Validity and reliability of assessment tools for measuring unsupported sitting in people with a spinal cord injury

Abstract

Objectives: To develop simple tests to assess the abilities of people with spinal cord injury (SCI) to sit unsupported and to assess the construct validity and test-retest reliability of these tests.

Design: Cross-sectional comparisons, convenience sample.

Setting: Biomechanical laboratory.

Participants: People (N=30) with SCI between the C6 and the L2 level of 2 months to 37 years duration before assessment. The sample was stratified by impairment level (at T8) and time since injury (1 y postinjury).

Interventions: Not applicable.

Main outcome measures: On 2 separate occasions, participants performed tests that measured the distance of upper-body sway and maximal torso leaning, errors made during a coordinated stability task, timed dressing/undressing of the upper body and alternating arm reaching, and percentage change in seated upper body/arm reaching.

Results: All tests showed good construct validity in that they distinguished between participants with higher (C6-T7) and lower (T8-L2) level impairments (P<.05) and between participants with acute (< or =1 y) and chronic (>1 y) lesions (P<.05). The tests also showed good to excellent test-retest reliability (intraclass correlation coeffiecient(3,1) range, .51-.91).

Conclusions: These simple and quick-to-administer tests have both construct validity and test-retest reliability. They would be appropriate for research and clinical purposes to quantify the abilities of people with SCI to sit unsupported.