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The Relationship Between Mouth Opening and Sleep Stage-Related Sleep Disordered Breathing

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To evaluate mouth opening during sleep and the possible correlations between mouth opening and specific patient characteristics. A total of 55 patients consecutively referred to assess snoring and suspected obstructive sleep apnea (OSA) were included. Sensors to record mouth opening were attached to each patient's face and synchronized with a standard polysomnogram. Mouth opening data were evaluated for each sleep stage as a percentage of maximum mouth opening. The patients were divided into 2 groups: patients with REM apnea hypopnea index (AHI) > NREM AHI (REM-dependent group = RD group), and patients with NREM AHI > REM AHI (NREM-dependent group = ND group). A total of 42 patients (male 69.0%, mean age 51.4 ± 12.9 years) underwent successful data collection. The amount of mouth opening during stage 1 (18.8% ± 14.6%) was significantly smaller than stage 2 (23.7% ± 16.4%, p < 0.01) and REM (29.2% ± 20.3%, p < 0.01). Age, body mass index (BMI), Epworth Sleepiness Scale (ESS) score, and AHI exhibited no correlation with mouth opening. The RD and the ND groups exhibited similar age, BMI, ESS, and AHI variables, but the ND group opened their mouths significantly more than the RD group during total sleep time (28.3% ± 13.6% vs 17.8% ± 17.3%, p < 0.01), stage 1 (23.2% ± 13.5% vs 12.9% ± 14.3%, p < 0.01), stage 2 (28.1% ± 17.9% vs 17.9% ± 17.4%, p < 0.01), and REM (34.7% ± 19.2% vs 21.9% ± 19.8%, p < 0.05). The ND patients opened their mouths wider than the RD patients during most sleep stages. The relationship between REM-dependent AHI and the amount of mouth opening may be a factor in the pathogenesis of OSA.
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181 Journal of Clinical Sleep Medicine, Vol. 7, No. 2, 2011
The Relationship Between Mouth Opening and Sleep Stage-
Related Sleep Disordered Breathing
Hiroko Tsuda, Ph.D.1; Alan A. Lowe, Ph.D.1; Hui Chen, Ph.D.1; John A. Fleetham, M.D.3,4; Najib T. Ayas, M.D.3,4; Fernanda R. Almeida, Ph.D.2
1Department of Oral Health Sciences,The University of British Columbia, Vancouver, BC, Canda; 2Department of Oral Biological
and Medical Sciences,The University of British Columbia, Vancouver, BC, Canada; 3UBC Hospital Sleep Disorders Program,
Respiratory Division, The University of British Columbia, Vancouver, BC, Canada; 4Respiratory Division, Department of Medicine,
The University of British Columbia, Vancouver, BC, Canada
SCIENTIFIC INVESTIGATIONS
A
variety of factors contribute to the development of ob-
structive sleep apnea (OSA). A better understanding of
these factors would help future therapeutic advances in OSA.1
Some physiological studies suggest that mouth opening in-
creases upper airway collapsibility.2-4 Miyamoto et al. reported
that the vertical mandibular posture is more open during sleep
in patients with OSA than in healthy adults. Furthermore,
sleep stage was a signicant factor in mandibular opening in
the supine position but not in the lateral position in patients
with OSA, as determined by using magnetic sensors attached
inside the subject’s mouth.5,6 One study has recommended that
jaw opening should be kept to a minimum for better treat-
ment success with oral appliance (OA) therapy in patients
with OSA.7 It has also been reported that patients with a large
amount of mouth breathing, which is only possible when both
the soft palatal seal and mouth are opened, are less adherent
to nasal continuous positive airway pressure (nCPAP) ther-
apy than patients with a small amount of mouth breathing.8
Furthermore, some patients with OSA have a higher percent-
age of obstructive events during REM compared to NREM
sleep.9,10 In these studies, REM-dependent subjects were re-
ported as being young and female, and this REM dependency
was suggested as a factor in understanding the difference in
the mechanism of obstruction between different types of pa-
tients with OSA. The clinical meaning of REM dependency
has not been fully investigated. However, since it has been
reported that sleep disordered breathing (SDB) during NREM
sleep, but not REM sleep, is associated with a risk of daytime
sleepiness,11 sleep staging should be considered to be a vari-
able that requires understanding.
Previous physiological studies have investigated the
amount of mouth opening and the subsequent collapse of
the upper airway; however, REM dependency or supine de-
pendency determined for the entire sleep duration was not
Study Objectives: To evaluate mouth opening during sleep
and the possible correlations between mouth opening and spe-
cic patient characteristics.
Methods: A total of 55 patients consecutively referred to as-
sess snoring and suspected obstructive sleep apnea (OSA)
were included. Sensors to record mouth opening were at-
tached to each patient’s face and synchronized with a standard
polysomnogram. Mouth opening data were evaluated for each
sleep stage as a percentage of maximum mouth opening. The
patients were divided into 2 groups: patients with REM apnea
hypopnea index (AHI) > NREM AHI (REM-dependent group =
RD group), and patients with NREM AHI > REM AHI (NREM-
dependent group = ND group).
Results: A total of 42 patients (male 69.0%, mean age 51.4 ±
12.9 years) underwent successful data collection. The amount
of mouth opening during stage 1 (18.8% ± 14.6%) was sig-
nicantly smaller than stage 2 (23.7% ± 16.4%, p < 0.01) and
REM (29.2% ± 20.3%, p < 0.01). Age, body mass index (BMI),
Epworth Sleepiness Scale (ESS) score, and AHI exhibited no
correlation with mouth opening. The RD and the ND groups
exhibited similar age, BMI, ESS, and AHI variables, but the
ND group opened their mouths signicantly more than the
RD group during total sleep time (28.3% ± 13.6% vs 17.8% ±
17.3%, p < 0.01), stage 1 (23.2% ± 13.5% vs 12.9% ± 14.3%,
p < 0.01), stage 2 (28.1% ± 17.9% vs 17.9% ± 17.4%, p < 0.01),
and REM (34.7% ± 19.2% vs 21.9% ± 19.8%, p < 0.05).
