A Review of Traumatic Axonal Injury following Whiplash Injury As Demonstrated by Diffusion Tensor Tractography

Post-Traumatic Craniocervical Disorders From a Postural Control Perspective: A Narrative Review

Mild traumatic brain injury (mTBI) and whiplash injury (WI) may lead to long-term disabling consequences known as post-concussive syndrome (PCS) and whiplash-associated disorders (WADs). PCS and WAD patients commonly complain of conditions encompassing dizziness, vertigo, headache, neck pain, visual complaints, anxiety, and neurocognitive dysfunctions. A proper medical work-up is a priority in order to rule out any acute treatable consequences. However investigations may remain poorly conclusive. Gathered in the head and neck structures, the ocular sensorimotor, the vestibular, and the cervical proprioceptive systems, all involved in postural control, may be damaged by mTBI or WI. Their dysfunctions are associated with a wide range of functional disorders including symptoms reported by PCS and WAD patients. In addition, the stomatognathic system needs to be specifically assessed particularly when associated to WI. Evidence for considering the post-traumatic impairment of these systems in PCS and WAD-related symptoms is still lacking but seems promising. Furthermore, few studies have considered the assessment and/or treatment of these widely interconnected systems from a comprehensive perspective. We argue that further research focusing on consequences of mTBI and WI on the systems involved in the postural control are necessary in order to bring new perspective of treatment.

Incidence and characteristics of physical disabilities in patients with postconcussion syndromefollowing mTBI

This study aimed to examine the incidence and characteristics of physical disabilities in patients with postconcussion syndrome (PCS) after a mild traumatic brain injury (mTBI). Of 203 patients diagnosed with PCS after mTBI, 10 patients with definite physical disabilities (worse than moderate disability on the Glasgow outcome scale [GOS], <4 points and inability to walk independently on the Functional Ambulation Category [FAC], <3 points) were enrolled. Ten of the 203 patients included in the analysis based on prespecified inclusion criteria were further evaluated. Seven patients had moderate disability on the GOS, whereas the remaining 3 showed severe disability. On the Modified Barthel Index, 5 patients were moderately dependent, and 2 patients were severely dependent. By the Motricity Index, 9 patients showed mild quadriparesis, and 1 had mild hemiparesis. All 10 patients could grasp-release their fingers as per the Modified Brunnstrom Classification. By contrast, 7 patients required verbal supervision for independent gait by the FAC, and the remaining 3 patients needed intermittent support from 1 person for independent gait. Approximately 5% of patients with PCS after mTBI had a definite physical disability, and most of these patients showed mild quadriparesis. These results suggest that a definite physical disability can occur in patients with PCS after mTBI.

Traumatic Brain Injury After Music-Associated Head Banging: A Scoping Review

Objective

To examine the literature to understand the extent that music-associated head banging (MAHB), a common form of self-expression that involves rhythmically swinging one's head to music, is a risk factor for traumatic brain injury (TBI), to identify areas for further research, and to inform primary prevention strategies.

Data Sources

A comprehensive search of several databases from database inception to June 30, 2021, was designed and conducted by an experienced librarian with input from study investigators.

Study Selection

Study inclusion criteria encompassed all study designs evaluating TBI associated with MAHB. Two independent reviewers reviewed all titles, abstracts, and full texts.

Data Extraction

Data were extracted by 2 independent reviewers, and results were summarized descriptively.

Data Synthesis

Of 407 eligible studies, 13 met inclusion criteria. All included studies were case reports from multiple countries describing a case of moderate-severe TBI occurring as a direct consequence of MAHB. Of the individuals reported (n=13), they had 1 or more of the following: traumatic subdural hematoma (n=8), internal carotid artery dissection (n=2), basilar artery thrombosis (n=2), traumatic vertebral artery aneurism (n=1), or intracerebral hemorrhage (n=1). No studies were found involving mild TBI after MAHB.

Conclusions

This scoping review suggests that MAHB is a risk factor for moderate-severe TBI, although the incidence of mild TBI after MAHB remains unknown. Additional research is needed to understand the association of TBI after MAHB through the spectrum of injury severity, including the potential sequelae of multiple subconcussive injuries.

