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Table 3 Test-retest reliability of measurement instruments of mobility in 65 older acute medical patients with cognitive impairment

From: Reliability of mobility measures in older medical patients with cognitive impairment

 

DEMMI

HABAM

POMA

SPPB

Gait speed a (n = 35)

5x chair rise test (n = 16)

2-min walk test (n = 35)

TUGb

(n = 33)

BI mobility subscale

Scale range and unit

0–100 points

0–26 points

0–28 points

0–12 points

Ratio scale (meter/second)

Ratio scale (seconds)

Ratio scale (meter)

Ratio scale (seconds)

0–40 points

Mean ± SD score 1st measure

38.5 ± 23.4

13.5 ± 7.6

10.5 ± 9.4

2.8 ± 3.2

0.62 ± 0.22

17.5 ± 4.1

71.5 ± 29.0

24.0 ± 13.5

18.7 ± 13.7

Mean ± SD score 2nd measure

38.7 ± 23.9

13.7 ± 7.8

10.9 ± 9.7

3.2 ± 3.6

0.67 ± 0.25

16.3 ± 5.2

75.9 ± 28.7

23.0 ± 12.2

19.5 ± 14.1

Mean difference absolute (95% CI)

0.3 (− 0.5 to 1.1)

0.2 (− 0.1 to 0.6)

0.4 (0.0 to 0.8)

0.4 (0.2 to 0.6)

0.04 (0.00 to 0.08)

−1.3 (− 3.1 to 0.6)

4.4 (0.8 to 8.1)

− 1.0 (− 2.6 to 0,6)

0.9 (0.1 to 1.6)

Mean difference relative to score of 1st measure

< 1%

1%

4%

14%

6%

7%

6%

4%

5%

P value for mean difference

0.52

0.22

0.04

< 0.001

0.04

0.16

0.02

0.22

0.03

σ2p

554.304

58.267

90.143

11.087

0.049

16.317

778.484

154.555

188.450

σ2o

0

0.01

0.062

0.074

0.001

0.44

8.221

0.169

0.288

σ2residual

5.239

1.106

1.153

0.372

0.007

5.838

55.479

9.999

4.519

ICCAGREEMENT

0.99

0.98

0.99

0.97

0.86

0.72

0.92

0.94

0.98

95% CI for ICC

0.99 to 0.99

0.97 to 0.99

0.98 to 0.99

0.92 to 0.98

0.75 to 0.93

0.38 to 0.89

0.84 to 0.96

0.88 to 0.97

0.96 to 0.99

P value for ICC

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

SEMAGREEMENT (absolute value)

2.29

1.06

1.10

0.67

0.09

2.51

7.98

3.19

2.19

SEMAGREEMENT (relative to scale range)

2.3%

4.1%

3.9%

5.6%

na

na

na

na

5.5%

SEMAGREEMENT (relative to mean 1st measure)

5.9%

7.9%

10.5%

23.9%

14.5%

14.3%

11.2%

13.3%

11.7%

Ï„ -correlation c

0.30; P < 0.01

−0.03; P = 0.77

0.38; P < 0.01

0.66; P < 0.01

0.18; P = 0.14

0.33; P = 0.08

0.22; P = 0.08

0.43; P < 0.01

0.15; P = 0.16

Normal distribution of differencesd

P < 0.001

P < 0.001

P < 0.001

P < 0.001

P = 0.03

P = 0.77

P = 0.01

P = 0.01

P < 0.001

95% LoA (log as function of X)

−0.11X + 0.3 to 0.11X + 0.3

−2.7 to 3.2

−0.22X + 0.4 to 0.22X + 0.4

−0.34X + 0.4 to 0.34X + 0.4

−0.34X + 0.04 to 0.34X + 0.04

−0.35X - 1.3 to 0.35X - 1.3

− 0.29X + 4.4 to 0.29X + 4.4

− 0.28X - 1 to 0.28X - 1

−0.26X + 0.9 to 0.26X + 0.9

MDC90

exact

5.3

2.5

2.6

1.5

0.21

5.8

18.5

7.4

5.1

rounded up

6

3

3

2

na

na

na

na

6

MDC95

exact

6.3

2.9

3.1

1.9

0.25

6.9

22.1

8.8

6.1

rounded up

7

3

4

2

na

na

na

na

7

  1. Abbreviations: DEMMI De Morton mobility index, HABAM Hierarchical assessment of balance and mobility, POMA Performance oriented mobility assessment, SPPB Short physical performance battery, TUG Timed up and go test, BI Barthel index, SD Standard deviation, CI Confidence interval, σ2p Variance between patients, σ2o Variance due to systematic differences between observations, σ2residual Residual variance, ICC Intraclass correlation coefficient, SEM Standard error of measurement, LoA Absolute limites of agreement with 95% confidence, X Test score, MDC90 Minimal detectable change with 90% confidence, MDC95 Minimal detectable change with 95% confidence, na Not applicable
  2. agait speed final score: maximum of 2 trials
  3. bTUG final score: mean of 2nd and 3rd trial
  4. cKendall’s Tau correlation between absolute difference and mean scores of two measures
  5. dShapirow Wilk test of Normality