FALLS OCCUR COMMONLY IN approximately one

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1 496 ORIGINAL ARTICLE Validation of the Chinese Translated Activities-Specific Balance Confidence Scale Margaret K. Mak, PhD, Anna L. Lau, PhD, Frances S. Law, MSc, Cecilia C. Cheung, MSc, Irene S. Wong, MSc ABSTRACT. Mak MK, Lau AL, Law FS, Cheung CC, Wong IS. Validation of the Chinese translated Activities-Specific Balance Confidence scale. Arch Phys Med Rehabil 2007; 88: Objectives: To translate contents of the Activities-Specific Balance Confidence (ABC) scale into Chinese (Cantonese), to examine the psychometric properties (internal reliability and validity) of this scale for use with Chinese older adults in Hong Kong, and to determine the level of self-perceived balance confidence of this population. Design: A 2-phase exploratory study: formative qualitative research and a cross-sectional survey to establish the psychometric properties of the Chinese translated ABC (ABC-C) scale. Setting: Community based. Participants: One hundred older community-dwelling subjects. Interventions: Not applicable. Main Outcome Measure: Measurement of perceived level of confidence in maintaining balance using the ABC-C scale. This instrument contains 16 items on indoor and outdoor activities requiring different levels of balance function. Results: Four of the 16 ABC-C scale items had to be modified to achieve content equivalence and cultural relevance to Hong Kong. Final test items of this scale showed high internal consistency with a Cronbach coefficient of.97. The instrument was found to have excellent test-retest and very good interrater reliability with intraclass coefficients of.99 and.85, respectively. Results of a factor analysis conducted on the scale showed evidence of a coherent 1-domain structure. The mean perceived balance confidence level standard deviation of 100 community-dwelling older adults in Hong Kong, performed by using the ABC-C scale, was Conclusions: Results of the present study verified that the ABC-C scale is a culturally relevant, valid, and reliable tool for measuring self-perceived balance confidence in Chinese older adults. These were reflected in very good to excellent internal consistency of items, test-retest and interrater reliability, and construct validity shown. Key Words: Accidental falls; Balance; Elderly; Fear; Rehabilitation. From the Hong Kong Polytechnic University, Hong Kong (Mak, Lau, Law, Cheung, Wong); Physiotherapy Department, The Cheshire Home, Chung Hom Kok, Hong Kong (Law); Physiotherapy Department, United Christian Hospital, Hong Kong (Cheung); and Tung Wah Group of Hospitals Fong Shu Chuen Social Service Building, Hong Kong (Wong). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated. Reprint requests to Margaret K. Mak, PhD, Dept of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, rsmmak@inet.polyu.edu.hk /07/ $32.00/0 doi: /j.apmr by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation FALLS OCCUR COMMONLY IN approximately one third of community-dwelling elderly people each year. 1-3 In older people, falls can cause physical injuries such as fractures and/or head injuries leading to restricted mobility, decreased performance in activities of daily living, and increased risk of placement in a nursing home. 4,5 Falls may also result in negative psychologic consequences such as fear of falling, which has been reported to occur in 29% to 92% of elderly people with a history of falls. 6,7 The wide variation could be attributable to differences in the methods used to measure fear of falling. 8 Although having some level of fear is reasonable and can promote effective coping skills in fall prevention, excess fear may compromise physical, psychosocial, and functional well-being The debilitating physical consequences of fear of falling are self-induced restriction of activities, physical deconditioning, and functional incapacity. Psychosocial consequences include increased risk of social isolation, damage to social identity, depression, anxiety, and poor quality of life. 7,12,13 Therefore, fear of falling is a construct that needs to be assessed, clearly understood, and managed in its own right. 14 Early identification and accurate measurement of fear of falling are 2 very important aspects of fall management. A common means of measuring fear of falling is to assess self-efficacy related to falls. This essentially involves assessing a person s perception of their capabilities to perform specific activities without falling. 15,16 Prior work has shown that a higher level of fall efficacy or a lower level of fear of falling is associated with better functional outcomes such as independent performances in activities of daily living. The Fall Efficacy Scale (FES) is the first standardized measure developed to document fall efficacy related to performances of daily functional activities by older adults. 20 This instrument was reported to have good test-retest reliability and high internal consistency. 21 However, FES measures fall efficacy restricted to simple indoor activities, which fails to provide information on perceived performances related to more complex functional activities. The FES also tended to show a ceiling effect with higher level functioning people living in the community. 21 An alternative we proposed is the Activities-Specific Balance Confidence (ABC) scale, which was developed to assess subjective balance confidence in ambulatory, communitydwelling older people. 21 Based on a psychologic concept relatively similar to fall efficacy, the ABC scale assesses a person s self perceived level of confidence in his/her ability to maintain balance required for performing daily functional activities. 22 This instrument contains 16 items, each representing a range of indoor and outdoor activities that require varying degrees of balance function. Respondents are asked to indicate their level of confidence in performing each activity by using a 0% to 100% scale distribution. The ABC scale has been shown

