The Potential Benefits of Spinal Manipulation for those Suffering the Symptoms of Concussion and the Post-Concussion Syndrome
Mild traumatic brain injuries are also known as concussions. It is estimated that these injuries have a prevalence of 3.8 million per year in the United States (1). In the majority of patients sustaining a concussion, symptoms resolve within 7–10 days. However, approximately 10–15% of these patients develop persistent symptomatology lasting weeks, months or even years after injury (2). This phase of chronic symptoms is known as the post-concussion syndrome. The patient is considered to be chronic when symptoms persist longer than 4-12 weeks.
It is assumed that the post-concussion syndrome manifests secondary to brain injury leading to alterations in brain biochemistry, neurophysiology, and metabolism; the problem is assumed to be in the brain. However, it is now understood that cervical spine injury is often involved in the post-concussion syndrome. In some cases, cervical spine injury may be primarily responsible for the symptoms of the post-concussion syndrome.
Studies have documented that there is considerable overlap of the signs and symptoms of mild traumatic brain injury, the post-concussion syndrome, and of whiplash injury to the cervical spine (2). In 2015, a study published in the journal The Physician and Sportsmedicine, titled “The Role of the Cervical Spine in Post-concussion Syndrome,” notes (2):
“Injury or dysfunction of the cervical spine has been shown to cause headaches, dizziness and loss of balance, nausea, visual and auditory disturbances, reduced cognitive function, and many other signs and symptoms considered synonymous with concussion.”
A proposed mechanism for persisting symptomatology following concussion (the post-concussive syndrome) is “concomitant low-grade sprain–strain injury of the cervical spine occurring concurrently with significant head trauma.”
“Any significant blunt impact and/or acceleration/deceleration of the head will also result in some degree of inertial loading of the neck potentially resulting in strain injuries to the soft tissues and joints of the cervical spine.”
“Acceleration/deceleration of the head–neck complex of sufficient magnitude to cause mild traumatic brain injury is also likely to cause concurrent injury to the joints and soft tissues of the cervical spine.”
It is “well established that injury and/or dysfunction of the cervical spine can result in numerous signs and symptoms synonymous with concussion, including headaches, dizziness, as well as cognitive and visual dysfunction; making diagnosis difficult.”
“The symptoms of headache and dizziness, so prevalent in concussion-type injuries, may actually be the result of cervicogenic mechanisms due to a concomitant whiplash injury suffered at the same time.”
|Signs and Symptoms of Concussion|| Signs and Symptoms of |
Whiplash Cervical Injury
Pressure in Head
|Neck pain|| Neck/shoulder pain|
Reduced/painful neck movements
Sensitivity to Light
| Difficulty remembering Confusion |
Feeling Like “In a Fog”
| Memory problems|
|Sensitivity to Noise||Ringing in Ears|
| Feeling Slowed Down|
“Don’t Feel Right”
Nervous / Anxious / Irritable
Sadness / More Emotional
Fatigue / Low Energy / Drowsiness
Trouble Falling Asleep
|Reduced/painful Jaw Movements|
Numbness, Tingling or Pain in Arm or Hand
Numbness, Tingling or Pain in Leg or Foot
Lower back pain
There is a probability that the forces required to cause a mild traumatic brain injury will also injure the soft tissues of the cervical spine. The range of linear impact accelerations causing concussion injury is between 60—160 G, with the peak occurring at 96 G (3). Whiplash injuries can occur at accelerations of 4.5 G (4). Thus it is highly likely that individuals who experience the G forces to sustain a concussion will also experience cervical spine injury.
Anatomically and physiologically, the cervical spinal cord is connected to the brainstem and brain.
- Numerous brain stem structures receive mono-synaptic inputs from the C2 dorsal root ganglion afferents, including (5): Lateral cervical nucleus; Central cervical nucleus; Caudal projections to C5 level; Cuneate nucleus, lateral cuneate nucleus; Nucleus tractus solitarius Intercalatus nucleus; Nucleus VIII of the vestibular system; Trigemino-cervical nucleus (for headache nociception)
- ‘Cervicogenic Vertigo’ is “both [a] monosynaptic and polysynaptic reflex pathways from the upper cervical spine afferents (associated with a rich innervation from joint and muscle proprioceptors in the cervical spine) to the brainstem structures associated with balance.” (2)
- Cervical ocular and vestibular reflexes can “initiate balance disturbances and symptoms associated with this [post-concussive] problem” (6).
