Whiplash-associated Disorders Group Research Articles

Neck muscle function improves after neck exercises in individuals with whiplash-associated disorders: a case–control ultrasound study with speckle-tracking analyses

A whiplash injury can alter neck muscle function, which remains years after the injury and may explain why symptoms such as persistent pain and disability occur. There is currently limited knowledge about dynamic neck muscle function in chronic whiplash-associated disorders (WAD), and about the extent to which altered muscle function can improve after rehabilitation. Ultrasound can detect mechanical neck muscle function by measuring real-time deformation and deformation rate in the muscles. This method was used for five dorsal neck muscles in participants with chronic WAD versus matched controls in resistant neck rotation. We obtained real-time, non-invasive ultrasound measurements using speckle tracking, multivariate analyses, and mixed-design ANOVA analyses. The results showed altered deformation in the three deepest neck muscle layers, with less deformation area in the WAD group compared to controls in rotation to the most painful side at baseline. Participants in the WAD group performed three months of neck-specific exercises, resulting in improved deformation in the deep neck muscles in WAD and with a similar deformation pattern to controls, and the significant group differences ceased. We reveal new and important insights into the capability of ultrasound to diagnose altered neck muscle function and evaluate an exercise intervention.

Results of neck-specific exercise for altered postural sway in individuals with chronic whiplash-associated disorders: a longitudinal case–control study

Postural sway has not been investigated before or after a neck exercise intervention in individuals with chronic whiplash-associated disorders (WAD). The aim of the study was to investigate postural sway in individuals with chronic WAD grades 2 and 3: (a) compared with healthy matched controls at baseline; (b) after three months of neck-specific exercise and (c) to investigate the correlation between postural sway with self-reported dizziness during motion and balance problems/unsteadiness. This is a longitudinal prospective experimental case–control intervention study. Individuals with WAD (n = 30) and age- and gender-matched healthy volunteers (n = 30) participated. Postural sway was assessed using an iPhone application. Measurements were carried out at baseline, and for those with WAD a second measurement was performed at the three-month follow-up when neck-specific exercise intervention ended. The WAD group performed significantly worse than the healthy group in both pathway and ellipse area double stance eyes closed at baseline (main outcome), but not at the three-month follow-up. The WAD group significantly improved after rehabilitation in both pathway double stance eyes closed and pathway single stance eyes open. The correlation between postural sway and self-rated dizziness during motion and balance problems was low to moderate. One may conclude that postural sway was improved after a neck-specific exercise programme. The study results strengthen earlier findings that individuals with WAD have worse balance outcome when they have to rely on neck proprioception (eyes closed). The study results may be important for the development of improved rehabilitation methods for WAD.

The effect of a neck-specific exercise program on cervical kinesthesia for patients with chronic whiplash-associated disorders: a case-control study

IntroductionCervical kinesthesia is an important part of movement control and of great importance for daily function. Previous research on kinesthesia in whiplash-associated disorders (WAD) has focused on grades I-II. More research is needed on WAD grade III. The aim of this study was to investigate cervical kinesthesia in individuals with WAD grades II-III before and after a neck-specific exercise intervention and compare them to healthy controls.MethodsA prospective, case-control study with a treatment arm (n = 30) and a healthy control arm (n = 30) was conducted in Sweden. The WAD group received a neck-specific exercise program for 12 weeks. The primary outcome to evaluate kinesthesia was neck movement control (the Fly test). Secondary outcomes were neck disability, dizziness and neck pain intensity before and after the Fly test. Outcomes were measured at baseline and post-treatment. The control arm underwent measurements at baseline except for the dizziness questionnaire. A linear mixed model was used to evaluate difference between groups (WAD and control) and over time, with difficulty level in the Fly test and gender as factors.ResultsBetween-group analysis showed statistically significant differences in three out of five kinesthetic metrics (p = 0.002 to 0.008), but not for the WAD-group follow-up versus healthy control baseline measurements. Results showed significant improvements for the WAD-group over time for three out of five kinaesthesia metrics (p < 0.001 to 0.008) and for neck disability (p < 0.001) and pain (p = 0.005), but not for dizziness (p = 0.70).ConclusionsThe exercise program shows promising results in improving kinesthesia and reducing neck pain and disability in the chronic WAD phase. Future research might benefit from focusing on adding kinesthetic exercises to the exercise protocol and evaluating its beneficial effects on dizziness or further improvement in kinesthesia.Impact statementKinesthesia can be improved in chronic WAD patients without the use of specific kinesthetic exercises.Trial registrationClinicalTrials.gov (NCT03664934), first registration approved 11/09/2018.

