Inter- and intra-tester reliability of the Balance Performance Monitor in a non-patient population

The intra-rater reliability of the Balance Performance Monitor when measuring sitting symmetry and weight-shift activity after stroke in a community setting

Objective: To examine the intra-rater reliability of sitting symmetry and weight-shift activity measurements in poststroke adults.

Design: An intra-rater reliability study.

Setting: A community setting.

Subjects: Adult stroke survivors attending stroke support groups within the community of Nottingham (UK).

Main measures: The Balance Performance Monitor used to measure sitting symmetry and weight-shift activity. Intraclass correlation coefficients (ICCs) and their 95% confidence intervals (95% CI) were calculated. The Bland-Altman method for assessing agreement is also presented.

Results: We tested 49 participants (median age 73 years; interquartile range 68-81 years). Between-test reliability for sitting symmetry was high: ICC (1,1) = 0.93 (95% CI 0.87 ≤ ICC5 ≤ 0.96). The mean difference between the measures (d̄) was-0.08 (95% CI-0.48 ≤ d̄ ≤ 0.31); the standard deviation of the differences (SDdiff) was 1.383. The coefficient of repeatability was 2.76; the 95% limits of agreement were -2.850 and 2.682. Between-test reliability for weight-shift activity was also high: ICC (1,1) = 0.86 (95% CI 0.775 ≤; ICC5 ≤; 0.92). Bland-Altman d̄= - 0.08 (95%CI-0.19 ≤ d̄ ≤ 0.35), SDdiff = 0.936. The coefficient of repeatability was 1.87; the 95% limits of agreement were-1.792 and 1.952.

Conclusions: The 95% CI for d for both parameters crossed zero, indicating that between-test bias is unlikely. Sitting symmetry and weight-shift activity measures demonstrated acceptable levels of reliability.

Randomized clinical trial into the impact of rigid foot orthoses on balance parameters in excessively pronated feet

Objective: To evaluate the effect of rigid foot orthoses on balance parameters in participants with clinically diagnosed excessively pronated feet.

Design: Randomized clinical trial.

Setting: University biomechanics laboratory.

Participants: Thirty female and 20 male healthy participants (mean 23.89 ± 2.2 years old) with excessively pronated feet, according to a validated foot classification system were randomly assigned to either a control or intervention group.

Interventions: Balance testing was performed using the Balance Performance Monitor with an over-the-counter rigid foot orthoses.

Main outcome measures: Standing balance in the form of mean balance (measures the participants ability to stand with an even load), medial–lateral sway and anterior–posterior sway. All participants were measured while standing bipedally.

Results: There was no significant mean difference in balance scores between the control and intervention group at baseline. After four weeks the results demonstrated no significant differences between mean) balance ( p > 0.05) and anterior–posterior sway ( p > 0.05). However, there was a reduction with the intervention group in medial–lateral sway ( p > 0.02).

Conclusion: The use of foot orthoses in the current study may have improved postural control by stabilizing the rear foot and thus maintaining balance. By the same argument, the benefits of limiting excessive foot pronation may contribute to effective control of internal rotation of the tibia and thereby reduce counter-rotatory motion at the knee and lower leg and maintain balance.

Improved single-limb balance after total knee arthroplasty

PURPOSE

Unsteady ambulation shortly after total knee arthroplasty (TKA) may cause falling. Postural sway may predict the risk of falling. This prospective single-blinded observational study therefore evaluated the effects of TKA on single-limb standing balance (SLSB) and factors related to change in SLSB.

METHODS

Patients with varus deformity and medial compartment degeneration were evaluated between September and December 2010. The Western Ontario and McMaster Universities Osteoarthritis Index and Kellgren/Lawrence scale were assessed, as were varus angle, number of painful knees, isometric peak torque of the quadriceps femoris, balance index of double limbs, and postural sway of single limbs.

RESULTS

Twelve patients were enrolled and 11 were analysed. The mean ± SD postural sway of single limbs (i.e., SLSB) was reduced significantly after TKA, from 30.3 ± 20.8 cm to 18.5 ± 9.3 cm (p = 0.02). Amelioration was in proportion to pre-operative postural sway (β = 0.92).

CONCLUSIONS

SLSB in patients with varus knees with osteoarthritis was improved significantly 11 days after TKA. Poorer pre-operative SLSB was associated with better post-operative SLSB. TKA may be useful for the immediate reduction of falling in patients with osteoarthritis.

