History, Knowledge, and Education of Sport-Related Concussion Among College Athletes in Japan

Survey Instrument

We used the questionnaire developed by Beidler et al for this study.¹² The survey was first translated into Japanese by the authors (C.T., M.O., Y.H.) and then reviewed by 3 certified ATs who were bilingual in Japanese and English for item clarity. During the translation process, some multiple-choice question options (eg, list of varsity sports, list of medical qualifications) were modified to fit the Japanese collegiate setting.

A pilot survey was conducted from May 3, 2021, to May 13, 2021. Japanese collegiate students (n = 11, mean age = 21.4 ± 1.4 years) who were not registered for varsity sports were asked to complete the survey and evaluate it for clarity to validate the quality of Japanese translation. Because the results of the pilot survey confirmed that the intent of the questions was correctly conveyed to the respondents, no additional changes were made to the questionnaire.

The survey consisted of 6 major categories (31 main questions) and took 10 to 15 minutes to complete: participant demographics (questions 1–14), SRC history (questions 16–20), recognition of SRC (questions 15 and 21–23), SRC knowledge (questions 24 and 25), attitudes toward SRC (questions 26–29), and sources of information about SRC (questions 30 and 31). For the purpose of this study, we analyzed data from the following sections: participant demographics, SRC history, and SRC knowledge. Access to certified medical staff (MED) was determined by the following question: “Do you have consistent access to allied health care professionals (medical doctor, physiotherapist/certified athletic rehabilitation therapist/physical therapist) at your current team?” (question 14) with 2 potential answers, yes (MED_YES) and no (MED_NO). History of SRC was determined by self-reported answer (yes or no) to the following question: “Have you ever been diagnosed with a concussion by a doctor?” (question 19). The SRC knowledge section consisted of 2 components: (1) recognition of SRC signs and symptoms and (2) general knowledge about SRC mechanisms, prognosis, and return to sport considerations (general knowledge).

Survey Distribution

This study was approved by the Human Research Ethics Committee of Waseda University (2021-095). An online survey was distributed using Qualtrics between August 1, 2021, and September 17, 2021. The researcher (C.T.) sent an anonymous survey link to the club representative, who then sent the survey link to its member athletes. Participation in the survey was voluntary, and participants were sent 1 reminder email during the survey period. Participants gave consent to be part of the study at the beginning of the online survey.

Statistical Analysis

Participating sports were categorized by the level of contact based on the classification published by Rice et al: contact (CON), limited contact (LTD), and noncontact (NC; Table 1).¹⁷ Some sports (n = 7) that were not listed in the original classifications were assessed and sorted by the authors (C.T., M.O., Y.H.).

Table 1. Classification of Sports by Level of Contact^a

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One point was added for each correct answer in the SRC knowledge section.⁷ The highest possible score was 49 points, which was the sum of scores from recognition of SRC signs and symptoms (34 points; 20 points for identifying correct SRC signs and symptoms and 14 points for identifying incorrect distractor signs and symptoms) and general knowledge (15 points). In this study, we deemed that a higher score represented better SRC knowledge.

Descriptive statistics were calculated for participant demographics and the SRC knowledge score. We used 2 × 3 χ² tests to examine the associations between (1) access to medical professionals (MED_YES, MED_NO), (2) a history of SRC (yes, no), and (3) previous SRC education (EDU_YES, EDU_NO) by the level of contact (CON, LTD, NC). If statistically significant differences were observed, pairwise comparisons were conducted with Bonferroni correction (ie, P value threshold at .017). We used 2 × 2 χ² tests to examine the influence of access to medical professionals on a history of SRC and previous SRC education. The Mann-Whitney U test, the Kruskal-Wallis test, and the Bonferroni test were used in multiple comparisons to analyze the association between SRC knowledge scores and level of contact, access to medical professionals, a history of SRC, and previous SRC education. Stepwise regression was used to examine whether SRC history or education contributed to SRC knowledge, independent of the level of contact and access to medical staff.

The statistical significance level was set at P < .05, and the statistical significance level for residual analysis was set at P < .005. All statistical analyses were performed with SPSS (version 28.0; SPSS Statistics for Windows, IBM Corp).