Demonstration of transverse ligament on 3D SPACE MRI in whiplash-associated disorder and nontraumatic conditions.

This study aims to delineate the three-dimensional (3D) SPACE MRI findings of the transverse ligament (TL) in whiplash-associated disorder (WAD) patients, and to compare them with those from a nontraumatic group. A retrospective analysis was performed on cervical spine MRI scans obtained from 46 patients with WAD and 62 nontraumatic individuals. Clinical features, including the WAD grade and stage, were recorded. The TL's morphological grade and the symmetricity of the lateral atlantodental interval was assessed using axial 3D T2-SPACE images. The morphological grading was evaluated using a four-point scale: 0 = homogeneously low signal intensity with normal thickness, 1 = high signal intensity with normal thickness, 2 = reduced thickness, 3 = full-thickness rupture or indistinguishable from surrounding structures. Additionally, the number of cervical levels exhibiting degeneration was documented. When comparing the WAD and nontraumatic groups, a significant difference was observed in the proportion of high-grade TL changes (grade 2 or 3) and the number of degenerated cervical levels. Logistic regression analysis revealed that high-grade TL changes and a lower number of degenerative levels independently predicted the presence of WAD. Within the WAD group, the subset of patients with high-grade TL changes demonstrated a significantly higher mean age than the low-grade group (grade 0 or 1). High-grade morphological changes in the TL can be detected in patients with WAD through the use of 3D SPACE sequences. Clinical relevance statement 3D SPACE MRI could serve as an instrumental tool in the assessment of TL among patients with WAD. Integrating MRI findings with patient history and symptomology could facilitate the identification of potential ligament damage, and may help treatment and follow-up planning.

The effects of physical exercise on structural, functional, and biochemical brain characteristics in individuals with chronic whiplash-associated disorder: A pilot randomized clinical trial.

Exercise for people with whiplash associated disorder (WAD) induces hypoalgesic effects in some, but hyperalgesic effects in others. We investigated the exercise-induced neurobiological effects of aerobic and strengthening exercise in individuals with chronic WAD. Sixteen participants (8 WAD, 8 pain-free [CON]) were randomised to either aerobic or strengthening exercise. MRI for brain morphometry, functional MRI for brain connectivity, and magnetic resonance spectroscopy for brain biochemistry, were used at baseline and after the 8-week intervention. There were no differences in brain changes between exercise groups in either the WAD or CON group, therefore aerobic and strengthening data were combined to optimise sample size. After the exercise intervention, the CON group demonstrated increased cortical thickness (left parahippocampus: mean difference = 0.04, 95% CI = 0.07-0.00, p = 0.032; and left lateral orbital frontal cortex: mean difference = 0.03, 95% CI = 0.00-0.06, p = 0.048). The WAD group demonstrated an increase in prefrontal cortex (right medial orbital frontal) volume (mean difference = 95.57, 95% CI = 2.30-192.84, p = 0.046). Functional changes from baseline to follow-up between the default mode network and the insula, cingulate cortex, temporal lobe, and somatosensory and motor cortices, were found in the CON group, but not in the WAD group. There were no changes post-exercise in brain biochemistry. Aerobic and strengthening exercises did not exert differential effects on brain characteristics, however differences in structural and functional changes were found between WAD and CON groups. This suggests that an altered central pain modulatory response may be responsible for differential effects of exercise in individuals with chronic WAD.

Associations Between Resting Heart Rate, Resting Blood Pressure, Psychological Variables and Pain Processing in Chronic Whiplash-Associated Disorder: A Cross-Sectional Study.

