Athletes who experience dizziness at the time of concussion injury are six times more likely to experience a protracted recovery than those who don't become dizzy, says a 2011 study (1), prompting researcers to suggest specific testing for the symptom at the time of injury.
Dizziness: only sign/symptom predicting protracted recovery
Researchers found that, other than dizziness, none of the twenty-two concussion signs or symptoms on the Post-Concussion Symptom Scale predicted whether recovery from concussion would be protracted (21 days or more to return to play) or rapid (7 days or less to RTP).
That neither amnesia (post-traumatic/retrograde) nor imbalance were significant risk factors for protracted recovery was surprising, said lead study author, Brian C. Lau, MD of the University of Pittsburgh School of Medicine, although he cautioned that both findings "should be interpreted cautiously" given previous research showing "retrograde amnesia and PTA as predictors of poor concussion outcomes (although not protracted recovery times per se)" and the fact that sensitive balance testing (e.g. BESS, Clinical Test of Sensory Interaction and Balance) was not used.
Separate on-field testing for dizziness, follow-up assessments urged
"Nonethless, if any additional, prospective studies confirm our finding that dizziness may indicate protracted recovery," said Lau, "clinicians should consider using separate, specific dizziness tests for dizziness" such as the Dizziness Handicap Inventory (DHI), "rather than relying on postural/balance tests [such as the BESS] as indicators of dizziness." Such tests, they believed, "would augment post-concussion assessment in addition to neurocognitive tests, symptom reports, and postural/balance tests."
The authors also urged follow-up vestibular assessements to further delineate the cause of dizziness and inform subsequent therapy and treatment.
Citing a 2010 study finding that patients who had at least two 2 rehabilitation visits for persistent dizziness after a concussion showed improvement in their DHI scores (2), the study said that on-field identification of dizziness could lead to earlier implementation of vestibular rehabiliation and other modalities to treat dizziness, which may expedite recovery from concussion.
Study details and limitations
The study involved male high school football players from the state of Pennsylvania who incurred a sport-related concussion during the preseason or regular season between 2002 and 2006. On-field concussion signs and symptoms were observed and recorded at the time of injury by members of the sports medicine staff (ie. certified athletic trainer, team physician). Balance was tested through Romberg, tandem walking, and heel-to-toe testing. Dizziness was assessed through direct questioning and self-report by the athlete.
The study was limited by several factors:
- It comprised only male high school football players so the results could not be generalized to older athletes, females, or other sports.
- Although concussion history was recorded, it is possible that the numbers may be underrepresent the actual number of athletes with previous concussions, which may have an unseen effect on recovery.
- Postural/balance tests specific for sports-related concussion such as the BESS, which may be more effective for use with high school age athletes, were not used.
- Variability in the assessment intervals regarding return to play decisions.
- Students who did not return to football or graduated resulted in participant attrition and consequently a portion of the sample was lost to follow-up.
1. Lau BC, Kontos AP, Collins MW, Mucha A, Lovell MR. Which On-Field Signs/Symptoms Predict Protracted Recovery From Sport-Related Concussion Among High School Football Players? Am J. Sports Med 2011;20(10) DOI:10.1177/0363546511410655 (published June 28, 2011 online ahead of print)(accessed November 5, 2011).
2. Alsalaheen BA, Mucha A, Morris LO, et al. Vestibular rehabilitation for dizziness and balance disorders after concussion. J Neurol Phys Ther. 2010;34(2):87-93.
3. Scopaz KA, Hatzenbuehler JR. Risk Modifiers for Concussion and Prolonged Recovery. Sports Health: A Multidisciplinary Approach 2013;20(10). DOI:10.1177/1941738112473059 (published online ahead of print January 17, 2013).
Posted November 7, 2011; updated April 23, 2013