EWJ Dec 2023 - Journal - Page 57
recently, it has been pointed out that, "this is a type of
diagnostic bias where undue emphasis is placed on one aspect of the presentation (the initial injury), which has the effect of obscuring other elements of the diagnostic
process" (Sharp & Jenkins, 2015, p.174).
the data reveals that the actual figure of those
with poorer outcomes is between 1 and 5%. This
over-calculation which has been mistakenly perpetuated throughout the MTBI literature for many years
occurred primarily because the operational definition
of MTBI in a large number of reported studies required only a momentary loss of consciousness and
was, therefore, over-inclusive. The figure was also elevated by a patient endorsing a single, non-specific symptom after 1 year (eg: headache) which led to
study authors considering them to have an unresolved
MTBI (Iverson, 2005, p.307). Ruff ’s data were reviewed (Rohling et al, 2012) and it was concluded that
there was compelling evidence against the existence
of a chronically impaired sub-group of MTBI with significant continued deficits. Rohling et al further concluded that, “misidentifying common daily cognitive,
somatic, and affective phenomena, which covary with stress
as post-concussive, can reify these symptoms and in someone
prone to being excessively focused on bodily sensations may
create a disorder where none would otherwise exist” (p.210).
This point is further reinforced by research by Waljas
et al (2015) who reported a 31% false positive rate for
persisting symptoms in a normal control group.
It is the case that pursuing this exclusively physical
/ medical explanation misses the relative and significant contribution of psychological and personality
factors, past medical history, systemic issues, secondary gain (usually, but not always, financial) and
confounding health issues (pain, iatrogenic effects of
medications):
There is "increasing recognition by clinicians and policy
makers of the relevance of a multifactorial bio-psycho-socioecological model to TBI (The Lancet, 2022, p.1029)
"prognosis in mild TBI is driven to a greater extent by what
the patient brings to the injury (eg: pre-injury co-morbidities
and mental health)..." (The Lancet, 2022, p.1037). This
latter argument echoes a similar view expressed by
Lingsma et al (2015) who had suggested that, “in moderate and severe TBI outcome is determined by what the injury
brings to the patient whereas in MTBI it is what the patient
brings to the injury and our data support this statement….the
combination of pre-existing psychiatric conditions, low education, and assault as a cause of injury as predictors of 6 month
outcome poses the question of whether persistent complaints
are fully attributable to the TBI” (p.92). This was followed
up by Van Der Naalt (2017) who remarked that, "the
risk of both cognitive and psychological symptoms co-exist
from the beginning and that those most at risk of poor outcome at 6 months post injury are those who express emotional
distress and maladaptive coping style at 2 weeks (when combined with pre-accident mental health problems, low education and older age)……" . These views were taken up
and echoed by Yeates et al (2017) who considered
that, “recovery from the injury is....shaped by
pre-injury, comorbid and contextual factors”.
What about symptom exaggeration?
Lippa et al (2016, p.271) state that, “concern regarding
symptom exaggeration is particularly warranted in situations
where primary or secondary gain is involved such as medicolegal evaluations..”. Whilst it is for the Court to judge
what an individual’s motivations might be in bringing
a personal injury claim, the Expert is expected to provide an opinion and can certainly point to incongruities and inconsistencies in a clinical presentation,
based on both clinical experience and knowledge of
published literature (Slick et al, 1999). It is worth bearing in mind that two separate investigations have reported a substantial base rate of 40% of malingering in
MTBI cases (Larrabee, 2003; Mittenberg et al, 2002 –
reported in Rohling et al, 2012).
A comprehensive explanation of persisting
symptoms had been suggested by Waljas et al (2015)
who had found that patients with greater injury severity do NOT report more persistent symptoms, that
patients with a pre-injury history of mental health
problems are more likely to have persistent symptoms
at one-month post-injury, and that although some patients with MTBI show differences on DTI imaging
compared with controls, these patients did not report
more symptoms than those with “normal” white matter. This led the authors to conclude that there
is, therefore, no direct association between the presence of white matter changes and the presence of
persisting symptoms.
What about Functional Neurological Disorder as
an explanation?
Picon et al (2021) stated that, “fear avoidance behavior
was most strongly related to unexpected neurological symptoms and anxiety was most strongly related to unexpected somatic symptoms” after a concussive injury (p.3).
More recently, Mavroudis et al (2023) have reported
that, “the lack of objective evidence for structural brain damage in PCS, combined with evidence of psychological factors
contributing to PCS symptoms and similarities with other
FNDs, suggests a strong case for considering PCS as an
FND…PCS symptoms may be influenced by psychological
and behavioral factors, which can exacerbate underlying neurological impairments and contribute to persistent symptoms”
(p.6).
“The manifestation of Post Concussion symptoms likely represents the cumulative effect of multiple variables, such as genetics, mental health history, current life stress, general
medical problems, chronic pain, depression and substance
abuse.....How people report their symptoms can also be influenced by personality factors and the presence of possible future financial gain (Waljas et al, 2015, p.544)
Summary
• Most head injuries are "mild"
• Full recovery is expected from a single MTBI. There
is no objective, measurable evidence of long-term
cognitive effects of a concussive injury.
• Definition and classification of MTBI can be
problematic. It pays to be aware of the weaknesses in
Despite the well-touted figure of 15% of the MTBI
population being the “miserable minority” (Ruff et al,
1996) who do not fully recover, a closer analysis of
EXPERT WITNESS JOURNAL
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DECEMBER 2023