Advancements in Imaging Technology: Do They (or Will They) Equate to Advancements in Our Knowledge of Recovery in Whiplash?

Synopsis It is generally accepted that up to 50% of those with a whiplash injury following a motor vehicle collision will fail to fully recover. Twenty-five percent of these patients will demonstrate a markedly complex clinical picture that includes severe pain-related disability, sensory and motor disturbances, and psychological distress. A number of psychosocial factors have shown prognostic value for recovery following whiplash from a motor vehicle collision. To date, no management approach (eg, physical therapies, education, psychological interventions, or interdisciplinary strategies) for acute whiplash has positively influenced recovery rates. For many of the probable pathoanatomical lesions (eg, fracture, ligamentous rupture, disc injury), there remains a lack of available clinical tests for identifying their presence. Fractures, particularly at the craniovertebral and cervicothoracic junctions, may be radiographically occult. While high-resolution computed tomography scans can detect fractures, there remains a lack of prevalence data for fractures in this population. Conventional magnetic resonance imaging has not consistently revealed lesions in patients with acute or chronic whiplash, a "failure" that may be due to limitations in the resolution of available devices and the use of standard sequences. The technological evolution of imaging techniques and sequences eventually might provide greater resolution to reveal currently elusive anatomical lesions (or, perhaps more importantly, temporal changes in physiological responses to assumed lesions) in those patients at risk of poor recovery. Preliminary findings from 2 prospective cohort studies in 2 different countries suggest that this is so, as evidenced by changes to the structure of skeletal muscles in those who do not fully recover. In this clinical commentary, we will briefly introduce the available imaging decision rules and the current knowledge underlying the pathomechanics and pathophysiology of whiplash. We will then acknowledge known prognostic factors underlying functional recovery. Last, we will highlight emerging evidence regarding the pathobiology of muscle degeneration/regeneration, as well as advancements in neuroimaging and musculoskeletal imaging techniques (eg, functional magnetic resonance imaging, magnetization transfer imaging, spectroscopy, diffusion-weighted imaging) that may be used as noninvasive and objective complements to known prognostic factors associated with whiplash recovery, in particular, poor functional recovery. J Orthop Sports Phys Ther 2016;46(10):861-872. doi:10.2519/jospt.2016.6735.

Non-rigid registration of cervical spine MRI volumes

Whiplash is the colloquial term for neck injuries caused by sudden extension of the cervical spine. Patients with chronic whiplash associated disorder (WAD) can experience neck pain for many years after the original injury. Researchers have found some evidence to suggest that chronic whiplash is related to the amount of intra-muscular fat in the cervical spine muscles. Hence, an important step towards developing a treatment for chronic WAD is a technique to accurately and efficiently measure the amount of intra-muscular fat in the muscles of the cervical spine. Our proposed technique for making this measurement is to automatically segment the cervical spine muscles using a fused volume created from multi-modal MRI volumes of the cervical spine. Multiple modes are required to enhance the boundaries between the different muscles to assist the following automatic segmentation process. However, before these multiple modes can be fused it is first necessary to accurately register these volumes. Hence, in this paper, we have proposed a new non-rigid multi-modal registration algorithm using the sum of conditional variance (SCV) with partial volume interpolation (PVI) similarity measure and Gauss-Newton (GN) optimization for the accurate registration of multi-modal cervical spine MRI volumes. The performance of the proposed approach is compared with the existing SCV based registration algorithm and the sum of the conditional squared deviation from the mode (SCSDM) method. The experimental results demonstrate that the proposed approach provides superior performance than the best existing approaches.