Autonomic nervous system dysfunction has been implicated in chronic whiplash-associated disorder (WAD). However, the relationship between autonomic variables (e.g., resting heart rate and blood pressure) and clinical factors in chronic WAD is not well understood. This study sought to examine the associations between resting heart rate, resting blood pressure, pain processing and psychological variables in chronic WAD and in pain-free controls. Secondary analysis of a cross-sectional study. University clinical research laboratory. Thirty-six people with chronic WAD Grade II (mean [SD] age 40.1 [14.6] years, 28 females) and 25 pain-free controls (35.6 [13.0] years, 17 females). Participants had resting heart rate, systolic and diastolic blood pressure measured. Pain processing measures comprised: (i) pain pressure threshold at the cervical spine, hand and leg, (ii) temporal summation at the cervical spine and hand, and (iii) conditioned pain modulation. Psychological outcomes included measures of kinesiophobia, pain catastrophizing and post-traumatic stress symptoms. Correlations between autonomic variables, pain processing and psychological variables were determined (P &lt; .05, 5% FDR). No significant correlations between autonomic and pain processing variables, or autonomic and psychological variables were found in the chronic WAD group. In the control group, diastolic blood pressure was positively correlated with cervical spine pressure pain threshold (r = 0.53, P = .007). An association between blood pressure and pain sensitivity was observed in the control group but not the chronic WAD group. Such an association appears to be disrupted in chronic WAD, which may infer involvement of autonomic pathways in the pathophysiology of this condition.

Changes in Pain Sensitivity and Conditioned Pain Modulation During Recovery From Whiplash-associated Disorders.

The objective of this study was to investigate the pain-sensory profile of patients with whiplash-associated disorders (WADs) prior and post 2 weeks of standardized rehabilitation and after a 6-month follow-up. Twenty-two WAD participants (grade II; 14 women) and 22 sex-matched and age-matched healthy pain-free controls were enrolled. Pressure pain thresholds (PPTs) were assessed at local and distal muscles. Conditioned pain modulation (CPM) of PPTs was assessed using cuff pressure around the upper arm. Referred area of pain following supra-threshold pressure stimulation of the infraspinatus muscle was recorded on a body chart. Psychometric variables (pain intensity, area of perceived pain, pain catastrophizing, kinesiophobia, sleep problems, and depression level) were assessed. WAD group additionally completed the Neck Disability Index. The WAD group demonstrated lower local PPTs compared with controls at all time points (P<0.05) and lower distal PPTs at baseline and at 2 weeks when compared with 6 months (within-group) (P<0.05). The WAD group had a reduced CPM response and larger induced referred pain areas compared with controls (P<0.05), while no within-group changes were observed at any time point. The WAD group reported higher pain intensity and perceived area of pain compared with controls at all time points (P<0.05) and a mean Neck Disability Index score of 41% at baseline, 16% at 2 weeks, and 4% at 6 months. Furthermore, the WAD group reported improvements in all other psychometric variables (P<0.05), although only pain catastrophizing levels were comparable to controls at 2 weeks. PPTs but not CPM improved in the WAD group and were comparable to controls following 2 weeks following standardized rehabilitation, indicating that normalization of CPM may not be required to recover from WAD.

Magnetic Resonance Spectroscopy Assessment of Brain Metabolite Concentrations in Individuals With Chronic Whiplash-associated Disorder: A Cross-sectional Study.

Pathophysiologic mechanisms underpinning ongoing pain in whiplash-associated disorder (WAD) are not well understood, however, alterations in brain morphology and function have been observed in this population and in other chronic pain conditions. This study investigated metabolite profiles of brain regions in people with chronic WAD compared with controls. Thirty-eight individuals with chronic WAD (mean [SD] age, 39.5 [11.3] years, 23 female individuals) and 16 pain-free controls (38.9 [12.7] years, 11 female individuals) underwent multivoxel brain magnetic resonance spectroscopy. At the anterior cingulate cortex (ACC), primary motor cortex (1MC), and somatosensory cortex (SSC), ratios of metabolite concentrations were calculated for N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myo-inositol (Ins), and glutamate/glutamine (Glx). Chronic WAD group participants completed clinical questionnaires and cold and pressure pain threshold assessment. Data were analyzed with hypothesis testing and Spearman correlations (P≥0.05), with Benjamini-Hochberg corrections (5% false discovery rate). No group differences were observed for NAA:Cr, NAA:Cho, Cr:Cho, Glx:NAA, Glx:Cr, Glx:Cho, Ins:NAA, Ins:Cr, Ins:Cho or Ins:Glx for left or right ACC, 1MC, or SSC following correction for multiple comparisons. No significant correlations were observed between metabolite ratios and any clinical variable. These results suggest that ongoing pain and disability in this population may not be underpinned by metabolite aberrations in the brain regions examined. Further research is required to progress our understanding of cortical contributions to neurophysiologic mechanisms in chronic WAD.