- Cervicogenic headache has been recognized for decades (7).
In 2006, researchers from the University of Guelph, Ontario, CAN, published a study in the journal Brain Injury, titled (8):
Is There a Relationship Between
Whiplash-Associated Disorders and Concussion in Hockey?
The authors examined the relationship between the occurrence of whiplash-associated disorders and concussion symptoms in hockey players. The study design was a prospective cohort observational study. Twenty hockey teams were followed prospectively for one season. Team therapists completed acute and 7-10 day follow-up evaluation questionnaires for all of the players who received either a whiplash mechanism injury or a concussion.
The authors found that essentially all patients who received a whiplash-mechanism injury also sustained some degree of mild traumatic brain injury. Likewise, all patients who received a mild traumatic brain injury also showed evidence of cervical spine injury. The authors concluded:
“There is a strong association between whiplash induced neck injuries and the symptoms of concussion in hockey injuries.”
“Both should be evaluated when dealing with athletes/patients suffering from either injury.”
In 2013, researchers from the University of Calgary, Calgary, Alberta, CAN, published a study in the Clinical Journal of Sport Medicine, titled (9):
Preseason Reports of Neck Pain, Dizziness, and Headache
as Risk Factors for Concussion in Male Youth Ice Hockey Players
The objective of this study was to determine the risk of concussion in youth male hockey players with preseason reports of neck pain, headaches, and/or dizziness. The authors pooled data from 2 prospective cohort studies. A total of 3,832 male ice hockey players aged 11 to 14 years (280 teams) participated.
Participants recorded baseline preseason symptoms of dizziness, neck pain, and headaches on the Sport Concussion Assessment Tool. Concussions that occurred during the season were recorded using a validated prospective injury surveillance system. The findings were as follows:
- Preseason reports of neck pain and headache increased the risk of concussion by 67%.
- Preseason dizziness increased the risk of concussion by 211%.
- A combination of any 2 symptoms (neck pain, headaches, dizziness) increased the risk of concussion by 265%.
The authors concluded:
“Male youth athletes reporting headache and neck pain at baseline were at an increased risk of concussion during the season. The risk was associated with dizziness and any 2 of dizziness, neck pain, or headaches.”
The implication of this study is that athletes with neck pain are at an increased risk for concussion. They suggest all such athletes should be identified prior to the season.
The studies reviewed below have concluded that injuries of the cervical spine are responsible for post-concussion syndrome signs and symptoms. The “post-concussive syndrome: signs and symptoms showed excellent clinical outcomes following treatment to the cervical spine.”
In 1990, researchers from the Department of Rheumatology, County Hospital of Aarhus, Denmark, published a study in the journal Cephalalgia, titled (10):
An Open Study Comparing
Manual Therapy with the use
of Cold Packs in the Treatment of Post-traumatic Headache
- The authors used 19 patients who had sustained head trauma and who were still suffering from headaches one year later. These patients entered a prospective clinical controlled trial to find out if specific manual therapy on the neck could reduce their headache.
- Ten patients were treated twice with manual therapy and nine patients were treated twice with cold packs on the neck. The pain index was calculated blindly.
- Two weeks after the last treatment the mean pain index was significantly reduced to 43% in the group treated with manual therapy compared with the pretreatment level. At follow-up five weeks later, the pain index was still lower in this group compared with the group treated with cold packs. The authors concluded:
“Manual therapy used in this study seems to have a specific effect in reducing post-traumatic headache.”
“The result supports the hypothesis of a cervical mechanism causing post-traumatic headache and suggests that post-traumatic dizziness, visual disturbances and ear symptoms could be part of a cervical syndrome.”
In 1994, researchers from the Department of Physiotherapy, University of Queensland, Australia, published a study in the journal Cephalalgia, titled (11):
Cervical Musculoskeletal Dysfunction in Post-Concussional Headache
The authors note, “persistent headache is a common symptom following a minor head injury or concussion, possibly related to simultaneous injury of structures of the cervical spine.”
This study measured aspects of cervical musculoskeletal function in a group of twelve patients with post-concussion headache and in a normal control group. The post-concussion headache group was distinguished from the control group by the presence of painful upper cervical segmental joint dysfunction, less endurance in the neck flexor muscles and a higher incidence of moderately tight neck musculature. The authors concluded:
“As upper cervical joint dysfunction is a feature of cervicogenic causes of headache, the results of this study support the inclusion of a precise physical examination of the cervical region in differential diagnosis of patients suffering persistent headache following concussion.”