Quantification of Acute Neck Pain Following Whiplash Injury by Computer-Aided Pressure Algesimetry

Until now the clinical investigation of cervical pain due to whiplash injury is mainly based on finger palpation. The present study introduces a PC-interactive pressure algesimetry to standardize cervical pain measurement. Pressure pain scores of the splenius and trapezius muscles of 23 patients with an acute cervical syndrome after whiplash injury were compared to those of 24 healthy subjects. The pressure painfulness of neck and shoulder muscles was significantly increased in whiplash patients. The splenii muscles showed an equally increased muscle pain whereas the trapezii muscles showed a left-sided preponderance of painfulness, possibly due to the seat belt position in this group of motor vehicle drivers. The computer-interactive pressure algesimetry enables a standardized and rater-independent quantification of the cervical syndrome with neck and shoulder pain caused by whiplash injury.

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: R(2) = 0.24-0.82, WAD: R(2) = 0.05-0.74) and deformation of the deepest muscles (controls: R(2) = 0.61-0.32, WAD: R(2) = 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.

Thoracic dysfunction in whiplash-associated disorders: a systematic review and meta-analysis protocol

BACKGROUND

Whiplash-associated disorder (WAD) research has largely focused on the neck, yet symptoms often include other areas. The prevalence of acute thoracic spine pain is reported ~66 %, which is perhaps unsurprising given the mechanism of injury involves a forceful loading/eccentric contraction of posterior thoracic structures such as the trapezius. Many individuals with WAD experience disability and pain beyond normal tissue healing time, termed chronic WAD. With the thoracic spine contributing to neck mobility, and 23 % of individuals complaining of thoracic pain 1 year post injury, it is time to look beyond the neck to fully understand the anatomical dysfunction in WAD.

METHODS/DESIGN

A systematic review protocol has been designed and will be reported in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P). A sensitive topic-based search strategy is planned from inception to the current date. Databases, grey literature and registers will be searched using terms and keywords derived from a scoping search. Two reviewers will independently search information sources, assess studies for inclusion and extract data. A third reviewer will check for accuracy. Data to be extracted include summary data: sample size and characteristics, timescales to reflect disorder state, patient-reported or performance-based measure and findings. Risk of bias within studies will be assessed using the Newcastle-Ottawa Scale. Quantitative meta-analysis approach will be used for homogenous data and where appropriate presented using subgroups. All other results will be presented using narrative summaries. Subgroups will, where possible, be based on patient-reported or performance-based measure of dysfunction and/or stage of condition (acute/sub-acute or chronic). Strength of the overall body of evidence will be assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

DISCUSSION

This is the first study to bring together evidence of thoracic dysfunction post whiplash and provide new insights into the scope and nature of thoracic dysfunction in WAD. With current management options being largely focused to a primary neck complaint and many patients going to become chronic in their presentations, this review may stimulate research and clinical interest in a largely under investigated, yet anatomically and kinematically related, spinal region.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015026983.

Comparative study of potential whiplash injuries for different occupant seated positions during rear end accidents

PURPOSE

Whiplash injuries to the cervical spine represent a considerable economic burden on society with medical conditions, in some cases persisting for more than a year. Numerous studies of whiplash injuries have been made for occupant normal seated position, leaving the analysis of neck injuries for out-of-normal positions not well documented. For that purpose, a detailed human cervical spine finite element model was developed.

METHODS

The analysis was made for four most common occupant seated positions, such as: Normal Position with the torso against the seat back and the head looking straight ahead, Torso Lean forward position with the torso away from the seat back for approximately 10°, Head Flexed position with the head flexed forward approximately 20° from the normal position and Head-Flexed with Torso Lean forward position with the head flexed forward approximately 20° and torso 10° from the normal position.

RESULTS

The comparative study included the analysis of capsular ligament deformation and the level of S-curvature of the cervical spine. The model developed predicted that Head Flexed seated position and Head-Flexed with Torso Lean forward seated position are most threatening for upper and lower cervical spine capsular ligament, respectively. As for the level of S-curvature, the model predicted that Head-Flexed with Torso Lean forward seated position would be most prone to neck injuries associated with it.

CONCLUSIONS

This study demonstrated that the occupant seated position has a significant influence on potential whiplash injuries.

