Table 3.
Category | Variable | Sensor location |
---|---|---|
Position and Angle Variables |
AP peak to peak amplitude |
LB [52] |
ML peak to peak amplitude |
LB [52] |
|
V peak to peak amplitude |
LB [52] |
|
AP and ML postural sway length during stance |
LB [43,51] |
|
Trunk tilt |
St [44] |
|
Angular Velocity Variables |
Min, mean, max AP |
Sha [50] |
Min, mean, max ML |
Sha [50] |
|
Min, mean, max V |
Sha [50] |
|
AP peak to peak amplitude |
LB [52] |
|
ML peak to peak amplitude |
Sha [50] |
|
V peak to peak amplitude |
LB [52] |
|
Postural sway velocity during stance |
LB [43,51] |
|
Mean squared modulus ratio for postural sway |
LB [46-48] |
|
AP RMS during stance |
LB [51] |
|
ML RMS during stance |
LB [51] |
|
V RMS during stance |
LB [51] |
|
3D RMS during stance |
LB [51] |
|
ML variability |
UB [73] |
|
Linear Acceleration Variables |
Median AP |
LB [74] |
SD of AP |
He [18], LB [74], Hi [18] |
|
Peak AP |
UB [75] |
|
Peak V |
UB [75] |
|
AP peak to peak amplitude |
LB [52] |
|
ML peak to peak amplitude |
LB [49,52,60] |
|
V peak to peak amplitude |
LB [52] |
|
AP RMS |
He [55], LB [55] |
|
ML RMS |
He [55], LB [55] |
|
V RMS |
He [55], LB [55,71] |
|
AP RMS during stance |
LB [51] |
|
ML RMS during stance |
LB [51] |
|
V RMS during stance |
LB [51] |
|
2D RMS (ML and AP) during stance |
LB [43] |
|
3D RMS |
LB [1,57] |
|
3D RMS during stance |
LB [51] |
|
Jerk |
St [42] |
|
Sit to stand AP range |
LB [74] |
|
Stand to sit AP range |
LB [74] |
|
Sit to stand Jerk |
LB [74] |
|
Dissimilarity of AST subcomponents |
LB [57,67] |
|
Dissimilarity of STS subcomponents |
LB [67,68,70] |
|
Spatial Variables |
Number of steps |
LB [60], Sha [50] |
Step length |
He [64], LB [60,64,72] |
|
Temporal Variables |
Gait Speed |
He [55,64], LB [40,44,55,64,72,74] |
Cadence |
He [64], LB [39,58,64], Kn [41], Sha [50], An [41] |
|
Step duration |
LB [74], Sha [50] |
|
Step duration variability |
He [55], LB [55] |
|
Stride time |
Fo [71] |
|
SD of stride time |
Fo [71] |
|
% GC double support |
Sha [50] |
|
TUG time |
LB [66,74], Sha [50] |
|
TUG subcomponent time |
LB [57,66], Sha [50] |
|
TUG: number of gait cycles |
Sha [50] |
|
STS time |
LB [66] |
|
STS subcomponent times |
LB [57], Th [42] |
|
SD of STS subcomponent times |
LB [66] |
|
Normalized SD of STS subcomponent times |
LB [58,66] |
|
Sit/stand transition duration |
St [17,45] |
|
Sit/stand SD of transition duration |
St [17] |
|
AST time |
LB [66] |
|
AST subcomponent times |
LB [57,58,68,70] |
|
SD of AST subcomponent times |
LB [66] |
|
Normalized SD of AST subcomponent times |
LB [67,68,70] |
|
Energy Variables | Kinetic Energy |
LB [49] |
Local wavelet energy |
St [45] |
|
Summed magnitude area of acceleration |
LB [57,58,67] |
|
25% quartile frequency |
He [18], Hi [18] |
|
50% quartile frequency |
He [18], Hi [18] |
|
75% quartile frequency |
He [18], Hi [18] |
|
Sway frequency during stance |
LB [51] |
|
Number of FFT peaks |
LB [61,62] |
|
Dominant FFT peak parameters |
LB [59,61,62] |
|
1st FFT peak parameters |
Sho [41], El [41], Wr [41], Kn [41], An [41] |
|
Ratio of magnitude of even harmonics to odd harmonics |
He [55,64], UB [44,75], LB [44,50,52,53,59,72] |
|
Area under 1st 6 harmonics divided by remaining area |
LB [57,58] |
|
Ratio of 1st 4 harmonics to magnitude of 1st 6 harmonics |
LB [57,58] |
|
ML spectral edge frequency |
St [42] |
|
Entropy of power spectrum |
LB [53] |
|
Correlation between left and right arm signals |
Sho [41], El [41], Wr [41] |
|
Maximum V acceleration Lyapunov Exponent |
Hi [56], Kn [56], An [56] |
|
Maximum AV Lyapunov Exponent |
UB [73], Hi [56], Kn [56], An [56] |
|
Autocorrelation coefficients of acceleration signal |
LB [39,65] |
|
Trunk level forces |
St [45] |
|
Continuous wavelet transform |
LB [63] |
|
Discrete wavelet transform |
St [45], LB [63] |
|
Detrended fluctuation fractal scaling index of acceleration derived stride time |
Fo [69] |
|
Fractal dimension of acceleration versus AV |
St [45] |
|
Number of abnormal sit/stand transitions | St [17] |
An, ankle, AP, anteroposterior, AST, Alternating Step Test, AV, angular velocity, COP, center of pressure, CoV, coefficient of variation, El, elbow, FFT, Fast Fourier Transform, Fo, foot, He, head, Hi, hip, GC, gait cycle, Kn, knee, LB, lower back, ML, mediolateral, RMS, Root Mean Square, SD, standard deviation, Sha, shank, Sho, shoulder, St, sternum, STS, sit-to-stand transitions, Th, thigh, TUG, Timed Up and Go, UB, upper back, V, vertical, Wr, wrist.