Participants

The average age of participants was 19.8 ± 1.3 years (male = 19.9 ± 1.3 years, female = 19.8 ± 1.3 years). Other participant demographic data are summarized in Table 2. The top 5 sports were American football (n = 95, 16.0%), lacrosse (n = 74, 12.5%), soccer (n = 56, 9.4%), rugby (n = 22, 3.7%), and track and field (n = 20, 3.4%).

Table 2. Participant Demographics (N = 593)

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There were 413 athletes in MED_YES (69.6%) and 180 athletes in MED_NO (30.4%; Table 2). Access to medical professionals by the level of contact was CON: MED_YES, n = 301 (78.2%), MED_NO, n = 84 (21.8%); LTD: MED_YES, n = 52 (58.6%), MED_NO, n = 36 (41.4%); and NC: MED_YES, n = 61 (50.4%), MED_NO, n = 60 (49.6%), which resulted in a statistically significant difference ( = 39.44, P < .001). Pairwise comparisons revealed that the CON group was more likely to have access to medical staff than the LTD and NC groups (versus LTD, = 14.3, P < .001; versus NC, = 34.9, P < .001).

History of SRC

A history of SRC was reported in 19.1% (n = 113) of the study participants, of whom 86.7% were in the CON group (Table 2). In the CON group (n = 385), a history of SRC was reported in 25.5% (n = 98) of athletes. Sport-related concussion history was reported in 8.0% (n = 7) and 6.6% (n = 8) of the athletes in the LTD and NC groups, respectively. The leading CON sports played by participants with a history of SRC were American football (n = 28), soccer (n = 16), lacrosse (n = 12), and rugby (n = 12); the LTD sports were baseball (n = 4), cycling (n = 1), figure skating (n = 1), and weight lifting (n = 1); and the NC sports were kyudo (n = 3), soft tennis (n = 2), sailing (n = 2), and track and field (n = 1). History of SRC was statistically different by the level of contact (CON, LTD, NC; = 27.2, P < .001). Pairwise comparisons revealed that the CON group was more likely to have a history of SRC than the LTD and NC groups (versus LTD, = 12.4, P < .001; versus NC, = 19.7, P < .001).

Japanese collegiate athletes with a history of SRC were statistically different by access to medical professionals ( = 4.5, P = .034). Collegiate athletes with a history of SRC had greater access to a medical professional compared with the MED_NO group (MED_YES, 21.3% [n = 88]; MED_NO, 13.9% [n = 25]).

The SRC knowledge score was higher among athletes with a history of SRC (total score: with a history of SRC, median [MD] = 36.0, without a history of SRC, MD = 33.0, U = 2034.5, P < .001; signs and symptoms score: with a history of SRC, MD = 22.0, without a history of SRC, MD = 21.0, U = 21 067.0, P < .001; general knowledge score: with a history of SRC, MD = 13.0, without a history of SRC, MD = 12.0, U = 21 278.5, P < .001). Stepwise regression revealed that history of SRC contributed to higher SRC knowledge, independent of the level of contact and access to medical staff (R² = 0.08, F_1,589 = 10.81, P = .001).

SRC Knowledge Score

The results of the SRC knowledge questions are summarized in Table 3. The average SRC knowledge total score was 33.4 ± 6.1 (range, 18–48). The breakdown of scores by subsection was as follows: identification of correct SRC signs and symptoms, 21.9 ± 4.3 (range, 13–34) and basic knowledge about SRC mechanisms and risks, 11.6 ± 3.0 (range, 3–15).

Table 3. SRC Knowledge Results^a

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Feeling off balance (n = 533, 89.9%), dizziness (n = 529, 89.2%), headache (n = 469, 79.1%), memory loss (n = 433, 73.0%), and loss of consciousness (n = 337, 56.8%) were the most recognized true signs and symptoms of SRC. The following false distractors were frequently selected by athletes: difficulty breathing (n = 175, 29.5%), numbness or tingling in the arms (n = 138, 23.3%), and bleeding from the nose (n = 100, 16.9%).