Measurement Properties of the Spinal Function Sort in Patients with Sub-acute Whiplash-Associated Disorders

PURPOSE

To extensively analyze the measurement properties the Spinal Function Sort (SFS) in patients with sub-acute whiplash-associated disorders (WAD).

METHODS

Three-hundred-two patients with WAD were recruited from an outpatient work rehabilitation center. Internal consistency was assessed by Cronbach's α. Construct validity was tested based on eight a priori hypotheses. Structural validity was measured with principal component analysis (PCA). Test-retest reliability and agreement was evaluated in a sub sample (n = 32) using intraclass correlation coefficient (ICC) and limits of agreement (LoA). The predictive validity of SFS for future work status at 1, 3, 6, and 12 months follow-up was determined by area under the curve (AUC) of receiver operating characteristics. Non-return to work (N-RTW) was defined with two cut-off points: workcapacity <50 and <100 %.

RESULTS

N-RTW decreased from 50%, 1 month follow-up, to 14%, 12 months follow-up. Cronbach's α was 0.98, PCA revealed evidence for unidimensionality. ICC was 0.86, LoA was ±33 points. Seven out of eight hypotheses for construct validity were not rejected. AUC reduced with a longer follow-up from 0.71 for 1 month to 0.61 at 12 months, for cut-off point <50%. For cut-off point <100% these values were 0.71 and 0.59.

CONCLUSION

In patients with sub-acute WAD test-retest reliability, internal consistency, construct- and structural validity of the SFS were adequate. LoA were substantial. Sensitivity to accurately predict N-RTW was poor. The predictive validity of the SFS for N-RTW of patients with sub-acute WAD from an outpatient work rehabilitation setting was only sufficient for the short term (1 month).

Lack of evidence for central sensitization in idiopathic, non-traumatic neck pain: a systematic review

BACKGROUND

Chronic neck pain is a common problem with a poorly understood pathophysiology. Often no underlying structural pathology can be found and radiological imaging findings are more related to age than to a patient's symptoms. Besides its common occurrence, chronic idiopathic neck pain is also very disabling with almost 50% of all neck pain patients showing moderate disability at long-term follow-up. Central sensitization (CS) is defined as "an amplification of neural signaling within the central nervous system that elicits pain hypersensitivity," "increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input," or "an augmentation of responsiveness of central neurons to input from unimodal and polymodal receptors." There is increasing evidence for involvement of CS in many chronic pain conditions. Within the area of chronic idiopathic neck pain, there is consistent evidence for the presence and clinical importance of CS in patients with traumatic neck pain, or whiplash-associated disorders. However, the majority of chronic idiopathic neck pain patients are unrelated to a traumatic injury, and hence are termed chronic idiopathic non-traumatic neck pain. When comparing whiplash with idiopathic non-traumatic neck pain, indications for different underlying mechanisms are found.

OBJECTIVE

The goal of this article was to review the existing scientific literature on the role of CS in patients with chronic idiopathic non-traumatic neck pain.

STUDY DESIGN

Systematic review.

SETTING

All selected studies were case control studies.

METHODS

A systematic search of existing, relevant literature was performed via the electronic databases Medline, Embase, Web of Science, Cinahl, PubMed, and Google Scholar. All titles and abstracts were checked to identify relevant articles. An article was considered eligible if it met following inclusion criteria: (1) participants had to be human adults (> 18 years) diagnosed with idiopathic non-traumatic chronic (present for at least 3 months) neck pain; (2) papers had to report outcomes related to CS; and (3) articles had to be full-text reports or original research (no abstracts, case-reports, reviews, meta-analysis, letters, or editorials).

RESULTS

Six articles were found eligible after screening the title, abstract and - when necessary - the full text for in- and exclusion criteria. All selected studies were case-control studies. Overall, results regarding the presence of CS were divergent. While the majority of patients with chronic traumatic neck pain (i.e. whiplash) are characterized by CS, this is not the case for patients with chronic idiopathic neck pain. The available evidence suggests that CS is not a major feature of chronic idiopathic neck pain. Individual cases might have CS pain, but further work should reveal how they can be characterized.

