Validity and reliability of the video-based standing-start 180° turn test (SS-180) in adults with and without Parkinson's disease (PD)
暂无分享,去创建一个
Objectives: To establish the external validity, test–retest characteristics
and intra- and inter-rater reliability of the video-based SS-180. Background: The SS-180 is being developed to facilitate research on
dysfunctional turning, a common problem in PD; quick and easy to
administer, it was designed for use beyond the laboratory setting. Subjects
walk twice to a target 3 m behind them, first turning 180° in an unspecified
direction, then requested to turn the opposite way. Turning Steps and Time
(Section 1), Turn Type (Section 2) and Independence, Continuity, Ground
Clearance, Stability and Posture (Section 3, scored 0–5) are then rated
from video. Methods: Thirty-eight adults with and without PD completed the SS-180
in a gait laboratory. To externally validate Sections 1 and 2, the video
rating of 20 turns was compared with 3D motion analysis. Test–retest
characteristics were established by testing 7 participants twice. Ten turns
were rated twice by the lead researcher (with a week’s interval) to establish
intra-rater reliability and by two researchers to establish inter-rater reliability. Results: Agreement between video- and motion-analysis was moderate
for Step Count (weighted 0.57) and good for Turn Type ( 0.78,
95% CI 0.70 to 0.86). The mean difference between Times rated both ways
was 0.02 sec in controls (95% limit of agreement 0.46 sec to 0.5 sec) and
0.9 sec in PD (95% limit of agreement 20% to 7%, logarithmically
transformed). When retested, controls turned as before but a median 0.2 sec
faster. In PD, Step Count was a median one less and the turn a median 0.6
sec faster when repeated; Turn Type did not change and the Section 3 Score
never changed more than one point, with the median change zero. The lead
researcher’s two ratings were in 100% agreement for Step Count, Turn
Type and Section 3 Score; mean Time difference was 0.13 sec (95% limit
of agreement 0.37 s
ec to 0.11 sec). Between raters, agreement was good
for Step Count ( 0.70), very good for Section 3 Score ( 0.82) and
100% for Turn Type; mean Time difference was 0.03 sec (95% limit of
agreement 0.42s to 0.48 sec). Conclusions: Video-rating the SS-180 produced results comparable with
a laboratory-based gold standard; turns changed minimally when repeated
and reliability proved acceptable, so research findings can be interpreted
with confidence. The SS-180 is in use and being refined for clinical
application.