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Table 1 Sensitivity and specificity for detecting near falls using single parameters.

From: Automated detection of near falls: algorithm development and preliminary results

Parameter axis NOT
Near Fall mean
Near Fall mean NOT
Near Fall
SD
Near Fall
SD
threshold Sensitivity (%) Specificity (%) Detection (%)**
Max* V 0.45 0.83 0.20 0.30 0.56 90.48 81.89 20.46
Max M-L 0.31 0.60 0.16 0.26 0.41 71.43 86.38 31.65
Max A-P 0.33 0.48 0.17 0.22 0.38 52.38 73.80 54.35
Maxdiff V 0.17 0.37 0.09 0.15 0.21 80.95 80.99 26.91
Maxdiff M-L 0.15 0.36 0.10 0.26 0.17 76.19 75.60 34.09
Maxdiff A-P 0.19 0.41 0.19 0.24 0.24 76.19 82.34 29.64
maxp2p V 0.71 1.40 0.29 0.53 0.88 90.48 80.39 21.80
maxp2p M-L 0.63 1.35 0.30 0.67 0.80 80.95 83.53 25.18
maxp2p A-P 0.75 1.38 0.43 0.57 0.93 76.19 82.93 29.30
maxp2pdiff V 0.34 0.69 0.19 0.26 0.48 85.71 88.02 18.65
maxp2pdiff M-L 0.30 0.72 0.20 0.52 0.35 80.95 76.95 29.90
maxp2pdiff A-P 0.42 0.86 0.36 0.48 0.52 80.95 81.59 26.49
Std V 0.13 0.19 0.06 0.05 0.16 61.90 74.55 45.82
Std M-L 0.11 0.16 0.04 0.05 0.13 66.67 79.94 38.90
Std A-P 0.13 0.17 0.05 0.04 0.15 61.90 79.34 43.34
Step regularity V 0.58 0.32 0.17 0.12 0.27 71.43 5.99 98.26
Stride regularity V 0.54 0.27 0.16 0.15 0.22 61.90 5.69 101.72
Symmetry V 1.13 1.36 0.39 0.57 1.24 61.90 79.79 43.13
  1. The sensitivity and specificity values obtained for detecting near falls (n = 21) as compared to non-near falls (n = 668) using single parameters. Non-near falls included regular gait intervals combined with the irregular (non-near falls) intervals (e.g., kicks, stepovers, stops).
  2. *Max = maximum acceleration amplitude; Maxdiff = maximum acceleration derivative; Maxp2p = maximum peak-to-peak acceleration amplitude; Maxp2pdiff = maximum peak-to-peak acceleration derivative; Std = standard deviation; V: vertical; M-L: medio-lateral; A-P: anterior-posterior.
  3. ** The detection % is the distance from the ideal ROC curve (the lower, the better).
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