Balance Accelerometry Measure vs. Balance Error Scoring System in children after concussion

摘要

Concussion, also known as mild traumatic brain injury, can cause dizziness and impaired balance. Sports-related concussions are very common in the U.S., especially in high-school and college. An assessment of balance can provide useful information for estimating prognosis following concussion. Low-technology methods of assessing balance such as the Balance Error Scoring System (BESS) are fast, inexpensive, and easy to use in children, but not very precise. Recently, a low-cost, higher-technology, accelerometer system called the Balance Accelerometry Measure (BAM) has been used to study high-school aged children with concussion. This study tested the hypothesis that the BAM is more sensitive to change over time than the BESS as children recover from concussion. This study also tested the hypothesis that the BAM has context validity based on correlations with the BESS and with subjective measures of dizziness and balance. Subjects included nine persons between the ages of 13 and 17 years who had experienced a concussion between 1 and 16 days prior to their initial evaluation and who were tested twice at about a 2-week interval. The acceleration data from the BAM were processed to compute the normalized anterior-posterior path length of sway. BESS testing was videotaped for later scoring. Subjective measures included the Dizziness Handicap Inventory, the Activities-specific Balance Confidence Scale, Global Rating of Change and the Post-concussion Symptoms Score from the ImPACT test. Results indicated that effect sizes for the BESS were larger than they were for the BAM. The effect size for the easiest BAM conditions was negative, indicating greater sway on the second evaluation. The BAM had good context validity regarding the BESS and poor context validity regarding subjective measures of dizziness and balance. This small n study of postural sway using the BAM suggested that an easily administered, low-cost test could be used in children to monitor recovery from concussion. A potentially novel finding using the BAM was that children with concussion may increase their exploratory sway behavior as they recover from concussion.