Diagnosing a Concussion: Utility of Spontaneous Headshake After a Kinematic Event

Spontaneous headshake after a kinematic event may be a clinical marker for concussion, according to study findings published in Diagnostics.

Researchers conducted a cross-sectional survey study to assess the predictive utility of spontaneous headshake after a kinematic event in the diagnosis of concussion. Participants were recruited from the Concussion Legacy Foundation and adults aged 30 and younger who played sports at any level were eligible for inclusion. The survey collected data regarding sociodemographic characteristics and sport participation. Five videos depicting a sports impact and consequential rapid, lateral headshaking were shown to participants. After viewing the videos, participants were asked whether they had ever made this type of motion following a collision and to indicate possible reasons (ie, vision changes, dizziness, a feeling of chills) for the motion. Additional questions were asked depending on the reasons indicated. Participants were then provided with a standard definition of concussion and asked questions about their concussion and headshaking history. True and false positives and negatives were determined in statistical analysis.

A total of 347 participants (median age, 27; women, 47.6%; White, 92.2%; North American, 79.3%; played collegiate level sports, 46.1%) completed the survey. Football, soccer, basketball, track and field, ice hockey, rugby, baseball, lacrosse, wrestling, and volleyball were the 10 most popular sports played.

Most participants (98.6%) reported a history of concussion, 90% of which occurred while playing sports. The median number of self-reported concussions was 6 and the median number of diagnosed concussions was 3. Most participants (40.0%) reported their most recent concussion occurred within the last year.

Rapid headshaking after a collision was reported by 68.9% of participants. The median number of times participants reported headshaking after a collision was 5 and the median number of times participants reported the movement due to a concussion was 4.

Disorientation or confusion (71.1%), dizziness (54.0%), vision changes (45.6%), and feeling like they needed to jumpstart their brain (52.3%) were the top 3 reasons participants reported as to why they exhibited spontaneous headshaking. Most participants (84.9%) reported that the most common reason as to why they exhibited headshaking was due to a symptom of concussion.

Headshaking had a sensitivity of 49.6% and a positive predictive value of 72.4% across all sports. Among football players specifically, headshaking had a sensitivity of 52.3%, specificity of 99.9%, positive predictive value of 91.9%, and estimated negative predictive value of 99.5%.

Study limitations included the reliance on self-reported data, retrospective study design, and reduced generalizability of results to countries outside of the US and Canada.

“Future studies should explore how the severity of symptoms relates to SHAAKE, how the time from the collision to the presentation of the movement influences sensitivity and specificity, as well as the outer limits of the time between collision to presentation to be considered as SHAAKE,” the study authors concluded.

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.