Quantifying balance control after spinal cord injury: Reliability and validity of the mini-BESTest

The balance evaluation systems test (BESTest), mini-BESTest and brief-BESTest as clinical tools to assess balance control across different populations: A reliability generalization meta-analysis

BACKGROUND

The Balance Evaluation Systems Test (BESTest) and two abbreviated versions, Mini-BESTest and Brief-BESTest are used to assess functioning of balance control systems. Its reliability across different populations remains to be determined.

OBJECTIVE

The present study followed reliability generalization procedures to estimate an average internal consistency and inter and intra-rater reliability for the BESTest, Mini-BESTest and Brief-BEStest. In this study, the heterogeneity of reliability coefficients in each instrument is evaluated. If heterogeneity is significant, a moderator analysis is performed to identify the characteristic which explains such variability.

METHODS

A search of the PubMed, Embase, PsycINFO, Web of Science, Scopus and CINAHL databases was carried out to February 10th 2024. Two reviewers independently selected empirical studies published in English or Spanish that applied the BESTest, Mini-BESTest and/or Brief-BESTest and reported any reliability coefficient and/or internal consistency with data at hand.

RESULTS

Sixty-four studies reported any reliability estimate BESTest, Mini-BESTest and/or Brief-BESTest scores (N. = 5225 participants). Mean Cronbach alpha for the Mini-BESTest and Brief-BESTest (total score = 0.92) indicating no variability in estimated internal consistency. Likewise, no variability was obtained for inter-rater and intra-rater mean agreement of the BESTest (ICC = 0.97; 0.94), Mini-BESTest (ICC = 0.95; 0.94) and Brief-BESTest (ICC = 0.96; 0.95). Mean scores, standard deviation of scores, mean age, gender, population type, mean history of the disorder, disease, raters´ experience, number of raters, rater formation, continent of study and design type presented statistically significant relationships with ICC and/or Cronbach´s alpha for BESTest and the two abbreviated versions.

CONCLUSIONS

The mean intraclass correlations and Cronbach alpha obtained for BESTest, Mini-BESTest and Brief-BESTest exhibited an excellent inter and intra-rater reliability and internal consistency. The average reliability obtained three scales adequate to be applied for screening balance problems in different populations. Some continuous and categorical moderator variables increase reliability and internal consistency of these scales.

Psychometric properties of the Mini-Balance Evaluation Systems Test (Mini-BESTest) among multiple populations: a COSMIN systematic review and meta-analysis

PURPOSE

To synthesize evidence regarding psychometric properties of the Mini-Balance Evaluation Systems Test (Mini-BESTest) in assessing postural control.

METHOD

Six databases were searched until October 15th, 2024. Two authors independently assessed the methodological quality and results of studies using the COSMIN checklist and Terweés criteria. The overall quality of the evidence was provided using the modified GRADE approach.

RESULTS

Ninety-one studies were included. The Mini-BESTest showed very good quality and sufficient structural validity (CFI: 0.91-0.99; TLI: 0.888-0.97; RMSEA: 0.05-0.45), internal consistency (α: 0.73-0.97), criterion validity (BESTest r: 0.65-0.95), convergent validity (e.g., Brief-BESTest r: 0.85-0.94; rs: 0.73-0.92; Berg Balance scale r: 0.58-0.85) and know-groups validity (AUC: 0.712-0.97; cutoffs: 9.0-22/28). However, the scale showed doubtful quality as well as sufficient and indeterminate reliability (inter-rater ICC: 0.56-0.998; r: 0.98; intra-rater ICC: 0.74-0.964) and measurement error (SEM: 0.45-3.03; MDC95: 1.23-8.40), respectively. Adequate quality and sufficient rating were found in most studies for responsiveness. The quality of evidence was moderate to low for structural validity and criterion validity, high to low for internal consistency, convergent validity, and high to very low for reliability, measurement error, know-groups validity, and responsiveness.

CONCLUSIONS

Moderate to high quality evidence was found for support structural validity, internal consistency, reliability, measurement error, criterion validity, hypothesis testing, and responsiveness of the Mini-BESTest only in some study populations.