Conclusions: The ND patients opened their mouths wider
than the RD patients during most sleep stages. The relation-
ship between REM-dependent AHI and the amount of mouth
opening may be a factor in the pathogenesis of OSA.
Keywords: Obstructive sleep apnea, REM-related obstructive
event, mouth opening
Citation: Tsuda H; Lowe AA; Chen H; Fleetham JA; Ayas NT;
Almeida FR. The relationship between mouth opening and
sleep stage-related sleep disordered breathing. J Clin Sleep
Med 2011;7(2):181-186.
BRIEF SUMMARY
Current Knowledge/Study Rationale: This study evaluated mouth
opening during sleep and correlations between mouth opening and
patients’ characteristics. Patients with NREM-dependent OSA opened
their mouth wider than REM-dependent patients. Disease severity,
BMI, age, and body position were not found to affect mouth opening
during sleep.
Study Impact: Mouth opening was not a causative factor or associ-Mouth opening was not a causative factor or associ-
ated with sleep apnea. However, considering the physiological mech-
anism of sleep, NREM-dependent OSA may be partially caused by
mouth opening.
182
Journal of Clinical Sleep Medicine, Vol. 7, No. 2, 2011
H Tsuda, AA Lowe, H Chen et al
METHODS
Subjects
Fifty-ve consecutive patients referred to the Sleep Disorder
Program at the University of British Columbia Hospital to as-
sess snoring and suspected OSA were included in this study.
The protocol had the prior approval of the clinical research eth-
ics board, UBC Ofce of Research Services. The aim of the
study was explained to all patients, and written informed con-
sent was obtained.
Sensor for Jaw Movement
Sensors for recording jaw movement, which use resonating
magnetic eld transducers (JAWSENS, nomics, Belgium), were
attached to each patient’s forehead and chin (Figure 1). The
data were evaluated simultaneously with a standard polysom-
nogram (PSG). The data from the magnet sensor were sampled
every 0.03 sec throughout the night. Before each patient went to
sleep, maximum open, grind, lateral movement, swallow, chew,
and mouth breathing were checked and calibrated in a supine
position in bed (Figure 2). After this initial data collection, the
data, expressed as a percentage of the maximum opening level,
were evaluated for each sleep stage. One hundred percent cor-
responds to a maximum opening of the mouth, and 0% corre-
sponds to a closed mouth position (teeth touching lightly).
Polysomnogram (PSG)
PSG data were analyzed manually according to the American
Academy of Sleep Medicine (AASM) criteria by polysomno-
graphic technologists blinded to the JAWSEN data. Each stage
was dened in 30-sec epochs, and the JAWSEN data were also
calculated as the average of each epoch. NREM stages 3 and 4
were combined and referred to as N3 in the analysis.
assessed in these studies. To better understand the causes of
each SDB event and the predictors of treatment success, it
may be useful to estimate how often, how long, and how wide
patients with OSA open their mouths during sleep, and the
correlation between mouth opening and patient characteristics
such as age, sex, body mass index (BMI), and apnea hypop-
nea index (AHI). The aim of this study was to evaluate mouth
opening during sleep and the possible correlations between
mouth opening and specic patient characteristics.
100% Max open
0% Closed mouth
Clench lips apart
Lateral shift
Grind
Chew Swallow Mouth breathing
Figure 2—Sample of PSG and JAWSENS data at the calibration
Lower line denes 0% as the closed mouth position, upper line denes 100% as the maximum opening position
2cm
2cm
Figure 1—JAWSEN sensors
Picture comes from instruction manual
183 Journal of Clinical Sleep Medicine, Vol. 7, No. 2, 2011
Mouth Opening and Sleep Disordered Breathing
mine the correlation between demographic variables and mouth
opening variables. The independent student t-test, the χ2 test,
and the Mann-Whitney test were used for comparisons between
the groups.
RESULTS
A total of 42 patients (male 69.1%, mean age 51.4 ± 12.9
years) successfully completed both the JAWSENS and PSG
data collection (Table 1, 2). Seven patients did not have com-
plete data on JAWSEN, and 6 patients had AHIs < 5/h. The
methods error test was performed 10 times for each distance
and was 0.17-0.44 according to different measures. The results
from the ruler and the measurements from the sensors had a
high correlation. The ICC value was 0.9995. Percent averages
of maximum mouth opening were calculated for specic sleep
stages. Stage 1 (N1) (18.8% ± 14.6%) had the smallest mouth
Data Analysis
Based on the PSG results, patients with an AHI < 5/h were
excluded from the analysis in order to exclude normal subjects.
Each subject’s demographic data such as age, sex, BMI, Epworth
Sleepiness Scale (ESS) score, Mallampati score, and medical
history were collected from the patient’s chart. After scoring
the data, the patients were divided into 2 groups: patients with
REM AHI > NREM AHI (REM-dependent group: RD group),
and patients with NREM AHI > REM AHI (NREM-dependent
group: ND group).12 Demographic, sleep-related, and mouth
opening data were determined for the 2 groups. The difference
between patients according to body position tendency (supine-
dependent or non-supine-dependent sleep apnea) was also esti-
mated according to a criteria previously described.13
Methods Error
To assess the methods error, 8 different distances on the ruler
(every 1 cm from 9-16 cm) were measured. The methods er-
ror (ME) was determined by the formula: ME = √Σd2/2(n-1)
where d is the difference between measurement pairs and n is
the number of pairs. To assess whether and how the measure-
ments from the sensor matched the measurements on the ruler,
we also measured 8 different distances (every 1 cm from 9-16
cm) and calculated an intraclass correlation coefcient (ICC).