Exercise-induced Hypoalgesia Is Impaired in Chronic Whiplash-associated Disorders (WAD) With Both Aerobic and Isometric Exercise.

Exercise-induced hypoalgesia (EIH) can be impaired in patients with chronic pain and may be dependent on exercise type. Factors predictive of EIH are not known. This study aimed to: (1) compare EIH in participants with chronic whiplash-associated disorders (WAD) to asymptomatic controls, (2) determine if EIH differs between aerobic and isometric exercise, (3) determine predictors of EIH. A pre-post study investigated the effect of single sessions of submaximal aerobic treadmill walking and isometric knee extension on EIH in 40 participants with chronic WAD and 30 controls. Pressure pain thresholds were measured at the hand, cervical spine, and tibialis anterior. Pain intensity, reported previous week physical activity, temporal summation, and conditioned pain modulation (CPM) were measured at baseline. Participants with WAD demonstrated impaired EIH. Although, the WAD participants demonstrated a partial EIH response (EIH induced at the hand during exercise), no EIH response was found immediately after exercise. There was no difference in EIH between exercise types. In the WAD group, moderate physical activity levels predicted EIH at the hand and high physical activity levels predicted impaired EIH at the neck. More efficient CPM predicted EIH at the hand and less efficient CPM predicted impaired EIH at the neck. These associations were found for isometric exercise only. Individuals with chronic WAD have impaired EIH with both aerobic and isometric exercise. Higher levels of physical activity and less efficient CPM may be associated with impaired EIH. This may have implications for exercise prescription in this patient group.

Small fibre pathology in chronic whiplash‐associated disorder: A cross‐sectional study

Mechanisms underpinning ongoing symptoms in chronic whiplash associated-disorder (WAD) are not well understood. People with chronic WAD can exhibit sensory dysfunction consistent with small nerve fibre pathology, including thermal hypoaesthesia and hyperalgesia. This study investigated small fibre structure and function in chronic WAD. Twenty-four people with chronic WAD (median [IQR] age 49 [15]years, 16 females) and 24 pain-free controls (50 [17]years, 16 females) were recruited. Intraepidermal nerve fibre density (IENFD) and dermal innervation were assessed by skin biopsy. This was performed at (a) the lateral index finger on the primary side of pain and (b) superior to the lateral malleolus on the contralateral side. Quantitative sensory testing was performed over the hand. The WAD group exhibited lower IENFD at the finger (WAD: median [IQR] 4.5 [4.9]fibres/mm; control 7.3 [3.9]; p=.010), but not the ankle (WAD: mean [SD] 7.3 [3.7]fibres/mm; control 9.3 [3.8]; p=.09). Dermal innervation was lower in the WAD group at the finger (WAD: median [IQR] 3.7 [2.8] nerve bundles/mm2 ; controls: 4.9 [2.1]; p=.017) but not the ankle (WAD: median [IQR] 2.1 [1.9] nerve bundles/mm2 ; controls: 1.8 [1.8]; p=.70). In the WAD group, hand thermal and light touch detection were impaired, and heat pain thresholds were lowered (p≤.037). Findings suggest small fibre structural and functional deficits in chronic WAD, implicating potential involvement of small fibre pathology. Our study found decreased intraepidermal nerve fibre density, reduced dermal innervation, thermal hypoaesthesia and hypersensitivity in people with chronic WAD, suggestive of small fibre pathology. This observation of peripheral nervous system pathology in chronic whiplash provides novel insights on mechanisms underpinning symptoms and challenges commonly held beliefs regarding this condition.

Intramuscular fat is present in cervical multifidus but not soleus in patients with chronic whiplash associated disorders.

