Marquette University
e-Publications@Marquette
Nursing Faculty Research and Publications
Nursing, College of
9-30-2012
The Effect of the Tri-Core® Cervical Pillow on Sleep
Outcomes among Whiplash Associated Disorder
(WAD) Patients
Jay S. Greenstein
Sport and Spine Rehab Clinical Research Foundation
Barton Bishop
Sport and Spine Rehab Clinical Research Foundation
Jean Edward
University of Louisville
Allen Huffman
Sport and Spine Rehab Clinical Research Foundation
Danielle Davis
Sport and Spine Rehab Clinical Research Foundation
See next page for additional authors
Published version. Topics in Integrative Health Care: An International Journal, Vol. 3, No. 3 (September
30, 2012). Permalink. © HealthIndex, Inc. 2012.
Authors
Jay S. Greenstein, Barton Bishop, Jean Edward, Allen Huffman, Danielle Davis, and Robert V. Topp
This article is available at e-Publications@Marquette: http://epublications.marquette.edu/nursing_fac/304
TOPICS IN INTEGRATIVE HEALTH CARE [ISSN 2158-4222] – VOL 3(3)
September 30, 2012
Research
The Effect of the Tri-Core® Cervical Pillow on
Sleep Outcomes Among Whiplash Associated
Disorder (WAD) Patients
Jay Greenstein, DC, CCSP, CGFI-L1, CKTP1, Barton Bishop, PT, DPT, CSCS, SCS, CGFI-L2, CKTP2,
Jean Edward, RN, BSN3*, Allen Huffman, DC, CKTP, BS4, Danielle Davis5, Robert Topp, RN, PhD6
Address: 1President, Sport and Spine Rehab Clinical Research Foundation, Rockville, MD, USA, 2Secretary, Sport
and Spine Rehab Clinical Research Foundation, Rockville, MD, USA, 3Research Assistant and Doctoral Student,
School of Nursing, University of Louisville, Louisville, KY, USA, 4Sport and Spine Rehab Clinical Research Foundation,
Rockville, MD, USA, 5Sport and Spine Rehab Clinical Research Foundation, Rockville, MD, USA, 6Professor and
Associate Dean for Research, College of Nursing, Marquette University, Marquette, WI, USA.
E-mail: Jean Edward, RN, BSN – [email protected]
*Corresponding author
Topics in Integrative Health Care 2012, Vol. 3(3) ID: 3.3004
Published on September 30, 2012 | Link to Document on the Web
Abstract
Objectives: The purpose of this study was to determine the effectiveness of a semi-customized
orthopedic cervical pillow on sleep outcomes in Whiplash Associated Disorder (WAD) patients.
Methods: A convenience sample of forty-three WAD patients who participated in this study
was randomly assigned to an intervention or control group. The intervention group was given a
Tri-Core® (Core Products International, Inc., Osceola) semi-customized orthopedic cervical
pillow for sleep. Both the intervention and control groups received the Funhab® rehabilitation
protocol (Sports and Spine Rehab Holdings Inc., Fort Washington). Outcome measures collected
at the initial visit (baseline) and at discharge in both groups included characteristics of selfreported sleep operationalized by research participants completing the Medical Outcomes
Study (MOS) Sleep questionnaire. Duration in the study varied among patients depending on
individual progression and needs. Data were analyzed using descriptive statistics and repeated
measures ANOVA.
Results: There were no differences between the control group and intervention group in sleep
problems, sleep disturbances and sleep adequacy. The only significant finding between groups
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was the improvement in self-reported snoring in the intervention group.
Conclusion: These findings indicate that WAD patients who use a semi-customized cervical
pillow in combination with a standard rehabilitation protocol did not experience improvements
in most of their sleep outcomes beyond those experienced by a control condition that used the
rehabilitation protocol alone. The single variable which did decline among patients who used
the TriCore® pillow and increased in the control condition was self-reported snoring. Future
research is warranted to further examine other sleep characteristics associated with snoring as
a result of using the TriCore® cervical pillow and the Funhab rehabilitation program.