Statistical Analysis
Statistical analyses were performed, and p values < 0.05
were considered signicant. Correlation between measure-
ments from the ruler and the sensor were tested by using the
ICC. The Friedman test, followed by the Wilcoxon signed ranks
test, was applied between the mouth opening variables and
sleep stages. A Pearson correlation test was applied to deter-
Table 1—Demographic and polysomnographic data of the study patients
Total RD group ND group p value
N 42 18 24
Male/female 29 / 13 10 / 8 19 / 5 NS
Age (years) 51.4 ± 12.9 52.9 ± 11.8 50.2 ± 13.7 NS
BMI (kg/m2) 30.4 ± 6.4 31.2 ± 7.3 29.7 ± 5.7 NS
ESS 11.2 ± 4.3 11.4 ± 4.8 11.2 ± 3.9 NS
Neck circumference (cm) 40.6 ± 4.5 40.2 ± 4.1 40.9 ± 4.8 NS
Mallampati score: I 0 0 0 NS
II 14 4 10
III 12 7 5
IV 14 7 7
Previous ENT surgery 9 (21.4%) 3 (16.7%) 6 (25.0%) NS
Nasal congestion 15 (35.7%) 6 (33.3%) 9 (37.5%) NS
AHI (/hours) 26.2 ± 18.8 22.3 ± 11.7 29.1 ± 22.6 NS
Min O2 (%) 84.5 ± 8.8 82.4 ± 10.5 86.0 ± 7.0 NS
Total sleep time (min) 367.6 ± 64.2 353.2 ± 57.2 378.4 ± 68.1 NS
Time of stage N1 (%) 10.8 ± 8.6 11.8 ± 9.6 9.7 ± 7.8 NS
Time of stage N2 (%) 70.7 ± 9.2 71.7 ± 9.3 70.0 ± 9.1 NS
Time of stage N3 (%) 2.2 ± 4.4 1.2 ± 3.0 3.0 ± 5.2 NS
Time of stage REM (%) 16.3 ± 5.5 15.3 ± 5.3 17.1 ± 5.7 NS
NS, no signicance (p > 0.05)
Table 2—Percentage of mouth opening in different body
positions and sleep stages
RD group ND group p value
Mouth opening in
Supine (%) 16.0 ± 19.1 28.2 ± 11.7 < 0.01
Side (%) 18.9 ± 17.9 28.1 ± 13.9 < 0.05
REM-supine (%) 19.6 ± 20.2 35.7 ± 17.7 < 0.01
NREM-supine (%) 16.4 ± 18.0 28.2 ± 10.9 < 0.01
REM-side (%) 24.2 ± 19.9 29.6 ± 19.9 NS
NREM-side (%) 17.5 ± 16.8 27.8 ± 16.1 < 0.05
p values mean a signicant mouth opening difference between RD group
and ND group; NS, no signicance (p > 0.05).
184
Journal of Clinical Sleep Medicine, Vol. 7, No. 2, 2011
H Tsuda, AA Lowe, H Chen et al
in most sleep stages. Severity of disease (AHI), BMI, age, and
body position were not found to affect mouth opening. Stage 1
(N1) had the smallest mouth opening when compared to stage
2 (N2) and REM. Koo and colleagues reported that OSA oc-
curring during REM is more frequent in women,9 and younger
women may be protected from OSA during NREM sleep, even
obese patients.10 Although there was no signicant difference
between the groups, in this study 44.4% of the RD group were
female compared to 20.8% of the ND group, which is similar
to what has been reported previously. In the RD group, patients
did not open their mouths much in any sleep stages including
REM, although most of their obstructive events occurred dur-
ing REM sleep. As only 20 patients (9 in the RD group and 11
in the ND group) had N3, this may be the reason that no signi-
cant difference was found between the two groups in this stage.
ND group subjects opened their mouths wider than did the
RD group patients, but the average amount of mouth opening
was not greater than 30% of the maximum opening. If it is hy-
pothesized that if a patient can open his or her mouth 50 mm
(normal range 40-60 mm),14 then for such patient 30% corre-
sponds to 15 mm. This is almost the same value as the mouth
opening used in previous physiological studies.2,3 In this study
design, we cannot conclude that mouth opening was a causative
factor for sleep apnea. However, considering the physiologi-
cal mechanism of sleep as previously reported in OSA patients,
the ND group’s obstructive events may be partially caused by
mouth opening.
When comparing our results to the previous study,6 this
report is in agreement in that sleep stage was found to be a
signicant factor in mouth opening. In the previous study, this
factor was only signicant when patients were in the supine
position. The differing results between the two studies may
be due to the differing methods of measurement and analysis
used. Also, the sensors were attached differently in each study.
In the study by Miyamoto and associates,6 the sensors were at-
tached on the molar area in the mouth and were calibrated on
opening when compared to stage 2 (N2) (23.7% ± 16.4%) and
REM (29.2% ± 20.3%) (Figure 3). The demographic variables
such as age, BMI, neck circumference, Mallampati score, ESS,
and AHI were found to have no correlation with the mouth
opening variables. A possible concern was whether it is pos-
sible that a patient would more likely be assigned to the RD
group than the ND group on the basis of chance alone due to
potentially small differences between REM AHI and NREM
AHI. We excluded patients whose REM AHI and NREM AHI
differences were < 5/h and performed the same analysis. There
was no difference in the ndings, so the results are presented for
all patients under the denition of previous criteria.12 The RD
group (n = 18) and the ND group (n = 24) exhibited similar age,
sex, BMI, ESS, AHI, neck circumference, Mallampati score,
previous upper airway surgery, nose congestion, and sleep-re-
lated variables (Table 1). The ND group patients opened their
mouths signicantly wider than the RD group during various
sleep stages (Figure 4): total sleep time (RD: 17.8% ± 17.3%,
ND: 28.3% ± 13.6%, p < 0.01), N1 (RD: 12.9% ± 14.3%, ND:
23.2% ± 13.5%, p < 0.01), N2 (RD: 17.9% ± 17.4%, ND: 28.1%
± 14.4%, p < 0.01), and REM (RD: 21.9 ± 19.8%, ND: 34.7%
± 19.2%, p < 0.05). Signicant mouth opening differences in
various body positions (Table 2), including time in the supine
and lateral position, REM in the supine position, and NREM
in the supine and side positions were identied between ND
and RD groups. The supine-dependent group (n = 17) and the
non-supine-dependent group (n = 25) also had similar age, sex,
BMI, ESS, AHI, neck circumference, Mallampati score, previ-
ous upper airway surgery, nasal congestion, sleep-related, and
mouth opening variables. In addition, it was difcult to visually
detect any specic pattern of the obstructive event from jaw
movement data.
