Table 2.
Mean Differences, Reliability, and Validity of POMA-G Between Groups According to Viewing Method, Frame Rate, and Bandwidtha
| Category | No. of Video Ratings b | Mean Difference (SD) | Regression Results for Mean Differences Between Groups | |||
|---|---|---|---|---|---|---|
| Contrast | P | Interrater Reliability, ICC (95% CI) c | Criterion Validity (95% CI) d | |||
| Viewing method | ||||||
| IP | 42 | 10.90 (1.68) | IP vs NS | .004 | NAe | 0.62 (0.37–0.87) |
| SM | 84 | 10.30 (1.86) | IP vs SM | .14 | 0.68 (0.54–0.78) | NAf |
| NS | 436 | 9.88 (2.27) | NS vs SM | .11 | 0.66 (0.61–0.71) | 0.74 (0.67–0.80) |
| Frame rate (at bandwidth of 768 kB/s) (fps) | ||||||
| 30 | 89 | 9.75 (2.45) | 30 vs 8 | .26 | 0.66 (0.52–0.76) | 0.80 (0.63–0.98) |
| 15 | 89 | 10.07 (1.99) | 30 vs 15 | .58 | 0.67 (0.54–0.77) | 0.75 (0.61–0.90) |
| 8 | 86 | 10.13 (2.05) | 15 vs 8 | .33 | 0.77 (0.67–0.84) | 0.79 (0.66–0.93) |
| Bandwidth (at frame rate of 30 fps) (kB/s) | ||||||
| 768 | 86 | 10.13 (2.05) | 768 vs 128 | .27 | 0.77 (0.67–0.84) | 0.80 (0.63–0.98) |
| 384 | 87 | 9.70 (2.41) | 768 vs 384 | .22 | 0.69 (0.57–0.78) | 0.72 (0.58–0.87) |
| 128 | 85 | 9.74 (2.43) | 384 vs 128 | .91 | 0.66 (0.52–0.76) | 0.70 (0.53–0.87) |
aCI = confidence interval; fps = frames per second; ICC = intraclass correlation coefficient; IP = in person; POMA-G = Tinetti Performance-Oriented Mobility Assessment gait scale; NS = normal speed; SM = slow motion.
bNumber of video ratings available for the comparisons, varying according to the number of raters for any given parameter and missing values for that parameter (eg, in-person ratings and/or raters deeming a video “unable to be rated”).
cReliability was based on Streiner and Norman.36(p133) CIs were estimated using the Fisher z transformation.
dValidity was estimated using the standardized regression coefficient for the relationship between test and criterion measures.
eWith a single IP rating, interrater reliability could not be estimated.
fThe criterion group in validity analyses was SM.