The true objective of the care of concussions is to prevent Every paratrooper realizing his annual medical visit in from a short-term recurrence18-20. his medical unit (of all of them supporting the 11° para- trooper’s brigade) from January 1to December 31 In a second part, post-traumatic chronic encephalopa- 2016, was included in our study and was given a self- thy may be related with a progressive neurodegenera- reported questionnaire. Military personnel who do not tion by a hyperphosphorylated tau protein deposition belong to paratrooper’s unit, paratrooper coming for in the brain. The development of this early dementia any other reason than his annual medical visit or who might be the consequence of a cumulative effect from does not answer to the questions from the main criterion long-term concussions. It comes out initially by atten- have been excluded from the study. tion and focus disorders and then evolves to the appa- rition of a depressive syndrome, of behavioral and Questionnaires were sent to the seven paratrooper’s cognitive disorders going up to dementia. Suicidal medical units. They have been distributed according to ideations are also one of the characteristics of this inclusion criteria and ethical and bioethics French guide- pathology20-22. lines. Quantitative variable with normal distribution were analyzed with a Student’s test and quantitative Unlike civilian sports, static line parachuting is a tactical variable with non-normal distribution were analyzed by set up mode for armed forces. While it is easy to medically a parametric Mann-Withney’s test. The qualitative varia- suspend an athlete with a suspicion of concussion, a para- bles were represented by their percentage and their trooper is to remain in full possession of his abilities to 95% confidence interval and were compared with a Chi2 comply with his mission after the drop. There is no availa- test, a Yates corrected test or a Fisher test, if indicated. ble data about concussion epidemiology among French Analyses with p < 0.05 were regarded as statistically paratroopers. Through our study, we want to determine if significant. static line parachuting may cause concussions. RESULTS MATERIELS AND METHODS Description of the study's population The main purpose of this study is to assess the preva- Over the duration of our study, 897 questionnaires lence of paratrooper victims of concussion after a static were answered, but three of them were excluded line drop. The secondary objectives are to describe the from the study because all main criterion data were distribution of symptoms revealing a concussion and to not answered. In total, 894 paratroopers have been measure concussion’s prevalence according to these included. In this population, the male/female ratio of variables: age, morphology and seniority in airborne 16/1, two paratroopers did not mention their gender. troops. Mean age of the study’s population was 29 years old We realized a descriptive and retrospective multicen- [18; 52]. Paratroopers are mean 1,75m tall [1,56; 1,95] ter study from simple self-reported questionnaires and weigh mean 74 kilograms [49; 102]. Mean num- seeking to reveal the occurrence of French paratroo- bers of drops by paratrooper was 71 during its career, per’s concussions. The first part of the questionnaires and the median was 60 jumps [1; 250].When they contains data related to the person answering it: age, answered the questionnaire, paratroopers have been height, weight, BMI, paratrooper’s experience (in serving in airborne troops for 7 years (mean duration) terms of number of drops and seniority in airborne [1; 34]. troop). The second part of the questionnaire eva- Prevalence of paratroopers who suffered a luates the concussion medicalhistory based on the concussion after parachuting experience mTBI standards. One case suspected of concussion is defined as a paratrooper answering at least one “yes” The number of paratroopers suspected of concussion to the following questions: after parachuting static-line drop was 201, which repre- sents 22% [CI 95% 19,”; 24,7] of the subjects included After static-line drop, have you ever suffered from? in the study. - Traumatic brain injury? - Loss of consciousness? Among them, 138 mentioned a traumatic brain injury, - Being groggy/stunned? 136 a “groggy/stunned” feeling, 21 a loss of conscious- - Amnesia? ness, 8 an amnesia, and none of them any convulsion - Out of control movements or shaking? after static-line parachuting. Table number 1 presents paratroopers suspected of concussion according to The third part of the questionnaire determines the pre- diagnostic criteria. (See Table 1). sence of a post-concussion syndrome. It has to be filled only by the paratroopers who completed “yes” at one Some paratroopers reported severalsymptoms that of the first five questions. Paratrooper reports symp- lead to diagnosis of concussion. “Traumatic brain toms appeared or developed long time after the drop, injury” and “groggy/stunned” is the most frequent their intensity, and their duration. We suspect a post- symptom’s combination (with or without loss of concussion syndrome for every paratrooper reporting consciousness). 75 paratroopers, representing 37% of VOL. at least three symptoms among the list, and if these paratroopers suspected of concussion reported this 94/3 symptoms evolved for longer than a week. combination. International Review of the Armed Forces Medical Services 20 Revue Internationale des Services de Santé des Forces Armées