A systematic review of validity and reliability assessment of measuring balance and walking at the level of International Classification of Functioning, Disability and Health (ICF) in people with spinal cord injury

Context: A spinal cord injury (SCI) is associated with a wide range of impairments in functioning, many limitations in activity, and restrictions for patients.Objectives: The present study aimed to systematically review the psychometric properties (reliability and validity) of outcome measures used to assess walking and balance in people with spinal cord injury.Methods: Databases such as PubMed, Embase, Scopus, and Web of Sciences were searched for relevant articles using various terms (title and abstract). Articles including the outcome measures of spinal cord injury patients and published in English from 2010 until 2021 were selected, and the quality of the selected studies was determined by applying the COSMIN checklist. Reliability and validity values were extracted, and conclusions were drawn about the psychometric quality of each measure.Results: A total of 1253 records were retrieved, and among them 22 potentially eligible articles were identified, 15 of which were included in the present study. The COSMIN tool (Consensus-based Standards for the selection of health status Measurement Instruments) was used to evaluate the quality level of imported articles based on the inclusion criteria.Conclusions: One consideration for testing people with disabilities is to observe the reliability and validity of the instrument, which was addressed in this study in various fields. In our study, seven tools for assessing SCI were evaluated, and it was found that the 10-meter walk (10MWT) tool performs better and more easily than other tools. The Mini-BESTest tool was suggested as a reliable tool for assessing standing balance in SCI subjects.

Clinical Static Balance Assessment: A Narrative Review of Traditional and IMU-Based Posturography in Older Adults and Individuals with Incomplete Spinal Cord Injury

Maintaining a stable upright posture is essential for performing activities of daily living, and impaired standing balance may impact an individual's quality of life. Therefore, accurate and sensitive methods for assessing static balance are crucial for identifying balance impairments, understanding the underlying mechanisms of the balance deficiencies, and developing targeted interventions to improve standing balance and prevent falls. This review paper first explores the methods to quantify standing balance. Then, it reviews traditional posturography and recent advancements in using wearable inertial measurement units (IMUs) to assess static balance in two populations: older adults and those with incomplete spinal cord injury (iSCI). The inclusion of these two groups is supported by their large representation among individuals with balance impairments. Also, each group exhibits distinct aspects in balance assessment due to diverse underlying causes associated with aging and neurological impairment. Given the high vulnerability of both demographics to balance impairments and falls, the significance of targeted interventions to improve standing balance and mitigate fall risk becomes apparent. Overall, this review highlights the importance of static balance assessment and the potential of emerging methods and technologies to improve our understanding of postural control in different populations.

The measurement properties of the Lean-and-Release test in people with incomplete spinal cord injury or disease

OBJECTIVE

To evaluate test-retest reliability, agreement, and convergent validity of the Lean-and-Release test for the assessment of reactive stepping among individuals with incomplete spinal cord injury or disease (iSCI/D).

DESIGN

Multi-center cross-sectional multiple test design.

SETTING

SCI/D rehabilitation hospital and biomechanics laboratory.

PARTICIPANTS

Individuals with motor incomplete SCI/D (iSCI/D).

INTERVENTIONS

None.

OUTCOME MEASURES

Twenty-six participants attended two sessions to complete the Lean-and-Release test and a battery of clinical tests. Behavioral (i.e. one-step, multi-step, loss of balance) and temporal (i.e. timing of foot off, foot contact, swing of reactive step) parameters were measured. Test-retest reliability was determined with intraclass correlation coefficients, and agreement was evaluated with Bland-Altman plots. Convergent validity was assessed through correlations with clinical tests.

RESULTS

The behavioral responses were reliable for the Lean-and-Release test (ICC = 0.76), but foot contact was the only reliable temporal parameter using data from a single site (ICC = 0.79). All variables showed agreement according to the Bland-Altman plots. The behavioral responses correlated with scores of lower extremity strength (0.54, P<0.01) and balance confidence (0.55, P < 0.01). Swing time of reactive stepping correlated with step time (0.73, P < 0.01) and cadence (-0.73 P < 0.01) of over ground walking.

CONCLUSIONS

The behavioral response of the Lean-and-Release test is a reliable and valid measure for people with iSCI/D. Our findings support the use of the behavioral responses to evaluate reactive stepping for research and clinical purposes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02960178.