Use of virtual reality to enhance balance and ambulation in chronic stroke: a double-blind, randomized controlled study

OBJECTIVE

To examine an additive effect of virtual reality on balance and gait function in patients with chronic hemiparetic stroke.

DESIGN

Twenty-four adults with hemiparetic stroke were randomly assigned to either an experimental group (n = 12) or a control group. Both groups underwent conventional physical therapy, 40 mins a day, 4 days a week for 4 wks. The experimental group received an additional 30 mins of virtual reality therapy each session. Balance performance was determined by the Balance Performance Monitor and Berg Balance Scale tests. Gait performance was determined by the 10-m walking test and Modified Motor Assessment Scale, and spatiotemporal parameters were obtained using GAITRite. Analysis of variance and correlation statistics were performed at P < 0.05.

RESULTS

In the balance test, the experimental group had improved Berg Balance Scale scores, balance and dynamic balance angles (ability to control weight shifting) compared with the controls (P < 0.05). In the gait performance test, the experimental group showed significant improvements in velocity, Modified Motor Assessment Scale scores, cadence, step time, step length, and stride length (P < 0.05). Improvement in dynamic balance angles was correlated with velocity and cadence (P < 0.01).

CONCLUSIONS

This study demonstrates that virtual reality has an augmented effect on balance and associated locomotor recovery in adults with hemiparetic stroke when added to conventional therapy.

Dual-task study of cognitive and postural interference: a preliminary investigation of the automatization deficit hypothesis of developmental co-ordination disorder

BACKGROUND

The purpose of this study was to investigate whether children with developmental co-ordination disorder and balance problem (DCD-BP) had greater problems than controls in performing a primary balance task while concurrently completing different cognitive tasks varying in oral or listening cognitive complexity, as well as to investigate the automatization deficit hypothesis of DCD-BP.

METHODS

Children with DCD-BP (n= 39), along with age-matched control counterparts (n= 39), were placed on automatic processing situation under dual-task conditions. All children were required to perform a primary task, five dual-task paradigms (oral counting task, auditory-verbal reaction task, auditory-choice reaction task, auditory-memory task and articulation alone) and an eyes-closed balancing task.

RESULTS

In the primary task condition, the differences were not statistically significant (P= 0.393) between children with and without DCD-BP. However, children with DCD-BP were significantly more impaired on three of five dual-task conditions (oral counting task: P= 0.003; auditory-verbal reaction task: P= 0.011; auditory-memory task: P= 0.041) compared with the single-task situation, with the exception of the auditory-choice reaction task (P= 0.471) and articulation alone (P= 0.067).

CONCLUSIONS

These results suggest that children with DCD-BP were more cognitively dependant and may have an automatization deficit.

Relationship of Visual Perceptual Deficit and Motor Impairment in Children with Developmental Coordination Disorder

The study explored the relations of visual perceptual deficits and motor impairments in 60 children with Developmental Coordination Disorder (120.8 ± 4.0 mo.) and 60 controls (121.0 ± 5.3 mo.), who were matched by sex (29 boys and 31 girls) and age. They were separately assessed on fine and gross motor-dexterity tasks of the Movement Assessment Battery for Children, static balance and reaction time of lower extremities with eyes open or closed, and the Test of Visual-Perceptual Skills–Revised. Analysis showed the children with Developmental Coordination Disorder performed significantly worse than the control group, but only the visual perception and motor skills with timed responses were significantly correlated. When visual information was controlled, no significant correlation was noted, so motor-free visual perception appears to be significantly related to motor performance having a speed component in these children.

The effect of a single haemodialysis session on functional mobility in older adults: a pilot study

OBJECTIVES

To undertake balance and functional mobility assessments in older maintenance haemodialysis patients before and after haemodialysis as a pilot study in order to gain initial data and to assess the feasibility and acceptability of this type of study.

DESIGN

Postural sway, three-metre timed "up and go" test (TGUGT), and dynamic single leg extensor power (LEP) were measured before and after a haemodialysis session.

SETTING AND SUBJECTS

Male and female maintenance haemodialysis patients aged over 60 years attending the Nottingham City Hospital.

MAIN MEASURES

Objective outcome measures were postural sway number and sway path (mm) by balance performance monitor, timed three-metre "up and go" test (s), and leg extensor power (W). Blood pressure and weight reductions were also measured. Subjective assessments of practicality and acceptability were made.

