Is the Berg Balance Scale an Internally Valid and Reliable Measure of Balance Across Different Etiologies in Neurorehabilitation? A Revisited Rasch Analysis Study

Concurrent Validity and Reliability of a New Balance Scale Used in Older Adults

Adults over the age of 70 are at risk of falling. Various balance tests have been developed to identify balance dysfunctions. Their disadvantages including ceiling effects and low sensitivity and duration led to the development of a new balance test. The present study was conducted to determine the concurrent validity, reliability, sensitivity, and specificity of the Zur Balance Scale (ZBS). In this descriptive, cross-sectional study, 76 senior adults were recruited from an independent senior living community and were administered the Berg Balance Scale (BBS) and the ZBS. The BBS was used as the standard of comparison. The ZBS includes head movements and time to maintain to balance. All the subjects completed the tests. Concurrent validity was r = 0.782 (p < 0.0001). The ZBS had high intra-test (0.897) and inter-test (0.934) correlation coefficients. Its sensitivity was 60 % and specificity 91 % for identifying falls. The dynamic portions of the ZBS capture the integration of the visual, vestibular, and somatosensory systems, as it mimics dynamic spatial aspects of daily activities. We conclude that the ZBS is reliable compared with BBS. It is a simple, easy to administer test that may predict future risk of falls.

Assessing the risk of self-harm in an adult offender population: an incidence cohort study

BACKGROUND

Self-harm is common among prisoners, particularly female prisoners. In 2007, concerned about the rising incidence, the prison service introduced a care-planning system called Assessment, Care in Custody, and Teamwork (ACCT). To date, it does not incorporate a standardised diagnostic test to estimate the risk of future self-harm.

OBJECTIVE

To identify potential screening instruments, or items from those instruments, to predict the risk of self-harm among prisoners.

PARTICIPANTS

Prisoners who had been assigned to an ACCT during the recruitment period.

DESIGN

A multistage prospective cohort study. Following a pilot study, instruments were administered to prisoners by interview at baseline, and followed up for 6 months (or until point of release if this was sooner) to ascertain self-harm status. Instruments were assessed for unidimensionality, scalability (Mokken) and quantitative structure (Rasch). Area under the curve (AUC) analysis was used to examine the ability of instruments and/or their items to predict future self-harm. Cox proportional hazards regression models were used to examine the multivariate predictive ability of the scales and various sociodemographic and sentencing factors.

SETTING

Three prisons (including one women's prison) in northern England.

MAIN OUTCOME MEASURES

A set of standardised questionnaires, including the Prison Screening Questionnaire (PriSnQuest), Revised Borderline Symptom List-23 (frequency-based responses) (BSL-23-F), Self-Harm Inventory (SHI), Patient Health Questionnaire (PHQ-9) and the Clinical Outcomes in Routine Evaluation - Outcome Measure (CORE-OM), together with sociodemographic and sentencing data.

RESULTS

In total, 450 prisoners consented to participate in the study, of whom 26% were female. The mean age of participants was 31.2 years. Over half of male prisoners recruited were on remand, compared with just over one-fifth (22.6%) of female prisoners. The average tariff of those sentenced was 41 months, of which 14.7 months, on average, had been served. Just over one-third of ACCTs had been initiated because of a known self-harm event, and over one-quarter (27.8%) of participants self-harmed during the follow-up period. Thus, almost half (46.7%) of those entered into the study were reported to have self-harmed, either from their index ACCT, or subsequently, or both. Cutting was the most frequent behaviour (51%). All screening instruments showed some evidence of unidimensionality, and four out of five showed scaling criteria consistent with ordinal scaling, so verifying the validity of the cut points. However, many showed gender bias and failure to fit the Rasch measurement model. While a resolution was made in most cases, both ordinal raw scores and latent interval scale estimates failed to show predictive value when applied within AUC analysis (0.491-0.566) or adjusted Cox proportional hazards models. However, good predictive values were shown for gender-specific sets of items, thus providing easily applied screening indexes.

CONCLUSIONS

While four out of five potential screening instruments were found to have acceptable psychometric properties within this setting, their predictive validity of all instruments was poor under AUC analysis. Gender-specific item sets were put together to form two screening indexes with formative indicators which gave reasonable AUC values, particularly so for females. The indexes provide identification of low-medium-high risk of self-harm, and so may help to inform potential care pathways and decisions to sign prisoners off from the ACCT. Future work should concentrate on refining a set of predictive screening items among different offender populations and investigating the time point at which this set of items should be administered. Future work may also look at the different magnitudes of risk as indicators for care pathways.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Neuronal injury in the motor cortex after chronic stroke and lower limb motor impairment: a voxel-based lesion symptom mapping study

Many studies have examined motor impairments using voxel-based lesion symptom mapping, but few are reported regarding the corresponding relationship between cerebral cortex injury and lower limb motor impairment analyzed using this technique. This study correlated neuronal injury in the cerebral cortex of 16 patients with chronic stroke based on a voxel-based lesion symptom mapping analysis. Neuronal injury in the corona radiata, caudate nucleus and putamen of patients with chronic stroke could predict walking speed. The behavioral measure scores were consistent with motor deficits expected after damage to the cortical motor system due to stroke. These findings suggest that voxel-based lesion symptom mapping may provide a more accurate prognosis of motor recovery from chronic stroke according to neuronal injury in cerebral motor cortex.

