Research Reports - Postconcussion symptom reporting following multiple mild traumatic brain injuries
J Neurotrauma. 2013 Mar 4
Silverberg N, Lange R, Millis S, Rose A, Hopp G, Leach S, Iverson G
Primary Objective: The relationship between prior mild traumatic brain
injury/injuries (MTBI) and recovery from a subsequent MTBI may be complex. The
present study investigated three factors hypothesized to influence this relation:
(i) the number of prior MTBIs, (ii) the interval between MTBIs, and (iii) the
certainty level of prior MTBIs. Research Design: Retrospective cross-sectional.
Methods and Procedure: Participants (N=105) were evaluated at a concussion clinic
on average one month after sustaining an MTBI, defined by World Health
Organization diagnostic criteria. Main Outcomes and Results: Approximately half
the sample had at least one prior MTBI. Subgroups with 0, 1, or 2+ prior MTBIs
did not differ in levels of current postconcussion symptom reporting on the
British Columbia Postconcussion Symptom Inventory. Time since the most recent
prior MTBI was significantly associated with current postconcussion symptom
reporting. This relation was best characterized as logarithmic, i.e., the impact
of prior MTBI(s) lessens exponentially as time elapses to a subsequent MTBI.
Defining prior MTBIs with a higher certainty level (i.e., probable versus
possible) was not consistently associated with greater postconcussion symptom
reporting. Conclusions: Participants with prior MTBIs did not report more
postconcussion symptoms than those with no history of prior MTBI. However, prior
MTBI(s) were associated with increased symptom reporting from a subsequent MTBI
to the extent they occurred closer in time. Having one or two prior remote MTBIs
was not associated with worse outcome from subsequent MTBI in this sample.