The presence of intramuscular fat (IMF) in the cervical spine muscles of patients with whiplash associated disorders (WAD) has been consistently found. The mechanisms underlying IMF are not clear but preliminary evidence implicates a relationship with stress system responses. We hypothesised that if systemic stress system responses do play a role then IMF would be present in muscles remote to the cervical spine. We aimed to investigate if IMF are present in muscle tissue remote (soleus) to the cervical spine in people with chronic WAD. A secondary aim was to investigate associations between IMF and posttraumatic stress symptom levels. Forty-three people with chronic WAD (25 female) and 16 asymptomatic control participants (11 female) participated. Measures of pain, disability and posttraumatic stress symptoms were collected from the WAD participants. Both groups underwent MRI measures of IMF in cervical multifidus and the right soleus muscle. There was significantly greater IMF in cervical multifidus in patients with WAD and moderate/severe disability compared to controls (p = 0.009). There was no difference in multifidus IMF between the mild and moderate/severe disability WAD groups (p = 0.64), or the control and mild WAD groups (p = 0.21). IMF in the right soleus was not different between the groups (p = 0.47). In the WAD group, we found no correlation between PDS symptoms and cervical multifidus IMF or between PDS symptoms and soleus IMF. Global differences in IMF are not a feature of chronic WAD, with differences in IMF limited to the cervical spine musculature. While the mechanisms for the development of IMF in the cervical spine following whiplash injury remain unclear, our data indicate that local factors more likely contribute to these differences.

The Discrepancy between Subjective and Objective Measures of Convergence Insufficiency in Whiplash-Associated Disorder versus Control Participants

Motor vehicle accidents (MVAs) are a pandemic associated with human suffering and a burden to national economies. Whiplash-associated disorders (WADs) after MVAs are associated commonly with disability claims, many of which are related to vision. Convergence insufficiency (CI) leads to visual disability associated with symptoms of ocular discomfort. We examined the incidence of symptoms and findings consistent with CI in a cohort of patients after MVA-related WAD compared with age-matched control participants. Prospective cohort study. Patients with WAD after MVA were recruited from the Orthopedic Emergency Department between July 2014 and March 2017. Control participants were recruited among hospital personnel and relatives of WAD patients. The Convergence Insufficiency Symptom Survey (CISS) questionnaire was completed by each participant, followed by a detailed visual examination including measurements of distance and near best-corrected Snellen visual acuity, distance and near cover test, Randot stereopsis, Maddox distance and Maddox-Thorington near heterophoria, near point of convergence, base-out step fusional reserves, and amplitude of accommodation using the push-away method. The CISS score and binocular measure findings of CI were recorded and analyzed using Student's t test, the chi-square test, and multiple logistic regression adjusted for age and gender. A pathologic CISS score of 16 or more occurred in 26 of 57 WAD patients (45.6%) compared with 6 of 39 control participants (15.4%; P= 0.002). Absolute CISS score was higher in the WAD group compared with the control group (15.3±10.0 vs. 7.7±7.7; P < 0.001). Findings consistent with CI occurred in 7.0% of WAD patients and 7.7% of control participants (P= 0.90). Visual symptoms suggestive of CI were reported more frequently among WAD patients compared with control participants, yet the incidence of examination findings indicating weakness of convergence was not increased. The discrepancy between subjective and objective measures of CI in WAD patients versus control participants stresses the importance of training healthcare personnel to assess disability using objective, validated standards of examination.

Lack of Gender and Age Differences in Pain Measurements Following Exercise in People with Chronic Whiplash-Associated Disorders

