SLEEP CHARACTERISTICS IN PATIENTS WITH WHIPLASH-ASSOCIATED DISORDERS: A DESCRIPTIVE STUDY
 
   

Sleep Characteristics in Patients with
Whiplash-Associated Disorders:
A Descriptive Study

This section is compiled by Frank M. Painter, D.C.
Send all comments or additions to:
   Frankp@chiro.org
 
   

FROM:   Topics in Integrative Health Care 2012 (Dec 31);   3 (4)

Jay Greenstein, DC, CCSP, CGFI-L1, CKTP, FMS;
Barton Bishop, DPT, SCS, CKTI, TPI, CGFI-MP2, CSCS;
Jean Edward, RN, BSN; Allen Huffman, DC, CKTP, BS;
Danielle Davis; Robert Topp, RN, PhD


Study Objectives:   The purpose of this study was to explore sleep habits and characteristics of patients with whiplash-associated disorders (WAD) presenting at an outpatient, chiropractic clinic using the Medical Outcomes Study (MOS) Sleep Scale.

Methods:   Fifty-one patients from an outpatient chiropractic and physical therapy clinic specializing in spinal rehabilitation participated in this cross-sectional, descriptive study. Data were collected using a descriptive survey, the Visual Analog Scale (VAS), the Neck Disability Index (NDI), and the self-administered 12-item MOS Sleep Scale. Data analysis included descriptive statistics to describe pain, disability, and sleep characteristics of the study sample, and computation of confidence intervals to determine differences in means of sleep characteristics between the non-WAD population (as determined by previous studies) and the study sample of WAD patients.

Results:   Results indicate that when compared to normative values of the non-WAD population, the sample of WAD patients in this study presents with significantly greater measures of neck disability (NDI), neck pain (VAS), sleep disturbance, snoring, shortness of breath and headache, sleep somnolence and sleep problems index I and II. This sample also presents with significantly lower measures of optimal sleep when compared to the general population.

Conclusion:   Consistent with previous research, findings from this study indicate that WAD patients have increased neck disability and pain, and poorer sleep outcomes, indicating the need for clinicians to assess sleep characteristics and incorporate interventions aimed at alleviating these symptoms when planning rehabilitation. Findings provide evidence for the need to further explore sleep disturbances among WAD patients to establish a stronger understanding of the course and prognosis of this condition.


From the FULL TEXT Article:

Introduction

Neck pain related to whiplash-associated disorders (WAD) constitutes a significant health issue that leads patients to seek medical care in chiropractic and other physical therapy, rehabilitative clinics. Studies have indicated that individuals experience multiple clinical manifestations of WADs that lead to chronicity including postural changes, disability, headache, fatigue, and sleep disturbances. [1-4] Although studies have shown that sleep disturbances occur as a result of chronic pain, few studies have explored the relationship between patients with WAD and sleep quality. [4-6]

Sleep disturbances that commonly occur during the initial period following the whiplash injury include delayed sleep latency and poor sleep quality. [4] Symptoms such as neck pain and tension headaches related to WAD are known to worsen with extended periods of poor posture, such as during night-time sleeping, causing significant sleep disturbances. [7, 8] Alteration in sleep quality in patients with WAD also leads to poor prognosis and increased chronicity of the condition. In a prospective cohort study by Hendriks et al. factors related to poor recovery in patients with WAD included higher levels of somatization and sleep difficulties. [9] Additionally, in a comparative study exploring sleep quality in patients with mechanical insidious neck pain and whiplash-associated neck pain, Valenza et al. found that individuals experiencing the latter showed poorer sleep quality. [3] Results also indicated significant differences in sleep quality, sleep latency, sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction among WAD patients when compared to healthy controls. [3] Several studies have indicated that the use of neck support devices, such as cervical pillows for sleep, can lead to improved posture, reduce cervical pain, while consequently improving sleep quality and WAD outcomes. [10-13] Therefore, improving sleep quality through the use of supportive therapies may have an impact on alleviating WAD symptoms and improved prognosis of the condition. This provides evidence for the need for chiropractic management of chronic WAD symptoms, with an emphasis on addressing pain and sleep disturbances as part of the evaluation and treatment of patients with WAD neck pain. However, limited literature regarding the characteristics and quality of sleep among WAD patients in relation to chiropractic health and management of chronic WAD symptoms warrants the need for further research. [2-4] Therefore, the purpose of this cross-sectional, descriptive study was to explore sleep habits and characteristics of patients with WAD presenting at an outpatient, chiropractic clinic using the MOS Sleep Scale.