LIMITATIONS

Very few studies available.

CONCLUSIONS

Literature about CS in patients with chronic idiopathic non-traumatic neck pain is rare and results from the available studies provide an inconclusive message. CS is not a characteristic feature of chronic idiopathic and non-traumatic neck pain, but can be present in some individuals of the population. In the future a subgroup with CS might be defined, but based on current knowledge it is not possible to characterize this subgroup. Such information is important in order to provide targeted treatment.

[Expert evidence in whiplash injury: interdisciplinary orthopaedic and biomechanical approach]

Considering the controversially discussed issue of whiplash injury a pragmatic approach based on our own experience in the area of forensic expert opinion is presented. Findings of accident analysis and biomechanics are correlated with the individual situation after the accident (initial clinical appearance), the course of the ailment and the indispensable physical examination. The latter leads to determination of the individual vulnerability (not increased/increased) which is important for the evaluation of the physical condition and estimation of the physical stress limit. These limits vary widely between individuals and must be considered carefully when relating dose and effect of accident severity to a possible physical injury. Determination of the accident severity is especially important when there are no objective signs of injury and the existence of a minor whiplash injury (Quebec Task Force degree 1 or 2) is in question.

[Whiplash injury analysis of cervical vertebra by finite element method]

Finite element method (FEM) is an effective mathematical method for stress analysis, and has been gradually applied in the study of biomechanics of human body structures. This paper reviews the construction, development, materials assignment and verification of FEM model of cervical vertebra, and it also states the research results of injury mechanism of whiplash injury and biomechanical response analysis of the cervical vertebra using FEM by researchers at home and abroad.

Whiplash and Concussion: Similar Acute Changes in Middle-Latency SEPs

Objective:

Middle-latency somatosensory evoked potentials (SEPs) following median nerve stimulation can provide a sensitive measure of cortical function. We sought to determine whether the mechanical forces of whiplash injury or concussion alter normal processing of middle-latency SEPs.

Methods:

In a cross-sectional pilot study 20 subjects with whiplash were investigated (50% between 0.5-2 months and 50% between 6-41 months post injury) and compared to 83 healthy subjects using a standard middle-latency SEP procedure. In a subsequent prospective study subjects with either acute whiplash (n=13) or Grade 3 concussion (n=16) were investigated within 48 hours and again three months post injury.

Results:

In the pilot study the middle-latency SEP component N60 was significantly increased in the ten subjects investigated within two months after whiplash. In contrast, the ten subjects examined more than six months after injury showed normal latencies. In the prospective study N60 latencies were increased after whiplash and concussion when tested within 48 hours of injury. At three months, latencies were improved though still significantly different from controls post whiplash and concussion.

Conclusion:

Both whiplash injury and concussion alter processing of the middle-latency SEP component N60 in the acute post traumatic period. The acute changes appear to normalize between three-six months post injury. The SEP similarities suggest that the overlapping clinical symptomatology post whiplash and concussion may reflect a similar underlying mechanism of rotational mild traumatic brain injury.

Predicting recovery from whiplash injury in the primary care setting

BACKGROUND

The effect of expectation of recovery on the recovery rate of whiplash patients in the primary care setting is not known.

METHODS

Whiplash patients were assessed in a primary care setting within 1 week of their collision for their expectations of recovery and were re-examined 3 months later for recovery.

RESULTS

Initial expectations of recovery predicted recovery. According to adjusted odds ratios, subjects who expected 'to get better slowly' had a recovery rate that was nearly 1.9 times that of subjects with poor recovery expectations. Subjects who expected 'to get better soon' had a recovery rate that was 2.6 times greater than either of those with poor recovery expectations.

DISCUSSION

In the primary care setting, asking patients with whiplash about their expectations of recovery is a useful predictor of their outcome.