Traumatic trigeminal neuropathy after whiplash injury: A case report

RATIONALE

Many studies using diffusion tensor tractography (DTT) have reported trigeminal neuropathy in various neurological diseases. However, no study on traumatic trigeminal neuropathy following whiplash has been reported.

PATIENT CONCERNS

A 51-year old female suffered an indirect head trauma resulting from a flexion-hyperextension injury. At approximately 30 minutes after onset, she began to sense a headache in the left frontal area and sensory changes in the left facial area, signs that intensified with the passage of time. At 7 days after onset, she visited the rehabilitation department of our university hospital and described the characteristics and severity of pain as follows: headache on the left frontal area including the forehead with intermittent squeezing and numbness sensations. Her visual analog scale pain score was 6 with her left cheek having a continuous, dull, swelling sensation (visual analog scale score: 1). On neurological examination, she revealed mild allodynia without hyperalgesia or somatosensory change on the head, cheek, tongue, and oral cavity.

DIAGNOSIS

Diffusion tensor imaging data were acquired 7 days after onset. On DTT, the left trigeminal nerve showed discontinuation in the middle portion compared to that of the right trigeminal nerve. Traumatic trigeminal neuropathy was diagnosed based on her clinical features and DTT findings.

INTERVENTION

She was prescribed carbamazepine (200 mg/day) and pregabalin (150 mg/day), and her facial pain was well-controlled to a tolerable level.

OUTCOMES

These drugs were stopped after approximately 7 month's administration, however, she did not complain of facial pain.

LESSONS

By using DTT, we demonstrated traumatic trigeminal neuropathy in a patient with whiplash. We suggest that DTT would be a useful tool for detection of traumatic trigeminal neuropathy in patients who show clinical features of trigeminal neuropathy following whiplash.

Changes in White Matter of the Cervical Spinal Cord after a Single Season of Collegiate Football

The involvement of the central nervous system (CNS), specifically the white matter tracts in the cervical spinal cord, was examined with diffusion tensor imaging (DTI) following exposure to repetitive head acceleration events (HAEs) after a single season of collegiate football. Fifteen National Collegiate Athletic Association (NCAA) Division 1 football players underwent DTI of the cervical spinal cord (vertebral level C1–4) at pre-season (before any contact practices began) and post-season (within 1 week of the last regular season game) intervals. Helmet accelerometer data were also collected in parallel throughout the season. From pre-season to post-season, a significant decrease (p < 0.05) of axial diffusivity was seen within the right spino-olivary tract. In addition, a significant decrease (p < 0.05) in global white matter fractional anisotropy (FA) along with increases (p < 0.05) in global white matter mean diffusivity (MD) and radial diffusivity (RD) were found. These changes in FA from pre-season to post-season were significantly moderated by previous concussion history (p < 0.05) and number of HAEs over 80 g (p < 0.05). Despite the absence of sports-related concussion (SRC), we present measurable changes in the white matter integrity of the cervical spinal cord suggesting injury from repetitive HAEs, or SRC, may include the entirety of the CNS, not just the brain.

How similar are whiplash and mild traumatic brain injury? A systematic review

INTRODUCTION

Mild traumatic brain injury (mTBI) and whiplash are two pathologies which appear in the follow-up of a cranio-cervical trauma. The objective of this study is to review their definitions, to discuss each entity.

METHODS

Whiplash and mTBI were defined. Then, a systematic literature review was carried out using the Pubmed database. Relevant studies after 1995 were selected, with 16 articles describing a link between whiplash and mTBI. 8 articles were analyzed after reading their abstracts.

RESULTS

Whiplash and mTBI have many similarities (symptoms, biomechanics, cognitive disorders, presence of diffuse axonal lesions on functional imaging) and some differences (in posture, more vestibular and balance disorders in whiplash). mTBIs result from linear accelerations between 60- 160g (gravity), studies on whiplash have shown that they can appear from 4.5g, which could explain biomechanically the frequent concomitant appearance. Cervical joint dysfunction can appear in persistent concussive syndrome, with upper cervical pain, less endurance of the cervical flexor muscles, and an increase in cervical stiffness leading to tension headache. This could explain neck pain in mTBI and headache in whiplash. An explanation to vestibular and cochlear disorders is given, and the two pathologies concomitantly could increase the symptoms.