RESULTS

Twenty-two patients enrolled. Complete data sets were collected for 14 subjects (11 male, three female). Results were analysed using the Wilcoxon signed ranks test for nonparametric data. There was no significant difference before and after dialysis in postural sway, timed "up and go" or leg extensor power. Eight patients did not complete the study and the reasons are examined.

CONCLUSIONS

There was no significant single-session effect. Results suggest that haemodialysis patients may be weaker and have reduced postural stability when compared to historical data on comparable undialysed patients. The study was logistically complex and would be difficult to expand using these methods, but the issues merit further consideration.

Does arthroplasty type influence knee joint proprioception? A longitudinal prospective study comparing total and unicompartmental arthroplasty

Proprioception was assessed after knee replacement to compare total (TKA) to unicompartmental (UKA) knee arthroplasty. Thirty-four patients were recruited; seventeen patients underwent TKA and seventeen patients underwent UKA. The patient's age was similar in both groups. Two measures of proprioception, joint position sense (JPS) and postural sway (PS) were measured. Function was assessed using the Oxford Knee Score (OKS). Measurements were taken pre-operatively and 6 months post-operatively on both the operated and contralateral leg. Pre-operatively, no differences in JPS or PS were found between groups or between limbs in either group. Post-operatively, both groups had significant improvement of JPS in the operated limb only (20% increase). The improvement in JPS was similar in both groups. PS also improved significantly in both groups although the improvement of PS in the UKA group was twice that for the TKA group. The OKS improved by a similar amount in both groups. Both UKA and TKA result in a significant improvement in proprioception. Dynamic aspects of proprioception improve more after UKA than TKA, which may explain, in part, why UKA patients have superior functional outcome to that of TKA patients.

Reliability of simple portable tests of physical performance in older people after hip fracture

OBJECTIVE

To investigate the test-retest reliability of measures of strength, balance, gait and functional performance when used with older people following hip fracture.

SUBJECTS

Thirty people (16 hospital inpatients and 14 community dwellers).

DESIGN

Subjects underwent two assessments: one day apart for the hospital inpatients and one week apart for the community dwellers.

MEASUREMENT

Strength (dynamometer, sphygmomanometer, spring balance, lateral step-up ability), balance (sway-meter, Functional Reach Test, single leg stance time, Step Test), gait (timed 6-m walk with steps taken, base of support and step length), and functional performance (PPME total score and timed supine-to-sit and sit-to-stand) were measured.

RESULTS

Eleven of the 14 continuously scaled measurement tools achieved excellent reliability (intraclass correlation coefficient (ICC) > 0.75) for one or more tests. A hand-held dynamometer was found to be the tool with the highest test-retest reliability for measuring hip muscle strength (ICC (3,1) 0.86 for affected hip abduction). For measurement of knee extension strength, a spring balance (ICC (3,1) 0.94 affected leg) was the most reliable. For testing balance, the Step Test (ICC (3,1) 0.94 for stepping with affected leg) and Functional Reach Test (ICC (3,1) 0.89) had the highest test-retest reliability. The ICC (3,1) values were 0.97 for walking velocity (comfortable pace) and 0.96 for the total score of the Physical Performance and Mobility Examination.

CONCLUSION

The test-retest reliability of a number of simple measures of physical performance is excellent when used with this population.

A randomized controlled trial of an enhanced balance training program to improve mobility and reduce falls in elderly patients

OBJECTIVES

To evaluate the effectiveness of an enhanced balance training program in improving mobility and well-being of elderly people with balance problems.

DESIGN

Prospective, single-blind, randomized, controlled trial.

SETTING

District general hospital.

PARTICIPANTS

One hundred ninety-nine patients aged 60 and older with a Berg Balance Scale (BBS) score of less than 45.

INTERVENTIONS

Six weeks enhanced balance training consisting of a series of repetitive tasks of increasing difficulty specific to functional balance. The control group received physiotherapy conforming to existing practice in elderly patients with mobility problems.

MEASUREMENTS

Ten-meter timed walk test (TWT), BBS, Frenchay Activities Index (FAI), Falls Handicap Inventory (FHI), and European Quality of Life questionnaire (Euroqol) measured at 6, 12, and 24 weeks after intervention.

