Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access
Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc
Journal website https://jocmr.elmerjournals.com

Original Article

Volume 17, Number 4, April 2025, pages 200-207

Evaluating Postural Sway in the Elderly Using Inertial Measurement Units: A Study on Center of Mass Measurements via Accelerometers and Gyroscopes

Figures

↓  Figure 1. The diagram for the experimental procedure.
Figure 1.
↓  Figure 2. Bar graph depicting COM postural sway in accelerometer (RMS, RANGE, SA, and SD) ranging from a variety of increasingly challenging conditions of base of support in (a) AP and (b) ML planes. COM: center of mass; RMS: root mean square of magnitude; RANGE: summation of the range of signals; SA: sway area; SD: summation of distance; AP: anteroposterior; ML: mediolateral.
Figure 2.
↓  Figure 3. Bar graph depicted COM postural sway in gyroscope (RMS, RANGE, SA, and SD) ranging from a variety of increasingly challenging conditions of base of support in (a) AP and (b) ML planes. COM: center of mass; RMS: root mean square of magnitude; RANGE: summation of the range of signals; SA: sway area; SD: summation of distance; AP: anteroposterior; ML: mediolateral.
Figure 3.

Tables

↓  Table 1. Demographic and Clinical Data
 
Characteristic Mean ± SD Min - Max
BMI: body mass index; SD: standard deviation.
Male/female, N (%) 58 (50.90%)/56 (49.10%)
Age (years) 65.90 ± 6.60 60.00 - 84.00
Weight (kg) 57.40 ± 9.40 38.00 - 90.00
Height (cm) 158.80 ± 7.70 145.00 - 175.00
BMI (kg/m2) 22.80 ± 3.80 15.80 - 40.00

 

↓  Table 2. AP and ML Planes of Accelerometer-Derived Sway Metrics for Each Test Condition
 
Sensor variable-plane SO STO TO SL
Mean ± SD (min - max) Mean ± SD (min - max) Mean ± SD (min - max) Mean ± SD (min - max)
SO: standing in a double stance; STO: semi-tandem stance; TO: tandem stance; SL: single-leg stance; RMS: root mean square of magnitude; RANGE: summation of the range of signals; SA: sway area; SD: summation of distance; AP: anteroposterior; ML: mediolateral.
RMS-AP 6.79 ± 1.56 (4.14 - 14.73) 7.59 ± 2.39 (4.79 - 25.31) 8.31 ± 2.32 (4.49 - 17.50) 16.43 ± 8.44 (6.99 - 43.68)
RANGE-AP 47.49 ± 22.84 (27.30 - 217.04) 54.61 ± 36.99 (30.23 - 340.39) 56.41 ± 18.85 (27.64 - 126.31) 132.22 ± 88.60 (43.84 - 513.53)
SD-AP 1,827.48 ± 442.49 (155.36 - 4,125.70) 2,051.46 ± 539.91 (1,247.46 - 5,208.08) 2,265.73 ± 675.61 (128.78 - 4,718.57) 3,664.93 ± 1,697.59 (263.45 - 10,243.82)
SA-AP 105.44 ± 23.84 (9.64 - 216.12) 117.38 ± 29.28 (75.57 - 287.88) 129.16 ± 37.58 (7.45 - 270.44) 203.91 ± 95.40 (16.64 - 562.37)
RMS-ML 6.42 ± 1.26 (3.98 - 11.74) 7.15 ± 2.32 (3.98 - 26.42) 8.13 ± 2.24 (4.61 - 21.80) 16.92 ± 9.16 (6.79 - 50.78)
RANGE-ML 44.34 ± 18.19 (23.00 - 162.58) 51.20 ± 36.15 (23.00 - 368.64) 55.70 ± 20.72 (27.48 - 164.75) 138.77 ± 95.19 (41.48 - 463.85)
SD-ML 1,715.77 ± 371.94 (172.02 - 3,150.02) 1,920.74 ± 476.83 (1,041.54 - 5,113.17) 2,220.84 ± 638.73 (151.54 - 6,118.31) 3,715.43 ± 1,062.16 (224.74 - 10,440.58)
SA-ML 99.93 ± 20.21 (10.87 - 183.46) 110.64 ± 26.26 (63.68 - 285.77) 126.48 ± 35.79 (8.49 - 344.33) 205.56 ± 88.28 (14.72 - 575.24)