Co-contraction of ankle muscle activity during quiet standing in individuals with incomplete spinal cord injury is associated with postural instability

Previous findings indicate that co-contractions of plantarflexors and dorsiflexors during quiet standing increase the ankle mechanical joint stiffness, resulting in increased postural sway. Balance impairments in individuals with incomplete spinal cord injury (iSCI) may be due to co-contractions like in other individuals with reduced balance ability. Here we investigated the effect of co-contraction between plantar- and dorsiflexors on postural balance in individuals with iSCI (iSCI-group) and able-bodied individuals (AB-group). Thirteen able-bodied individuals and 13 individuals with iSCI were asked to perform quiet standing with their eyes open (EO) and eyes closed (EC). Kinetics and electromyograms from the tibialis anterior (TA), soleus and medial gastrocnemius were collected bilaterally. The iSCI-group exhibited more co-contractions than the AB-group (EO: 0.208% vs. 75.163%, p = 0.004; EC: 1.767% vs. 92.373%, p = 0.016). Furthermore, postural sway was larger during co-contractions than during no co-contraction in the iSCI-group (EO: 1.405 cm/s² vs. 0.867 cm/s², p = 0.023; EC: 1.831 cm/s² vs. 1.179 cm/s², p = 0.030), but no differences were found for the AB-group (EO: 0.393 cm/s² vs. 0.499 cm/s², p = 1.00; EC: 0.686 cm/s² vs. 0.654 cm/s², p = 1.00). To investigate the mechanism, we performed a computational simulation study using an inverted pendulum model and linear controllers. An increase of mechanical stiffness in the simulated iSCI-group resulted in increased postural sway (EO: 2.520 cm/s² vs. 1.174 cm/s², p < 0.001; EC: 4.226 cm/s² vs. 1.836 cm/s², p < 0.001), but not for the simulated AB-group (EO: 0.658 cm/s² vs. 0.658 cm/s², p = 1.00; EC: 0.943 cm/s² vs. 0.926 cm/s², p = 0.190). Thus, we demonstrated that co-contractions may be a compensatory strategy for individuals with iSCI to accommodate for decreased motor function, but co-contractions may result in increased ankle mechanical joint stiffness and consequently postural sway.

Diagnostic tests to assess balance in patients with spinal cord injury: a systematic review of their validity and reliability

Background

Sophisticated biomechanical instruments can assess balance in patients with spinal cord injury (SCI) with accuracy and precision; however, they are costly and time consuming to use. Clinical diagnostic tests to assess balance in patients with SCI are less costly and easier to use, but there is limited literature available regarding their reliability and validity.

Objectives

To review systematically articles reporting the validity and reliability of diagnostic tests used to assess balance function in patients with SCI.

Methods

We searched for articles in the English language from the earliest record to December 15, 2020, which reported validity or reliability of any clinical instrument or diagnostic test used to assess balance in patients with SCI. Articles assessing balance in paraplegic patients with causes other than SCI were excluded. Databases included MEDLINE, AMED, EMBASE, HMIC, PsycINFO, CINAHL, Scopus, and Google Scholar. The COSMIN Risk of Bias checklist was used to assess the studies included and PRISMA-DTA guidelines were applied.

Results

We included 16 articles that assessed the validity or reliability of 10 diagnostic tests. The Functional Reach Test (FRT), Berg Balance Scale (BBS), and Mini-Balance Evaluation Systems Test (Mini-BESTest) were assessed by more than 1 study, while the remaining 7 diagnostic tests including the Function in Sitting Test, T-Shirt Test, Motor Assessment Scale item 3, Sitting Balance Score, 5 Times Sit-to-Stand Test, Tinetti scale, and Sitting Balance Measure were assessed by 1 study each. The FRT has good-to-excellent test-retest reliability, excellent inter-rater reliability, and good construct, concurrent, and convergent validity. The BBS has excellent inter-rater and intra-rater reliability, high internal consistency, and good concurrent and construct validity. The Mini-BESTest has excellent test-retest reliability, excellent inter-rater reliability, high internal consistency, and good concurrent, convergent, and construct validity.

Conclusions

The FRT, BBS, and Mini-BESTest appear to be valid and reliable clinical instruments to assess balance function in patients with SCI.