DISCUSSION
In this study, NREM-dependent patients with OSA opened
their mouths wider than did REM-dependent patients with OSA
Percentage of wakeful maximum
mouth opening %
40
35
30
25
20
15
10
5
0
-5
-10
**
**
**
*
Sleep Stages
N1 N2 N3 REMAverage
RD group ND group
Figure 4—Amount of mouth opening in each sleep stage
between REM-dependent (RD) and NREM-dependent (ND)
groups
Statistical signicance *p < 0.05,**p < 0.01
Percentage of wakeful maximum
mouth opening %
60
50
40
30
20
10
0
Sleep Stages
N1 N2 N3 REM
**
**
Figure 3—Mouth opening in each sleep stage
Statistical signicance **p < 0.01
185 Journal of Clinical Sleep Medicine, Vol. 7, No. 2, 2011
Mouth Opening and Sleep Disordered Breathing
to draw conclusions about these relationships without analyz-
ing the breathing route directly. An interesting report related to
mouth breathing found that men breathe a signicantly higher
percentage of total ventilation through their mouths compared
to women, and that this increases with age.17 We could specu-
late that the typical patient who has NREM-dependent char-
acteristics is likely to be a male who suffers from OSA caused
by mouth breathing and exhibits wide mouth opening. Patients
with REM dependency are more likely to be female with few
episodes of mouth opening and mouth breathing. This might
be a factor in understanding the pathology of OSA in women
or the reason why there is a low percentage of OSA among
young women. In addition, it has been reported that female pa-
tients and supine-dependent male patients were more likely to
experience treatment success with OA therapy.18 We could not
nd any typical mouth opening followed by an apnea event,
as there were many kinds of mouth opening patterns in each
subject. Also it was difcult to dene the start or end points
of mouth opening. This study used the percentage of awake
maximal opening as a variable. Further studies are required to
explore and compare different denitions for mouth opening
during sleep. As mentioned in the limitations of this study, the
amount or type of mouth opening could not fully explain spe-
cic characteristics of the disease. However, REM dependency
was the only variable that exhibited a correlation with mouth
opening, and we suggest that REM dependency be explored
as an important variable in future studies. Future research is
required to determine the relationships between mouth open-
ing, mouth breathing, gender, and REM-dependent OSA. Such
studies could further determine the mechanism of the obstruc-
tive event in REM-dependent patients and assess whether REM
dependency is a useful indicator for the diagnosis or prediction
of treatment success with nCPAP, OA, or surgery.
CONCLUSION
For our patients, the amount of mouth opening during N1
sleep was signicantly less than during the other sleep stages.
The ND patients opened their mouths wider than did the RD
patients during most sleep stages. This study demonstrates
the relationship between REM dependency and the amount
of mouth opening, and this could explain the pathogenesis of
REM-dependent OSA.
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the incisors. In our study, sensors were attached on the forehead
and chin, which results in a greater distance between the sen-
sors than those in the previous study. In our study, the sensors
were calibrated with the patient lying on the bed. In addition,
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186
Journal of Clinical Sleep Medicine, Vol. 7, No. 2, 2011
H Tsuda, AA Lowe, H Chen et al
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ACKNOWLEDGMENTS
The authors would like to thank Mrs. Ingrid Ellis for her editorial assistance in the
nal preparation of this manuscript. A MITACS Accelerate Internship Grant supported
in part the post-doctoral fellowship salary of H. Tsuda.
SUBMISSION & CORRESPONDENCE INFORMATION
Submitted for publication May, 2009
Submitted in nal revised form October, 2010
Accepted for publication October, 2010
Address correspondence to: Fernanda R. Almeida, 2199 Wesbrook Mall, Vancouver,
BC, CANADA V6T 1Z3; Tel: (604) 822-3623; Fax: (604) 822-3562; E-mail: falmeida@
interchange.ubc.ca
DISCLOSURE STATEMENT
This was not an industry supported study. The authors have indicated no nancial
conicts of interest.
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... Our analysis ( The development of MJM-based sleep testing technologies can be divided into two main periods, each marked by distinct sensor types: the magnetometry-based device (Nomics, Liège, Belgium) (2008-2020) [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] and the single-point contact sensor integrating an accelerometer and gyroscope (Sunrise, Namur, Belgium) (2020-2024). [35][36][37][38][39][40][41][42][43][44][45][46] Each period is characterized by extensive evidence demonstrating the physiological relevance and clinical utility of machine learning-based MJM analysis for sleep staging, OSA diagnosis, 15,26,36 and monitoring OSA therapy. ...
... Regardless of the technology used, MJM recordings are well-known for their seamless integration into clinical settings. MJM acquisition and analysis have consistently been performed using the two aforementioned capturing devices, throughout all stages of research, from basic physiology studies, 14,17,18,34,38 to machine learning experiments 15,16,33,37 and clinical studies. 22,25,35,36,44 As early as 2008, the MJM signal was integrated into PSG recording software as a surrogate for conventional respiratory signals. ...
... 22,25,35,36,44 As early as 2008, the MJM signal was integrated into PSG recording software as a surrogate for conventional respiratory signals. [15][16][17][18][19][20][21][22] Since then, the visual display of specific MJM patterns alongside conventional PSG signals have become common in clinical research. This integration allows researchers to establish clear evidence of synchronization, relationships, and, ultimately, equivalence between MJM as a surrogate signal and other referential signals in sleep medicine. ...