RESULTS

The mean age +/- standard deviation of subjects was 82.7 +/- 5.6, and baseline characteristics were comparable between the groups. Both groups showed improvements in TWT (intervention: 22.5-16.5 seconds, P =.001; control: 20.5-15.8 seconds, P =.054), BBS (intervention: 33.3-42.7, P =.001; control: 33.4-42.0, P <.0001), FAI (18-21, P =.02 in both groups), FHI score (intervention: 31-17, P =.0001; control: 33-17, P =.0001) and Euroqol score (intervention: 58-65, P =.04; control: 60-65, P =.07). There were no intergroup differences at any time. More patients reported increased confidence in walking indoors (36% vs 28%; P =.04) and outdoors (27% vs 18%; P =.02) in the enhanced balance-training group.

CONCLUSION

Exercise programs significantly improve balance and mobility in patients with balance problems, independent of strategy. Enhanced balance training may, in addition, improve confidence and quality of life but needs further investigation.

Postural control in the elderly: an analysis of test-retest and interrater reliability of the COP-COM variable

OBJECTIVES

To estimate the test-retest and interrater reliability of the center of pressure-center of mass (COP-COM) variable of postural control in the elderly.

DESIGN

The biomechanic variable COP-COM, which represents the distance between the COP and the COM, was determined from 2 AMTI force platforms and 3 OPTOTRAK position sensors. Measurements were taken in quiet position, double leg stance, and eyes open and eyes closed conditions.

SETTING

Laboratory environment.

PARTICIPANTS

Forty-five healthy subjects, 8 patients with diabetes neuropathy, and 7 stroke survivors, all of whom were at least 60 years old.

INTERVENTIONS

Subjects were evaluated on 2 separate occasions within 7 days by the same evaluator to determine test-retest reliability. Interrater reliability was determined the same day.

MAIN OUTCOME MEASURES

The biomechanic variable COP-COM, which represents the distance between the COP and the COM in terms of root mean square. The mean of 4 trials of the COP-COM variable for each condition was used for statistical analysis. Intraclass correlation coefficients (ICCs) were used.

RESULTS

The COP-COM variable has good reliability for both the test-retest and interrater studies, but its reliability varies according to the direction of the COP-COM. For the test-retest and interrater studies, the ICC ranged from.89 to.93 in the anteroposterior direction and from.74 to.79 in the mediolateral direction.

CONCLUSION

The equivalence of the test-retest and interrater coefficients obtained suggests that the measurement error of the COP-COM variable is mainly linked to the biologic variability of this measure over a short period of time. Using the mean of 4 trials stabilizes the COP-COM variable enough to be potentially used to evaluate clinical change.

Validity of weight distribution and sway measurements of the Balance Performance Monitor

BACKGROUND AND PURPOSE

The Balance Performance Monitor (BPM) is a device which provides auditory and visual feedback on weight distribution and the magnitude of lateral and anterior-posterior sway during quiet standing. This study investigated the validity of the measurements provided by the BPM using a Kistler force plate (KFP) as the gold standard.

METHOD

Percentage weight distribution between the BPM foot plates was validated using both a series of calibration weights and the vertical component of ground reaction force, measured by the KFP, during normal standing in 18 young normal subjects. The lateral and anterior-posterior sway indices from the BPM were validated against the standard deviation of the position of the centre of pressure, again obtained using the KFP, during normal standing with eyes open and eyes closed and standing with feet together with eyes open. Concurrent validity of the percentage weight distribution measurements was assessed by calculating the 'limits of agreement' between the corresponding measurements from the BPM and KFP and the 95% confidence intervals for these 'limits'. Differences in the units of measurement obtained from the BPM and KFP resulted in the concurrent validity of the sway indices being assessed using correlation and regression.

RESULTS

Excellent agreement was found between the percentage weight distribution values provided by the BPM and the KFP, which showed that the BPM may read only 3% of body weight above or below that given by the KFP. High correlations (r = 0.61-0.99) were found between both the lateral and anterior-posterior sway indices from the BPM and the motion of the centre of pressure from the KFP in the respective direction. Despite this, further analysis of regression equations and the 95% prediction intervals showed poor concurrent validity of the BPM sway indices in relation to KFP measurements. This was thought to be due to the different methods by which the sway indices and the motion of the centre of pressure were calculated.

CONCLUSIONS

The BPM may be used to provide a valid measure of the symmetry aspect, but not necessarily the steadiness aspect of postural control.