Multidimensional associative factors for improvement in pain, function, and working capacity after rehabilitation of whiplash associated disorder: a prognostic, prospective outcome study

BACKGROUND

Whiplash associated disorders (WAD) have dramatic consequences for individual and public health. Risk factors for better and worse outcomes are important to optimize management. This study aimed to determine short- and mid-term associative co-factors of neck pain relief, improved physical functioning, and improved working capacity (dependent variables) in patients suffering from whiplash associated disorder who participated in a standardized, inpatient pain management program.

METHODS

Naturalistic, observational, prospective cohort study. Outcome was measured by standardized assessment instruments. Co-factors covered sociodemographics, comorbidities, social participation, affective health, and coping abilities. Stepwise, multivariate linear regression analysis was performed at discharge and at the 6-month follow-up.

RESULTS

All regression models explained high proportions of variance (53.3% - 72.1%). The corresponding baseline level was significantly associated with a change in every dependent variable (explained variances: 11.4%-56.7%). Pain relief significantly depended on improved function and vice-versa (3.4%-14.8%). Improved ability to decrease pain was associated with pain relief at discharge (9.6%). Functional improvement was associated with decreased catastrophizing (19.4%) at discharge and decreased depression (20.5%) at the 6 month follow-up.

CONCLUSIONS

Pain relief, improved physical function and working capacity were associated with each other. Improved coping (catastrophizing and ability to decrease pain) and reduced depression may act as important predictors for pain relief and improved function. These findings offer toe-holds for optimized therapy of chronic WAD.

Anthropometric specifications, development, and evaluation of EvaRID--a 50th percentile female rear impact finite element dummy model

OBJECTIVES

Whiplash-associated disorders (WADs), or whiplash injuries, due to low-severity vehicle crashes are of great concern in motorized countries and it is well established that the risk of such injuries is higher for females than for males, even in similar crash conditions. Recent protective systems have been shown to be more beneficial for males than for females. Hence, there is a need for improved tools to address female WAD prevention when developing and evaluating the performance of whiplash protection systems. The objective of this study is to develop and evaluate a finite element model of a 50th percentile female rear impact crash test dummy.

METHODS

The anthropometry of the 50th percentile female was specified based on literature data. The model, called EvaRID (female rear impact dummy), was based on the same design concept as the existing 50th percentile male rear impact dummy, the BioRID II. A scaling approach was developed and the first version, EvaRID V1.0, was implemented. Its dynamic response was compared to female volunteer data from rear impact sled tests.

RESULTS

The EvaRID V1.0 model and the volunteer tests compared well until ∼250 ms of the head and T1 forward accelerations and rearward linear displacements and of the head rearward angular displacement. Markedly less T1 rearward angular displacement was found for the EvaRID model compared to the female volunteers. Similar results were received for the BioRID II model when comparing simulated responses with experimental data under volunteer loading conditions. The results indicate that the biofidelity of the EvaRID V1.0 and BioRID II FE models have limitations, predominantly in the T1 rearward angular displacement, at low velocity changes (7 km/h). The BioRID II model was validated against dummy test results in a loading range close to consumer test conditions (EuroNCAP) and lower severity levels of volunteer testing were not considered.

CONCLUSIONS

The EvaRID dummy model demonstrated the potential of becoming a valuable tool when evaluating and developing seats and whiplash protection systems. However, updates of the joint stiffness will be required to provide better correlation at lower load levels. Moreover, the seated posture, curvature of the spine, and head position of 50th percentile female occupants needs to be established and implemented in future models.