The highest percentage of correct answers among the general knowledge questions was observed for, “If you are experiencing any signs and symptoms of SRC after a blow to the head or sudden movement of the body, you should not return to play” (n = 557, 94.0%). The response with the lowest percentage of correct answers was observed for, “A concussion is an injury to the (brain)” (n = 436, 73.3%). The most selected answer to, “What are possible complications of sustaining multiple concussions?” and “What are complications of returning to sporting activity while still experiencing possible concussion symptoms?” was, “No complications exist” (multiple concussions, n = 583 [98.3%]; return to play, n = 580 [97.8%]). Also, “memory problems” was the least selected among the correct answers (multiple concussions, n = 345 [58.2%]; return to play, n = 268 [45.2%]).

We found significant differences in SRC knowledge scores by the level of contact (MD total score: CON = 34.0, LTD = 32.0, NC = 32.0, = 24.47, P < .001; MD signs and symptoms score: CON = 22.0, LTD = 21.0, NC = 20.0, = 23.23, P < .001; MD general knowledge score: CON = 13.0, LTD = 12.0, NC = 12.0, = 9.50, P = .009). When the frequency of correct answers by the level of contact was analyzed by CON and LTD + NC, we found significant differences between CON and LTD + NC (total score, P < .001; signs and symptoms score, P < .001; general knowledge score, P = .002). Sport-related concussion knowledge scores were higher in the MED_YES than the MED_NO group (MD total score: MED_YES = 34.0, MED_NO = 32.0, U = 27 841.5, P < .001; MD signs and symptoms scores: MED_YES = 22.0, MED_NO = 20.0, U = 28 351.5, P < .001; MD general knowledge score: MED_YES = 13.0, MED_NO = 12.0, U = 30 828.0, P < .001). The detailed breakdown of SRC knowledge results is summarized in Table 3.

Previous SRC Education

Previous SRC education by the level of contact resulted in a statistically significant difference ( = 71.80, P < .001). Pairwise comparisons revealed that the CON group was more likely to have had previous SRC education than the LTD and NC groups (versus LTD, = 37.0, P < .001; versus NC, = 48.9, P < .001). A greater proportion of athletes with previous SRC education were classified in MED_YES ( = 47.4, P < .001).

Sport-related concussion knowledge scores were higher among athletes with a previous SRC education than those without a previous SRC education (total score: with previous SRC education, MD = 36.0; without previous SRC education, MD = 32.0; U = 26 832.0, P < .001; signs and symptoms score: with previous SRC education, MD = 23.0; without previous SRC education, MD = 20.0; U = 30 266.5, P < .001; general knowledge score: with previous SRC education, MD = 13.0; without previous SRC education, MD = 12.0; U = 28 935.0, P < .001). Stepwise regression revealed that SRC education contributed to higher SRC knowledge, independent of the level of contact and access to medical staff (R² = 0.13, F_1,589 = 42.82, P < .001).

History of SRC

A previous study of collegiate athletes in the United States and Ireland, where public awareness of SRC prevention is higher than in Japan, found that 29.6% and 31.8% of respondents, respectively, had an SRC history.^3,18 Indeed, our results indicated that 19.1% of study participants reported a history of SRC. However, we should interpret these data with caution because (1) the self-reported history of SRC may not always reflect the actual number of SRCs, especially when the respondents lack SRC knowledge, and (2) the current study limited the answers to diagnosed SRCs, thereby omitting possible or undiagnosed cases.³

When examined by the level of contact, the CON group had the most participants with an SRC history (25.5%) when compared with the LTD (8.0%) and NC (6.6%) groups. This finding is much lower than that in a study by Suzuki et al, who reported that 77.1% of Japanese collegiate athletes in the CON group had an SRC history.⁵ This discrepancy may have been influenced by the difference in the definition of SRC history: Suzuki et al’s study defined it as subjective recall of SRC signs and symptoms, whereas our study asked participants to report the number of diagnosed SRCs. Therefore, if our participants were asked if they had ever experienced SRC signs and symptoms, the results may have been higher. Nonetheless, in agreement with previous studies, Japanese collegiate sports also observed a greater SRC prevalence in CON than in LTD and NC sports.^14,15