In 2014, researchers from the University of Calgary, Alberta, CAN, and the University of British Columbia, Vancouver, British Columbia, CAN, published a study in the British Journal of Sports Medicine, titled (12):
Cervicovestibular Rehabilitation in Sport-related Concussion:
A Randomised Controlled Trial
These authors note “concussion is a common injury in sport. Most individuals recover in 7-10 days but some have persistent symptoms. The objective of this study was to determine if a combination of vestibular rehabilitation and cervical spine physiotherapy decreased the time until medical clearance in individuals with prolonged post-concussion symptoms.”
This study was a randomized controlled trial. Consecutive patients with persistent symptoms of dizziness, neck pain and/or headaches following a sport-related concussion (12-30 years, 18 male and 13 female) were randomized to the control or intervention group.
Both groups received weekly sessions with a physiotherapist for 8 weeks or until the time of medical clearance. Both groups received postural education, range of motion exercises and cognitive and physical rest until asymptomatic followed by a protocol of graded exertion. The intervention group also received cervical spine and vestibular rehabilitation. The primary outcome of interest was medical clearance to return to sport, which was evaluated by a study sport medicine physician who was blinded to the treatment group.
In the treatment group, 73% of the participants were medically cleared within 8 weeks of initiation of treatment, compared with 7% in the control group. This difference, 70% v. 7%, is quite clinically significant. The authors concluded:
“A combination of cervical and vestibular physiotherapy decreased time to medical clearance to return to sport in youth and young adults with persistent symptoms of dizziness, neck pain and/or headaches following a sport-related concussion.”
In 2015, researchers from Canadian Memorial Chiropractic College and State University of New York at Buffalo, published a study in the journal The Physician and Sportsmedicine, titled (2):
The Role of the Cervical Spine in Post-concussion Syndrome
This paper reviews the existing literature surrounding the numerous proposed theories of post-concussive syndrome and introduces another potential, and very treatable, cause of this chronic condition; cervical spine dysfunction due to concomitant whiplash-type injury.
The authors note that the symptoms of concussion are due to neuronal dysfunction and not due to structural damage of the involved neurons, which is “why conventional structural imaging techniques such as CT and MRI are typically unremarkable.”
The authors discuss the cases of 5 patients who were diagnosed with post-concussive syndrome, who experienced very favorable outcomes following various treatment and rehabilitative techniques aimed at restoring cervical spine function; treatment included spinal manipulation.
These authors propose that a cervical injury, suffered concurrently at the time of the concussion, acts as a “major symptomatic culprit in many post-concussive syndrome patients.”
These authors present 5 case studies of patients diagnosed with post-concussive syndrome who were treated successfully in a chiropractic clinic. Their improvement was rapid and documented using standard measurement outcomes, and the results were long lasting. Treatment included:
- Active Release Therapy (ART)
- Localized vibration therapy over the affected muscles
- Spinal manipulative therapy (SMT) of the restricted joints
- Low-velocity mobilizations (on 1 patient)
These authors conclude:
“Management of persistent post-concussion symptoms through ongoing brain rest is outdated and demonstrates limited evidence of effectiveness in these patients.”
“Instead, there is evidence that “skilled, manual therapy- related assessment and rehabilitation of cervical spine dysfunction should be considered for chronic symptoms following concussion injuries.”
In 2016, researchers from Temple University and Indiana University, published a study in the Journal of Athletic Training, titled
Cervical Injury Assessments for Concussion Evaluation
The objective of this study was to provide information on clinical tests that can differentiate cervical injury from pathologic conditions of vestibular or central origin. We will review the three most clinically supported tests below.
The authors note that concussion symptoms may actually be caused by cervical injury. They state:
“Cervical injuries and concussion can share similar mechanisms and nearly identical symptoms or causes.”
“If patients exhibit dizziness, headache, or other symptoms after a collision, they are almost automatically diagnosed as having sustained a concussion. Patients with cervical injury after a pathomechanical event affecting the head or neck may manifest nearly identical symptoms.”
“Symptoms or causes alone may be insufficient to differentiate between patients with a concussion and patients with cervical injuries.”