CONCLUSION

To our knowledge, no studies define distinct boundaries between these two pathologies, which overlap on many points. An explanation is their concomitant onset, due to the biomechanics of the trauma and anatomical reasons. Larger-scale studies of rigorous scientific quality are needed to answer the question of the difference between whiplash and mTBI.

Brain Network Disruption in Whiplash

BACKGROUND AND PURPOSE

Whiplash-associated disorders frequently develop following motor vehicle collisions and often involve a range of cognitive and affective symptoms, though the neural correlates of the disorder are largely unknown. In this study, a sample of participants with chronic whiplash injuries were scanned by using resting-state fMRI to assess brain network changes associated with long-term outcome metrics.

MATERIALS AND METHODS

Resting-state fMRI was collected for 23 participants and used to calculate network modularity, a quantitative measure of the functional segregation of brain region communities. This was analyzed for associations with whiplash-associated disorder outcome metrics, including scales of neck disability, traumatic distress, depression, and pain. In addition to these clinical scales, cervical muscle fat infiltration was quantified by using Dixon fat-water imaging, which has shown promise as a biomarker for assessing disorder severity and predicting recovery in chronic whiplash.

RESULTS

An association was found between brain network structure and muscle fat infiltration, wherein lower network modularity was associated with larger amounts of cervical muscle fat infiltration after controlling for age, sex, body mass index, and scan motion (t = -4.02, partial R ²  = 0.49, P < .001).

CONCLUSIONS

This work contributes to the existing whiplash literature by examining a sample of participants with whiplash-associated disorder by using resting-state fMRI. Less modular brain networks were found to be associated with greater amounts of cervical muscle fat infiltration suggesting a connection between disorder severity and neurologic changes, and a potential role for neuroimaging in understanding the pathophysiology of chronic whiplash-associated disorders.

Diffusion-Tensor-Tractography-Based Diagnosis for Injury of Corticospinal Tract in a Patient with Hemiplegia Following Traumatic Brain Injury

This paper reports a mechanism for corticospinal tract injury in a patient with hemiplegia following traumatic brain injury (TBI) based on diffusion tensor tractography (DTT) finding. A 73-year-old male with TBI resulting from a fall, without medical history, was diagnosed as having left convexity epidural hematoma (EDH). He underwent craniotomy and suffered motor weakness on the right side of the body. Two weeks after onset, he was transferred to a rehabilitation department with an alerted level of consciousness. Four weeks after onset, his motor functions were grade 1 by the Medical Research Council’s (MRC) standards in the right-side limbs and grade 4 in the left-side limbs. The result of DTT using the different regions of interest (ROIs) showed that most of the right corticospinal tract (CST) did not reach the cerebral cortex around where the EDH was located, and when the ROI was placed on upper pons, a disconnection of the CST was shown and a connection of the CST in ROI with the middle pons appeared. However, the right CST was connected to the cerebral cortex below the pons regardless of ROI. This study is the first report to use DTT to detect that the discontinuation of the left CST in the cerebral cortex and injury lesions below the lower pons and between the upper and lower pons are responsible for motor weakness in a patient.

Diagnosis of Complex Regional Pain Syndrome I Following Traumatic Axonal Injury of the Corticospinal Tract in a Patient with Mild Traumatic Brain Injury

A 54-year-old male suffered from direct head trauma resulting from a fall while working. At approximately two months after the accident, he began to feel pain (burning sensation) and swelling of the dorsum of the right hand and wrist. He showed the following clinical features among the clinical signs and symptoms of revised diagnostic criteria for complex regional pain syndrome (CRPS): spontaneous pain, mechanical hyperalgesia, vasodilation, skin temperature asymmetries, skin color changes, swelling, motor weakness. No specific lesion was observed on brain MRI taken at ten weeks after onset. Plain X-ray, electromyography, and nerve conduction studies for the right upper extremity detected no abnormality. A three-phase bone scan showed hot uptake in the right wrist in the delayed image. On two-month diffusion tensor tractography, partial tearing of the corticospinal tract (CST) was observed at the subcortical white matter in both hemispheres (much more severe in the left CST). In addition, the fiber number of the right CST was significantly decreased than that of seven normal control subjects. CRPS I of the right hand in this patient appeared to be related to traumatic axonal injury of the left CST following mild traumatic brain injury.