Article
Purpose This review aims to highlight the pivotal role of the mandibular jaw movement (MJM) signal in advancing artificial intelligence (AI)‐powered technologies for diagnosing obstructive sleep apnea (OSA). Methods A scoping review was conducted to evaluate various aspects of the MJM signal and their contribution to improving signal proficiency for users. Results The comprehensive literature analysis is structured into four key sections, each addressing factors essential to signal proficiency. These factors include (1) the comprehensiveness of research, development, and application of MJM‐based technology; (2) the physiological significance of the MJM signal for various clinical tasks; (3) the technical transparency; and (4) the interpretability of the MJM signal. Comparisons with the photoplethysmography (PPG) signal are made where applicable. Conclusions Proficiency in biosignal interpretation is essential for the success of AI‐driven diagnostic tools and for maximizing the clinical benefits through enhanced physiological insight. Through rigorous research ensuring an enhanced understanding of the signal and its extensive validation, the MJM signal sets a new benchmark for the development of AI‐driven diagnostic solutions in OSA diagnosis.
... Breathing with the mouth open during sleep is a common phenomenon for patients with OSA. 8 A previous study found that keeping the mouth open resulted in a prolonged airway and shrank the oropharyngeal lumen irrespective of the severity of OSA. Simultaneously, sleeping with the mouth wide open combined with larger tonsils contributes to a narrower oropharyngeal airway. ...
... Recent studies showed that patients with a higher percentage of oral and oronasal breathing periods had severer OSA and lower SpO 2 than common snorers and healthy subjects did. 4,6,8,15 Previous studies showed that participants who completely breathed with the nose (NMP) tended to have more stable SpO 2 during sleep, 4,7,8 which is consistent with the findings of the present study. However, in we further classified mouth puffing into IMP, CMP, and SMP. ...
... Recent studies showed that patients with a higher percentage of oral and oronasal breathing periods had severer OSA and lower SpO 2 than common snorers and healthy subjects did. 4,6,8,15 Previous studies showed that participants who completely breathed with the nose (NMP) tended to have more stable SpO 2 during sleep, 4,7,8 which is consistent with the findings of the present study. However, in we further classified mouth puffing into IMP, CMP, and SMP. ...
Article
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Purpose This study aimed to investigate (1) the role of mouth puffing phenomenon and upper airway features in obstructive sleep apnea (OSA) and (2) whether mouth-taping during sleep alleviated the severity of OSA. Participants and Methods Seventy-one participants underwent a two-night home sleep test (the first day sleeping normally; the second day sleeping with their mouths being taped); their oximetry desaturation index (ODI) and mouth puffing signals (non-mouth puffing, complete mouth puffing, intermittent mouth puffing (IMP), and side mouth puffing) were detected by a validated fingertip pulse oximeter and a mouth puffing detector. The participants were grouped into the ODI-improved group and the ODI-not-improved group according to their sleeping test results. The radiograph was taken by cone-beam computed tomography and cephalometries. Upper airway features including airways, soft tissues, and oral cavity variables were measured. Results Participants with severe OSA showed a higher IMP percentage compared with those with normal, mild, and moderate OSA (severe: 33.78%, moderate: 22.38%, mild: 14.55%, normal: 0.31%, p < 0.001). In all participants, the ODI and the percentage of SpO2 under 90 (T90) were positively related to body mass index (BMI) (r = 0.310 and 0.333, respectively), while ODI and T90 were negatively correlated with the minimum width of the airway (r = −0.473 and −0.474, respectively); all mentioned relationships were significant (p < 0.05). Conclusion IMP proportions were found to be higher in the half of participants whose ODI did not improve after mouth-taping and in those with severe OSA. Moreover, OSA patients with higher ODI, higher T90, and higher proportions of IMP were more likely to have a narrower upper airway.
... Importantly, sleeping with the mouth open is deemed to be a risk for Obstructive Sleep Apnea (OSA)-a disorder where the upper airway is partially or completely obstructed during sleep [66]. At present, OSA studies rely on video [134] or external transducers attached to the face [129] to determine the mouth position. We postulate that these methods are unappealing and cumbersome. ...
Article
Full-text available
The mouth offers valuable insights into the condition of the human body. Yet, deploying intraoral sensors to measure oral temperature or jaw movements poses challenges in safety and acceptability. Consequently, real-world data for intraoral research is scarce. To address this gap, we leverage the widespread use of dental retainers and enhance them with Densor: an electronic sensing platform requiring only a standard smartphone for charging and data retrieval using a Near Field Communication interface. Its low power architecture enables prolonged sensing on a single charge, making it suitable for sleep studies. It can provide practitioners with feedback on treatment compliance, and is even able to detect if the user is speaking or drinking water. Densor presents an intraoral, actively powered, battery-free platform featuring multi-modal sensors and an extended lifespan.
... The relationship between the mouth puffing phenomenon and OSA has now been evaluated for the first time in this study. Similar findings have been reported in other studies that patients who have a higher percentage of oral and oro-nasal breathing periods have more serious OSA and lower SpO2 than common snorers or healthy subjects [10,12,13,15,25]. However, our findings also indicate that mouth breathing should be divided into two categories, IMP and CMP, defined on a minute by minute basis. ...
Article
Full-text available
Purpose This study aimed to design a device to monitor mouth puffing phenomena of patients with obstructive sleep apnea when mouth-taped and to employ video recording and computing algorithms to double-check and verify the efficacy of the device. Methods A mouth puffing detector (MPD) was developed, and a video camera was set to record the patients’ mouth puffing phenomena in order to make ensure the data obtained from the device was appropriate and valid. Ten patients were recruited and had polysomnography. A program written in Python was used to investigate the efficacy of the program’s algorithms and the relationship between variables in polysomnography (sleep stage, apnea-hypopnea index or AHI, oxygen-related variables) and mouth puffing signals (MPSs). The video recording was used to validate the program. Bland–Altman plot, correlations, independent sample t-test, and ANOVA were analyzed by SPSS 24.0. Results Patients were found to mouth puff when they sleep with their mouths taped. An MPD was able to detect the signals of mouth puffing. Mouth puffing signals were noted and categorized into four types of MPSs by our algorithms. MPSs were found to be significantly related to relative OSA indices. When all participants’ data were divided into minutes, intermittent mouth puffing (IMP) was found to be significantly different from non-mouth puffing in AHI, oxygen desaturation index (ODI), and time of oxygen saturation under 90% (T90) (AHI: 0.75 vs. 0.31; ODI: 0.75 vs. 0.30; T90: 5.52 vs. 1.25; p < 0.001). Participants with severe OSA showed a higher IMP percentage compared to participants with mild to moderate OSA and the control group (severe: 38%, mild-to-moderate: 65%, control: 95%; p < 0.001). Conclusions This study established a simple way to detect mouth puffing phenomena when patients were mouth-taped during sleep, and the signals were classified into four types of MPSs. We propose that MPSs obtained from patients wearing the MPD can be used as a complement for clinicians to evaluate OSA.