Introduction
Whiplash-associated disorders (WADs) commonly occur as a result of motor vehicle accidents (MVAs)
and can lead to substantial long-term negative effects on health.1 WADS are soft-tissue injuries
characterized by hyperextension, hyperflexion or lateral movements of the head. 2As a result of these
injuries, individuals experience multiple clinical manifestations of WADs including changes in posture,
pain, disability, headache, fatigue, and sleep disturbances. 3,4Berglund et al. found that individuals who
were exposed to whiplash injury as a result of rear-end collisions reported substantial changes in health
outcomes including headaches, back pain, fatigue and sleep disturbances when compared to an
unexposed comparison group.1
Sleep disturbances predominantly occur during the initial period following the whiplash injury 5. In a
study by Schlesinger et al. research participants with whiplash injuries experienced delayed sleep
latency and poorer sleep quality when compared to controls.5 Additionally, symptoms such as neck pain
and tension headaches that worsen with extended periods of poor posture, especially during night-time
sleeping, are known to cause significant sleep disturbances. 6,7 The literature identifies the importance of
modifying night-time sleeping positions in conjunction with physical therapy and postural exercises to
alleviate sleep disturbances and other related WAD symptoms5-7.
The use of neck support pillows helps to modify night-time sleeping positions to achieve optimal
physiological positioning of the spine.6,7Several studies have explored the effects of various neck support
and cervical pillows on reducing cervical pain, improving neck disability, and other WAD symptoms while
consequently improving sleep quality and outcomes.8-11Although numerous studies have attempted to
explore the effects of using cervical pillows in improving sleep outcomes, there is still contradictory
evidence and need for further research that delineates the relationship between the use of cervical
pillows and improved WAD outcomes. Further research is warranted to further explore the effects of
utilizing cervical pillows to establish effective physiotherapy in improving sleep in WAD patients.
Therefore, the purpose of this study was to determine the effectiveness of a semi-customized
orthopedic cervical pillow on sleep outcomes in WAD patients. The hypothesis tested in this study was:
WAD patients utilizing a semi-customized cervical pillow will have improved characteristics of selfreported sleep compared to WAD patients who did not utilize a semi-customized cervical pillow.
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Methods
A convenience sample of 43 patients was recruited from an outpatient chiropractic and physical therapy
clinic specializing in spinal rehabilitation. A sample size of 21 subjects per group will result in sufficient
statistical power (0.80) to detect an effect size of .90 with and type I error set a priori at .05.12 The study
was explained to interested individuals by a member of the research staff, and informed consent was
obtained prior to any data collection or interventions. Research participants were included in the study
if they presented to the clinic for the treatment of an injury sustained from a motor vehicle accident
diagnosed with cervical spine pain, with or without radiculopathy, and between the ages of 18-65.
Before inclusion in the study, a diagnosis of WAD was established by clear causation between the
trauma the subject incurred based on their history, examination and subsequent cervical spine
symptomatology. Furthermore, the research participant’s condition was to be treated initially through
nonsurgical approaches. Exclusion criteria included patients who presented with a diagnosis which was
not deemed to be amenable to conservative management by the patient’s physician. This study was
approved by the University of Louisville Institutional Review Board (IRB#10.0199) and met human
ethical considerations consistent with the Helsinki Declaration.
Data Collection
Data was collected from all research participants prior to randomization using coin flips into one of the
two study groups at (baseline) and again following completion of their treatment (discharge). Outcome
measures included characteristics of self-reported sleep operationalized by research participants
completing the MOS Sleep questionnaire. The MOS sleep questionnaire is a 12-item questionnaire
concerning quantity and quality of sleep, sleep habits, and waking and daytime symptoms for the
previous four weeks. The literature supports the use of the MOS sleep questionnaire to evaluate many
conditions causing sleep disturbances.13This questionnaire was utilized to measure shortness of breath,
headaches, sleep somnolence, sleep problems, sleep disturbances, sleep adequacy, sleep duration, and
snoring. In addition, two summary index measure scores were utilized to measure overall sleep
problems. Sleep Problem Index I is a brief summation index that includes awakening short of breath or
with a headache; trouble staying awake during the day; trouble falling asleep; awakening during sleep
and having trouble falling asleep; getting enough sleep to feel rested in the morning; and, getting the
amount of sleep needed. Sleep Problem Index II is a more comprehensive summation index that
includes all items in Index I and the time taken to fall asleep; disturbed sleep; and sleepiness or
drowsiness during the day. All domain scales and index measures were scored on a transformed 0-100
metric, with higher scores on these two indices indicating more sleep problems. 14Once each subject had
completed the MOS questionnaire, all original numbers were calculated to obtain a percentage. Higher
item scores reflect more of the attribute being measured by the scale and lower scores indicate less of
that attribute.
