: Among service members (SMs) with mild traumatic brain injury (mTBI) admitted to
an Intensive Outpatient Program (IOP), we identified qualitatively distinct subgroups
based on post-concussive symptoms (PCS) and characterized changes between subgroups
from admission to discharge. Further, we examined whether co-morbid posttraumatic
stress disorder (PTSD) influenced changes between subgroups.
: Quasi-experimental. Latent transition analysis identified distinctive subgroups
of SMs and examined transitions between subgroups from admission to discharge. Logistic
regression examined the effect of PTSD on transition to the Minimal subgroup (low
probability of any moderate-very severe PCS) while adjusting for admission subgroup
: National Intrepid Center of Excellence (NICoE) at Walter Reed National Military
: 1,141 active duty SMs with persistent PCS despite prior treatment.
: NICoE 4-week interdisciplinary IOP.
Main Outcome Measure(s)
: Subgroups identified using Neurobehavioral Symptom Inventory items at admission and
: Model fit indices supported a 7-class solution. The seven subgroups of SMs were
distinguished by diverging patterns of probability for specific PCS. The Minimal subgroup
was most prevalent at discharge (39.4%), followed by the Sleep subgroup (high probability
of sleep problems, low probability of other PCS; 26.8%). 41% and 25% of SMs admitted
within the Affective (i.e., predominantly affective PCS) and Sleep subgroups remained
within the same group at discharge, respectively. The 19% of SMs with co-morbid PTSD
were less likely to transition to the Minimal subgroup (odds ratio=0.28; p<.001) and were more likely to remain in their admission subgroup at discharge (35.5%
with PTSD vs. 22.2% without).
: The majority of SMs achieved symptom resolution following participation in the IOP,
with most transitioning to subgroups characterized by reduced symptom burden. SMs
admitted in the Affective and Sleep subgroups, as well as those with PTSD, were most
likely to have continuing clinical needs at discharge, revealing priority targets
for resource allocation and follow-up treatment.