Methods

Sample

In this cross-sectional, descriptive study, a convenience sample consisting of 51 patients were recruited from an outpatient chiropractic and physical therapy clinic specializing in spinal rehabilitation. Prior to data collection, the study was explained to interested individuals by a member of the research staff, and informed consent was obtained. Inclusion criteria were involvement in a MVA at any period before inclusion; presentation to the clinic for treatment of injuries sustained from accident; diagnoses of cervical spine pain, with or without radiculopathy; and, ages between 18 to 65 years. Additionally, a diagnosis of WAD was established by clear causation between trauma associated from the MVA and subsequent cervical spine symptomatology based on history and examination of the research participants. Participants were included in the study only if their conditions were amenable to treatment with nonsurgical approaches during the initial stages of management. Exclusion criteria are diagnoses which were not deemed to be appropriate for conservative management by patient’s physician. This study was approved by the University of Louisville, Institutional Review Board (IRB#10.0199).

Data Collection

Several determinants and variables related to WAD and sleep outcomes were evaluated using a descriptive survey, the Visual Analog Scale (VAS), the Neck Disability Index (NDI), and the self-administered 12-item MOS Sleep Scale. After obtaining written informed consents, each research participant received these questionnaires that were completed at the outpatient clinic. The 0-10 VAS Pain Score is commonly used in clinical practice to identify pain severity and measured severity of neck pain in this study. [14] At each point in data collection, subjects responded to the question “On a scale of 1 to 10 how much neck pain are you experiencing right now, with 1 being ‘no pain’ and 10 being the ‘worst pain imaginable’?” The NDI measured how patients perceive their performance of activities of daily living. The NDI has been the gold standard for evaluating disability in patients with neck injuries. [15] Scores on the NDI range from 0 to 100 with higher numbers indicating greater disability.

The MOS Sleep Scale measured sleep quantity and quality, sleeping habits, and waking and daytime symptoms occurring during a four week period prior to completing the questionnaire. [16] The MOS-sleep questionnaire has been shown to be reliable and valid in evaluating various conditions causing sleep disturbances [17, 18] The MOS-sleep questionnaire was specifically used to measure shortness of breath, headaches, sleep somnolence, sleep problems, sleep disturbances, sleep adequacy, sleep duration, and snoring. [16] In addition, overall sleep problems were measured using two summary index measure scores: Sleep Problem Index I and Sleep Problem Index II.

Sleep Problem Index I provides a brief summation index of variables including awakening with shortness of breath or headache; trouble staying awake during the day; trouble falling asleep; awakening during sleep and having trouble falling back asleep; getting enough sleep to feel rested in the morning; and, getting the adequate amount of sleep needed.

Sleep Problem Index II represents a more comprehensive summation index that incorporates all items in Index I as well as: time taken to fall asleep; sleep not quiet; and, sleepiness or drowsiness during the day. Once each participant had completed the MOS-sleep questionnaire, all original numbers were calculated to obtain a percentage. All subscales and index measure were scored on a transformed 0-100 metric, with higher scores on these two indices indicating more sleep problems and poorer sleep quality. [19, 20]

Data Analysis

Data analysis to address the purpose was conducted in three phases. First, descriptive statistics (frequencies, means, standard deviations, correlations etc.) were calculated to describe the pain, disability and sleep characteristics of study sample with WAD (See Table 1). Second, confidence intervals were computed to determine if the mean of non-WAD population (derived from general population samples from previous studies) was within the 95% confidence interval. represented by the sample of WAD patients. This statistic compared the sample of WAD patients with non-WAD patients on measures of neck disability, pain and sleep characteristics (See Table 2). Finally, male and female WAD patients were compared on measures of disability, pain and sleep characteristics using independent t-tests (See Table 3). All inferential statistics employed p<.05 as the level of statistical significance.