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Procedures
Following baseline data collection all research participants were prescribed the Funhab® rehabilitation
protocol (Sports and Spine Rehab Holdings Inc., Fort Washington, MD). Patients progressed along the
program at varying rates and were discharged at different times based on individual needs. Funhab® is
an evidenced-based rehabilitation protocol aimed at maximizing appropriate clinical tools inclusive of
spinal manipulation, soft tissue and additional articular manual therapies, physiotherapies and
rehabilitative functional exercises. This protocol is comprised of an exercise treatment and progression
that addresses local, regional and global neuro-musculoskeletal dysfunction of the neck by integrating
both the biomechanical and neurological components of rehabilitation. In addition to manual therapy
and physiotherapies, the protocol takes the patient through postural, local, regional and then full body
exercise progressions in an attempt to maximize their overall level of function and correct muscular
imbalances and dysfunctions. The Funhab® protocol prescription and implementation is an 11-level
treatment progression and is based on the patient’s region of pain and biomechanical dysfunction or
functional limitation that needs to be corrected. Patients progress to advanced exercise levels once they
are able to perform exercises at their current level without any pain. Once patients reach level 11 they
are discharged from care.
Research participants assigned to the control group received the usual care for WADs provided at the
clinic, which consisted of the Funhab® protocol, and slept on their regular pillow. Research participants
assigned to the intervention group received the same Funhab® protocol and were also provided with a
Tri-Core® (Core Products International, Inc., Osceola, WI) semi-customized orthopedic cervical pillow for
sleep. Following the Tri-Core® sizing guidelines (petite, midsize, and standard) the size of the pillows
were customized to each subject. Customization was done to insure the patient's head was maintained
in neutral as it relates to cervical flexion and extension when the subject was lying supine. Additionally,
intervention research participants were given instructions on how to properly sleep on the pillow to
maximize comfort and design features.
Data Analysis
The data was used to address the aims of the study in two steps. First, the two study groups were
compared at baseline on descriptors and outcome variables to determine the efficacy of the
randomization procedure (See table 1). The second step in the analysis involved comparing the two
study groups on the outcome measures. Since the optimal versus non-optimal sleep variable was
dichotomous, a cross tabulation table was constructed, presenting the raw and percentage values of
individuals within the two treatment groups who fell into these two categories (Table 2). Continuous
outcome variables were analyzed to address the hypotheses by calculating repeated measures ANOVA
with Tukey-Kramer post hoc comparisons to determine if the two groups differed over time.
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Table 1. Description of the sample
Variable
Group
Mean + SD
Pillow
6.36 + 1.06
Usual Care
0
Pillow
16.23 + 4.35
Usual Care
15.52 + 2.06
Pillow
7.55 + 6.35
Usual Care
9.52 + 7.74
Pillow
34.05 + 11.02
Usual Care
39.67 + 12.78
Female
Pillow
14
Male
Pillow
8
Reported Number of Nights Per Week
Using Pillow
Number of Visits
Days Since Onset of Symptoms
Age
Gender
t-value
p<
N/A
N/A
.67
.51
.92
.36
1.55
.13
.043
.84
Table 2. Optimal vs. Not Optimal Sleep by time and treatment condition
Condition
Baseline
Post-Treatment
Optimal
Not optimal
Optimal
Not optimal
Control
7 (33%)
14 (67%)
8 (38%)
13 (62%)
Intervention
5 (23%)
17 (77%)
8 (36%)
14 (64%)
Results
As table 1 indicates, the two groups presented at baseline with a similar gender distribution, age and
days since onset of symptoms. The group prescribed the TriCore® pillow used the device an average of
6.36 nights (91%) per week while they were engaged in the study. Both study groups participated in a
similar number of therapy sessions in the clinic (control = 15.52 + 2.06, intervention = 16.23 + 4.35
visits). The two study groups did not significantly differ at baseline on any of their measures of sleep
(See table 3).
