109,1269-1275[Abstract/Free Full Text]
  16. Mehta, A, Qian, J, Petocz, P, et al A randomized, controlled study of a mandibular advancement splint for obstructive sleep apnea. Am J Respir Crit Care Med 2001;163,1457-1461[Abstract/Free Full Text]
  17. Skinner, MA, Robertson, CJ, Kingshott, RN, et al The efficacy of a mandibular advancement splint in relation to cephalometric variables. Sleep Breath 2002;6,115-124[CrossRef][Medline]
  18. Sullivan, CE, Issa, FG, Berthon-Jones, M, et al Reversal of obstructive sleep apnea by continuous positive airway pressure applied through the nares. Lancet 1981;1,862-865[ISI][Medline]
  19. Broca, M Sur les projections de la tete, et sur un nouveau procede de cephalometric. Bull Soc Anthropol Paris 1862;3,514-544
  20. Solow, B, Tallgren, A Natural head position in standing subjects. Acta Odontol Scand 1971;29,591-607[ISI][Medline]
  21. Capuano-Pucci, D, Rheault, W, Aukai, J, et al Intratester and intertester reliability of the cervical range of motion device. Arch Phys Med Rehabil 1991;72,338-340[ISI][Medline]
  22. Youdas, JW, Carey, JR, Garrett, TR Reliability of measurements of cervical spine range of motion: comparison of three methods. Phys Ther 1991;71,98-104[Abstract/Free Full Text]
  23. Rechtschaffen, A Kales, A eds. A manual of standardized terminology, techniques and scoring systems for sleep stages of human subjects. 1968 US Department of Health, National Institute of Neurological Disease and Blindness. Bethesda, MD:
  24. American Sleep Disorders Association.. EEG arousals: scoring rules and examples; a preliminary report from the Sleep Disorders Atlas Task Force of the American Sleep Disorders Association. Sleep 1992;15,173-184[Medline]
  25. Ware, JE, Jr, Sherbourne, CD The MOS 36-item short-form health survey (SF-36): I. Conceptual framework and item selection. Med Care 1992;30,473-483[ISI][Medline]
  26. Weaver, TE, Laizner, AM, Evans, LK, et al An instrument to measure functional status outcomes for disorders of excessive sleepiness. Sleep 1997;20,835-843[ISI][Medline]
  27. Engleman, HM, Kingshott, RN, Wraith, PK, et al Randomized placebo-controlled crossover trial of continuous positive airway pressure for mild sleep apnea/hypopnea syndrome. Am J Respir Crit Care Med 1999;159,461-467[Abstract/Free Full Text]
  28. Johns, MW A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep 1991;14,540-545[ISI][Medline]
  29. Ferguson, KA, Ono, T, Lowe, AA, et al A short-term controlled trial of an adjustable oral appliance for the treatment of mild to moderate obstructive sleep apnea. Thorax 1997;52,362-368[Abstract]
  30. Hollowell, DE, Suratt, PM Mandible position and activation of submental and masseter muscles during sleep. J Appl Physiol 1991;71,2267-2273[Abstract/Free Full Text]
  31. Kushida, CA, Rao, S, Guilleminault, C, et al Cervical positional effects on snoring and apneas. Sleep Res 1999;2,7-10
  32. Kushida, CA, Sherrill, CM, Hong, SC, et al Cervical positioning for reduction of sleep-disordered breathing in mild-to-moderate OSAS. Sleep Breath 2001;5,71-78[CrossRef][Medline]
  33. Kingshott, RN, Engleman, HM, Deary, IJ, et al Does arousal frequency predict daytime function? Eur Respir J 1998;12,1264-1270[Abstract]




This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Article Archive
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via ISI Web of Science (2)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Skinner, M. A.
Right arrow Articles by Taylor, D. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Skinner, M. A.
Right arrow Articles by Taylor, D. R.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS