Psychometrics

Early research by its author involving 32 individual raters across a number of therapy disciplines using 35 stroke patients and 28 elderly rehabilitation residents found that initial results showed excellent agreement for both inter- and intra-rater reliability with intra-class correlation coefficients of r = 0.98 and 0.97, respectively. In addition, standardized Cronbach’s alpha estimates were high in both elderly residents (α = 0.87) and stroke patients (α = 0.98), indicating strong internal consistency (Berg, 1992). A longitudinal study, also involving its author, of elderly and stroke subjects examined at baseline, and at 3, 6, and 9 months, and at 2, 4, 6, and 12 weeks (stroke) found that Cronbach’s alphas at each evaluation were greater than 0.83 and 0.97 showing strong internal consistency for the measure (Berg, Wood-Dauphine, & Williams, 1995). A study by Conradsson et al. (2007) (n = 45; mean age, 82 years; mean Mini-Mental State Examination, 17.5) found test-retest reliability to be excellent at r = 0.97 where the mean score was 30.3 points. Subsequent research, also involving stroke patients, found that correlations between the BBS and the Barthel Index were excellent with a range of 0.80 to 0.94 (Blum & Korner-Bitensky, 2008). The same study found that correlations between the BBS and Fugl-Meyer balance subscale were considered adequate to excellent with a range of 0.62 to 0.94. Results of a study by Chou et al. (2006) generally concur with results mentioned previously where they too found excellent correlations between the BBS and the Barthel Index at 0.88 and between the BBS and the motor functioning subscale of the Fugl-Meyer Assessment (0.71) 2 weeks post-stroke. (Blum & Korner-Bitensky, 2008). A study by Muir, Berg, Chesworth, and Speechley (2008) argued that dichotomizing the BBS at a score of 45 (those above and those below) resulted in the following probabilities for falling: 58% (20/34) of people with BBS scores at or below 45 fell, whereas only 39% of people (60/153) with scores above 45 fell. Further analysis suggested that the optimal single cutoff value for any fall was 54 and that for multiple falls it was 53 and for injurious falls it was also 54. The high cutoff values required to optimize sensitivity in each fall outcome category suggest that balance impairment alone may not define increased fall risk and that falls are frequent among people with scores above 45 (Muir, Berg, Chesworth, & Speechley, 2008). Finally, an examination to identify elderly people (age range: 65 to 94 years old) who are at risk for falling found that at a cutoff score of 35 the BBS had a sensitivity of 30% and specificity of 96%, at 40 the sensitivity was 45% and specificity was 96%, and at the suggested cutoff score of 45 sensitivity was 64% and specificity was 90% (Riddle & Stratford, 1999).

Advantages

Disadvantages

Falls and the risk of falling in general can be complex, and several mechanisms may complicate the issue (i.e., disease process, medication, cognitive decline, or the aging process) increasing a person’s chances of falling, thus quantifying that risk may be difficult. The problem is highlighted by the fact that validation efforts that have argued that a cutoff score of 45/56 is necessary for independent ambulation and that failure to reach this score indicate a need to consider a gait aid, provision of assistance or supervision have not generally been accepted. As Stevenson, Connelly, Murray, Hugget, and Overend (2010) suggest, currently there is not enough evidence for using BBS scores to prescribe gait aids as limitations of the identified threshold values resulted in the misclassification of > 25% of subjects involving clients who were 65 years of age or older who were able to complete the 2-Minute Walk Test with or without a gait aid, suggesting further research is needed to identify threshold values along with specific subject populations. Other studies have also noted the presence of floor/ceiling effects.

Administration

The BBS is an activity-based observational tool whereby the rater scores client performance as he or she engages in 14 balance activities. Of the maximum possible score of 56 its author suggests the following interpretation of results: 0 to 20, wheelchair bound; 21 to 40, walking with assistance; 41 to 56, independent ambulation; and scores ≤ 45 as indicative of a high risk of falling. There is also some research to suggest that a change of 8 points is necessary to document a change in function between 2 administrations. Tools needed are a stop watch; 2 chairs, 1 with arm rests; measuring tape/ruler; an object to pick up off the floor; 15 feet of walkway; and a step stool.

Permissions

The BBS is free to use in clinical practice. Use of the measure in research and/or publication can be obtained by contacting the creator of the original work at the address following or contacting the Copyright Clearance Center pertaining to the authors’ various publications. Further information can be found in the following journal article:

Berg, K., Wood-Dauphinee, S., Williams, J., & Maki, B. (1992). Measuring balance in the elderly: Validation of an instrument. Canadian Journal of Public Health, 83(2), S7-11.

Summary

Contact