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Table 3. Sleep measures by time and treatment condition
Control Group
Intervention Group
Baseline
PostTreatment
Raw and
Percentage
Change
Baseline
PostTreatment
Raw and
Percentage
Change
SOB/Headache
16.19 + 2.33
17.14 + 3.05
.95 (6%)
30.00 + 3.07
23.64 + 3.84
-6.63 (21%)
Sleep
Somnolence
42.84 + 2.79 31.09 + 2.64*
-11.75 (27%)
39.36 + 2.05
28.15 + 1.83
-11.21 (28%)
Sleep Problems
Index I
45.42 + 1.90 32.51 + 2.14*
-12.91 (28%)
53.02 + 1.75
36.65 +
2.27*
-16.37 (31%)
Sleep Problems
Index II
48.39 + 1.87
33.33 + 2.21
-15.06 (31%)
55.41 + 1.85
36.70 +
2.23*
-18.71 (33%)
Sleep
Disturbance
50.12 + 2.50 31.74 + 2.87*
-18.38 (37%)
60.64 + 2.69
37.57 +
3.01*
-23.07 (38%)
Sleep Adequacy
64.76 + 2.94 47.14 + 3.23*
-17.62 (27%)
70.45 + 2.46
51.36 +
2.92*
-19.09 (27%)
Duration of Sleep
(hours/night)
6.10 + 1.81
6.21 + 1.47
.9 (17%)
33.64 +
3.51*
-9.09 (21%)
6.38 + 1.50
5.31 + 1.61
.28 (5%)
Snoring
34.29 + 3.80 40.00 + 4.20*
+5.71
(16%)
42.73 + 3.28
* indicates a significant change within a study group over time (p<.05)
Shading indicates differences between groups at a specific time
Chi square analysis indicated that neither group significantly changed their perceptions of obtaining
optimal or non-optimal sleep over the duration of the study. Depending on the data collection time
(baseline or at discharge post-treatment), table 2 indicates that between 23% and 38% of the sample
reported getting adequate sleep. Table 3 indicates that neither group significantly changed their reports
of shortness of breath or headache (SOB/headache) or duration of sleep over the course of the study,
although the intervention group decreased 21% on SOB/headache, while the control group increased on
this variable by 6%.
Additionally, the control group significantly decreased their somnolence, while the intervention group
did not significantly change over the duration of the study. However, the percentage decline in
somnolence appears clinically indistinguishable between the two groups (27% to 28%). Similarly,
although the intervention group exhibited a significant decline in Sleep Problems Index II (See table 3)
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the percentage decline in this measure appeared clinically indistinguishable from the control group (31% to -33%). The analysis also indicated that both the control group and the intervention group
reported similar significant declines over the course of the study on the outcomes of sleep disturbance (37% to -38%), sleep adequacy (-27%) and sleep problems on index I (-28% to -31%). Thus, sleep
somnolence, sleep disturbance and sleep adequacy declined similarly within each study group over the
duration of the study, while optimal sleep and SOB/headache did not change among either group during
the study.
The reports of snoring indicated a significant time by group interaction effect (p<.05). The post hoc
analysis indicated that the control group significantly increased their self-reported snoring by 16% over
the duration of the study, while the intervention group reported significant decreases in their snoring by
21%. These significant increases in the control group and decreases in treatment group in snoring
resulted in the treatment group reporting significantly less snoring than the control and the post
treatment time point.
Discussion
Cervical and neck support pillows have been used frequently by WAD patients to assist in reducing
cervical pain and consequently improving overall sleep quality and other outcomes. Previous studies
indicate that WAD patients who use a cervical pillow improve their sleep outcomes including improving
sleep problems, adequacy and other sleep disturbances.8-11 However, findings from this study indicate
that WAD patients who use the TriCore® cervical pillow in combination with the Funhab® rehabilitation
protocol did not experience improvements in sleep outcomes other than self-reported snoring beyond
the improvements in sleep experienced by the control condition that used the Funhab® rehabilitation
protocol alone. The single variable which did improve among patients who used the TriCore pillow, but
not in the control condition, was self-reported snoring. Thus, the TriCore Pillow intervention appears to
have a significant effect on reducing snoring among cervical neck patients. Despite limitations in these
findings, previous studies have indicated the effectiveness of rehabilitative programs utilizing neck
support pillows in decreasing pain and improving sleep outcomes. 8-11 In a randomized clinical trial that
studied the effects of a comprehensive rehabilitative program and sleeping neck support on patients
with chronic cervicobrachialgia, findings indicated that individuals who utilized the neck support pillow
had a significant decrease in sleep disturbances caused by pain. 7 In another randomized crossover study,
Lavin et al., explored the effects of three types of cervical pillows on sleep in patients with chronic neck
pain.15 Findings from this study indicated significant improvements in overall sleep quality and
significantly longer sleep duration for the water-based cervical pillow compared to the roll and standard
pillow.15 Although sleep duration did not appear to significantly change within or between the groups in
the current study the group using the cervical pillow reported sleeping 17% (54 minutes) longer at
posttest compared to the control who reported sleeping 5% (17 minutes) longer at the posttest.
