A Wearable "Balance Booster" - Stepping Closer to the Market

The Functional Gait Assessment (FGA) is a reliable and valid measure of gait function related to postural stability and has been shown to be effective in classifying fall risk in older adults and predicting unexplained falls in community-dwelling older adults (Wrisley, Marchetti et al. 2004; Wrisley and Kumar 2010). It has also been validated in stroke survivors (Lin, Hsu et al. 2010) and patients with Parkinson's disease (Leddy, Crowner et al. 2011) and has less flooring and ceiling effect than the Dynamic Gait Index (Lin, Hsu et al. 2010). The FGA includes a 10-item scale; each item is scored from 0 to 3 (3=normal, 2=mild impairment, 1=moderate impairment, 0=severe impairment). The maximum score is 30; minimum score, 0. Higher scores represent a better outcome. To be included in the count of participants, subjects' FGA scores needed to improve more than 4 points, which is the Minimally Clinically Important Difference (MCID) (Beninato et al. 2014).

The 4-Stage Balance Test is part of the STEADI protocol recommended by the Centers for Disease Control and Prevention (CDC) to assess fall-risk in elderly individuals. It includes four gradually more challenging postures the subject performs; 1) Stand with feet side by side; 2) Stand with feet in semi-tandem stance; 3) Stand with feet in tandem stance; 4) Stand on one leg. Subjects pass if they can hold the stance for 10 seconds and then move on to the next stance. A fail during tasks 1, 2, or 3 indicates a high risk of falling, i.e., a total performance time of less than 30 seconds.

The 10m-walk is routinely done in rehabilitation and has excellent reliability in chronic stroke patients. In addition, gait speed has been found to be an important predictor of survival in older adults (Hardy, Perera et al. 2006), further emphasizing its importance as a clinical outcomes measure. Gait speed (10-meter walk, timing only the middle 6 meters to allow for acceleration and deceleration) was assessed by instructing subjects to walk at their normal speed. A difference of 0.10m/sec is defined as the Minimally Clinical Important Difference (MCID) (Perera, Mody et al. 2006). Lower scores (# of seconds) on this measure indicate a better outcome. To be included in the count of participants, subjects' times on the 10M Walk Test needed to improve by more than 0.10m/sec, the MCID.

Powell and Myers (1995) developed the Activities-specific Balance Confidence (ABC) Scale to detect levels of balance confidence in elderly persons. The ABC scale is a one-page questionnaire that asks questions about balance confidence when performing 16 different tasks. The items are rated on a scale of 0 to 100; a score of 0 indicates no confidence and a score of 100 indicates complete confidence when performing the task. The overall score is calculated by adding the individual items then dividing by the total number of items (16). The higher the score, the greater the person's balance confidence; thus, higher scores indicate that subjects are more confident of their balance. The ABC Scale was assessed only at baseline to document the level of balance confidence the subjects had before beginning the study intervention.