Measuring the Effects of Mild Head Injury
ABSTRACT & COMMENTARY
Synopsis: Clinical assessments of balance parallel laboratory measures of postural stability in documenting post-injury postural control deficits in mild head-injured subjects.
Source: Riemann BL, Guskiewicz KM. Effects of mild head injury on postural stability as measured through clinical balance testing. Journal of Athletic Training 2000;35:19-25.
Mild head injury (mhi) in athletes continues to present a special challenge to physicians responsible for making decisions about when safe return to competition following injury can be permitted. Criteria for return have traditionally included neuropsychological assessment and, more recently, measures of postural control. Riemann and Guskiewicz used a clinical balance testing procedure to assess the effects of mild head injury on postural stability in 16 mild head-injured athletes and 16 matched controls. The subjects were assessed for postural stability on days 1, 3, and 5 post-injury using a clinical balance battery consisting of three stances (double leg, single leg, and tandem) on two surfaces (firm and foam). A Balance Error Scoring System (BESS) was devised, which was calculated by adding one error point for each error. The errors included 1) lifting hands off the iliac crests; 2) opening the eyes; 3) stepping, stumbling, or falling; 4) moving the hip into more than 30° of flexion or abduction; 5) lifting the forefoot or heel; and 6) remaining out of the testing position for more than 5 seconds. The BESS had been previously described, and its reliability established.1
To ascertain if the clinical balance measures would parallel laboratory measures of balance, the subjects were also assessed using the Sensory Organization Test (SOT) on a NeuroCom Smart Balance Master. The SOT test protocol consisted of three 20-second trials under three visual conditions (eyes open, eyes closed, sway referenced) and two support surfaces (stable, sway referenced). Mild head injury was defined as a Glasgow coma score greater than 12, less than 20 minutes of unconsciousness, hospitalization for less than 48 hours, and negative findings on neuroimaging.
Riemann and Guskiewicz found nine of the 16 mild head-injured subjects had post-concussion symptoms up to three days post-injury, and two complained of symptoms up to five days post-injury. The MHI subjects had higher error scores on the BESS than the control subjects on day one post-injury on the firm surface and on days 1 and 3 post-injury on the foam surface. For the SOT scores, the MHI subjects had increased postural instability on day 1 post-injury in comparison to the control subjects, and in comparison to their own day 3 post-injury scores.
COMMENT BY DAVID H. PERRIN, PhD, ATC
Riemann et al have previously demonstrated that athletes experiencing mild head injury have balance deficits up to three days post-injury, sometimes in the absence of deficits in neurocognition.1 The primary limitation of these studies has been the need to use sophisticated and expensive laboratory equipment to measure postural stability. In this study, Riemann and Guskiewicz found balance deficits up to three days post-injury on a foam surface with the clinical balance measures. Interestingly, the testing on the laboratory balance device found deficits only to day 1 post-injury. Riemann and Guskiewicz attributed the differences in findings with the two methods of testing to the potential of having assessed different aspects of postural control. They also postulated that differences in the scale of the measurements might have contributed to the disparate findings.
The process of deciding when a head-injured athlete can safely return to competition is a complex one. Physicians are too often faced with this dilemma in the absence of objective criteria upon which to base the decision. The findings of this paper are encouraging, in that they offer a clinically useful and readily available method by which to evaluate postural control in head-injured subjects. In all probability, a combination of cognitive testing and objective assessment of postural stability offers the best battery of information upon which to decide if a head-injured athlete is ready for return to competition. Further study on the validity of this system of clinical evaluation of postural control in head-injured subjects is indicated. This model has the potential of adding an important component to the evaluation tools readily accessible to the attending team physician.
Reference
1. Riemann BL, et al. Relationship between clinical and forceplate measures of postural stability. J Sport Rehabil 1999;8:71-82.
A clinical balance battery testing procedure in mild head-injured athletes found deficits in postural control:
a. up to 10 days post-injury.
b. up to seven days post-injury on a hard surface.
c. the same as deficits found through laboratory measures of balance.
d. up to three days post-injury on a foam surface.
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