“Whereas concussion and cervical injury may induce almost identical symptoms, their treatment methods differ.”
Patients with cervical injury respond immediately to soft tissue massage, passive stretching, strength training, cryotherapy, thermotherapy, vestibular maneuvers, and cervical manipulations.
The common symptoms of concussion include:
- Disturbances in memory
- Disturbances in concentration
- Sleep disturbance
- Neck pain
- IrritabilityBlurred vision
Cervical spine injury, especially of the upper cervical spine, disrupts normal afferent input into the brainstem and brain.
Commonality Symptoms of Concussion and Cervicogenic Injury
|Chronic traumatic encephalopathy||YES||NO|
|Decreased cervical range of motion||NO||YES|
|Decreased isometric neck strength||YES||YES|
With the large overlap of symptoms between cervical injury and concussion, objective testing to differentiate between the two are critically important. When test show that cervical injury is causing abnormal physiology in the brainstem and brain, treatment should be directed to the cervical spinal injuries. These tests are summarized in a form at the end of the bibliography for this paper. “The primary reason more clinicians were not incorporating cervicogenic tests into their routine evaluations of head trauma was a lack of education and awareness of the appropriate tests and methods.”
- The key to the differential diagnosis of cervicogenic syndromes is testing if cervical afferents cause symptoms or disruptions in balance and ocular motor control.
- Each test attempts to remove visual and vestibular influences and isolate cervical position or movement-sensory information.
- “The reproduction of symptoms or loss of motor-control accuracy during testing then can be attributed to cervical spine involvement.”
Cervical joint-reposition error test (JPET)
- The JPET is the ability to relocate the head to a starting neutral position after maximal rotation or flexion or extension with eyes closed.
- It is performed by attaching a laser pen to the top of the patient’s head. A target is aligned with the point of the laser pen on the wall, and patients are instructed to close their eyes. They passively flex the neck and are instructed to return to the starting position. The process is repeated for extension and left and right rotation. After each trial, a mark is made on the target where the laser pen tip stops. The distance from the marked point to the center of the target is then measured.
Smooth-pursuit neck-torsion test (SPNTT):
- Smooth eye movements occur as the eyes follow a moving object while the head is still.
- The patient sits or stands in a neutral position.
- The patient actively rotates the neck 45° to the right or left and performs a smooth pursuit eye-tracking test.
- Neck rotation will reduce smooth pursuit among patients with vertigo due to whiplash-associated disorders but will not reduce it among healthy control participants or patients with central or peripheral vertigo.
Head-neck differentiation test (HNDT)
- The HNDT is performed with the patient sitting in a chair that rotates.
- The patient is instructed to look at a point on the wall and hold the head still while the clinician rotates the body under the head.
- If symptoms worsen, it indicates cervicogenic vertigo.
Explanations of the biological mechanisms for the improvement and resolution of the signs and symptoms of the post-concussive syndrome by treating the cervical spine typically involve the improvement of either cervical spine nociceptive or proprioceptive input into the central neural axis.
It is anatomically/biologically probable that these cervical spine injuries cause many, and in some cases, most of the symptoms of the post-concussion syndrome.
The Marshall study (2) from The Physician and Sportsmedicine, is most appropriate (and gratifying) to the chiropractic profession. It documents that traditional chiropractic cervical spine management, including spinal manipulation, of chronic patients diagnosed with “post-concussive syndrome” results in rapid and sustained improvement in “post-concussive” signs and symptoms. This allowed the athlete to return to full competition.
All patients suffering from the post-concussive syndrome should be referred to a chiropractor for cervical spine evaluation and treatment.
- Langlois JA, Rutland-Brown W, Wald MM; The epidemiology and impact of traumatic brain injury: a brief overview; Journal of Head Trauma Rehabilitation; Sept-Oct 2006; Vol. 21; No. 5; pp 375–378.
- Marshall CM, Vernon H, Leddy JJ, Baldwin BA; The Role of the Cervical Spine in Post-concussion Syndrome; The Physician and Sportsmedicine; July 2015; Vol. 43; No. 3; pp. 274-284.
- Broglio SP, Surma T, Ashton-Miller JA; High school and collegiate football athlete concussions: A biomechanical review; Annals of Biomedicine Engineering; January 2012; Vol. 40; No. 1; pp. 37–46.
