Spinal cord injury and time to instability in seated posture.
Arch Phys Med Rehabil 2013;
94:1615-20. [PMID:
23422406 DOI:
10.1016/j.apmr.2013.02.008]
[Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 01/24/2013] [Accepted: 02/06/2013] [Indexed: 10/27/2022]
Abstract
OBJECTIVE
To investigate seated postural control in persons with spinal cord injury (SCI) compared with age-matched controls.
DESIGN
Cohort.
SETTING
University research laboratory.
PARTICIPANTS
Adults (N=36; mean age ± SD, 22.5 ± 3.2y): 7 persons with high SCI (HI group; injury level greater than T10), 11 persons with low SCI (LI group; injury level between T10 and L4), and 18 persons with non-SCI.
INTERVENTION
Not applicable.
MAIN OUTCOMES MEASURES
Participants sat on a force platform on a custom-built wooden box with their arms by their side. Postural control was quantified in several ways. Participants completed a functional reach test. The amount of postural sway was quantified by characterizing the center of pressure (COP) trajectory by determining median velocity and root mean square of the signal. In addition, the virtual time to contact to the functional boundary was quantified. Last, the instability index was determined as the ratio of the COP area to the functional boundary.
RESULTS
There were no group differences in COP-based metrics (P>.05). There was no difference between SCI groups in functional reach (P>.05). The HI group had a smaller virtual time to contact (VTC) than the control group (.50 ± .20s vs .98 ± .24s, P<.05). Both SCI groups had a greater instability index than the control group, with the HI group having the largest amount of instability (P<.05).
CONCLUSIONS
The observations suggest that VTC analysis is appropriate to investigate seated postural control. It is proposed that including VTC of seated postural control as an outcome measure will provide novel information concerning the effectiveness of various rehabilitation approaches and/or technologies aimed at improving seated postural control in persons with SCI.
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