 

↓  Table 3. AP and ML Planes of Gyroscope-Derived Sway Metrics for Each Test Condition
 
Sensor variable-plane SO STO TO SL
Mean ± SD (min - max) Mean ± SD (min - max) Mean ± SD (min - max) Mean ± SD (min - max)
ST: standing in a double stance; STO: semi-tandem stance; TO: tandem stance; SL: single-leg stance; RMS: root mean square of magnitude; RANGE: summation of the range of signals; SA: sway area; SD: summation of distance; AP: anteroposterior; ML: mediolateral.
RMS-AP 13.76 ± 6.60 (6.60 - 37.87) 15.89 ± 7.80 (6.60 - 57.53) 18.08 ± 7.53 (7.38 - 49.57) 48.52 ± 38.48 (13.33 - 221.85)
RANGE-AP 100.68 ± 77.87 (35.78 - 428.28) 123.64 ± 106.13 (35.78 - 809.96) 131.41 ± 79.71 (404.35 - 479.31) 368.33 ± 314.66 (91.81 - 2,030.45)
SD-AP 3,927.88 ± 1,702.50 (278.63 - 10,457.95) 4,480.53 ± 1,812.35 (1,965.70 - 11,185.88) 5,176.23 ± 2,027.73 (309.03 - 14,579.99) 10,358.00 ± 5,467.50 (1,805.89 - 29,778.82)
SA-AP 209.19 ± 91.48 (15.20 - 549.83) 237.03 ± 96.96 (108.02 - 604.03) 274.22 ± 109.74 (16.39 - 755.50) 542.40 ± 288.58 (98.16 - 1,608.70)
RMS-ML 12.31 ± 6.84 (5.91 - 52.28) 18.07 ± 14.11 (5.91 - 116.08) 25.48 ± 13.57 (7.41 - 88.73) 64.98 ± 39.69 (16.49 - 193.58)
RANGE-ML 94.32 ± 90.73 (33.13 - 665.48) 141.74 ± 166.90 (36.20 - 1,265.98) 182.92 ± 115.91 (43.99 - 720.27) 467.52 ± 324.89 (124.74 - 1,944.65)
SD-ML 3,452.58 ± 1,618.41 (212.47 - 13,451.28) 4,989.07 ± 2,760.91 (1,712.87 - 19,905.53) 7,346.36 ± 3,819.67 (566.10 - 25,711.87) 15,186.71 ± 7,620.50 (1,418.84 - 42,005.72)
SA-ML 180.95 ± 81.34 (11.95 - 681.07) 258.82 ± 140.16 (93.46 - 1,024.37) 378.90 ± 195.82 (29.87 - 1,339.51) 778.13 ± 391.17 (76.09 - 2,170.28)

 

↓  Table 4. Spearmen’s Rho Correlation Coefficient of Accelerometer Compared With Gyroscope Derived From Inertial Measurement Unit
 
Sensor variable Correlation coefficient
r P-value
RMS: root mean square of magnitude; RANGE: summation of the range of signals; SA: sway area; SD: summation of distance; AP: anteroposterior; ML: mediolateral.
RMS-AP 0.81 < 0.001
RMS-ML 0.86 < 0.001
RANGE-AP 0.82 < 0.001
RANGE-ML 0.84 < 0.001
SD-AP 0.79 < 0.001
SD-ML 0.85 < 0.001
SA-AP 0.79 < 0.001
SA-ML 0.85 < 0.001

 

↓  Table 5. ICC of Accelerometer Compared With Gyroscope Derived From Inertial Measurement Unit
 
Sensor variable ICC
ICC(2,1) Lower 95% Upper 95% P-value
ICC: intraclass correlation coefficient; RMS: root mean square of magnitude; RANGE: summation of the range of signals; SA: sway area; SD: summation of distance; AP: anteroposterior; ML: mediolateral.
RMS-AP 0.58 0.55 0.65 < 0.001
RMS-ML 0.54 0.45 0.62 < 0.001
RANGE-AP 0.64 0.56 0.70 < 0.001
RANGE-ML 0.60 0.52 0.67 < 0.001
SD-AP 0.63 0.56 0.70 < 0.001
SD-ML 0.50 0.39 0.59 < 0.001
SA-AP 0.65 0.58 0.71 < 0.001
SA-ML 0.52 0.42 0.60 < 0.001