Test–retest reliabty of center of pressure measures of postural stability during quiet standing in a group with musculoskeletal disorders consisting of low back pain, anterior cruciate ligament injury and functional ankle instability

Department of Physical Therapy, University of Social Welfare and Rehabilitation, Tehran, Iran.
Gait & posture (Impact Factor: 2.3). 02/2009; 29(3):460-4. DOI: 10.1016/j.gaitpost.2008.11.016
Source: PubMed

ABSTRACT Reliability is a population-specific property, but to the authors' knowledge there has been no study to determine the test-retest reliability of the postural stability measures such as center of pressure (COP) measures in the population of patients with musculoskeletal disorders (MSDs), while their clinical applications have been presented in literature. So, 33 patients with low back pain (LBP), anterior cruciate ligament (ACL) injury and functional ankle instability (FAI) randomly completed postural measurements with three levels of difficulty (rigid surface-eyes open, rigid surface-eyes closed, and foam surface-eyes closed) in two sessions. COP data were used to calculate standard deviation of amplitude, standard deviation of velocity, phase plane portrait, mean total velocity and area (95% confidence ellipse). Relative reliability of these measures was assessed using intraclass correlation coefficient (ICC) and absolute reliability using standard error of measurement (SEM) and coefficient of variation (CV). Also, minimal metrically detectable change (MMDC) was calculated to quantify intervention effects. Among different COP parameters, mean total velocity in all conditions of postural difficulty showed high to very high reliability, with ICC range of 0.74-0.91, SEM range of 0.09-0.40cm/s, CV range of 5.31-8.29% and MMDC range of 0.19-0.79cm/s. Phase plane portrait in anteroposterior-mediolateral (AP-ML) and ML direction were other best parameters with respect to the level of reliability. Mean total velocity and phase plane portrait parameters are suggested as good candidates to use for quantification and assessment of balance performance and identifying those with MSDs.

Download full-text


Available from: Soheil Sohani, Jul 08, 2015
1 Follower
  • Source
    • "ICCs depend on between-subject variability [14] and ''only have meaning when applied to specific populations'', according to Streiner and Norman [15]. The level of reliability is populationspecific [13] and has not yet been evaluated for VI individuals. Accepted measures of postural stability in standing balance characterize the variability of human movement [16]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Individuals with visual impairment (VI) have irreparable damage to one of the input streams contributing to postural stability. Here, we evaluated the intra-session test-retest reliability of the Wii Balance Board (WBB) for measuring Center of Pressure (COP) magnitude and structure, i.e. approximate entropy (ApEn) in fourteen legally blind participants and 21 participants with corrected-to-normal vision. Participants completed a validated balance protocol which included four sensory conditions: double-leg standing on a firm surface with eyes open (EO-firm); a firm surface with eyes closed (EC-firm); a foam surface with EO (EO-foam); and a foam surface with EC (EC-foam). Participants performed the full balance protocol twice during the session, separated by a period of 15 minutes, to determine the intraclass correlation coefficient (ICC). Absolute reliability was determined by the standard error of measurement (SEM). The minimal difference (MD) was estimated to determine clinical significance for future studies. COP measures were derived from data sent by the WBB to a laptop via Bluetooth. COP scores increased with the difficulty of sensory condition indicating WBB sensitivity (all p < 0.01). ICCs in the VI group ranged from 0.73 to 0.95, indicating high to very high correlations, and the normal group showed moderate to very high ICCs (0.62-0.94). The SEM was comparable between groups regardless of between-subject variability. The reliability of the WBB makes it practical to screen for balance impairment among VI persons.
    Gait & Posture 12/2015; 41(In Press). DOI:10.1016/j.gaitpost.2014.11.012 · 2.30 Impact Factor
  • Source
    • "The first and last 5 seconds of each measurement are trimmed in order to discard any transient effects, resulting in measurements of 30 seconds . The trimmed data is then filtered using an 8th order Butterworth filter with a cut-off frequency of 10 Hz to remove any high frequency noise, which (Salavati et al., 2009 "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, a tool to assess a person’s fall risk with the Nintendo Wii Balance Board based on Center of Pressure (CoP) recordings is presented. Support Vector Machine and K-Nearest Neighbours classifiers are used to distinguish between people who experienced a fall in the past twelve months and those who have not. The classifiers are trained using data recorded from 39 people containing a mix of students and elderly. Validation is done using 10-fold cross-validation and the classifiers are also validated against additional data recorded from 12 elderly. A cross-validated average accuracy of 96.49% +/- 4.02 is achieved with the SVM classifier with radial basis function kernel and 95.72% +/- 1.48 is achieved with the KNN classifier with k = 4. Validation against the additional dataset of 12 elderly results in a maximum accuracy of 76.6% with the linear SVM.
    International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC), Lisbon, Portugal; 01/2015
  • Source
    • "Postural stability was assessed through three reliable and discriminative outcome measures for DJ (5–20 s after landing) and for SLS (15 s): (1) The mean COP speed ('COP speed'), which is the total COP path length divided by trial time (Doyle et al., 2007; Huurnink et al., 2014b; Kiers et al., 2012; Paillard et al., 2006; Salavati et al., 2009). (2) The mean COP sway ('COP sway'), which is the mean absolute distance of the COP trajectory to the average COP position (Clark et al., 2010; Jakobsen et al., 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: We aimed to verify whether the static phase after a single leg drop jump (DJ) landing on a force plate may serve as a proxy for a single leg stance (SLS) balance task, as this would increase the application possibilities of landing tasks in the evaluation of sensorimotor function in relation to injury rehabilitation or performance assessment. Twenty-five healthy participants performed two sessions of five valid trials for both tasks in a reproducibility-agreement design. Three postural stability outcome measures ('COP speed', 'COP sway' and 'Horizontal GRF') were calculated for DJ (5-20s after landing) and for SLS (15s), and were averaged per session. Paired T-tests revealed a learning effect of SLS for postural stability (4.6-6.1%; P-values <0.03), in contrast to DJ (P-values >0.27). Only session 2 resulted in superior postural stability for SLS compared to DJ for 'COP speed' (5.0%; P=0.017) and 'Horizontal GRF' (8.2%; P=0.001). Bland and Altman methods demonstrated inter-session SD's of difference for DJ of 11-12% and for SLS of 10-12%, while inter-task SD's of difference ranged 10-17%. Precision ('SD within') was better for SLS concerning 'COP speed' (14-15% vs 13%) and 'Horizontal GRF' (18-20% vs 14-15%). In conclusion, postural stability during DJ and SLS cannot be considered interchangeable, due to a learning effect for SLS and inferior precision for DJ. However, a DJ task may be used as a proxy for static postural stability, although more than three trials are needed to achieve individual errors similar to SLS for 'COP speed' (4) and 'Horizontal GRF' (5).
    Journal of Biomechanics 06/2014; 47(12). DOI:10.1016/j.jbiomech.2014.06.019 · 2.50 Impact Factor