Diagnosis of Tinnitus Due to Auditory Radiation Injury Following Whiplash Injury: A Case Study

We report on a patient with tinnitus who showed injury of auditory radiation following whiplash injury, demonstrated by diffusion tensor tractography (DTT). A 48-year-old male patient suffered from a car crash resulting in flexion-hyperextension injury of his head after being hit from behind by a moving car while waiting at a signal while driving a car. Three days after the car crash, he began to feel tinnitus in both ears and his tinnitus became aggravated with the passage of time. No specific lesion was observed on a conventional brain MRI performed two weeks after the car crash. Although he visited several hospitals, the precise cause of his tinnitus was not detected. Two years after the car crash, he underwent evaluation for his tinnitus at the ear, nose and throat department of a university hospital. The pure tone audiometry was evaluated in a sound-proof room to screen his hearing status for the frequencies of 250-8000 Hz and no specific abnormality was detected. Although he was also tested for speech audiometry, there was also no specific abnormality. In order to assess his tinnitus, a tinnitogram was conducted to evaluate the frequency content and the loudness. His tinnitus was characterized at an intensity of 40 dB and a frequency of 4000 Hz. However, no abnormality was observed in either ear on physical examination. On DTT, the auditory radiation showed severe narrowing and tearing in both hemispheres. To summarize, neural injury of the auditory radiation was demonstrated in a patient with tinnitus following whiplash injury, using DTT.

Differences in Corticoreticulospinal Tract Injuries According to Whiplash in Mild Traumatic Brain Injury Patients

Background: This study investigated differences in postural control ability (PCA) and corticoreticulospinal tract (CRT) injury severity according to whiplash in patients with mild traumatic brain injury (mTBI).

Methods: Thirty-one patients with mTBI and 21 healthy control subjects were recruited for this study. The balance error scoring system (BESS) was used for PCA assessment. Based on their whiplash history, the patients were classified into two groups: group A—mTBI with whiplash injury; group B—mTBI without whiplash injury. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), and tract volume (TV) values were estimated for the reconstructed CRTs in all subjects.

Results: Significant differences were observed among the total BESS scores of patient groups A and B and the control group (p < 0.05). The patient group A BESS score was significantly higher than that of patient group B, and that of the patient group B was significantly higher than that of the control group. No significant differences were detected among the FA and ADC values of the CRTs of the two patient groups and the control group (p > 0.05). However, the TV values of the CRT did reveal significant differences; the TV of patient group A was significantly lower than those of patient group B and the control group, and that of patient group B was significantly lower than that of the control group (p < 0.05).

Conclusions: We observed greater CRT injury severity and PCA impairment in mTBI patients with whiplash than in mTBI patients without whiplash. The results indicate that whiplash might lead to a greater level of severity in axonal injuries in mTBI patients.

Central Pain Due to Injury of the Spinothalamic Tract Misdiagnosed as Complex Regional Pain Syndrome: A Case Report

Objectives: We report on a patient with whiplash injury who had central pain, due to injury of the spinothalamic tract (STT), but who was misdiagnosed as complex regional pain syndrome (CRPS). Case description: While a minivan in which a 43-year-old female was seated in the passenger seat was stopped for a signal, a truck collided with the minivan from behind, and the minivan then repeatedly collided with trucks in front and behind the minivan. Her head repeatedly struck the minivan seat resulting in whiplash injuries. After onset, she felt pain in both legs with mild motor weakness in all four extremities and memory impairment. Eight years after onset, she was diagnosed at a university hospital as CRPS type 1 with the clinical features of hyperalgesia and mild edema and motor weakness of both legs. She visited another university hospital nine years after onset and complained of pain in the right arm and both legs, constant tingling and burning pain along with allodynia and hyperalgesia. She also showed mild weakness in the four extremities, mild edema of both legs, and memory impairment. On diffusion tensor tractography (DTT), the left spinothalamic tract (STT) showed marked narrowing, and the right STT revealed mild narrowing and partial tearing. In addition, partial tears were observed in both corticospinal tracts and the right corticoreticulospinal tract. Discontinuations were observed in the left corticoreticulospinal tract and the left fornical crus. Conclusion: Injury of the STT was demonstrated on DTT in a patient with central pain following whiplash injury. Previously, the patient was misdiagnosed as CRPS.