Background: Individuals with chronic whiplash associated disorders (WAD) present persistent pain in the absence of structural pathology. In these people, altered central pain processing and central sensitization are observed. The role of personal factors, such as gender and age, on pain processing mechanisms in chronic WAD, however, is still unclear. Objectives: This study investigated possible gender- and age-related differences in selfreported and experimental pain measurements in people with chronic WAD. Besides the exercise-induced response on pain measurements between gender and age subgroups was recorded. Study Design: Case-control study. Setting: University Hospital, Brussels. Methods: Self-reported pain and experimental pain measurements (pressure pain thresholds [PPT], occlusion cuff pressure, temporal summation, and conditioned pain modulation) were performed in 52 individuals (26 chronic WAD patients and 26 healthy controls), before and after a submaximal cycle exercise. Results: Lower PPTs and occlusion cuff pressures were shown in chronic WAD in comparison with healthy controls. No gender and age differences regarding PPTs, occlusion cuff pressures and conditioned pain modulation were found in chronic WAD. Within the chronic WAD group, men showed higher self-reported pain compared to women and younger adults showed enhanced generalized pain facilitation compared to older adults. In addition, chronic WAD patients are able to inhibit exercise-induced hyperalgesia, but no gender and age differences in pain response following exercise were found. Limitations: This study was sufficiently powered to detect differences between the chronic WAD and control group. However, a sufficient power was not reached when patients were divided in age and gender groups. Furthermore, only mechanical stimuli were included in the experimental pain measurements. Besides, psychosocial factors were not taken into account. Conclusion: Some alterations of altered pain processing are present in chronic WAD patients, however not in response to exercise. No gender and age differences in pain measurements were observed in people with chronic WAD.

The qualitative grading of muscle fat infiltration in whiplash using fat and water magnetic resonance imaging

Background contextThe development of muscle fat infiltration (MFI) in the neck muscles is associated with poor functional recovery following whiplash injury. Custom software and time-consuming manual segmentation of magnetic resonance imaging (MRI) is required for quantitative analysis and presents as a barrier for clinical translation. PurposeThe purpose of this work was to establish a qualitative MRI measure for MFI and evaluate its ability to differentiate between individuals with severe whiplash-associated disorder (WAD), mild or moderate WAD, and healthy controls. Study Design/SettingThis is a cross-sectional study. Patient SampleThirty-one subjects with WAD and 31 age- and sex-matched controls were recruited from an ongoing randomized controlled trial. Outcome MeasuresThe cervical multifidus was visually identified and segmented into eighths in the axial fat/water images (C4–C7). Muscle fat infiltration was assessed on a visual scale: 0 for no or marginal MFI, 1 for light MFI, and 2 for distinct MFI. The participants with WAD were divided in two groups: mild or moderate and severe based on Neck Disability Index % scores. MethodsThe mean regional MFI was compared between the healthy controls and each of the WAD groups using the Mann-Whitney U test. Receiver operator characteristic (ROC) analyses were carried out to evaluate the validity of the qualitative method. ResultsTwenty (65%) patients had mild or moderate disability and 11 (35%) were considered severe. Inter- and intra-rater reliability was excellent when grading was averaged by level or when frequency of grade II was considered. Statistically significant differences (p<.05) in regional MFI were particularly notable between the severe WAD group and healthy controls. The ROC curve, based on detection of distinct MFI, showed an area-under-the curve of 0.768 (95% confidence interval 0.59–0.94) for discrimination of WAD participants. ConclusionsThese preliminary results suggest a qualitative MRI measure for MFI is reliable and valid, and may prove useful toward the classification of WAD in radiology practice.

The Effect of Visual Feedback of the Neck During Movement in People With Chronic Whiplash-Associated Disorders: An Experimental Study.

Study Design Controlled laboratory study. Background Chronic whiplash-associated disorder (WAD) is an important health issue associated with poor recovery outcomes. Sensorimotor incongruence (SMI), defined as a mismatch between the efference copy in the brain and afferent sensory feedback from the body, is proposed as a possible underlying cause of chronic pain. Objectives To determine whether SMI causes sensory disturbances or pain in people with chronic WAD and healthy controls. Methods Sixty-four participants (30 with chronic WAD and 34 healthy controls) participated in a visual feedback experiment involving the neck and a bimanual coordination experiment involving the arms. In both experimental setups, SMI was induced by modifying the visual feedback during movement. Sensory disturbances and pain were the primary outcomes. Results A statistically significant difference in perceived sensory disturbance between conditions was found in the WAD group (P<.001). Intensity scores were highest for induced SMI, but only for visual feedback of the neck and not for visual feedback of the arms. This effect was not present in the control group (P = .139). Sensorimotor incongruence did not affect pain in either group. Conclusion Persons with chronic WAD are more susceptible to sensory disturbances owing to SMI, and this effect is specific to the region affected by pain. The hypothesis that SMI causes pain was not substantiated by the results of the present study. J Orthop Sports Phys Ther 2017;47(3):190-199. Epub 3 Feb 2017. doi:10.2519/jospt.2017.6891.

