Fall Injury Avoidance Strategy Scale (FIAS): Development and Validation of a Scale to Quantify Fall-Related Protective Movements

To develop and validate the Fall Injury Avoidance Scale (FIAS), a novel video-screening tool to assess protective movements and injury risk during standing-height falls among older adults. Secondary analysis of video-recorded experimental falls. Laboratory setting. Twenty-three older adults (aged 66-84 years; 4 males, 19 females) at risk of injurious falls. Not applicable. Participants experienced a total of six standardized experimentally-induced (backwards, left, and right directions). Fall movements were recorded using a motion capture system and commercially-available cameras. Hip and head peak acceleration were extracted from custom MatLab scripts. FIAS score (sum of 4 evidence-based protective fall movements, range 0-8) and the occurrence of head impact were determined by two independent raters using standardized and structured questionnaire. Inter-rater reliability, construct validity, responsiveness, and diagnostic utility of FIAS score were evaluated. A total of 274 experimental falls were analyzed. FIAS score indicated excellent inter-rater reliability (ICC(2,k) = 0.85 (95%CI [0.81-0.88], p<0.001). The higher FIAS scores were significantly associated with the lower hip peak acceleration (B=-1.01, 95%CI [-1.47, -0.56], p<0.001) and head peak acceleration (B=-6.08, 95%CI [-709, -5.06], p<0.001), and lower odds of head impact (Odds Ratio [OR]=0.20, 95%CI [0.12, 0.33], p<0.001). FIAS score also demonstrated significant responsiveness to the training-induced changes (F=18.74, p<0.001). Diagnostic analysis suggested that FIAS score ≥ 6 showed the high specificity (95.5%) for ruling out head impact falls. FIAS is a reliable, valid, and responsive tool to assess the protective fall movements and injury risk among older adults, which has potential utility in screening and prevention of fall-related injuries.