Assessment of driving-related performance in chronic whiplash using an advanced driving simulator

Driving is often nominated as problematic by individuals with chronic whiplash associated disorders (WAD), yet driving-related performance has not been evaluated objectively. The purpose of this study was to test driving-related performance in persons with chronic WAD against healthy controls of similar age, gender and driving experience to determine if driving-related performance in the WAD group was sufficiently impaired to recommend fitness to drive assessment. Driving-related performance was assessed using an advanced driving simulator during three driving scenarios; freeway, residential and a central business district (CBD). Total driving duration was approximately 15min. Five driving tasks which could cause a collision (critical events) were included in the scenarios. In addition, the effect of divided attention (identify red dots projected onto side or rear view mirrors) was assessed three times in each scenario. Driving performance was measured using the simulator performance index (SPI) which is calculated from 12 measures. z-Scores for all SPI measures were calculated for each WAD subject based on mean values of the control subjects. The z-scores were then averaged for the WAD group. A z-score of ≤-2 indicated a driving failing grade in the simulator. The number of collisions over the five critical events was compared between the WAD and control groups as was reaction time and missed response ratio in identifying the red dots. Seventeen WAD and 26 control subjects commenced the driving assessment. Demographic data were comparable between the groups. All subjects completed the freeway scenario but four withdrew during the residential and eight during the CBD scenario because of motion sickness. All scenarios were completed by 14 WAD and 17 control subjects. Mean z-scores for the SPI over the three scenarios was statistically lower in the WAD group (-0.3±0.3; P<0.05) but the score was not below the cut-off point for safe driving. There were no differences in the reaction time and missed response ratio in divided attention tasks between the groups (All P>0.05). Assessment of driving in an advanced driving simulator for approximately 15min revealed that driving-related performance in chronic WAD was not sufficiently impaired to recommend the need for fitness to drive assessment.

[The relationship between whiplash injury and temporomandibular joint dysfunction]

This article aims to discuss the possible relationship between rapid extension-flexion of the neck-whiplash injury and temporomandibular disorders (TMD). Clinical experience and studies revealed that whiplash injury may cause TMD. The pathophysiology of TMD is described as well as clinical and imaging diagnostic criteria. The treatment modalities for TMD are: physiotherapy, nonsteroidal anti-inflammatory drugs and occlusal splints.

Verification of whiplash-associated disorders in forensic medical practice. Part II--Objectivization of injuries

In clinical practice, cervical spine distortion or whiplash-associated disorders (WADs) are diagnosed exclusively on the basis of subjective complaints presented by the patients and by information that they were involved in traffic collisions. Therefore, from the forensic point of view, it is essential to verify all diagnosed WADs in the context of an extremely important and already proven mental component of the reported complaints and lack of objective changes in imaging examinations. The study presents suggestions regarding objectivization of acute episodes of cervical spine distortion in traffic accident victims based on medical criteria and accident circumstances. The knowledge of technical aspects of the circumstances of WADs facilitates medical evaluation of their consequences; moreover, the use of combined criteria allows for the assessment of probability of WADs in a particular traffic accident victim.

Verification of whiplash-associated disorders in forensic medical practice. part I--assessment of the injury circumstances and biomechanics

For many years, researchers involved in automotive industry and forensic medicine, as well as insurance companies have shown great interest in the issues of etiology and prevention of cervical spine distortion. The etiopathogenesis of whiplash-associated disorders (WADs) remains controversial and its morphological determinants have not been explicitly determined to date. The subjective nature of complaints causes great difficulties in objective assessment of the consequences of acceleration-deceleration injuries and in verification of compensation claims. The objective of the study was to present biomechanical relationships and circumstances accompanying WADs using population-based studies, statistical data of insurance companies and analysis of recordings of event data recorders installed by vehicle producers. The knowledge of technical aspects of WAD circumstances should facilitate medical assessment of the above-mentioned consequences.

German version of the whiplash disability questionnaire: reproducibility and responsiveness

BACKGROUND

The Whiplash Disability Questionnaire (WDQ) poses a validated tool for the assessment of patients who experience whiplash-associated disorders. A German translation and cross-cultural adaptation was recently produced and presented high validity and internal consistency. As a follow-up, the presented study tests the translated Whiplash Disability Questionnaire's (WDQ-G) retest reliability and responsiveness to change.

