Concussions: Pathophysiology, management, and their impact on the season

While the 2014 season will probably be better remembered from an injury aspect for the upswell in ulnar collateral ligament tears and certain teams being decimated by various bumps and bruises, the effects of concussions on the game and the players should not be forgotten or tempered. Even with the effort to reduce concussive injuries in MLB that brought about the policies that affected how the injury was managed that has now been in place for a fourth season, we still see players felled by the elusive and often lingering effects concussions have on the whole body, not just the brain.

One particularly revealing and vivid discussion of the effects a concussion can have on the body was recently penned by Eno Sarris at FanGraphs, where he outlined beautifully and painfully a day in the life of a concussed John Jaso. If you haven't already, please take the time to read the piece, which you can find here. In it, Jaso describes many of the tangible and not so tangible symptoms of a concussion and their effects on his everyday activities, baseball or otherwise. All in all, it is a great primer for much of the symptomatology often seen with head injuries.

The symptoms and effects of a concussion can be complex and the same can be said about the pathophysiology. Typically, a concussion is defined as a complex process that involves the brain secondary to trauma and results in a rapid onset impaired neurologic function, with or without the loss of consciousness. There are a number of mechanisms that can lend themselves to causing injury; in baseball, the more frequently seen mechanisms include being hit by batter or thrown balls (such as foul tips or hit by pitches as a batter) and collisions, be it with other players or with the field itself, either with the ground or outfield wall.

Initial symptoms are usually a disturbance in function, versus a damage to the structural integrity of the brain. Symptoms seen clinically can involve physical, cognitive, and emotional deficits that typically resolve in a short amount of time, but have the potential to debilitate for longer, even permanently. Cognitive symptoms can include confusion, Jaso's aforementioned 'fogginess', disorientation, delayed responses—both motor and verbal—to stimuli, and even amnesia. Somatic symptoms such as headaches, photophobia, nausea/vomiting, and tiredness can also hamper the inflicted; emotional lability and even sleep disturbances are also be part of the myriad symptoms seen with concussion.

With so many variables at play in respect to sustaining a concussion, the policies implemented in the 2011 season focused not only on develop methods to better recognize and test for concussive symptoms, but to also establish a consistent and cohesive approach to the evaluation and treatment of a concussion and to the protocol for return to play. Baseline measures of neurocognitive health have been collected from all players before the beginning of each season through the administration of the ImPACT Test, with these results assisting the evaluation of a player who does end up concussed, as their baseline numbers will be compared to post-injury ImPACT test results and guide clinician decision-making as to whether a player is truly recovered; it is common for players to report absence of symptoms despite remaining neurologically impeded by a concussion. Acute, on-field testing via the use of the SCAT2 tool was also part of the concussion protocol implementation.

With the pathophysiology and testing/diagnosis methods of concussions discussed, let's now return to the field and look at who has suffered a concussion in 2014; below is a list of players who have spent time on the either the 7- or 15-day disabled list for a concussion, with their respective mechanisms and the number of games they have missed (Editor's note: table now includes Yan Gomes and Starling Marte's second newly diagnosed concussion per comments below):

* denotes player with prior concussion sustained. ** no games missed per player Baseball Prospectus player card Injury History.

Overall, this season has seen a slight rise in DL-worthy concussions—19 2021—compared to 2013; last year, 18 players landed on the DL with a concussion, five more than the previous season. In general, it is Jaso and his catching brethren that are the primary sufferers, with a fair number of outfielders also showing up on the list, primarily with collision-related concussions. These players have also missed some significant amounts of time to their injuries, with a wide swath of games missed observed, from the standard seven games to Jaso's 60 games. Another troubling trend seen in the data is the propensity for players to suffer multiple concussions during their careers.

Of course, this brief look at concussions doesn't include the numerous foul tips suffered by catchers who remain somewhat subclinical symptomatically, enabling the afflicted player to pass his respective concussion test immediately after and beyond the initial insult. This exercise also doesn't include the like of Mike Aviles, who is day-to-day with whiplash and general dizziness, but has seen these symptoms evolve into concussion-like, many days after taking a dive in the outfield. Looking back at Jaso's revelations, this effect is reflected in his words, with an even more disturbing trend noted—the desire for players to sometimes ignore their symptoms days, even weeks, after the initial injury, with difficulties in sleeping, mood swings, or sudden inability to perform everyday activities being what prompts them to disclose their injury and seek care.

Four seasons into a more concentrated effort to curtail concussions and their ramifications has seen the injury slowly on the rise in terms of numbers that lend themselves to DL stints; as mentioned, there are many other concussive events that are being suffered and are either not being identified immediately, ignored altogether, or do not become clinically tangible until well after the initial insult. Many of these concussions simply cannot be avoided; however, a number of these injuries could very well be avoided or at the least minimized with more endeavors dedicated to safety equipment optimization. Catcher's equipment, batting helmets, baseball caps, and even the warning tracks and outfield padding are all aspects of the baseball environment that could lend themselves to revision for a better protected player against concussions. Behaviorally, it is incumbent upon the player to admit when they are injured; despite advances in concussion testing approaches, it is the word of a player that ultimately will determine how well their injury will be treated.

***

Data courtesy of Baseball Prospectus and Pro Sports Transactions.

Stuart Wallace is an associate managing editor and writer at Beyond The Box Score. You can follow him on Twitter at @TClippardsSpecs.

References: Dines, J. S. (2012). Sports medicine of baseball. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.