A history of SRC was also associated with access to medical professionals, as those without access did not report a history of SRC as often as those who did. This finding is similar to the finding of Wallace et al that high school athletes with no access to an AT were 5 times more likely not to report SRCs because they did not think they had sustained an SRC at the time of injury.¹⁶ These high school athletes without access to an AT were also less knowledgeable about SRC compared with those with access to an AT. Therefore, it can be argued that the medical support system has a great influence on athletes’ SRC knowledge and behavior. Because Japanese collegiate athletes particularly lacked knowledge about return to play from SRC (Table 3), there is an urgent need to prepare an environment that can effectively follow up on SRC when it occurs. As it stands, athletes without MED are left to rely on nonmedical professionals (eg, coaches, parents, and teammates). Therefore, further educational efforts to improve self-awareness and detection of SRC, as well as education on properly seeking medical support, are warranted, especially in Japanese athletes.

SRC Knowledge Score

The mean knowledge score of SRC signs and symptoms was lower than that reported in the United States, which used the same questionnaire as this study in collegiate athletes, but higher than in Ireland (United States = 23.0 ± 3.2, Ireland = 20.1 ± 2.5, Japan = 21.8 ± 4.3).³ Only feeling off balance and dizziness were recognized correctly by more than 80.0% of the respondents in our study. This finding is unique to Japanese athletes because previous studies that investigated similar questions in the United States, the United Kingdom, and Ireland consistently revealed that headache was the most frequent of the SRC signs and symptoms identified by athletes.^18–20 Although the reason behind this discrepancy is unknown, we speculate that Japanese athletes may have viewed feeling off balance and dizziness as a particularly unique set of symptoms of SRC, which led to these symptoms ranking high. Similar to athletes in a study conducted in the United States, Japanese athletes tended to select vestibular and ocular-related symptom clusters, but only about 20% of athletes correctly identified symptoms associated with anxiety and mood.⁹

In addition, there was a difference in scores for signs and symptoms by the level of contact and access to medical staff. Compared with the LTD, NC, and MED_NO groups, the CON and MED_YES groups are believed to have more frequent exposure to SRC based on the higher incidence rates reported in the latter groups. Therefore, it can be inferred that these individuals have increased opportunities to receive appropriate education regarding SRC. Consequently, it is presumed that they also have a higher level of knowledge.

Sport-related concussion history and SRC education contributed to higher SRC knowledge, independent of the level of contact and access to medical staff. Therefore, continued educational efforts are warranted by the national governing bodies, especially for those who have never experienced SRC, to improve baseline knowledge about SRC. Furthermore, we believe that more detailed information about SRC signs and symptoms should be included in SRC education, as we observed poor performance on the knowledge test among our study participants.

Previous SRC Education

The high SRC knowledge scores of the CON group compared with the LTD and NC groups indicate the need for more active SRC education in LTD and NC sports. Although CON sports are prone to a higher SRC incidence, we identified that LTD and NC sports are not exempt from SRC.¹⁴ Therefore, focused efforts to increase the SRC education opportunities among LTD and NC sports are warranted.

Previous SRC education was associated with access to medical professionals. This suggests the need to increase medical provisions for those participating in LTD and NC sports who demonstrated lower SRC knowledge scores compared with those participating in CON sports. However, because SRC education also influenced the SRC knowledge score independently of access to medical staff, an emphasis on improving educational efforts may be more practical. Because only 11 national sports governing bodies among the 90 in Japan currently have SRC guidelines, there is room for growth and improvement in this area.⁸ Nevertheless, it is relevant to note that SRC knowledge and education do not always directly contribute to better SRC reporting behavior modification.^21,22 Therefore, future educational efforts in Japan must not only focus on improving the baseline knowledge of SRC but also on promoting behavioral change by intervening holistically.²²

Limitations

The current survey was administered only to collegiate athletes and not to other populations of various age groups. Furthermore, SRC history and previous education experience were self-reported; therefore, their accuracy may be limited. The knowledge score may also be subject to bias because of the question format in which respondents were given a list of choices to answer with. The validity of the SRC educational content could not be verified because it was outside the scope of our study.