Morphology of Cervical Spine Meniscoids in Individuals With Chronic Whiplash-Associated Disorder: A Case-Control Study.

Study Design Case-control study. Background Cervical spine meniscoids are thought to contribute to neck pain and hypomobility in individuals with chronic whiplash-associated disorder (WAD); however, their morphology has not been studied in a clinical population. Objectives To investigate cervical spine meniscoid morphology in individuals with chronic WAD. Methods Twenty volunteers with chronic WAD (mean ± SD age, 39.3 ± 11.0 years; 10 female) and 20 age- and sex-matched controls (age, 39.1 ± 10.6 years) underwent cervical spine magnetic resonance imaging. Lateral atlantoaxial and zygapophyseal joints (C2-3 to C6-7) were inspected for meniscoids. Length of meniscoid protrusion was measured and composition (adipose/fibrous/fibroadipose) assessed. Data were analyzed using Wilcoxon signed-rank tests and linear and logistic regression (P<.05). Results Meniscoids were identified in the chronic WAD (n = 317) and control (n = 296) groups. At the lateral atlantoaxial joints, median meniscoid length was greater in the control group (ventral, 6.07 mm; dorsal, 7.24 mm) than the WAD group (ventral, 5.01 mm; P = .06 and dorsal, 6.48 mm; P<.01). At the dorsal aspect of zygapophyseal joints, meniscoids were more frequently fibrous in the chronic WAD group (odds ratio = 2.38, P<.01; likelihood ratio test: χ22, 9.02; P = .01). Conclusion In individuals with chronic WAD, lateral atlantoaxial meniscoids were shorter and dorsal cervical zygapophyseal meniscoids were more fibrous, suggesting alterations in meniscoid composition. This may have pathoanatomical implications in chronic WAD. J Orthop Sports Phys Ther 2016;46(10):902-910. Epub 3 Sep 2016. doi:10.2519/jospt.2016.6702.

Changes in Dorsal Neck Muscle Function in Individuals with Chronic Whiplash-Associated Disorders: A Real-Time Ultrasound Case–Control Study

Impaired neck muscle function leads to disability in individuals with chronic whiplash-associated disorder (WAD), but diagnostic tools are lacking. In this study, deformations and deformation rates were investigated in five dorsal neck muscles during 10 arm elevations by ultrasonography with speckle tracking analyses. Forty individuals with chronic WAD (28 women and 12 men, mean age = 37 y) and 40 healthy controls matched for age and sex were included. The WAD group had higher deformation rates in the multifidus muscle during the first (p < 0.04) and 10th (only women, p < 0.01) arm elevations compared with the control group. Linear relationships between the neck muscles for deformation rate (controls: R2 = 0.24–0.82, WAD: R2 = 0.05–0.74) and deformation of the deepest muscles (controls: R2 = 0.61–0.32, WAD: R2 = 0.15–0.01) were stronger for women in the control group versus women with WAD, indicating there is altered interplay between dorsal neck muscles in chronic WAD.

Potential associations between chronic whiplash and incomplete spinal cord injury.

This research utilized a cross-sectional design with control group inclusion. Preliminary evidence suggests that a portion of the patient population with chronic whiplash may have sustained spinal cord damage. Our hypothesis is that in some cases of chronic whiplash-associated disorders (WAD), observed muscle weakness in the legs will be associated with local signs of a partial spinal cord injury of the cervical spine. University based laboratory in Chicago, IL, USA. Five participants with chronic WAD were compared with five gender/age/height/weight/body mass index (BMI) control participants. For a secondary investigation, the chronic WAD group was compared with five unmatched participants with motor incomplete spinal cord injury (iSCI). Spinal cord motor tract integrity was assessed using magnetization transfer imaging. Muscle fat infiltration (MFI) was quantified using fat/water separation magnetic resonance imaging. Central volitional muscle activation of the plantarflexors was assessed using a burst superimposition technique. We found reduced spinal cord motor tract integrity, increased MFI of the neck and lower extremity muscles and significantly impaired voluntary plantarflexor muscle activation in five participants with chronic WAD. The lower extremity structural changes and volitional weakness in chronic WAD were comparable to participants with iSCI. The results support the position that a subset of the chronic whiplash population may have sustained partial damage to the spinal cord. NIH R01HD079076-01A1, NIH T32 HD057845 and the Foundation for Physical Therapy Promotion of Doctoral Studies program.