... However, the authors are aware that the lack of adequate verticality control with Somnodent Flex TM is a weak point of the device. During sleep, the spontaneous opening of the mouth leads to mandibular post-rotation and retroposition, jeopardizing the efficacy of the therapy [44]. For this reason, the authors of the current study propose to carry out subsequent simulations by integrating the device with front vertical retention hooks for elastic. ...
Article
Objective The study aims to evaluate the stresses and the deformations generated at the periodontal level by two mandibular advancement devices (MADs) using finite element analysis. Methods A three-dimensional digital model of the skull of a 29-year-old patient was created using a CBCT. The 3D models of two MADs (Somnodent FlexTM and Somnodent AvantTM) were reconstructed from scanning prototypes based on the patient’s anatomy. The overall geometry was imported into software for the finite element study. A force of 11.18 N representing an advancement of 9.5 mm was applied to the devices. A finite element analysis wfas subsequently performed. Results Somnodent FlexTM generates a peak of 3.27 kPa on periodontal ligaments and 287 kPa on teeth. For Somnodent AvantTM the maximum stress is 4.53 kPa on periodontal ligaments and 467 kPa on teeth. Conclusion Different activation mechanisms of the devices generate stresses of different entities.
... The advantages of using a device such as Orthoapnea TM are, in particular, the possibility of having lateral excursions, useful, for example, in the bruxist patient and the ability of the device to force the jaw to advance further if the patient tends to open mouth during sleep. This phenomenon, which is a typical tendence in OSA, decreases the efficiency of MAD (causing mandibular postrotation and retroposition) and, therefore, the effectiveness of the therapy [61,62]. In lateral mechanical devices such as Somnodent TM or Herbst TM , since there is no real limit to the opening of the mouth, vertical elastics of adequate length and strength can be used to keep the two parts of the splint in contact. ...
Article
Full-text available
AIM: The purpose of this study is to compare the stress effects developed on the periodontal ligaments and teeth by three different types of mandibular advancement devices (MADs) using a finite element method (FEM) analysis. Introduction: Obstructive sleep apnea (OSA) is a disease with a high prevalence and, in recent years, the use of MADs as an alternative or support treatment to the continuous positive airway pressure (CPAP) has spread. Their use finds relative contraindications in the case of partial edentulism and severe periodontal disease. Given the widespread of periodontal problems, it is essential to know the effects that these devices cause on the periodontal ligament of the teeth. Materials and methods: Starting from the computed tomography (CT) scan of a patient’s skull, 3D reconstructions of the maxilla and mandible were implemented. Three different MADs were prepared for the patient, then 3D scanned, and lastly, coupled with the 3D models of the jaws. The devices have two different mechanics: One has a front reverse connecting rod (OrthoapneaTM), and two have lateral propulsion (SomnodentTM and HerbstTM). A FEM analysis was performed to calculate the stress applied on periodontal ligaments, on every single tooth and the displacement vectors that are generated by applying an advancement force on the mandible. Results: HerbstTM and SomnodentTM devices present very similar stress values, mainly concentrated on lateral teeth, but in general, the forces are very mild and distributed. The maximum stresses values are 3.27 kPa on periodontal ligaments and 287 kPa on teeth for SomnodentTM and 3.56 kPa on periodontal ligaments and 302 kPa on teeth for HerbstTM. OrthoapneaTM has, instead, higher and concentrated stress values, especially in the anterior maxillary and mandibular area with 4.26 kPa and 600 kPa as maximum stress values, respectively, on periodontal ligaments and teeth. Conclusions: From the results, it is concluded that devices with a bilateral mechanism generate less and more distributed stress than an anterior connecting rod mechanism. Therefore, they may be advisable to patients with compromised periodontal conditions in the anterior area.
Article
Preclinical and human physiological studies indicate that topical, selective TASK 1/3 K ⁺ channel antagonism increases upper airway dilator muscle activity and reduces pharyngeal collapsibility during anaesthesia and nasal breathing during sleep. The primary aim of this study was to determine the effects of BAY2586116 nasal spray on OSA severity and whether individual responses vary according to differences in physiological responses and route of breathing. 10 people (5 females) with OSA (AHI=47±26events/h (mean±SD)) who completed previous sleep physiology studies with BAY2586116 were invited to return for three polysomnography studies to quantify OSA severity. In random order, participants received either placebo nasal spray (saline), BAY2586116 nasal spray (160µg), or BAY2586116 nasal spray (160µg) restricted to nasal breathing (chinstrap or mouth tape). Physiological responders were defined a priori as those who had improved upper airway collapsibility (critical closing pressure ≥2cmH 2 O) with BAY2586116 nasal spray (NCT04236440). There was no systematic change in apnea-hypopnea index (AHI3) from placebo vs. BAY2586116 with either unrestricted or nasal only breathing versus placebo (47±26 vs. 43±27 vs. 53±33events/h, p=0.15). However, BAY2586116 (unrestricted breathing) reduced OSA severity in physiological responders compared to placebo (e.g., AHI3= 28±11 vs. 36±12events/h, p=0.03 and ODI3= 18±10 vs. 28±12events/h, p=0.02). Morning blood pressure was also lower in physiological responders after BAY2586116 versus placebo (e.g., systolic blood pressure= 137±24 vs. 147±21mmHg, p<0.01). In conclusion, BAY2586116 reduces OSA severity during sleep in people who demonstrate physiological improvement in upper airway collapsibility. These findings highlight the therapeutic potential for this novel pharmacotherapy target in selected individuals.
