Update June 13, 2019 – I shared this article with Dr. John Neidecker, a Sports Medicine Physician, Sports Concussion Specialist and present Vice President of the Association of Ringside Physicians who was kind enough to read the entire study, the critique, and weighed in with the following views:
Please let me read the full study and I will get back to you. However – off the bat a couple of things… 1) the events of what led to the choke is a very important thing to keep in mind. e.g.- Was there a concussive event prior causing impairment of the fighter and choke setup?
2) Although KD testing IMO seems to be a nice screening tool it has not been tested enough to be truly validated. It has flaws – effort specifically. Also – concussion is a multifaceted injury and vision does not seem to be always impacted.
After review I would tend to agree with
@SamStellpflug critique. Authors definitely go out on a limb on statements about choke effects. What were the “events” that led to the choke? It’s a shame b/c I believe if they improved methods & cleaned up stats it could be a good study
Earlier this year I highlighted debate among physicians addressing whether chokes in combat sports play any role in CTE.
More recently a study published in the journal of Brain Injury suggests that MMA bouts (or training sessions) ending in a choking submission result in cognitive consequences similar to concussion. Like last year’s article this recent suggestion has received some criticism from other doctors.
In the recent study, titled The King-Devick test in mixed martial arts: the immediate consequences of knock-outs, technical knock-outs, and chokes on brain functions, the authors looked at King-Devick times (an accepted concussion evaluation tool) in MMA trainees and competitors. They looked at training/bouts that ended via head trauma events and those that ended via submission events. The authors noted that both KO and non KO ‘events’ led to a slowing of King-Devick testing. From this they concluded that “athletes who sustained non-head trauma “events” also demonstrated slowing on their K-D tests, suggesting these “events” may also cause some impairment in
brain function indicative of a concussion“.
The full abstract and conclusion read as follows:
The aim of this prospective cohort study was to determine the effect of an ‘event,’ defined as a knockout
(KO), technical knock-out (TKO), choke, or submission, on King-Devick (K-D) test times in mixed
martial arts (MMA) athletes. MMA athletes (28.3 ± 6.6 years, n = 92) underwent K-D testing prior to and
following a workout or match. Comparison of baseline and post-workout/match K-D times to assess any
significant change. K-D tests worsened (longer) in a majority of athletes following an ‘event’ (N = 21)
(49.6 ± 7.8 s vs 46.6 ± 7.8 s, p = 0.0156, Wilcoxon signed-rank test). K-D tests improved (shorter)
following a standard workout or match in which no ‘event’ occurred in a majority of cases (n = 69) (44.2
± 7.2 s vs 49.2 ± 10.9 s, p = <0.0001, Wilcoxon signed-rank test). Longer duration (worsening) of postmatch
K-D tests occurred in most athletes sustaining an ‘event’; K-D tests shortened (improved) in a
majority of athletes not sustaining an ‘event’. Our study suggests MMA athletes suffering an ‘event’ may
have sustained a brain injury similar to a concussion.
The vast majority of MMA athletes sustaining an “event” with
witnessed head trauma (KO or TKO) had significant slowing
of their K-D test. It is probable that slowing of the post-match
or post-training K-D test in this population indicates that the
athlete has sustained a concussive type brain injury.
Furthermore, athletes who sustained non-head trauma
“events” also demonstrated slowing on their K-D tests, suggesting
these “events” may also cause some impairment in
brain function indicative of a concussion. Our findings suggest
that any MMA athlete with a slowed post-match or posttraining
K-D test requires further evaluation by a medical
professional trained in concussion management.
This conclusion drew strong criticism from Samuel J. Stellpflug and Robert C. LeFevere of the Department of Emergency Medicine, Regions Hospital, Saint Paul, MN, USA. In reply to the the above study the doctors summarized their criticism of the conclusions as follows:
In summary, this study doesn’t establish a link between
transient choking and significant worsening in K-D times, nor
between transient chokes and anoxic brain injury with cerebral
changes comparable to concussion. The listed supporting references
don’t support either of these claims. Additionally, the brief
hypoxia associated with transient chokes is analogous to brief
vasovagal syncope, which does not cause lasting brain injury.
Concussions involve a traumatic force causing injury that can
have long-lasting effects. There is no established reason to
believe, based on the different mechanisms, that brief hypoxia
causes the lasting damage that a concussion can cause. Lastly,
there is a limitation in terming these MMA chokes as nontraumatic
scenarios when the totality of the physical transgressions
that lead to the choke is taken into account. Overall, this
study does not provide any convincing data that chokes in
combat sports cause injuries to the brain similar to concussion.
It would be of value to the combat sports community to have a study conducted involving grapplers who tap out due to chokes (who do not sustain any head impacts in the process as they would in an MMA competition) to see if the K-D scores are negatively impacted. Such a study can help further this debate and add clarity to the competing points of view.