The Toronto concussion study: a cross-sectional analysis of balance deficits following acute concussion in community-dwelling adults

Objective: To characterize balance deficits in community-dwelling adults following acute concussion.Design: Cross-sectional observational study.Methods: Individuals with acute concussion (n=100) and healthy controls (n=20) completed the BESS (Balance Error Scoring System) and quiet standing trials on forceplates with the eyes open, closed, or during a cognitive dual task. BESS score and centre-of-pressure root mean square and high-frequency power (0.4-3Hz) were used to characterize group differences. In a secondary analysis, participants were subdivided based on self-reported symptoms of balance problems and dizziness using the SCAT-3 (Sport Concussion Assessment Tool - Third Edition) Symptom Checklist.Results: In comparing individuals with concussion and controls, BESS score (16.0 ± 6.0 vs 12.6 ± 3.8; F(1,116) = 5.814, p = .017) and anteroposterior [F(1.78, 204.2) = 11.93, p < .001] and mediolateral [F(1, 114) = 10.05, p = .002] high-frequency power revealed significant group differences. Dividing individuals based on self-reported symptoms revealed significant differences in mediolateral high frequency power, such that participants reporting balance and dizziness problems as well as those participants not reporting balance or dizziness symptoms following concussion were less stable than controls.Conclusions: Deficits in clinical and posturographic measures of balance occur in community-dwelling adults with concussion. These measures do not align with self-reported balance symptoms. Future research and clinical practice aimed at careful selection of optimized balance assessment is recommended.

Measuring postural stability with an inertial sensor: validity and sensitivity

Introduction/purpose

To examine the concurrent validity, and sensitivity, of an inertial sensor for use in the assessment of postural sway.

Methods

This was a laboratory-based, repeated-measures design with ten healthy participants. Concurrent validity was tested between an inertial sensor, forceplate, and rigid-body kinematics across three commonly used balance tests. Further, the inertial sensor measures were compared across eight commonly used tests of balance. Variables manipulated include stance position, surface condition, and eyes-open versus eyes-closed.

Results

The inertial sensor was correlated to both the forceplate-derived measures (r=0.793) and rigid-body kinematics (r=0.887). Significant differences between the balance tests were observed when tested with the inertial sensor. In general, there was a three-way interactions between the three balance factors (surface, stance, and vision) leading to pairwise comparisons between each balance test. The root-mean-square showed an increase across tasks of greater difficulty ranging from an average of 0.0368 with two legs, eyes-open to 0.911 when tested during tandem stance, eyes-closed tested on a foam pad.

Conclusion

The new inertial sensor shows promise for use in the assessment of postural sway. Additionally, the inertial sensor appears sensitive to differences in balance tasks of varying degrees of difficulty when tested in a healthy sample of young adults. This inertial sensor may provide new opportunities for further research in the assessment of balance changes in the mild traumatic brain injury population.

Multidirectional measures of seated postural stability

OBJECTIVE

To quantify the limits of stability during a leaning/reaching task and determine (1) test-retest reliability and (2) effect of movement direction and foot support.

DESIGN

Test-retest reliability design.

BACKGROUND

Seated reaching and leaning are used in rehabilitation programs to assess and train sitting balance and motor function. Continuous (as opposed to ordinal), multidirectional measures of seated postural stability have not been previously presented.

METHODS

Twelve older adults performed a seated reaching/leaning task while net body centre of pressure displacement and velocity were measured with three forceplates (under buttocks and each foot) over two separate days. Conditions of movement direction (forward, backward, lateral) and foot support (with and without) were randomized.

RESULTS

Except for the backward movement in the supported foot condition, all measures had moderate to very high reliability. Measurements were sensitive to both foot support and movement direction.

RELEVANCE

Centre of pressure measures provide reliable measures which may be useful for clinical assessment of seated postural stability.