Table 1.   Correlations with number of visits, days since onset, initial neck disability index and Pain (VAS)
 
Number of Visits
Days Since Onset of Symptoms
NDI
VAS for pain
Number of Visits
Pearson Correlation
1
.034
.253
-.112
p value (2-tailed)
 
.828
.102
.476
Age
Pearson Correlation
.014
-.269
.228
.046
p value (2-tailed)
.927
.056
.108
.749
Days Since Onset of Symptoms
Pearson Correlation
.034
1
-.156
-.198
p value (2-tailed)
.828
 
.275
.163
NDI
Pearson Correlation
.253
-.156
1
.239
p value (2-tailed)
.102
.275
 
.092
VAS
Pearson Correlation
-.112
-.198
.239
1
p value (2-tailed)
.476
.163
.092
 
MOS Sleep Scale Total
Pearson Correlation
.007
.200
.175
.200
p value (2-tailed)
.963
.159
.220
.159
Sleep Quantity (raw score)
Pearson Correlation
-.179
.163
-.128
.160
p value (2-tailed)
.251
.252
.372
.261
Optimal sleep (dichotomy)
Pearson Correlation
.021
.179
.086
.163
p value (2-tailed)
.891
.209
.550
.252
Sleep Disturbance
Pearson Correlation
-.037
.129
.070
.188
p value (2-tailed)
.813
.368
.626
.186
Snoring
Pearson Correlation
.204
-.160
.236
.072
p value (2-tailed)
.189
.262
.096
.617
Sleep Short of Breath or Headache
Pearson Correlation
-.031
.242
.257
.111
p value (2-tailed)
.844
.087
.069
.439
Sleep Adequacy
Pearson Correlation
.122
.173
.132
.004
p value (2-tailed)
.437
.224
.354
.978
Sleep Somnolence
Pearson Correlation
-.091
.219
.089
.179
p value (2-tailed)
.565
.126
.537
.214
Sleep Problems Index I
Pearson Correlation
.038
.257
.157
.106
p value (2-tailed)
.810
.068
.272
.457
Sleep Problems Index II
Pearson Correlation
-.014
.212
.164
.164
p value (2-tailed)
.928
.135
.251
.249



Table 2.   Comparing WAD with Non WAD individuals
 
 
N
Minimum
Maximum
Mean
Std. Deviation
 
Normal values
95%
Confidence
Interval
NDI (%)
51
18
74
43.92
12.20
6.981
40.52 – 47.32*
VAS for pain
51
4
10
7.76
1.41
0
7.36 – 8.15*
MOS Sleep Scale Total
51
2
82
48.63
17.77
45.96
43.68 – 53.58
Sleep Quantity (raw score)
51
2
10
5.63
1.73
6.933
5.15 – 6.11
Optimal Sleep (dichotomy)
51
0
1
.25
.44
.543
0.13 – 0.37*
Sleep Disturbance
51
.00
100
54.54
25.74
24.472
47.37 - 61.71*
Snoring
51
0
100
41.18
34.50
28.332
31.57 – 50.79*
Sleep Short of Breath or Headache
51
0
100
20.78
26.82
9.452
13.31 – 28.25*
Sleep Adequacy
51
0
100
67.25
25.85
60.472
60.05 – 74.45
Sleep Somnolence
50
.00
100
39.46
24.68
21.892
32.57 – 46.33*
Sleep Problems Index I
51
0
80
47.78
18.44
25.792
42.64 – 52.92*
Sleep Problems Index II
51
2.80
86.60
50.76
18.74
25.792
45.54 – 55.98*
Note:   1 Kato et al, 2012; 2 Hays, Martin, Sesti, Spritzer, 2005; 3 Spritzer & Hays, 2003.
  *Indicates the 95% CI does not include the mean of the general (non-WAD) population




Table 3.   Comparing male and female WAD patients

 
 
N
Mean
Std. Deviation
t-statistic
df
P<
Age
Female
30
40.53
12.204
1.358
49
.181
Male
21
35.71
12.846
 
 
 
MOS Sleep Scale Total
Female
30
52.15
15.284
1.725
49
.091
Male
21
43.60
20.140
 
 
 
Sleep Quantity (raw score)
Female
30
5.45
1.821
-.874
49
.386
Male
21
5.88
1.596
 
 
 