Similarly, the use of rubber pillows have also shown to be effective in reducing waking cervical pain and
improved sleep quality and pillow comfort.15 Valenza et al., also reported that patients with mechanical
neck pain and WAD pain reported poorer sleep quality and efficiency, and higher levels of sleep latency,
disturbances, and use of medication.17
In a blinded study that tested the effects of four different neck pillows with different shapes and fillings
on neck pain, headache, and quality of sleep among 52 patients with chronic non-specific neck pain,
there were positive effects of neck support pillows on all three variables. 10There were no differences
regarding the types of pillows used and their effects on neck pain, headache, and quality of sleep. Based
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on these findings, Persson concluded that neck support pillows must be carefully selected to meet
individual needs and is an important aspect of physiotherapy in patients with neck pain. 10 Unfortunately,
few of these previous studies employed a control group in the design and thus the positive finding
attributable to the various pillow interventions are suspect to threats to internal validity. The current
study employed a true control group and a cervical pillow group both of whom received the Funhab®
rehabilitation protocol.
Although both of these groups reported similar improvements in their sleep outcomes, the intervention
group reported decreases in snoring, while snoring appeared to increase in the control group.
Reductions in snoring attributable to using the Tri-Core® semi-customized orthopedic cervical pillow are
significant. Snoring is a common symptom of obstructive sleep apnea (OSA). 18,19 OSA has been
associated with a variety of significant health problems including the development of hypertension,
coronary artery disease, heart failure, stroke, diabetes and other metabolic disorders. 20, 21 OSA is a result
of obstructed airflow due to a collapsed pharynx which results in progressive asphyxia typically until the
person is awakened.19 Misalignment of the neck among WAD patients may contribute to OSA 22 A
possible benefit of using the Tri-Core® semi-customized orthopedic cervical pillow may be the correction
of misalignment of the neck among WAD patients, resulting in less snoring. Reishtein concluded in his
review of the area that effective treatment of OSA, indicated by a reduction in snoring, can reduce the
risk of these health problems.23 Thus, further study is indicated to determine if the reductions in snoring
realized among WAD patients through the use of the Tri-Core® semi-customized orthopedic cervical
pillow can reduce OSA and the comorbidities associated with this condition.
Limitations
The findings of this study must be interpreted cautiously due to a number of potential threats to internal
and external validity. The convenience sample likely did not represent all WAD patients, although
mandating a random sample of WAD patients participate in the study would be unethical. The sample
size was selected to detect a large effect size of the intervention and may not have been sufficient to
detect important changes in the outcomes that in fact did result from the intervention. Important
variables related to the subject’s sleep characteristics were not included in the protocol. These variables
included weight, body mass index, alcohol consumption, and use of stimulants or sleeping aids.
Knowledge of these variables may have provided insight into the combined effects of these factors and
sleep characteristics. Sleep characteristics including snoring were collected through subject’s using an
established self-report tool. This tool, although exhibiting validity in previous studies (reference 12)
does not measure objective sleep characteristics.
Conclusions
With these limitations in mind the findings of this study have implications for future research and clinical
practice. The results indicate that the Tri-Core® semi-customized orthopedic cervical pillow does not
have any deleterious effects on sleep outcomes and appears to reduce self-reports of snoring. WAD
patients who use this pillow in combination with the Funhab® rehabilitation protocol appear to improve
their sleep outcomes but not at a statistically significant level beyond a control condition. The increase
in sleep duration reported by the pillow group over the duration of the study (54 minutes), while not
statistically significant, may be clinically important for practitioners whose WAD patients are obtaining a
low duration of sleep. Future research may wish to examine other sleep characteristics which may be
associated with snoring as a result of WAD patients using the Tri-Core® pillow including qualitative
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remarks about restfulness and somnolence. Clinicians may wish to prescribe the Funhab® protocol with
the Tri-Core® pillow with patients (or their sleeping partners) with complaints of snoring.
Acknowledgments
This study was funded by the Sport and Spine Rehab Clinical Research Foundation (SSRCRF).
References
1. Berglund A, Alfredsson L, Jensen I, Cassidy D, Nygren A. The association between exposure to a rearend collision and future health complaints. J Clin Epidemiol 2001;54:851–856.
2. Spitzer WD, Skrovron ML, Salmi LR, et al. Scientific monograph of the Quebec Task Force on
Whiplash-Associated Disorders: redefining “whiplash” and its management. Spine 1995;20(suppl):1S73S.