Risk of traffic accidents after onset of vestibular disease assessed with a surrogate marker

OBJECTIVES

To determine if the risk of traffic accidents increases after disease onset in patients with acute vestibular disorders. That could provide a valid rationale for guidelines on driving restrictions.

METHODS

5,260,054 patient data (> 18 years of age) from a statutory health insurer were used to identify traffic injuries in incident cases of Menière's disease (MD) and vestibular neuritis (VN) in 2010-2013. Incident diagnoses were defined as the absence of such diagnoses in the preceding 5 years. Comparators were insured individuals with no such diagnoses throughout 2005-2017. The surrogate for traffic injuries were whiplash injuries coded in ICD-10 as diagnosis of sprain of ligaments of the cervical spine without structural changes.

RESULTS

We identified 4509 incident patients with Menière's disease and 25,448 with vestibular neuritis and 5,102,655 controls with no such diagnoses throughout the observation period. The incidence of traffic injuries was increased for both vestibular disorders prior to the time point of diagnosis-MD 0.72 [0.47; 0.97] and VN 0.66 [0.56; 0.76] compared to controls (0.46 [0.46; 0.47]). The temporal course of incidence in whiplash injuries showed no increase and was 0.64 [0.41; 0.88] for MD at diagnosis and 0.73 [0.48; 0.98] after diagnosis, for VN it was 0.81 [0.70; 0.92] at diagnosis and 0.65 [0.55; 0.74] after diagnosis.

CONCLUSIONS

Although these data were not originally collected to address the research question, they provide a valid body of evidence. There is no rationale for driving restrictions, which substantially interfere with the individuals' quality of life, in patients with incident MD and VN.

Impact of mild traumatic brain injury on cingulate functions

Mild traumatic brain injury (mTBI) is a condition of normal neuroimaging, because conventional MRI is not sensitive to brain lesions. Neurocognitive deficits persist for years after injury in 15% of patients. Persistent TAI can continue after the trauma and contribute to progressive disability. Neuropathologic studies underestimate the total axonal damage, by failure to identify fine-caliber unmyelinated fiber. Swollen axons represent the "tip of the iceberg" of damage. Progression of molecular changes, including mitochondrial dysfunction, leads to secondary injuries. Primary low-intensity "invisible injury" is solely detectable at ultrastructural levels. Over the long term, mTBI is not a static event but a progressive injury, increasing risk of neurodegenerative diseases. Lack of evidence of brain injury has led to the development of more sensitive methods: morphometric MRI (VBM, DTI) and functional techniques (fMRI, PET, SPECT). By deformation of the surface of gray matter cingulate gyrus and disruption of long-coursing WM of CB structures, striking the falx, mTBI causes alteration of cingulate functions. Postconcussion, blast, and whiplash-associated disorders are the main mechanisms providing behavior and cognitive symptoms after mTBI.

Scale for retrospective assessment of immediate concussion symptoms

The retrospective diagnosis of concussion is often missed by clinicians. We present a brief scale for retrospective assessment of the immediate concussion symptoms (ICS) to facilitate the diagnosis of patients without visible head injury or full loss of consciousness. We administered the scale to 90 survivors of car accidents (mean age 42.0, SD=13.6; 33 males, 57 females) at 2 to 33 months after their accident. Our scale consists of 6 items and these were endorsed by the following % of our respondents: feeling dazed (64.4% of our 90 respondents), stunned (73.3%), confused (70.0%), disoriented (62.2%), dizzy (57.8%), and loss of consciousness (22.2%). The statistical properties of the scale are satisfactory (Cronbach alpha = 0.74). The scale correlates with post-accident insomnia (r=0.28), depression (r=0.29), and also with Rivermead measure of the chronic post-concussion syndrome (r=0.34). The ICS scale could be used as a starting point in longitudinal research with brain imaging procedures to evaluate the stages of recovery from the initial concussion. Attached are the English, Spanish, French, German, Italian, Russian, and Czech versions of our scale.