4. Discussion
PCS patients are characterized by their heterogeneity and the syndrome
is in many ways used as an umbrella-term for several complex and
overlapping physiological and psychological pathologies. When examining
the cases we found that, while having had similar experiences, they had
different primary symptoms, different concerns and varying degrees of
emotional and physical debilitation. Some researchers have argued that
dividing PCS into various subcategories, or so called ‘post-concussion
disorders’, could be used to improve outcomes and better treat
underlying causes.28,57–59 Others have suggested the
use of the RPQ, with additional questionnaires, as a possible
classification system.60 While categorizing the cause
and effect relationships remains important in advancing the treatment of
PCS, the exact mechanisms between symptomatology and pathology is still
unclear. Bearing this in mind, there is a need for a rehabilitation that
is multifaceted, explorative and tailored to the
individual.4 To further reflect on this process, the
following section will examine the nature of PCS pathology and
rehabilitation through the lens of the EBD model, while contextualizing
our cases.
4.1 Best Research Evidence
Dysfunction of the ANS, or dysautonomia, acutely following a mTBI has
been linked to symptoms of exercise intolerance, lowered tolerance to
mental and physical stimuli, decreased cognitive ability, increased
stress response and emotional dysfunction.28,61,62Prolonged dysautonomia is prevalent in the PCS group, with a recent
review finding at least one form of autonomic dysregulation in the
majority of patients.27 Evidence shows that the ANS
plays a central role in psychological well-being63–65and that declining mental health after a mTBI is unfortunately a common
occurrence,35,66 with PCS patients demonstrating
higher incidence rates of both depression and anxiety compared to
controls.67,68 Our cases reported an inability to deal
with large crowds and various degrees of anxiety, frustration, worry or
depression as well as reduced tolerance to external stimuli contributing
to social isolation. This is in line with what is often observed in the
clinical practice where many PCS patients will abstain from social
activities to prevent symptom exacerbation. This abstinence functions as
a negative feedback loop creating further withdrawal and worsening
symptoms. Considering that prolonged social isolation is linked to poor
mental health outcomes in the general population,69,70it is not entirely clear to what extent the relationship with PCS is
causal or correlated. Furthermore, depression and anxiety might be risk
factors for initially developing PCS.71,72 Yet,
studies on rodents have found evidence of causality, in which induced
mTBI disrupts limbic system function, subsequently leading to long
lasting depressive, fearful and anxious
behavior.73–75 Whatever the case, the
neuropsychological nature of PCS makes providing psychosocial coping
strategies a viable part of the multidisciplinary approach, and some
reviews have supported the use of cognitive behavioral therapy in
improving psychosocial outcomes76; however, more
research is needed.
Meditation and mindfulness,77–80 body awareness
therapy,81–83 breathing exercises and
stretching,84,85 have shown to be effective ways of
modulating the ANS, lower sympathetic activity and improve biomarkers of
stress in various populations. Little evidence exists on treatments
specifically addressing dysautonomia as a result of mTBI, although one
pilot study did show improvements in QOL and self-efficacy on a group of
PCS patients after undergoing a mindfulness-based
intervention.86 Moreover, studies show that meditation
can improve cognition and regulate CBF,77,87 making it
an area of interest considering that CBF disruptions are linked to mTBI
and PCS symptomatology.24,88 The efficacy of
meditation techniques and body awareness strategies can vary between
individuals89 and some techniques can be harder to
conceptualize than others, which was illustrated by Case 3 who expressed
difficulty in this regard. Our modified BBAT intervention in Study B was
directed at addressing the high arousal and stimuli intolerant state of
our cases, hopefully modulating the ANS and reducing PCS symptoms. While
both cases reported positive associations with the sessions, only Case 4
experienced symptom relief and significant improved QOL. Considering
that the intervention lasted 3 weeks, a longer duration of exposure may
have been required to more accurately assess the protocol, as a duration
of up to 8 weeks has been necessary before experiencing the full
benefits of similar methods.90
Exercise intolerance is a common phenomenon in PCS patients and all of
our cases reported having experienced symptom exacerbation during
physical activity. Studies have found increased blood pressure (BP), HR
and arterial CO2 in PCS patients compared to healthy controls during
exercise, which may be linked to the changes in CBF and a reduced
ability of the ANS to regulate orthostatic BP.22,91,92This exercise intolerance occurs at different ranges of HR and while
finding the appropriate range for the individual can be challenging,
abstaining from exercise and physical activity entirely is not
recommended.92 Both cases in Study A showed a
significant decrease in their PCS symptoms post-intervention and were
ultimately able to increase their HR intensity, relative to their
maximum HR, during exercise by 15% and 12%, for Case 1 and 2
respectively, without symptom exacerbation. However, as the cases
simultaneously underwent cervical treatment, it is not possible to
isolate the results of the exercise intervention completely. Yet our
findings are in line with other studies showing improvements in
physiological exercise biomarkers and PCS symptoms using similar
protocols.59,91,93 This may be partly due to changes
in CBF, as a pilot study, using fMRI, found that PCS patients had a
normalization of brain activity and CBF after the implementation of a
submaximal aerobic intervention.94 An important aspect
of the protocol is keeping intensity levels below symptom threshold,
before gradually increasing the intensity while assessing individual
response. Early initiation of aerobic exercise has been associated with
a faster recovery95; however, overexertion at
different stages post-mTBI can be detrimental15,96–98and some evidence suggests that the appropriate intensity is
timing-based.99 It is therefore recommended that
practitioners monitor progress under controlled conditions and with the
proper testing tools. A high quality and specifically developed method
for testing this is the Buffalo Concussion Treadmill
Test,100 but other testing methods with comparable
protocols could be similarly applied.
