A Scoping Review of Registered Clinical Studies on Mild Traumatic Brain Injury and Concussion (2000 to 2019)

BACKGROUND: While many patients with mild traumatic brain injury (mTBI) or concussion recover completely, prolonged postconcussion symptoms remain a challenge for patients and an opportunity for clinical research. This has led to numerous research initiatives over the last 2 decades. OBJECTIVE: To review the characteristics of clinical studies on management of mTBI/concussion; and to examine their definitions of mTBI/concussion. METHODS: This scoping review included all clinical studies on diagnosis and management of patients with mTBI/concussion registered at www.clinicaltrials.gov from 2000 to June/2019. The terms "mild TBI/concussion" were used for the primary search. Definitions of mTBI/concussion were obtained from the protocols. When a definition was missing in the website, the study's investigators were contacted for clarification. RESULTS: There were 225 interventional and 95 observational studies. Most of the studies are focused on treatment (54.7%) or diagnosis (37.5%), while 3.4% examined preventive measures, 2.8% evaluated prognostic instruments, and 1.6% developed registries. Most of the studies in this American database were single-center initiatives led by American and Canadian institutions. The definitions of mTBI/concussion differed widely among 109 studies. CONCLUSION: The results of this review suggest that most of the clinical studies are focused on diagnosis and non-pharmacological therapies for patients with mTBI/concussion. The large number of differing definitions of mTBI/concussion among the studies creates significant limitations when comparing studies. The requirements for registering research protocols on mTBI/concussion should include the necessity to state the definition being used. There is a need for consensus on a uniform definition of concussion.