Chokes in mixed martial arts. Comment on Hubbard et al. Brain Injury (2019; 33: 349-354).

This letter to the editor is in response to "The King-Devick test in mixed martial arts: the immediate consequences of knock-outs, technical knock-outs, and chokes on brain functions" by authors Hubbard et al., published in Brain Injury (2019; 33: 349-354). This study explored the impact of events significant enough to end mixed martial arts training sessions or matches, with "event" meaning a knock-out, technical knock-out, or event without head trauma; the measuring stick was the King-Devick test (K-D). This communication clarifies the portion of their study and manuscript focusing on "events without observed head trauma." These events without head trauma were choke-outs, near choke-outs, and non-choke submissions. Fourteen athletes sustained these types of events; nine had worse post-event K-D times, one had no change, and five had post-event improvement. Despite this non-significant result, the authors frame an argument that these non-traumatic events cause anoxic brain injury resulting in similar cerebral changes that occur in concussive injuries. This is not founded on the results in their study, nor in the literature available on the topic, which is also misrepresented in this manuscript.