Many patients with mild TBI (mTBI) will have post-concussive syndrome and the evaluation of post-concussive symptoms requires an understanding of the multiple factors relevant to the production and maintenance of symptoms following TBI. The purpose of this study was to evaluate the transcranial Doppler (TCD) determined incidence of abnormal cerebral hemodynamics in patients with long-term effects of wartime mTBI.
Material and Methods: The National Intrepid Center of Excellence (NiCoE) at the Walter Reed National Military Medical Center has advanced a 4-week intensive outpatient program that leverages an interdisciplinary holistic patient and family based approach to evaluate and treat service members (SMs) with unremitting symptoms from combat related mTBI. A retrospective review of TCD studies was performed on 174 SMs (4 females) admitted to the NiCoE with post-concussive headaches (mean 38.5± 6.9 years, range 24 to 52). Demographic data was collected by patient self-reports at time of TCD examinations. The average time after last mTBI was 4.6 ± 3.7 years and there were 151 (87%) and 23 (13%) patients with multiple and single mTBI, respectively. All subjects were consented to Protocol #362504 prior to any data collection and analysis. TCD recordings of mean cerebral blood flow velocities (CBFV in cm/sec) and Pulsatility Indices (PI) were recorded. Comprehensive TCD protocol was applied in all cases.
Results: In our cohort there were 46 (26%) with normal cerebral hemodynamics and 128 (74%) patients with abnormal cerebral hemodynamics. 31(18%) and 28 (16%) demonstrated abnormally high CBFV and PIs in one or more vessels, respectively. Abnormally low CBFV’s and PI’s were in one or more vessels observed in 20 (11.5%) and 75 (43%) of patients, respectively. Majority of studied patients had patchy pattern of abnormal data presented in one or few vessels. There were only 2 (1%) and one (0.5%) patients with abnormally high CBFV’s and PI’s present in all studied vessels.
Conclusion: These findings demonstrate that cerebral hemodynamics disturbances are frequent findings in the majority of patients with long-term effects of combat mTBI, therefore utilization of TCD examination is recommended for their recognition and subsequent management.