Rasch analysis of the modified version of the postural assessment scale for stroke patients: postural stroke study in Gothenburg (POSTGOT)

Background

The modified version of the Postural Assessment Scale for Stroke Patients (SwePASS) is a new ordinal outcome measurement designed to assess postural control in patients with stroke. Before implementation of SwePASS into the clinical setting, it is necessary to know its measurement properties. Thus, the aim of the study was to evaluate the measurement properties of the SwePASS.

Methods

Rasch analysis, based on data of 150 SwePASS assessments was made the first week after stroke onset. The measurement properties referred to were unidimensionality, local independence, invariance, category function, targeting of persons and items and the reliability.

Results

The initial analysis showed disordered thresholds in four items. After adjustment of the scoring categories, this was resolved. However, analyses of local dependency revealed correlations between two of the items. These two items were collapsed into one. After adjustments, the person separation index that acts as an indicator of the whole model fit was 0.96. The adjusted SwePASS is a global scale that works the same way regardless of gender, age and location of stroke lesion. Overall, the population had better postural control than was targeted with the items in the scale.

Conclusions

Rasch analysis of the adjusted SwePASS showed that the scale was unidimensional. In SwePASS, equal capacity in postural control provides the same response to an individual item in patients with stroke, regardless of gender, age and location of stroke lesion. Regarding clinical implications, before introducing SwePASS in clinical routine and to confirm the results, further research including a larger sample with poorer postural control is suggested.

Computer-adaptive balance testing improves discrimination between community-dwelling elderly fallers and nonfallers

OBJECTIVES

To build an item response theory-based computer adaptive test (CAT) for balance from 3 traditional, fixed-form balance measures: Berg Balance Scale (BBS), Performance-Oriented Mobility Assessment (POMA), and dynamic gait index (DGI); and to examine whether the CAT's psychometric performance exceeded that of individual measures.

DESIGN

Secondary analysis combining 2 existing datasets.

SETTING

Community based.

PARTICIPANTS

Community-dwelling older adults (N=187) who were aged ≥65 years (mean age, 75.2±6.8y, 69% women).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The BBS, POMA, and DGI items were compiled into an initial 38-item bank. The Rasch partial credit model was used for final item bank calibration. CAT simulations were conducted to identify the ideal CAT. CAT score accuracy, reliability, floor and ceiling effects, and validity were examined. Floor and ceiling effects and validity of the CAT and individual measures were compared.

RESULTS

A 23-item bank met model expectations. A 10-item CAT was selected, showing a very strong association with full item bank scores (r=.97) and good overall reliability (.78). Reliability was better in low- to midbalance ranges as a result of better item targeting to balance ability when compared with the highest balance ranges. No floor effect was noted. The CAT ceiling effect (11.2%) was significantly lower than the POMA (40.1%) and DGI (40.3%) ceiling effects (P<.001 per comparison). The CAT outperformed individual measures, being the only test to discriminate between fallers and nonfallers (P=.007), and being the strongest predictor of self-reported function.

CONCLUSIONS

The balance CAT showed excellent accuracy, good overall reliability, and excellent validity compared with individual measures, being the only measure to discriminate between fallers and nonfallers. Prospective examination, particularly in low-functioning older adults and clinical populations with balance deficits, is recommended. Development of an improved CAT based on an expanded item bank containing higher difficulty items is also recommended.

Validation of the Brazilian version of the Clinical Gait and Balance Scale and comparison with the Berg Balance Scale

OBJECTIVE

To validate the Clinical Gait and Balance Scale (GABS) for a Brazilian population of patients with Parkinson's disease (PD) and to compare it to the Berg Balance Scale (BBS).

METHODS

One hundred and seven PD patients were evaluated by shortened UPDRS motor scale (sUPDRSm), Hoehn and Yahr (HY), Schwab and England scale (SE), Falls Efficacy Scale International (FES-I), Freezing of Gait Questionnaire (FOG-Q), BBS and GABS.

RESULTS

The internal consistency of the GABS was 0.94, the intra-rater and inter-rater reliability were 0.94 and 0.98 respectively. The area under the receiver operating characteristic (ROC) curve was 0.72, with a sensitivity of 0.75 and specificity of 0.6, to discriminate patients with a history of falls in the last twelve months, for a cut-off score of 13 points.

CONCLUSIONS

Our study shows that the Brazilian version of the GABS is a reliable and valid instrument to assess gait and balance in PD.