Optimal Sleep (dichotomy)
Female
30
.23
.430
-.415
49
.680
Male
21
.29
.463
 
 
 
Sleep Disturbance
Female
30
60.71
24.424
2.115
49
.040
Male
21
45.73
25.557
 
 
 
Snoring
Female
30
40.00
33.631
-.288
49
.774
Male
21
42.86
36.489
 
 
 
Sleep Short of Breath or Headache
Female
30
25.33
23.450
1.464
49
.150
Male
21
14.29
30.426
 
 
 
Sleep Adequacy
Female
30
68.67
25.152
.462
49
.646
Male
21
65.24
27.316
 
 
 
Sleep Somnolence
Female
29
43.67
23.201
1.434
48
.158
Male
21
33.64
26.029
 
 
 
Sleep Problems Index I
Female
30
52.13
16.672
2.075
49
.043
Male
21
41.58
19.458
 
 
 
Sleep Problems Index II
Female
30
55.63
16.474
2.316
49
.025
Male
21
43.79
19.935
 
 
 
Note: *p<.05



Results

The sample consisted of 51 patients (30 females and 21 males) seeking care at a chiropractic and rehabilitative clinic 6/29/2010 through 2/8/2011. All of these patients presented with an initial primary diagnosis of cervical segmental dysfunction and all but two subjects also presented to the clinic with a secondary related diagnosis, of which lumbar segmental dysfunction (59%, n=30) and thoracic segmental dysfunction (33%, n=17) were most frequently diagnosed. The sample had a mean age of 36.55 (+/-12.57), with the majority of the sample being female (58.8%, n=30). The average number of days since the onset of symptoms was 7.73 (6.75) days since the onset of symptoms. None of the sleep characteristics were correlated with number of visits to the clinic, days since onset of symptoms, neck disability or pain (Table 1). Table 2 indicates 95% confidence interval (CI) represented by the study sample and the mean value for these measures based upon the general non-WAD population. [21-23] When comparing the mean values from the general population it appears that the WAD population presents for treatment at the clinic with significantly greater measures of neck disability (NDI), neck pain (VAS), sleep disturbance, snoring, shortness of breath and headache, sleep somnolence and sleep problems index I and II (Table 2). The WAD population in this study also presents with significantly lower measures of optimal sleep when compared to the general population. However, the WAD population did not report different amounts of sleep adequacy than the general population. Finally, Table 3 indicates that the female WAD patients reported significantly higher sleep disturbance, sleep problems 1 and problems 2 than the male WAD patients.


Methods

The findings indicate that WAD patients present with several differences in neck disability and pain, and sleep quantity and quality when compared to the general, non-WAD population. No characteristics of sleep represented by the MOS Sleep Scale were related to the number of visits to the clinic, days since onset of symptoms, neck disability, or neck pain. Interestingly, it does not appear that the patients’ perceptions of disability or pain were related to their self-reported sleep characteristics. This may indicate that the WAD population in this study does not define their disability in terms of pain or poor sleep, but rather by another measure (such as ability to perform functional tasks) that was not examined in this study. The lack of a definitive symptom-associations experienced by WAD patients in this study population is consistent with the literature, which indicates that as a multifactorial condition, the course and prognosis of WAD are difficult to predict and treat. [24-25] Studies have indicated that improving sleep quality of WAD patients through supportive therapies, such as the use of cervical neck pillows, may contribute to alleviating WAD symptoms and improving overall prognosis of the condition. [10-13] However, there are limited findings on the direct impact of sleep quality on the prognosis of WAD due to the complexities in assessing the impact of individual WAD symptoms on the outcomes of the condition. Individuals have different experiences of WAD symptoms and outcomes, and consequently require a multifactorial approach to rehabilitative therapy and recovery. Therefore, continued research is warranted to explore how this population defines and perceives their disability, in relation to other factors, including pain and sleep.