Mechanical properties of the trapezius during scapular elevation in people with chronic whiplash associated disorders – A case-control ultrasound speckle tracking analysis

BackgroundApproximately 50% of people with Whiplash Associated Disorders (WAD) report longstanding symptoms. The upper trapezius is commonly painful yet its mechanical properties are not fully understood. ObjectivesThis study examined the deformation of different depths of the upper trapezius muscle during a scapular elevation task (shoulder shrugging) before and following loaded arm abduction. Design and MethodsA cross-sectional case-control study of 36 people (26 female and 10 male, mean age 38 (SD 11)) with chronic WAD and 36 controls, matched for age and gender. Real-time ultrasound recordings of upper trapezius were taken during both scapular elevation tasks. Post-process speckle tracking analysis was undertaken of three different sections of the upper trapezius muscle (superficial, middle, deep). ResultsThe WAD group had lower deformation of the superficial section of the upper trapezius compared to the control group in both concentric and eccentric phases of scapular elevation (p < 0.05) especially before the loaded arm abduction. After arm abduction, the deformation of the trapezius was reduced in both groups but only significantly in the WAD-group (p = 0.03). Within-group analysis revealed that the control group least engaged the deep section of upper trapezius during the task (p < 0.01). ConclusionThis study, measuring mechanical deformation of the upper trapezius during a scapular elevation task indicates that persons with WAD may display different patterns in engagement of the muscle sections than those in the control group. Further research is needed to replicate and understand the reasons for and implications of this possible change in motor strategy within upper trapezius.Clinical Trials.gov, Number: NCT01547624.

The geography of fatty infiltrates within the cervical multifidus and semispinalis cervicis in individuals with chronic whiplash-associated disorders.

Cross-sectional. To quantify the magnitude and distribution of muscle fat infiltration (MFI) within the cervical multifidus and semispinalis cervicis muscles in participants with chronic whiplash-associated disorders (WADs) compared to those who have fully recovered from a whiplash injury and healthy controls. Previous research has established the presence of increased MFI throughout the cervical extensor muscles of individuals with WAD when compared to healthy controls. These changes appear to be greater in the deepest muscles (eg, multifidus and semispinalis cervicis) than in the more superficial muscles. A detailed analysis of the distribution of MFI within these deep extensor muscles in chronic WAD, recovered, and control groups would provide a foundation for further investigation of specific mechanisms, etiologies, and targets for treatments. Fifteen participants (WAD, n = 5; recovered, n = 5; and control, n = 5) were studied using a 3-D fat-water separation magnetic resonance imaging sequence. Bilateral measures of cervical multifidus and semispinalis cervicis MFI in 4 quartiles (1 [medial] to 4 [lateral]) at cervical levels C3 through C7 were included in the analysis. Intrarater and interrater reliability were established. A mixed-model analysis was performed to control for covariates, identify interaction effects, and compare MFI distribution between groups. The limits of agreement confirmed strong intrarater and interrater agreement at all levels (C3-C7). Sex, age, and body mass index were identified as significant covariates for MFI. Significant interactions were found between group and muscle quartile (P<.001) and between muscle quartile and cervical level (P<.001). Pairwise comparisons for intraquartile MFI between groups revealed significantly greater MFI in the WAD group when compared to the recovered group in the first quartile (P<.001), second quartile (P<.001), and third quartile (P = .03). When compared to the control group, the WAD group had significantly greater MFI in the first quartile (P = .002) and the second quartile (P = .045). The control group had significantly higher MFI in comparison to the recovered group in the first quartile (P = .048). This study provides preliminary data mapping the spatial distribution of MFI in the cervical multifidus and semispinalis cervicis muscles in individuals with chronic WAD, those who have recovered from a whiplash injury, and healthy controls. Muscle fat infiltration is more concentrated in the medial portion of the muscles in all participants. However, the magnitude of MFI in the medial quartiles (1 and 2) is greatest in the chronic WAD group.