Whiplash is commonly associated with PCS and exists both as part of the
symptomatology, as well as a comorbidity. It has similar injury
biomechanics to mTBI, such as the abrupt acceleration and deceleration
of the cervical spine and head, and shares a majority of
symptoms.101 One of the underlying mechanisms behind
this may be cranial nerve trauma, including the vagus nerve which
regulates the ANS,102,103 either as a direct result of
impact, or as a secondary effect based on changes in arthrokinematics
and joint degeneration.104,105 Cervical trauma has
been linked to oculomotor deficiencies32,106,107 and
whether as a result of whiplash or otherwise, issues with convergence,
accommodation and saccades occur regularly after mTBI and often lingers
in patients with PCS.19,108 Screening for this, and
possibly referring to neuro-ophthalmologic treatment, is
recommended.109
All our cases reported cervical stiffness and pain, and evidence shows
that a high prevalence of various cervical and periarticular impairments
are common after a mTBI. These include postural imbalances, myofascial
triggers, muscle weakness, decreased joint mobility and weakness of
cervical flexors associated with cervicogenic
headaches.110,111 Considering this, and that up to
50% of whiplash patients still report symptoms a year after
injury,112 cervical pathology is a critical
consideration in the PCS rehabilitation.113–115 Both
cases in Study A reported reductions in cervical associated symptoms
such as dizziness, nausea, and headaches, although only Case 2 improved
in CCFT grading. These findings are inconclusive, but other studies have
suggested that deep flexor strengthening can have a positive effect on
neck-related issues in some PCS patients114 and that
cervical and vestibular rehabilitation may reduce cervicogenic
symptoms.116,117 A variety of manual treatments may
also improve outcomes, however, efficacy seems highly individual and
more research is needed.113,118 Clinically, some PCS
patients are sensitive to cervical treatment and may respond with
symptom exacerbation to mobilizations, manipulations, strengthening
exercises and even stretching.
4.2 Clinical Expertise
When initiating the PCS rehabilitation, identifying potential physical
and mental barriers to activity, and acknowledging these limitations, is
an important part of the planning. The process requires submaximal
testing and treatment, and a deliberate slow progression as symptom
thresholds are often low in the early stages. By taking inspiration from
other chronic pain protocols, a proper pacing strategy can be useful in
building tolerance to the treatment,119 and using
positive reinforcement and education on the nature of PCS can help
demystify the condition. This includes focusing on solutions and brain
plasticity instead of limitations when communicating with the patient,
after the initial explanation on pathology, and may help avoid the
unwanted nocebo effects that many chronic pain patients can be
susceptible to.120,121 Setbacks and symptom volatility
are to be expected even with thoughtful consideration to programming,
which is why the practitioner benefits from listening to the patient and
adjusting volume and intensity accordingly, as well as including an
appropriate frequency of examination and re-testing. Working on
acceptance of current disability may help improve emotional outcomes and
patient self-efficacy,122 and celebrating short term
goals helps improve patient motivation and long term
compliance.123,124 Lastly, a key part of administering
the rehabilitation is knowing when a referral is indicated and if
treatment is outside the bounds of expertise of the practitioner.
4.3 Patient preferences
PCS is in many ways a “hidden condition” not easily visible and with
no current standardized biomarkers for diagnosis,125and the path towards rehabilitation is often confusing, and uncertain,
for patients and practitioners alike. Most general practitioners are not
well equipped to treat PCS patients, which is highlighted by the lack of
standardized care, and rest is often the only offered treatment
strategy. Our cases expressed dissatisfaction with their healthcare
providers and felt neglected, as well as not having been taken
seriously. One of the emerging themes derived from the cases was the
importance of meeting other patients in similar circumstances who could
relate to them and inhabit an acknowledging space to freely share
experiences and discuss daily obstacles. This acknowledgement and social
exchange was seen as a central part of coping with the condition, and
should be viewed by practitioners as a legitimate consideration for
rehabilitation in the clinical practice. The use of deliberate framing
and the facilitation of a constructive and accommodating environment in
our studies were beneficial in dealing with the psychosocial challenges.
Cases further highlighted that being in a safe environment, and
adjusting for unwanted mental and physical overstimulation, resulted in
less exacerbation of symptoms. Besides the benefits of rehabilitation on
their mood, stamina and cognitive function, our cases expressed a sense
of meaning in their daily lives when having something to attend,
especially considering that three of the cases were on sick leave, with
none regularly engaging in scheduled social events. The interventions
themselves were seen as motivating factors, regardless of any
improvement in symptoms, suggesting that an active approach has an
inherent advantage compared to a passive or non-active approach even
before considering outcomes. Through the gathering of the qualitative
data, including the group feedback sessions, our cases helped clarify
valuable areas of concern illuminating patient preferences and
individual perspectives on the intervention protocols which would not
have been possible otherwise.
4.4 Model of Conclusion
By taking advantage of the three dimensions of the EBP model as a
methodological approach to the PCS cases, this paper incorporated the:
Best Research Evidence, Clinical Expertise and Patient Preferences,
through an examination of the benefits of two distinct intervention
protocols. These results illustrate how an active and individualized
approach can represent important qualities that can be applied into
further and larger studies, and we recommend additional studies
regarding exposure to active, individualized and graded treatments to
patients dealing with PCS. Based on the results and discussion in this
paper, we have summarized relevant findings and suggestions in the
following modified EBP model (Fig. 7), which may be of help to
practitioners in the clinical practice.
FIGURE 7