Article
Background: Continuous positive airway pressure (CPAP) delivered via an oronasal mask is associated with lower adherence, higher residual AHI and increased CPAP therapeutic pressure compared to nasal masks. However, the mechanisms underlying the increased pressure requirements are not well understood. Research question: How do oronasal masks affect upper airway anatomy and collapsibility? Study design and methods: 14 OSA patients underwent a sleep study with both a nasal and oronasal mask, each for half the night (order randomized). CPAP was manually titrated to determine therapeutic pressure. Upper airway collapsibility was assessed using the Pcrit technique. Cine MRI was done to dynamically assess the cross-sectional area of the retroglossal and retropalatal airway throughout the respiratory cycle with each mask interface. Scans were repeated at 4cmH2O and at the nasal and oronasal therapeutic pressures. Results: The oronasal mask was associated with higher therapeutic pressure requirements (ΔM±SEM; +2.6±0.5, p<0.001) and higher Pcrit (+2.4±0.5cmH2O, p=0.001) compared to the nasal mask. The change in therapeutic pressure between masks was strongly correlated with the change in Pcrit (r2=0.73, p=0.003). Increasing CPAP increased both the retroglossal and retro-palatal airway dimensions across both masks. After controlling for pressure and breath-phase, the retropalatal cross-sectional area was moderately larger when using a nasal versus an oronasal mask (+17.2mm2, CI95%: 6.2-28.2, p<0.001) while nasal breathing. Interpretation: Oronasal masks are associated with a more collapsible airway than nasal masks, which likely contributes to the need for a higher therapeutic pressure.
Article
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Sleep-disordered breathing (SDB) occurring during rapid eye movement (REM) sleep occurs more frequently in women than men. We sought to characterize REM SDB prevalence by gender and age to identify factors that could account for this discrepancy. Subjects with REM SDB were identified among 2,486 patients referred to a university sleep laboratory with an apnea-hypopnea index (AHI) >or= 5 events per hour. REM SDB was defined as non-REM (NREM) AHI <or= 15/h and REM AHI/NREM AHI ratio >or= 2. Regression analyses were utilized to determine factors associated with REM SDB. REM SDB prevalence was 40.8% in women and 21.0% in men. After adjusting for age and obesity, female sex remained a risk factor for REM SDB (odds ratio, 3.0; 95% confidence interval [CI], 1.8 to 4.2). REM SDB prevalence waned with increasing age in both sexes, such that the odds of having REM SDB fell by 26.7% (95% CI, 15.2 to 38.2%) per decade. REM AHI/NREM AHI decreased with age only in women, falling 10.9% (95% CI, 5.5 to 16.3%) per decade. NREM AHI in women increased the most with age (16.0%; 95% CI, 11.1 to 20.9%) per decade, and least with body mass index (BMI) [13.0%; 9.1 to 16.9%] for every 5-unit BMI increase when compared to REM AHI for women and either index for men. REM SDB prevalence decreases with age in women as does REM AHI/NREM AHI, perhaps secondary to a disproportionate age-dependent rise in NREM vs REM AHI in women. Younger women may be protected from SDB during NREM sleep, even in the face of obesity. These patterns may reflect age-related decreases in female hormones.
Article
Study objective To evaluate the tolerability and to find predictors of treatment success for an individually adjusted, one-piece mandibular advancement device in patients with snoring and obstructive sleep apnea. Design Prospective study. Setting Departments of Respiratory Medicine and Orthodontics, Umeå University. Patients Six hundred nineteen of 630 patients (98%), who consecutively received treatment for sleep apnea and snoring from February 1989 to August 2000, were followed up. They had a mean apnea-hypopnea index of 16 (range, 0.0 to 76) and a mean body mass index of 28 (range, 19 to 42). Measurements Interviews, questionnaires, and overnight sleep apnea recordings. Patients with an apnea-hypopnea index of ≥ 10 in the supine and/or lateral position were considered to have obstructive sleep apnea. A lateral apnea-hypopnea index of < 10, together with a supine apnea-hypopnea index of ≥ 10, defined supine-dependent sleep apneas. Results One hundred forty-eight of the 619 patients (24%) discontinued treatment. Female gender predicted treatment success, defined as an apnea-hypopnea index of < 10 in both the supine and lateral positions, with an odds ratio of 2.4 (p = 0.01). In the women, the odds ratios for treatment success were 12 for mild sleep apnea (p = 0.04), and 0.1 for complaints of nasal obstruction (p = 0.03). In the men, the odds ratios for treatment success were 6.0 for supine-dependent sleep apneas (p < 0.001), 2.5 for mild sleep apnea (p = 0.04), 1.3 for each millimeter of mandibular advancement (p = 0.03), and 0.8 for each kilogram of weight increase (p = 0.001). Conclusions The mandibular advancement device is recommended for women with sleep apnea, for men with supine-dependent sleep apneas defined by a lateral apnea-hypopnea index of < 10, and for snorers without sleep apnea. Men who increase in weight during treatment reduce their chance of treatment success and are advised to be followed up with a new sleep apnea recording with the device.
Article
Nasal obstruction has been associated with apneic episodes during sleep. However, the normal distribution of nasal and oral air flow while asleep has not been investigated. To determine the normal route of ventilation during sleep, we studied 7 healthy men and 7 healthy women using a sealed face mask that mechanically separated nasal and oral air flow. Standard sleep staging techniques were employed. The subjects slept 297 +/- 29 (SEM) min, with a mean of 197 +/- 15 min of ventilation recorded. Ventilation was decreased during sleep as has been previously demonstrated. However, during sleep, we found that men breathed a greater percentage of total ventilation through the mouth (29.0 +/- 8.2%) than did women (5.0 +/- 1.0%, p less than 0.02). The same trend applied during wakefulness but did not reach significance (p = 0.06). Although none was symptomatic, 4 subjects, all men, had more than 3 apneas per hour. These 4 men had a greater percentage of mouth ventilation (37.3 +/- 19.0%) than did the other 10 subjects with few or no apneas (8.1 +/- 2.7%, p less than 0.02). It was also noted that increasing age in men was associated with an increasing percentage of mouth ventilation (r = 0.83 p less than 0.03) but this relationship was not observed in women. We conclude that mouth breathing may be associated with apneas during sleep and that breathing through the mouth occurs commonly in men, particularly in those who are older. This suggests that nasal breathing may be important in the maintenance of ventilatory rhythmicity during sleep.