Preliminary assessment of balance with the Berg Balance Scale in adults who have a leg amputation and dwell in the community: Rasch rating scale analysis

BACKGROUND

Self-report measures of balance and multidimensional mobility assessments are common for people with a leg amputation, yet clinical assessment of balance ability remains less explored. The Berg Balance Scale (BBS), typically used for other populations with impaired balance, has been used for young people with a high level of functioning after traumatic amputation but rarely for older people after vascular amputation.

OBJECTIVE

The study objective was to examine the psychometric properties of the BBS with Rasch rating scale analysis to determine the validity and utility of the BBS in assessing balance ability in adults who have a leg amputation and dwell in the community.

DESIGN

Rating scale analysis was applied to BBS scores obtained from a single assessment.

METHODS

Adult volunteers (men and women) who had a leg amputation (any level and etiology) and dwelled in the community were recruited from a hospital-based community support group and a prosthetic clinic. Rating scale analysis of the BBS was used to assess unidimensionality, internal validity, goodness of fit, structural integrity, and person and item analyses.

RESULTS

The study participants were 40 people (26 men and 14 women; 57.8 [SD=9.7] years old) with leg amputations (24 transtibial, 13 transfemoral, and 3 bilateral) of mixed etiology (32 vascular and 8 nonvascular). The psychometric properties of the BBS confirmed that it measures the unidimensional construct of balance ability with adequate validity and with goodness of fit and structural integrity that meet the acceptability criteria. Person measures revealed that some participants scored near the top of the BBS, suggesting a ceiling effect; item measures revealed that participants with leg amputations had the most difficulty performing the following tasks: standing with 1 leg in front, turning 360 degrees, and placing alternate foot on a stool.

LIMITATIONS

Limitations included a convenience sample and a lack of rater reliability testing.

CONCLUSIONS

The BBS cohered with the unidimensional construct of balance ability and had strong internal validity for use in a variety of people with leg amputations.

Chemotherapy induced peripheral neuropathy: the modified total neuropathy score in clinical practice

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a common, potentially reversible side effect of some chemotherapeutic agents. CIPN is associated with decreased balance, function and quality of life (QoL). This association has to date been under-investigated.

AIMS

To profile patients presenting with CIPN using the modified Total Neuropathy Score (mTNS) in this cross-sectional study and to examine the relationship between CIPN (measured by mTNS) and indices of balance, quality of life (QoL) and function.

METHODS

Patients receiving neurotoxic chemotherapy regimens were identified using hospital databases. Those who did not have a pre-existing neuropathy were invited to complete mTNS, Berg Balance Scale (BBS), timed up and go (TUG), and FACT-G QoL questionnaire. mTNS scores were profiled and also correlated with BBS, TUG and FACT-G using Spearmans correlation coefficient.

RESULTS

A total of 29 patients undergoing neurotoxic chemotherapy regimens were tested. The patients mTNS scores ranged between 1 and 12 (median = 5), indicating that all patients had clinical evidence of neuropathy on mTNS. No significant correlations were found between mTNS and BERG (r = -0.29), TUG (r = 0.14), or FACT-G (r = 0.05).

CONCLUSIONS

This study found a high prevalence of CIPN in patients treated with neurotoxic chemotherapy regimens. The mTNS provided a clinically applicable, sensitive screening tool for CIPN which could prove useful in clinical practice. mTNS did not correlate with BBS, TUG or FACT-G in this sample, possibly due to relatively mild levels of CIPN and consequent subtle impairments which were not adequately captured by gross functional assessments.

Can we scientifically and reliably measure the level of consciousness in vegetative and minimally conscious States? Rasch analysis of the coma recovery scale-revised

OBJECTIVES

(1) To appraise, by the means of Rasch analysis, the internal validity and reliability of the Coma Recovery Scale-Revised (CRS-R) in a sample of patients with disorder of consciousness (DOC); and (2) to provide information about the comparability of CRS-R scores across persons with DOC across different settings and groups, including different etiologies.

DESIGN

Multicenter observational prospective study.

SETTING

Two rehabilitation wards, 1 intermediate care facility, and 2 nursing homes in Italy.

PARTICIPANTS

Consecutively admitted patients (N=129) for which assessments at 2 different time points were available, giving a total sample of 258 observations.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

CRS-R.

RESULTS

After controlling for any possible dependency between persons' measures collected at different time points, and for uniform differential item functioning by etiology showed by the visual subscale, Rasch analysis demonstrated adequate satisfaction of all the model's requirements, including adequate ordering of scoring categories, unidimensionality, local independence, invariance (χ(2)21=27.798, P=.146), and absence of differential item functioning across patients' sex, age, time, and setting. The reliability (person separation index=.896) was adequate for individual person measurement. We devised a practical raw score to measure conversion tables based on the CRS-R calibrations.

CONCLUSIONS

The CRS-R is a psychometrically sound and robust measurement tool. The linear measures of ability derived from the CRS-R total scores do satisfy all the principles of scientific measurement and are sufficiently reliable for high stakes assessments, such as the diagnosis of the level of consciousness in individual patients. Future studies are needed to directly explore the capabilities of the CRS-R measures to reduce the risk of vegetative state misdiagnosis.