The Community Balance and Mobility Scale (CBMS)

Abstract

The Community Balance and Mobility Scale (CBMS) is a specialized, performance-based clinical outcome measure developed to evaluate the ambulatory skills and dynamic balance of higher-functioning individuals, particularly those recovering from Traumatic Brain Injury (TBI). Designed to overcome the ceiling effects often observed when using traditional scales like the Berg Balance Scale in this population, the CBMS assesses complex mobility tasks essential for successful community integration. The scale has demonstrated excellent internal consistency, high inter-rater and test-retest reliability, and strong evidence of construct validity, correlating significantly with objective laboratory measures of gait and self-report measures of balance confidence.

Keywords

Community Balance and Mobility Scale, CBMS, traumatic brain injury, TBI, balance assessment, mobility, ambulatory skills, dynamic stability, community integration, rehabilitation.

Authors

Howe, J. A., Inness, E. L., Venturini, A., Williams, J. I., Verrier, M. C.

Purpose

The primary purpose of the Community Balance and Mobility Scale (CBMS) is to provide an accurate and systematic measurement tool for assessing the functional balance and complex mobility skills of individuals recovering from neurological injuries, specifically TBI, who are capable of independent ambulation but still exhibit balance impairments. This scale focuses on the high-level tasks necessary for full engagement in community life and daily activities.

The scale was developed because existing measures often failed to adequately challenge or differentiate among higher-functioning patients. By focusing on dynamic and complex movements, the CBMS facilitates effective tracking of progress during specialized rehabilitation programs and helps clinicians determine the true effectiveness of interventions aimed at restoring full ambulatory skills and community integration post-injury.

Construct

The CBMS measures the construct of Dynamic Stability and Mobility for Community Living. This construct encompasses the ability to perform complex, dynamic activities requiring rapid changes in direction, shifts in posture, and environmental navigation—skills essential for independent community functioning that go beyond simple static balance or basic walking. The scale specifically evaluates dynamic postural control necessary for navigating environments outside of a structured clinical setting.

The items within the CBMS are designed to capture deficits in balance that impact crucial activities of daily living and leisure pursuits. By correlating with laboratory measures of gait (such as walking velocity and step variability) and self-report measures of participation and confidence, the CBMS validates its focus on functional capacity relevant to real-world mobility challenges.

Validity

The validity of the CBMS has been established through several phases of research, primarily focusing on individuals with TBI.

• Content Validity: Content validity was ensured during the item generation process through the direct involvement of patients with TBI (n=7) and expert clinicians (n=17), ensuring the scale items accurately reflect relevant challenges faced in community mobility.

• Construct Validity: Construct validity is strongly supported by significant associations between CBMS scores and objective measures of function. Correlations were demonstrated with laboratory measures of dynamic postural control and spatiotemporal measures of gait, including walking velocity, step length, step width, and step time (r values ranging from 0.38 to 0.87). Furthermore, scores correlated significantly with markers of dynamic stability, such as variability in step length and step time (r values ranging from 0.46 to 0.70).

• Concurrent Validity: The CBMS showed significant associations with established self-report measures, including the Activities-specific Balance Confidence (ABC) scale (r=0.60) and the Community Integration Questionnaire (CIQ) (r=0.54).

• Sensitivity: The CBMS demonstrates better sensitivity and is less susceptible to a ceiling effect than the commonly used Berg Balance Scale, making it superior for capturing change and evaluating ability in higher functioning ambulatory patients with TBI.

Reliability

The CBMS exhibits excellent reliability across multiple domains, confirming its utility as a consistent and trustworthy clinical outcome measure.

• Internal Consistency: The scale shows high internal consistency, indicated by a strong Cronbach’s alpha of 0.96.

• Inter- and Intra-Rater Reliability: Both inter-rater and intra-rater reliability are exceptionally high, with intraclass correlation coefficients (ICC’s) reported at 0.977 for both measures, indicating consistency regardless of the administrator.

• Test-Retest Reliability: Test-retest reliability is also robust, measuring 0.975 for immediate retest and 0.898 for a 5-day interval retest.

Factor Analysis

While the primary psychometric studies emphasize reliability and validity through correlation with external measures, the high internal consistency (Cronbach’s alpha of 0.96) strongly suggests that the scale measures a single, cohesive underlying construct, which is dynamic mobility for community reintegration. Further formal factor analysis may provide detailed insight into the specific components of the dynamic mobility construct captured by the scale items.

Instrument

Test Type: Performance-based assessment, Observational clinical tool.

Format: Standardized administration of dynamic tasks, scored numerically based on performance criteria.

Language Available: English (Primary validation language).