Article
We investigated the influence of mouth opening on upper airway (UA) collapsibility in six healthy sleeping volunteers. UA collapsibility was measured during continuous negative airway pressure trials that consisted of the progressive decrease in pressure in a nasal mask, with simultaneous recording of esophageal pressure and instantaneous flow. Measurements were made under two experimental conditions: mouth closed (MC), and mouth open (MO). Cephalometric measurements were obtained with subjects awake in the same position for both experimental conditions. UA critical pressure (Pcrit) was derived from the relationship between the breath-by-breath values of the maximal inspiratory airflow and the corresponding mask pressure. Pcrit was significantly less negative during MO than during MC (MO, -12.7 +/- 4.8 cm H2O; MC, -16.4 +/- 6 cm H2O, mean +/- SD; p = 0.03). Mouth opening was associated with a significant increase in the total respiratory resistance (MO, 3.8 +/- 1.6 cm H2O/ml/s; MC, 3.0 +/- 1.6 cm H2O/ml/s-1, p = 0.03). Besides an increase in the distance between the teeth and a reduction in the distance between the hyoid bone and the mandible, no significant changes in cephalometric parameters were found between MO and MC. We conclude that mouth opening increases UA collapsibility during sleep and that mouth opening may contribute to the occurrence of sleep-related breathing abnormalities.
Article
The aim of this study was to develop a method of studying the effects of mandibular advancement on oropharyngeal airway dimensions in the sagittal plane in conscious, supine patients. Six white, dentate, male patients with proven obstructive sleep apnoea had sagittal fluoroscopic recordings taken in the resting supine position. Images were recorded at four frames per second as the mandible was advanced with the teeth in contact to maximum protrusion and then opened. Software in the fluoroscopic imaging system permitted measurement of the change in mandibular position together with oropharyngeal airway dimensions expressed as the narrowest dimension observable in the post-palatal and post-lingual sites. Plotting of airway dimensions during mandibular advancement enabled estimation of the degree of protrusion associated with maximal airway benefits. Progressive mandibular advancement produced variable adaptive changes in the post-palatal and post-lingual regions of the oropharynx. The amount of airway opening appeared to be related to the horizontal and vertical relationships of the face and to the dimensions of the soft palate. The changes in post-palatal and post-lingual airway dimensions were not always identical, despite the observation that both tongue and soft palate were seen to move in unison, with close contact being maintained between the two structures. Jaw opening resulted in synchronous posterior movement of both tongue and soft palate, with consequent narrowing of oropharyngeal airspace. Fluoroscopy is a simple method of assessing upper airway changes with mandibular advancement in the conscious patient. The technique should facilitate the selection of subjects for whom mandibular advancement would seem advantageous. The nature of the adaptive response is dependent on individual structural variation. It is suggested that, where artificial mandibular advancement with dental devices is considered beneficial, jaw opening should be kept to a minimum.
Article
To test whether the mandible opens more during deep sleep and whether the mandibular position is affected by body position during sleep, the vertical mandibular position was recorded intraorally using a magnet sensor at the same time as a standard sleep study in seven normal healthy male adults. Measurements were recorded during the period before sleep onset (WAKE) and during sleep. Two-way ANOVA showed that vertical mandibular position was significantly affected by sleep stage but not by body position (supine vs lateral recumbent). The proportion of time during which the mandible was in a near-closed position (0-2.5 mm) significantly and progressively decreased, and significantly more time was spent at wider gaps (2.5-5 mm) as non-rapid-eye-movement (NREM) sleep deepened. In REM sleep, the proportion of time during which the mandible was at wider gaps was significantly greater than in WAKE and stage 1 (but not later stages) of NREM sleep. It was concluded that mandibular posture during sleep in healthy adults is significantly influenced by sleep stage but not by body position. Mandibular opening progressively increases with the depth of NREM sleep stage, and the mandible is more open in REM sleep than in light NREM sleep.
Article
To evaluate the effect of a mandibular advancement device in patients with supine-dependent sleep apnea and patients with non-supine-dependent sleep apnea. Prospective study. Department of Respiratory Medicine, University Hospital, Umeå, Sweden. Twenty-six patients with obstructive sleep apnea. Individually fabricated and adjusted mandibular advancement devices. Overnight polysomnographic sleep recordings with and without the device. Supine-dependent sleep apnea was defined when the supine apnea-hypopnea index was > or = 10, together with a lateral apnea-hypopnea index of < 10. Non-supine-dependent sleep apnea was considered when the lateral apnea-hypopnea index was > or = 10. In 12 patients with supine-dependent sleep apnea, the device reduced the supine apnea-hypopnea index from a median of 41 (range, 16 to 70) to 5.9 (range, 0.0 to 15) (p < 0.01). In 14 patients with non-supine-dependent sleep apnea, the treatment reduced the supine apnea-hypopnea index from 44 (range, 1.8 to 73) to 21 (range, 6.3 to 60) (p < 0.05) and the lateral apnea-hypopnea index from 21 (range, 12 to 70) to 4.5 (range, 0.0 to 31) (p < 0.01). The odds ratio for a successful apnea reduction to an apnea-hypopnea index of < 10 in both the supine and the lateral positions was 30 for supine-dependent sleep apnea adjusted for age, obesity, mandibular advancement, and mandibular opening (p < 0.01). Successful apnea reduction with a mandibular advancement device is highly related to supine-dependent sleep apnea.