Journal of Rehabilitation Medicine 51-1CompleteIssue | Page 40

Factors associated with persistent post-concussion symptoms
between presence of persisting novel PCS and anxiety
symptoms, as well as with mental and to a lesser extent
physical quality of life on the SF-12. That is, individu-
als who reported lower QoL also reported persisting
novel or worsening PCS.
Of the predictive factors examined, 3 were signi-
ficantly associated with persistent PCS: premorbid
psychological issues, LOC, and having no recall of
receiving information at discharge from ED. Older
age was associated with less PCS reporting than in
the middle or younger age-groups, but this was not a
significant predictor in the final model. The strongest
predictor, namely premorbid mental health issues, has
been associated with persistent PCS in numerous stu-
dies to date (2, 8–10, 23, 24, 38). It has been speculated
previously that individuals with a pre-injury psychiatric
history may respond to the experience of mTBI and PCS
with greater anxiety, which may, in turn, exacerbate
their PCS (37). The association of anxiety with PCS
reporting supports this premise and is consistent with
recent findings by van der Naalt et al. (10).
Nevertheless, the presence of LOC was also associa-
ted with persistent PCS, suggesting that the severity of
the injury did also contribute to persistent symptoms
in this study. The study sample had relatively mild
injuries, with only 19.8% having any reported LOC.
Previous studies have shown mixed findings, but many
have not examined LOC as a predictor, or not found it
to be a significant predictor (9). Some previous studies
of mTBI outcomes have only included cases with some
LOC (2, 8, 37), whereas others have also included a
substantial majority without documented LOC (4, 24).
From the results of the present study, it would appear
that the occurrence of LOC may be an important injury
severity marker. The duration of LOC has possibly
proven less useful in previous studies, due to variability
in methods of its measurement (7, 9).
Finally, it was apparent that a higher percentage
of participants who reported novel PCS post-injury
reported not receiving information about mTBI and
PCS at discharge from ED than those who were unsure.
Of participants unsure about whether they received
information, a higher proportion did not report novel
PCS than did. This lends some support to the use of
such information. Although an inexpensive and rela-
tively simple form of intervention, the results of our
recently completed implementation trial suggested
that achieving reliable distribution of such informa-
Bosch M, McKenzie JE, Ponsford J, Turner S, Chau M, Tavender EJ, et
al. Evaluation of a targeted, theory-informed implementation intervention
designed to increase uptake of emergency management recommendations
regarding adult patients with mild traumatic brain injury: Results of the
NET cluster randomised trial. PLoS Med (in submission).
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37
tion is extremely difficult 1 . However, it also needs to
be pointed out that those who did recall receiving the
information did not report significantly fewer symp-
toms that those who did not recall it at this long time
after injury.
This study had limitations and results need to be
viewed in light of several factors. All predictive models
accounted for only a small proportion of the variance,
suggesting that there are other factors accounting for
reporting of PCS at follow-up that were not measured
in the current study (e.g. maladaptive coping (10), post-
injury neuropsychological functioning (9), and pre-
sence of neck pain in the ED, PCS and post-traumatic
stress at 2 weeks post-injury (39)). The participants in
this study had very mild injuries, with more than 80%
having no LOC and 95.6% having a GCS of 15/15 on
presentation to the ED. In part this reflected the fact that
only patients with GCS of 14 or 15 were included in
the study. However, 85.7% were not scanned, making it
possible that some complicated mTBI participants were
included in the study, which could have confounded
the results. The mean age of participants of 54 years
was older than that seen in most mTBI samples, with a
higher than usual proportion of women and of injuries
due to falls. This may reflect that the participating EDs
in this study were predominantly short stay units rather
than trauma centres, where many large mTBI studies
have historically been conducted and more complex
trauma cases are likely to be included, with more as-
sociated injuries other than mTBI and potential for
post-traumatic stress. This highlights the importance
of considering sampling methods in relation to findings
from mTBI studies. Only a small proportion of EDs
approached agreed to participate in the NET trial and
these were predominantly short-stay units rather than
trauma centres. This may have influenced the rates of
symptom reporting for the above-mentioned reasons.
Furthermore, follow-up took place at a wide-ranging
interval of 130–321 days post-injury. Whilst time post-
injury was not associated with symptom reporting, this
relatively long delay after injury may have influenced
reliability of recall of information provided. Although
all intervention centres were instructed to use the
designated information booklets, we cannot be sure
that they provided this information rather than some
other form of information. Finally, there are limitations
related to data collection via the telephone; namely,
the inability to control the participant’s environment
or see their body language.
Overall, this study has identified that the majority
of individuals presenting to EDs with uncomplicated
mTBI (GCS 14–15) make a good recovery. A relatively
small, but significant, proportion (18.7%) have signifi-
cant persisting problems. They are more likely to have
J Rehabil Med 51, 2019