3. Dehner C, Heym B, Maier D, Sander S, Arand M, Elbel M, Hartwig E, Kramer M. Postural control
deficit in acute QTF grade II whiplash injuries. Gait & Posture 2008;28(1):113-9.
4. Kristjansson E, Jónsson H Jr. Is the sagittal configuration of the cervical spine changed in women
with chronic whiplash syndrome? A comparative computer-assisted radiographic assessment. J
Manipulative Physiol Ther 2002; 25(9):550-5.
5. Schlesinger I., Hering-Hanit R., Dagan Y. Sleep disturbances after whiplash injury: Objective and
subjective findings. Headache 2001;41:586-589.
6. Braddom RL. Management of cervical pain syndromes. In DeLisa JA, Gans BM, eds. Rehabilitation
Medicine, 2nd ed. Philadelphia: Lippincott, 1993: 1036-1046.
7. Bernateck M, Karst M, Merkesdal S, Fischer MJ, Gutenbrunner C. Sustained effects of
comprehensive inpatient rehabilitative treatment and sleeping neck support in patients with chronic
cervicobrachialgia: a prospective and randomized clinical trial. Internat J Rehabi Res 2008;31(4):342-6.
8. Ambrogio N, Cuttiford J, Lineker S, Li L. A comparison of three types of neck support in fibromyalgia
patients. Arthritis Care Res 1998;11:405-410.
9. Hagino C, Boscariol J, Dover L, Letendre R, Wicks M. Before/after study to determine the
effectiveness of the align-right cylindrical cervical pillow in reducing chronic neck pain severity. J
Manipulative Physiol Ther 1998;21;89-93.
10. Persson L. Neck pain and pillows- A blinded study of the effect of pillows on non-specific neck pain,
headache and sleep. Adv Physiotherapy 2006;8:122-127.
11. Shields N, Capper J, Polak T, Taylor N. Are cervical pillows effective in reducing neck pain? New
Zealand J Physiotherapy 2006;34(1):3-9.
9|P age
TOPICS IN INTEGRATIVE HEALTH CARE [ISSN 2158-4222] – VOL 3(3)
September 30, 2012
12. Cohen, J. Statistical Power for the Behavioral Sciences. Hillsdale, N.J.: Lawrence Erlbaum Associates,
1977.
13. Allen RP, Kosinski M, Hill-Zabala CE, Calloway MO. Psychometric evaluation and tests of validity of
the Medical Outcomes Study 12-item Sleep Scale (MOS sleep). Sleep Med 2009;10(5): 531-9.
14. Rao V, Spiro J, Vaishnavi S, et al. Prevalence and types of sleep disturbances acutely after traumatic
brain injury. Brain Injury 2008; 22:381-386.
15. Lavin R, Pappagallo M, Kuhlemeier K. Cervical pain: a comparison of three pillows. Archives of
Physical Medicine and Rehabilitation 1997;78:193-198.
16. Gordon SJ, Grimmer-Somers K, Trott P. Pillow use: the behavior of cervical pain, sleep quality and
pillow comfort in side sleepers. Man Ther 2009;14(6):671-678.
17. Valenza MC, Valenza G, Gonzalez-Jimenez E, De-la-Llave-Rincon A, Arroyo-Morales M, Fernandezde-las-Penas C: Alteration in sleep quality in patients with mechanical insidious neck pain and whiplashassociated neck pain. Amer J Phys Med Rehabil 2012;9 (1), 1-8.
18. Lurie A. Obstructive sleep apnea in adults: epidemiology, clinical presentation, and treatment
options. Adv Cardiol 2011;46, 1-42.
19. Fava C, Montagnana M, Favaloro EJ, Guidi GC, Lippi G. Obstructive sleep apnea syndrome and
cardiovascular diseases. Sem Thrombosis and Hemostasis 2011;37(3), 280-297.
20. Lurie A. Cardiovascular disorders associated with obstructive sleep apnea. Adv Cardiol
2011;46:197-266.
21. Lurie A. Metabolic disorders associated with obstructive sleep apnea in adults. Adv Cardiol
2011;46:67-138.
22. Weigand L, Zwillich CW. Obstructive sleep apnea. Disease-a-month: DM 1994;40(4):197-252.
23. Reishtein JL. Obstructive sleep apnea: a risk factor for cardiovascular disease. J Cardiovascular
Nursing 2011;26(2): 106-116.
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