Interjoint coordination between the ankle and hip joints during quiet standing in individuals with motor incomplete spinal cord injury

Individuals with motor incomplete spinal cord injuries (iSCI) often have impaired abilities to maintain upright balance. For able-bodied (AB) individuals, the ankle and hip joint accelerations are in antiphase to minimize the postural sway during quiet standing. Here we investigated how interjoint coordination between the ankle and hip joints was affected in individuals with iSCI, leading to their larger postural sway during quiet standing. Data from 16 individuals with iSCI, 14 age- and sex-matched AB individuals, and 13 young AB individuals were analyzed. The participants performed quiet standing during which kinematic and kinetic data were recorded. Postural sway was quantified using center-of-pressure velocity and center-of-mass acceleration. Individual ankle and hip joint kinematics were quantified, and the interjoint coordination was assessed using the cancellation index (CI), goal-equivalent variance (GEV), nongoal-equivalent variance (NGEV), and uncontrolled manifold (UCM) ratio. Individuals with iSCI displayed greater postural sway compared with AB individuals. The contribution of ankle angular acceleration toward one's sway was significantly greater for those with iSCI compared with AB groups. CI and the UCM ratios were not statistically different between the groups, while GEV and NGEV were significantly greater for the iSCI group compared with the AB groups. We demonstrated that individuals with iSCI show larger postural sway compared with the AB individuals during quiet standing, primarily due to larger ankle joint acceleration. We also demonstrated that the interjoint coordination between ankle and hip joint is not affected in individuals with iSCI, which is not successfully able to reduce the large COM acceleration.NEW & NOTEWORTHY There are limited studies investigating the biomechanics of standing balance for individuals with motor incomplete spinal cord injury (iSCI). Through our study, we found that these individuals with iSCI demonstrated increased postural sway primarily due to increased ankle joint accelerations. In addition, the ankle-hip coordination was equivalent between able-bodied individuals and those with motor incomplete spinal cord injury, which was not able to reduce the large body acceleration.

Reliability and Validity of the Functional Gait Assessment in Incomplete Spinal Cord Injury

Background

There are limited psychometrically sound measures to assess higher level balance in individuals with incomplete spinal cord injury (iSCI).

Objectives

To evaluate interrater and intrarater reliability and convergent validity of the Functional Gait Assessment (FGA) in individuals with iSCI.

Methods

Twelve participants (11 male, 1 female) 32 to 73 years old with chronic motor iSCI, American Spinal Injury Association Impairment Scale C (n = 2) or D (n = 10), were included. Participants completed five outcome measures during a single test session including lower extremity motor scores from the International Standards for the Neurological Classification of Spinal Cord Injury, FGA, 10-Meter Walk Test (10MWT), Walking Index for Spinal Cord Injury (WISCI-II), and the Spinal Cord Injury Functional Ambulation Profile (SCI-FAP).

Results

Inter- and intrarater reliability for the FGA were excellent. Interrater reliability was excellent with intraclass correlation coefficient (ICC) scores greater than 0.92 (p < .001). Interrater reliability against an expert was also excellent for all raters, with an ICC greater than or equal to 0.92 (p < .01). Intrarater reliability was excellent with an ICC score of greater than 0.91 (p < .002) for all raters. Validity of the FGA with 10MWT was -0.90 (p = .000), FGA with WISCI-II was 0.74 (p = .006), and FGA with SCI-FAP was -0.83 (p = .001).

Conclusion

The FGA is a reliable and valid outcome measure to use when assessing gait and balance in individuals with motor iSCI. The FGA provides clinicians with a single tool to utilize across a variety of neurologic diagnoses.

Characterization of standing balance after incomplete spinal cord injury: Alteration in integration of sensory information in ambulatory individuals

BACKGROUND

Up to one-third of individuals with a recent spinal cord injury (SCI) and most of the individuals with an incomplete lesion are able to regain partial balance and walking ability after the first-year post-injury. However, most individuals experience injurious falls while standing and frequent losses of balance post-rehabilitation, which can result in physical injuries and a fear of falling.

RESEARCH QUESTION

Control of balance during quiet standing depends on the integration of sensory information. Since SCI causes sensory and motor impairments, understanding the underlying mechanisms of how postural control is regulated is of significant importance for targeted and guided rehabilitation post-SCI.

METHODS

We characterized the impact of a variety of challenging conditions on the standing balance for eight participants with incomplete SCI with walking ability compared to twelve age-matched able-bodied individuals using a waist-mounted inertial measurement unit (IMU). We compared balance biomarkers derived from IMUs' readouts under conditions that challenged balance by affecting somatosensory (i.e., standing on hard vs. foam surfaces) and visual (i.e., eyes open vs. closed) inputs. We performed a three-way ANOVA or a Kruskal-Wallis test to characterize changes in postural control post-SCI based on reliance on somatosensory and visual information using balance biomarkers.

