The construct and concurrent validity of brief standing sway assessments in children with and without cerebral palsy.
James B Tracy, Drew A Petersen, Benjamin C Conner and 7 others
PMID 33421952WHAT IT FOUND
For children with cerebral palsy, brief standing sway tests of 5 to 25 seconds can match the validity of the standard 30-second test.
This applies specifically to eyes-closed measures in the side-to-side or rotational directions, potentially helping clinicians assess children who cannot stand still long enough for traditional protocols.
Key findings
01Seven sway measures maintained construct validity at shorter durations (5-25 s) compared to the standard 30-s test, specifically showing large effect sizes between children with CP and typical development.
02These shorter-duration measures also maintained concurrent validity, correlating strongly (r = 0.83-0.98) with the results from the full 30-second trials.
03The valid short-duration measures were exclusively found in the eyes-closed condition and involved either the mediolateral (side-to-side) direction or the transverse plane.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The sample size was small, particularly after removing 10 children for fidgeting, leaving only 31 participants for analysis. The study only included children who could walk independently (GMFCS Level I and II), so results may not apply to children with more severe mobility impairments. Repeatability and reliability of these short-duration measures were not assessed; it is unknown if they can track changes over time or response to treatment. The analysis only looked at measures that were already valid at 30 seconds, so it does not tell us if short durations can detect smaller impairments that the 30-second test might also miss. The study did not validate whether center-of-pressure sway is a perfect proxy for postural control, only that shorter durations match longer durations for this specific metric.
Declared interests
The authors declare no financial or personal conflict of interest.
The easy way to misread this
Do not assume that short-duration sway tests are valid for all directions or conditions. This study only supports short tests for eyes-closed, side-to-side, or rotational sway. Eyes-open tests and front-to-back sway measures did not maintain validity at shorter durations.