METHODS

The WDQ-G was assessed on three different measurement events: first upon entry (ME1), second four days after entry (ME2), and third at discharge (ME3). Test-retest reliability data from ME1 and ME2 was analysed in a group of stable patients to obtain the intraclass correlation coefficient (ICC) and the standard error of measurement (SEM). To test the instrument's responsiveness, WDQ-G change data were compared to concurrent instruments. The probability of each instrument, to correctly distinguish patients of the stable phase (ME1 to ME2) from patients who deemed to have improved between from ME1 to ME3, was analysed.

RESULTS

In total, 53 patients (35 females, age=45 ± 12.2) were recruited. WDQ-G scores changed from ME1 to ME2 by 5.41 ± 11.6 points in a stable group. This corresponds to a test-retest reliability of ICC=0.91 (95% CI=0.80-0.95) with a SEM of 6.14 points. Minimal Detectable Change, at 95% confidence, was calculated to be 17 points change in scores. Area under Receiver Operator Characteristics of the WDQ-G's responsiveness revealed a probability of 84.6% (95% CI=76.2%-93%) to correctly distinguish between improved and stable patients. Optimal sensitivity (73.2%) and specificity (76.2%) was established at 11-point change.

CONCLUSIONS

High retest reliability and good responsiveness of the WDQ-G support clinical implementation of the translated version. The data suggest, that change in total score greater than eleven points can be interpreted as clinical relevant from a patient's perspective. Minimal Important Change is suggested at 15 points where there is still high specificity and a 90% confidence MDC.

Finite element modeling of potential cervical spine pain sources in neutral position low speed rear impact

The rate of soft tissue sprain/strain injuries to the cervical spine and associated cost continue to be significant; however, the physiological nature of this injury makes experimental tests challenging while aspects such as occupant position and musculature may contribute to significant variability in the current epidemiological data. Several theories have been proposed to identify the source of pain associated with whiplash. The goal of this study was to investigate three proposed sources of pain generation using a detailed numerical model in rear impact scenarios: distraction of the capsular ligaments; transverse nerve root compression through decrease of the intervertebral foramen space; and potential for damage to the disc based on the extent of rotation and annulus fibre strain. There was significant variability associated with experimental measures, where the range of motion data overlapped ultimate failure data. Average data values were used to evaluate the model, which was justified by the use of average mechanical properties within the model and previous studies demonstrating predicted response and failure of the tissues was comparable to average response values. The model predicted changes in dimension of the intervertebral foramen were independent of loading conditions, and were within measured physiological ranges for the impact severities considered. Disc response, measured using relative rotation between intervertebral bodies, was below values associated with catastrophic failure or avulsion but exceeded the average range of motion values. Annulus fibre strains exceeded a proposed threshold value at three levels for 10g impacts. Capsular ligament strain increased with increasing impact severity and the model predicted the potential for injury at impact severities from 4g to 15.4g, when the range of proposed distraction corresponding to sub-catastrophic failure was exceeded, in agreement with the typically reported values of 9-15g. This study used an enhanced neck finite element model with active musculature to investigate three potential sources of neck pain resulting from rear impact scenarios and identified capsular ligament strain and deformation of the disc as potential sources of neck pain in rear impact scenarios.

Pre-activation and muscle activity during frontal impact in relation to whiplash associated disorders

OBJECTIVE

For the evaluation of neck injury the relative distance was observed between a marker placed on the forehead and a marker placed on the shoulder and also by change of the angle. To compare the severity of head injury a value of maximum head acceleration was used, HIC and a 3 ms criterion. All criteria were related to the activity of musculus sternocleidomastoideus and musculus trapezius in a situation of expected or unexpected impact.

MATERIALS AND METHODS

The situation was recorded using a Qualisys system, head acceleration of probands in three axes was recorded using the accelerometer, activity of neck muscles was monitored by a mobile EMG.