Despite the lack of correlation between disability, pain, and sleep measures, the WAD population in this study reported greater neck disability and pain, sleep disturbances, snoring, shortness of breath and headache, sleep somnolence, and sleep problems, and poorer optimal sleep when compared to the general population. These findings are consistent with previous studies examining the complex nature of WAD symptoms. [2, 4, 26-28] In a study comparing fifty WAD patients and fifty healthy, age- and sex-matched controls, Haggman-Henrikson, Grongvist, and Eriksson found that in comparison to the healthy controls, the majority of WAD patients reported frequent pain in the jaw-face, neck, shoulders, head, and back, along with symptoms such as such stress and sleep disturbances. [27] Similarly, Berglund et al. found a higher prevalence of symptoms such as headaches, thoracic and lower back pain, fatigue, ill health, and sleep disturbances among WAD patients when compared to the general population. [2] Although current study findings did not indicate strong correlations between sleep and other WAD symptoms, Schlesinger, Hering-Hanit, and Dagan, found a significant correlation between sleep disturbances, physical whiplash injury symptoms, and anxiety. [4] However, the relationship between sleep and WAD symptoms is poorly understood, warranting the need for further research. According to Radanov, Mannion and Ballinari “sleep disturbance is the result of pain, which is a consequence of the trauma, and this may explain the development of comparable symptoms in pain conditions of different origin.” [28] (p.656) This statement is particularly significant to the findings of the current study and provides evidence for the need to further explore sleep disturbances among WAD patients to establish a stronger understanding of the course and prognosis of this condition.

There is a dearth of research on the progression of disability in patients with WAD, making it challenging for clinicians to develop appropriate rehabilitative interventions and programs to minimize symptoms such as disability, pain and poor sleep, and improve quality of life of WAD patients. [29] Despite extensive research on the pathophysiology of WAD, understanding of prognostic factors that contribute to the progression of WAD symptoms remains unclear. [24-25, 30-31] Furthermore, the lack of studies examining sleep quality and other characteristics among WAD patients in relation to chiropractic health and management of chronic WAD symptoms warrants the need for further research. [2-4, 26] Findings from this study contribute to this gap by providing an understanding of the prognostic factors of disability, pain, and sleep in a sample of WAD patients in comparison to the general population.

Limitations

The purpose of this study was to explore sleep habits and characteristics of patients with WAD presenting at an outpatient clinic. This description included comparing sleep habits of WAD patients with population values from non-WAD patients. This methodology is susceptible to a number of threats to internal and external validity. The limited sample accessed from a single clinic may not represent all WAD patients. Since data were collected only once there was no way to determine if sleep characteristics changed as a result of therapy or if improvements in pain and disability were related to changes in sleep characteristics resulting from therapy. Further, non-WAD patients were not measured in this study and employing estimates of population pain, disability and sleep parameters based upon past studies and this approach may not yield an accurate description of these parameters for various subgroups of non-WAD patients. These limitations may be addressed in future studies to further validate the sleep habits and characteristics of WAD patients. Although beyond the scope of this study future studies may also wish to examine the impact of sleep characteristics on healing or rates of recovery among WAD patients.


Conclusion

Although findings from this study indicate that WAD patients have significantly greater problems with neck disability, pain and sleep compared to the general population, it is important to acknowledge that the WAD population is heterogenous, including patients with varying levels of disability, pain, beliefs, and social backgrounds. [32] Therefore, assessing patients’ needs on an individual basis and tailoring rehabilitation programs according to individual needs is essential in creating a successful intervention aimed at determining prognosis of WAD and improving outcomes. Clinicians can utilize these findings to improve rehabilitative interventions for WAD patients that involve a thorough assessment of individual factors and characteristics.

Findings from this study indicate that WAD patients have poor sleep outcomes, indicating the need for clinicians to assess sleep characteristics and incorporate interventions aimed at alleviating these symptoms when planning rehabilitation. Evaluating current therapies and interventions based on these findings may help identify innovative, multifactorial methods to alleviate both sleep disturbances and pain among WAD patients. [27-28] In order to provide a better understanding of the relationship between sleep, WAD symptoms, prognosis, and outcomes, it is recommended that future studies focus on measuring sleep characteristics of WAD patients as an integral prognostic factor. Continued research in understanding sleep disturbances in relation to disabilities and pain among WAD patients enhances clinician knowledge and development of rehabilitative interventions aimed at alleviating symptoms and improving overall quality of life.


Acknowledgments This study was funded by the Sport and Spine Rehab Clinical Research Foundation (SSRCRF).


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