- Spitzer WO, Skovron ML, Salmi LR, Cassidy JD, Duranceau J, Suissa S, et al; Scientific monograph of the Quebec Task Force on Whiplash-Associated Disorders: redefining whiplash and its management; Spine; April 15, 1995; Vol. 20; No. 8 supplemental; pp. 1S–73S.
- Richmond FJR, Corneil BD; Afferent mechanisms in the upper cervical spine; Vernon H, Editor; The cranio-cervical syndrome: mechanisms, assessment, and treatment. Oxford, UK; Butterworth Heinemann; 2003.
- Treleaven J, Jull G, LowChoy N; The relationship of cervical joint position error to balance and eye movement disturbances in persistent whiplash; Manual Therapy; May 2006; Vol. 11; No. 2; pp. 99–106.
- Bogduk N; Anatomy and Physiology of Headache; Biomedicine and Pharmacotherapy; 1995; Vol. 49; No. 10; pp. 435-445.
- Hynes LM, Dickey JP; Is there a relationship between whiplash-associated disorders and concussion in hockey? A preliminary study; Brain Injury; February 2006; Vol. 20; No. 2; pp. 179-88.
- Schneider KJ, Meeuwisse WH, Kang J, Schneider GM, Emery CA; Preseason reports of neck pain, dizziness, and headache as risk factors for concussion in male youth ice hockey players; Clinical Journal of Sport Medicine; July 2013; Vol. 23; No. 4; pp. 267-72.
- Jensen OK, Nielsen FF, Vosmar L; An open study comparing manual therapy with the use of cold packs in the treatment of post-traumatic headache; Cephalalgia; October 1990; Vol. 10; No. 5; pp. 241–250.
- Treleaven J, Jull G, Atkinson L; Cervical musculoskeletal dysfunction in post-concussional headache; Cephalalgia; August 1994; Vol. 14; No. 4; pp. 273–279.
- Schneider KJ, Meeuwisse WH, Nettel-Aguirre A, Barlow K, Boyd L, Kang J, et al; Cervicovestibular rehabilitation in sport-related concussion: a randomised controlled trial; British Journal of Sports Medicine; September 2014; Vol. 48; No. 17; pp. 1294–1298.
- Cheever K,Kawata K, Tierney R, Galgon A; Cervical Injury Assessments for Concussion Evaluation; Journal of Athletic Training; December 2016; Vol. 51; No, 12; pp. 1037–1044.
Tests To Identify Presence of Cervical Injury
Cervical spine injury alters cervical afferents to the vestibular nucleus (balance, posture, and eye stability/movements). These tests remove visual and vestibular influences and isolate cervical position and cervical afferent influences. The reproduction of symptoms (dizziness, vertigo, balance disturbance) or loss of motor-control accuracy during testing suggests cervical spine involvement.
|Clinical Test||How to Perform||Results|
| Cervical Joint Repositioning Error Test (JPET)|
The ability to relocate the head to a starting neutral position after maximal rotation or flexion or extension with eyes closed.
After each test, a mark is made on the target where the laser pen tip stops, and the distance from the marked point to the center of the target is measured
| Attach a laser pen to the top of the patient’s head. |
A target is aligned with the point of the laser pen on the wall, and patients are instructed to close their eyes.
They passively flex the neck and are instructed to return to the starting position.
The process is repeated for extension and left and right rotation
|Distance From Target|
____________ Flexion Error
____________ Extension Error
Rt. Rotation Error
Lt. Rotation Error
|Smooth Pursuit Neck Torsion Test (SPNTT)|
Neck torsion will reduce smooth pursuit among patients with vertigo due to neck disorders but will not reduce it among healthy control participants or patients with central or peripheral vertigo
|The patients sits in a neutral position The patient actively rotates the neck 45° to the right or left and performs a smooth pursuit eye-tracking test (following a moving object, like the tip of the doctor’s finger)||Left|
|Head Neck |
Head Cannot Hold Still While Body Spins on Chair with Other Symptom Provocation.
If symptoms worsen, it indicates cervicogenic vertigo
| The patient sits in a chair that rotates.|
The patient is looks at a point on the wall and holds the head still while the clinician rotates the body under the head
“Authored by Dan Murphy, D.C.. Published by ChiroTrust® – This publication is not meant to offer treatment advice or protocols. Cited material is not necessarily the opinion of the author or publisher.”
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