Moments after a head injury, it can be difficult for the layperson to know what signs to look for to tell if a concussion has happened. Even for athletic trainers and coaches, it can be difficult. Sadly, this can result in delayed medical treatment for the concussion or other traumatic brain injury (TBI). This is why new research published in the journal Diagnostics is so exciting. Spontaneous Headshake After A Kinematic Event (SHAAKE) has been recognized as a new sign that could help us identify up to 33% of undiagnosed concussions.
What Is Spontaneous Headshake After a Kinematic Event (SHAAKE)?
According to Concussion Legacy Foundation (CLF) CEO and co-founder Chris Nowinski, PhD, after a hit to the head, individuals will sometimes quickly shake their heads back and forth. This motion, what the study defines as a SHAAKE, usually:
- Is initiated within seconds or minutes of an impact
- Involves lateral rotation side to side at a rate of 2 to 8 movements per second
- Lasts less than two seconds
- Does not occur for another reason, such as a form of communication
For ages, we have seen this specific motion depicted in movies, on television, and even in cartoons, but it has never before been studied or named, nor has it appeared on any medical or sports organization’s list of potential concussion signs. Until now.
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The Significance of the SHAAKE Study Results
In the study of 347 current and former athletes aged 18-29, lead author Dr. Nowinski and his colleagues found that athletes displaying SHAAKEs reported that they had a concussion 72% of the time. When it came to football players, the relationship was even stronger: a full 92% of SHAAKEs associated with a concussion.
Overall, of the athletes that were shown video examples of SHAAKEs and asked about their experiences with them, 69% self-reported exhibiting a SHAAKE. Of those who said they exhibited it, 93% reported a SHAAKE in association with concussion at least once. As a whole, the athletes reported exhibiting SHAAKEs a median of five times in their lives.
3 Common Reasons Why Athletes Exhibit SHAAKE
The study found that the three most common reasons athletes reported for exhibiting a SHAAKE were:
- Disorientation or confusion (25%)
- Feeling the need to jumpstart the brain (23%)
- Changes to the perception of space, or perception of one’s body in space (14%).
Other reasons athletes reported for exhibiting a SHAAKE associated with a concussion included headache, dizziness, inability to keep their train of thought, and changes to vision, hearing, or balance. There were also reasons athletes reported exhibiting a SHAAKE that were not associated with concussion, which included neck pain, chills, pain that was not a headache, and an emotional reaction to the preceding event.
“The SHAAKE study is definitely opening us up to a welcome new sign for flagging concussions as they happen,” says Mid-Atlantic Concussion (MAC) Alliance Medical Director and President Vincent Schaller, MD, DABFM, CIC. “Too many concussions go undiagnosed.”
The researchers note that the main limitation of the study comes from the self-reporting of concussions previously sustained by the athletes, which can lead to a potential for some kind of recall bias. Additionally, most respondents were from the United States and Canada, and it has yet to be established if SHAAKE varies by country or culture.
Tua Taglovailoa’s Concussion History and SHAAKE Motions
Dr. Nowinski points to SHAAKE motions as a concussion sign after Miami Dolphins quarterback Tua Tagovailoa’s controversial undiagnosed concussion during a game on September 25, 2022. In that game, after Tagovailoa’s head hit the ground, he rapidly shook his head side to side two separate times, before stumbling and collapsing. Dr. Nowinski notes that at the time, doctors attributed the collapse to a prior back injury, not a concussion. Had Tagovailoa been diagnosed with a concussion, he likely would not have been playing in a game the following Thursday, where he lost consciousness and displayed the fencing posture after experiencing a suspected second concussion in four days and was removed from the field in a stretcher. It should be noted that Tagovailoa subsequently sustained a serious concussion in September 2024.
Time to Update Our List of Potential Concussion Signs
“In the athletes we studied, about three out of every four SHAAKEs happened because of a concussion,” say senior author Dan Daneshvar, MD, PhD, Chief of Brain Injury Rehabilitation in the Department of Physical Medicine and Rehabilitation at Spaulding Rehabilitation and Harvard Medical School “Based on our data, SHAAKE is a reliable signal that a concussion may have occurred, like an athlete clutching their head after contact, being slow to get up, or losing their balance.”
Dr. Daneshvar, who also serves as co-chair of Sports Concussion Clinic at Mass General Brigham, adds, “Just like after these other concussion signs, if athletes exhibit a SHAAKE, they should be removed from play and evaluated for a potential concussion.”
“Sports and medical organizations should immediately add SHAAKE to their lists of potential concussion signs,” says Dr. Nowinski. “Coaches, medical professionals, and concussion spotters should be trained to recognize when a SHAAKE happens and remove athletes for further assessment. It’s an easy change, with no downside, that could prevent catastrophic outcomes and save careers.”
“We recently saw what Dr. Nowinski explained was a SHAAKE displayed by Cardinals Tight End Trey McBride during the game against the Dolphins after a hard hit to the head,” says Dr. Schaller. “The research shows SHAAKE is over 70% predictive of concussions, which would make any display of the motion a good reason to check for a TBI. Hopefully the NFL will listen to these research findings and train its staff and independent neurologists who are tasked with watching for concussions on what to look for.”
MAC Alliance: Your Concussion Specialists in the Mid-Atlantic Region
MAC Alliance concussion specialists create individualized treatment plans for each patient’s unique recovery journey. We use clinically proven brain-testing and monitoring tools to diagnose and treat traumatic brain injuries, including:
- BrainScope® One-EEG head injury assessment
- Cambridge Brain Sciences® neurocognitive testing
- ImPACT® neurocognitive testing
- RightEye® infrared eye-tracking
- SPECT Scan 3D metabolic brain imaging
- Sway Balance Systems® vestibular balance assessments
We also offer affordable hyperbaric oxygen therapy at our HBOT Center and ocular therapy in our Hockessin location.
Contact us for information.