Population Group: Individuals with neurological impairments, primarily those recovering from TBI.

Age Group: Adults. Age-referenced data across decades is available from the authors to assist in interpreting patient scores relative to healthy individuals of the same age group.

Population Details: Specifically designed for ambulatory patients who are high-functioning but still experience balance impairments that limit their full engagement in community activities. Clinical feedback suggests applicability to high-functioning clients with diagnoses other than TBI, though further formal studies are necessary.

Test Methodology: The scale requires the patient to perform a series of progressively challenging dynamic balance and mobility tasks that simulate real-world community demands (e.g., rapid turns, stepping over obstacles, tandem walking). Performance is rated by a trained clinician.

Keywords

Dynamic balance, TBI rehabilitation, mobility assessment, clinical outcome measure, postural control, ICC, internal consistency, gait analysis, ambulation.

Authors

Author ORCID Identifier: Not provided in source material.

Affiliation Email addresses: [email protected] or [email protected]

Correspondence Address: Correspondence details are generally associated with the primary authors at their respective rehabilitation centers (e.g., Toronto Rehabilitation Institute, based on email domains).

Permissions & Fee and Test Year

Test Year: 2006 (Year of primary publication and validation).

Permissions: Users should contact the authors directly for information regarding clinical use, training, permissions, and any associated fees for the scale, as indicated by the provided contact emails.

Reference’s

Howe, J. A., Inness, E. L., Venturini, A., Williams, J. I. Verrier, M. C. (2006). The Community Balance and Mobility Scale–a balance measure for individuals with traumatic brain injury. Clinical rehabilitation, 20(10), 885-95.

Inness, E. L., Howe, J. A., Niechwiej-Szwedo, E., et al. (2009). Measuring Balance and Mobility after Traumatic Brain Injury: Validation of the Community Balance and Mobility Scale (CB&M). Physiotherapy Canada, 63(2), 199-208.

Zbarsky, K, Parsley D, Clegg H, Welch T, Fernandes C, Jaglal S, Inness E, Williams J, McIlroy WE, Howe J. (2010) [Abstract] Community Balance & Mobility Scale (CB&M): Age-related reference values. Physiotherapy Canada, 62 (Suppl), 46.

Items of the The Community Balance and Mobility Scale (CBMS)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The original PDF for the scale introduction and details can be downloaded here: The Community Balance and Mobility Scale (CBMS)

The consequences of postural dyscontrol are pervasive and have a significant impact on activities of daily living, community mobility and social, work and leisure pursuits. The Community Balance and Mobility Scale (CB&M) was designed to evaluate balance and mobility in patients who, although ambulatory, have balance impairments which reduce their full engagement in community living.

The following is a brief summary of the key measurement properties of the CB&M established to date with individuals with traumatic brain injury (TBI). Content validity was obtained by the involvement of patients with TBI (n=7) and clinicians (n=17) during the item generation process. The CB&M demonstrates intraclass correlation coefficients (ICC’s) of 0.977 for both intra- and inter-rater reliability, 0.898 and 0.975 for test-retest reliability (5-day and immediate, respectively) and Cronbach’s alpha of 0.96 for internal consistency.¹

Additional studies have shown that in ambulatory patients with TBI, the CB&M is less susceptible to a ceiling effect than the commonly used Berg Balance Scale and better able to capture change in this higher functioning group.²

The construct validity of the CB&M was supported by associations with laboratory measures of dynamic postural control and measures of community integration and balance confidence.² Statistically significant correlations were demonstrated between the CB&M and spatiotemporal measures of gait including walking velocity, step length, step width and step time (r values ranging from 0.38 to 0.87). Importantly, variability in step length and step time, used as a marker of dynamic stability, also correlated significantly with CB&M scores (r values ranging from 0.46 to 0.70). Significant associations were also achieved with self-report measures of balance confidence and participation in the community using the Activities-specific Balance Confidence (ABC) scale (r=0.60) and the Community Integration Questionnaire (r=0.54), respectively.

The CB&M has been able to capture the decline in balance that occurs with aging in healthy individuals supporting the validity and sensitivity of the scale.³ Healthy age-referenced data across the decades is available from the authors to assist in interpretation of patient scores. Determining if patients are within the range of healthy values for their age group is helpful in identifying the presence and degree of balance impairment.

Clinical feedback and user reports have indicated that the scale is also appropriate for high-functioning clients with diagnoses other than traumatic brain injury but further studies are warranted.

The positive results support that the CB&M is a reliable and valid clinical outcome measure for detecting dynamic instability and evaluating change in ability in the higher functioning ambulatory patient with TBI.