RESULTS

Maximum head acceleration was 12.1 g for non-visual and 8.2 g for visual. HIC36 was 5.7 non visual and 4.0 for visual. 3-ms criterion was 11.5 g for non-visual and 7.8 g for visual. The average time of muscle activation of the observed group without visual perception is 0.027 s after hitting an obstacle, with visual perception 0.127 s before the crash.

CONCLUSIONS

Kinematic values indicate more favourable parameters for neck injuries for visual. Head injury criteria show an average decrease of about 30% for visual. We can conclude that the visual perception means a significant increase in pre-activation of the observed muscle group of almost 400% and lower activation in both following phases of approximately 40%.

Evaluation of the internal and external biofidelity of current rear impact ATDs to response targets developed from moderate-speed rear impacts of PMHS

The goal of this study is to evaluate both the internal and external biofidelity of existing rear impact anthropomorphic test devices (BioRID II, RID3D, Hybrid III 50th) in two moderate-speed rear impact sled test conditions (8.5g, 17 km/h; 10.5g, 24 km/h) by quantitatively comparing the ATD responses to biomechanical response targets developed from PMHS testing in a corresponding study. The ATDs and PMHS were tested in an experimental seat system that is capable of simulating the dynamic seat back rotation response of production seats. The experimental seat contains a total of fourteen load cells installed such that external loads from the ATDs and PMHS can be measured to evaluate external biofidelity. The PMHS were instrumented to correspond to the instrumentation contained in the ATDs so that direct comparison between ATDs and PMHS could be made to evaluate internal biofidelity. The NHTSA Biofidelity Ranking system was used to quantitatively evaluate the biofidelity of the ATDs and an additional tool was introduced and utilized which allows for the biofidelity score to be partitioned into components of amplitude, phase, and shape. For internal biofidelity, the BioRID II and RID3D were more biofidelic than the Hybrid III in the 17 km/h test, and the BioRID II was most biofidelic in the 24 km/h test. For external biofidelity, the BioRID II was most biofidelic in the 17 km/h test, while both the BioRID II and the RID3D were more biofidelic than the Hybrid III in the 24 km/h test. Overall, the BioRID II demonstrated the best biofidelity in both the 17 km/h and 24 km/h tests.

Trauma-associated tinnitus: audiological, demographic and clinical characteristics

Background

Tinnitus can result from different etiologies. Frequently, patients report the development of tinnitus after traumatic injuries. However, to which extent this specific etiologic factor plays a role for the phenomenology of tinnitus is still incompletely understood. Additionally, it remains a matter of debate whether the etiology of tinnitus constitutes a relevant criterion for defining tinnitus subtypes.

Objective

By investigating a worldwide sample of tinnitus patients derived from the Tinnitus Research Initiative (TRI) Database, we aimed to identify differences in demographic, clinical and audiological characteristics between tinnitus patients with and without preceding trauma.

Materials

A total of 1,604 patients were investigated. Assessment included demographic data, tinnitus related clinical data, audiological data, the Tinnitus Handicap Inventory, the Tinnitus Questionnaire, the Beck Depression Inventory, various numeric tinnitus rating scales, and the World Health Organisation Quality of Life Scale (WHOQoL).

Results

Our data clearly indicate differences between tinnitus patients with and without trauma at tinnitus onset. Patients suffering from trauma-associated tinnitus suffer from a higher mental burden than tinnitus patients presenting with phantom perceptions based on other or unknown etiologic factors. This is especially the case for patients with whiplash and head trauma. Patients with posttraumatic noise-related tinnitus experience more frequently hyperacousis, were younger, had longer tinnitus duration, and were more frequently of male gender.

Conclusions

Trauma before tinnitus onset seems to represent a relevant criterion for subtypization of tinnitus. Patients with posttraumatic tinnitus may require specific diagnostic and therapeutic management. A more systematic and – at best - standardized assessment for hearing related sequelae of trauma is needed for a better understanding of the underlying pathophysiology and for developing more tailored treatment approaches as well.