RESULTS

We observed a reduced stability performance, an increased control demand, and a less effective active correction post-SCI in all standing conditions. Due to impaired somatosensory feedback, individuals with incomplete SCI showed a higher and lower reliance on visual and somatosensory information, respectively, for maintaining balance (p < 0.05).

SIGNIFICANCE

Using a single waist-mounted IMU, the proposed method could characterize standing balance in individuals with incomplete SCI compared to able-bodied participants. Having high clinical utility and sufficient resolution with discriminatory ability, our method could be used in the future to objectively evaluate the effectiveness of rehabilitative interventions on the balance performance of individuals with SCI.

Postural control strategy after incomplete spinal cord injury: effect of sensory inputs on trunk-leg movement coordination

BACKGROUND

Postural control is affected after incomplete spinal cord injury (iSCI) due to sensory and motor impairments. Any alteration in the availability of sensory information can challenge postural stability in this population and may lead to a variety of adaptive movement coordination patterns. Hence, identifying the underlying impairments and changes to movement coordination patterns is necessary for effective rehabilitation post-iSCI. This study aims to compare the postural control strategy between iSCI and able-bodied populations by quantifying the trunk-leg movement coordination under conditions that affects sensory information.

METHODS

13 individuals with iSCI and 14 aged-matched able-bodied individuals performed quiet standing on hard and foam surfaces with eyes open and closed. We used mean Magnitude-Squared Coherence between trunk-leg accelerations measured by accelerometers placed over the sacrum and tibia.

RESULTS

We observed a similar ankle strategy at lower frequencies (f ≤ 1.0 Hz) between populations. However, we observed a decreased ability post-iSCI in adapting inter-segment coordination changing from ankle strategy to ankle-hip strategy at higher frequencies (f > 1.0 Hz). Moreover, utilizing the ankle-hip strategy at higher frequencies was challenged when somatosensory input was distorted, whereas depriving visual information did not affect balance strategy.

CONCLUSION

Trunk-leg movement coordination assessment showed sensitivity, discriminatory ability, and excellent test-retest reliability to identify changes in balance control strategy post-iSCI and due to altered sensory inputs. Trunk-leg movement coordination assessment using wearable sensors can be used for objective outcome evaluation of rehabilitative interventions on postural control post-iSCI.

Cosine tuning determines plantarflexors' activities during human upright standing and is affected by incomplete spinal cord injury

Plantarflexors such as the soleus (SOL) and medial gastrocnemius (MG) play key roles in controlling bipedal stance; however, how the central nervous system controls the activation levels of these plantarflexors is not well understood. Here we investigated how the central nervous system controls the plantarflexors' activation level during quiet standing in a cosine tuning manner where the maximal activation is achieved in a preferred direction (PD). Furthermore, we investigated how spinal cord injury affects these plantarflexors' activations. Thirteen healthy adults (AB) and thirteen individuals with chronic, incomplete spinal cord injury (iSCI) performed quiet standing trials. Their body kinematics and kinetics as well as electromyography signals from the MG and SOL were recorded. In the AB group, we found that the plantarflexors followed the cosine tuning manner during quiet standing. That is, MG was most active when the ratio of plantarflexion torque to knee extension torque was ~2:-3, whereas SOL was most active when the ratio was ~2:1. This suggests that the SOL muscle, despite being a monoarticular muscle, is sensitive to both ankle plantarflexion and knee extension during quiet standing. The difference in the PDs accounts for the phasic activity of MG and for the tonic activity of SOL. Unlike the AB group, the MG's activity was similar to the SOL's activity in the iSCI group, and the SOL PDs were similar to those in the AB group. This result suggests that chronic iSCI affects the control strategy, i.e., cosine tuning, for MG, which may affect standing balance in individuals with iSCI.NEW & NOTEWORTHY Soleus muscle shows a tonic activity whereas medial gastrocnemius muscle shows a phasic activity during quiet standing. Cosine tuning and their preferred direction account for the different muscle activation patterns between these two muscles. In individuals with chronic incomplete spinal cord injury, the preferred direction of gastrocnemius medial head is affected, which may result in their deteriorated standing balance.