2 VALIDATION OF A BALANCE CONFIDENCE SCALE, Mak 497 Table 1: Characteristics of Study Sample Characteristics Main Study (N 100) Frequency (%) Test-Retest Reliability (n 25) Interrater Reliability (n 31) Age (y) Sex Female Marital status Single Married Widowed Divorced Use of walking aids No indoor Yes Use of walking aids No outdoor Yes Need assistance to walk outdoor Fall history in past mo Habit of regular exercise (times/ wk) to have good psychometric properties with high internal consistency (Cronbach.96), excellent test-retest reliability (r.92), good convergent validity with the physical activities subscale of the physical self-efficacy scale (r.63), and discriminant validity. 21 This instrument has already been modified for use with an older British population showing good internal consistency and test-retest reliability. 23 However, the scale has neither been translated nor been validated for use with Chinese populations. Cultural differences between Western and Chinese societies may influence elderly people s conceptualization of self-perceived balance confidence and cultural relevance of activities assessed by the instrument. The aims of this study were (1) to translate the contents of the ABC scale into Chinese (Cantonese) to achieve content equivalence, (2) to examine the psychometric properties of the Chinese translated ABC scale (ABC-C) with Chinese older adults in Hong Kong including internal reliability (internal consistency, test-retest, interrater reliability) and internal validity (construct), and (3) to determine the level of self-perceived balance confidence of this population. METHODS To achieve the research objectives, the study was conducted in 2 phases. Phase 1 translated contents of the ABC scale into Chinese (ABC-C) and examined content equivalence. Phase 2 involved validation of the ABC-C scale for use with the Chinese elderly population in Hong Kong. Phase 1 The original ABC description was first examined for content equivalence. This included (1) conceptual equivalence, which refers to the sameness of concept or meaning underpinning the test questions asked in the instrument between the original and translated languages; (2) semantic equivalence, which refers to the denotative and connotative sameness of words between the 2 language versions (that is, the explicit meaning of the translated test items as words and their concurrence with the original source language); and (3) technical equivalence, which examines the technical features of language and their relation to the sociocultural context, including fluency, clarity, and comprehensibility. 24 Only items of the scale that were considered to have shown inadequate conceptual and cultural relevance were subjected to a further review by an expert panel. The panel comprised 10 physiotherapists who had more than 10 years of work experience including 3 or more years working with older adults. The panel members were asked to rate the cultural relevance of activities assessed in the test items of the ABC scale to Hong Kong. This involved the use of a 5-point rating scale, ranging from very irrelevant (1) to very relevant (5). For an activity rated culturally irrelevant, the judges were asked to justify and suggest an alternative culturally relevant activity. The next step involved a forward translation of all test items (including revised ones from the previous step) and testing instructions of the ABC scale from original English language into Chinese (colloquial Cantonese). The Chinesetranslated contents were then translated into English (backward translation) to ascertain that their original meanings were retained. This process involved 2 independent professional translators who were briefed thoroughly on the purpose and function of the scale so to facilitate translation of contents that would be more meaning rather than semantic driven. The English-translated contents were then compared by the investigators with the original English-version ABC scale to verify they had achieved conceptual, semantic, and technical equivalence. The final ABC-C scale was pilot tested with 3 older adults to ascertain its fluency, clarity, and comprehensibility. Phase 2 To validate the ABC-C scale, 100 Cantonese-speaking community-dwellers were recruited from 5 communitybased elderly centers. Inclusion criteria included aged 65 years and older and independence in indoor ambulation with or without aids. People who had communication deficits and cognitive impairment (Mini-Mental State Examination score 18) were excluded. Table 1 shows the sociodemographic

3 498 VALIDATION OF A BALANCE CONFIDENCE SCALE, Mak Table 2: Results of 4 Modified Activities of the ABC Scale Cultural Relevance of Items Interjudge Agreement per Rating (%) Original Items of the ABC Scale Modified Items of the ABC-C Scale 3. Bend over and pick up a slipper from the front of Bend over and pick up a slipper from the floor a closet floor 8. Walk outside the house to a car parked in the Get into or out of a transportation you mostly driveway use 9. Get into or out of a car Walk out of the house to get to one form of transportation 16. Walk outside on icy sidewalks Walk outside on wet and slippery pavement NOTE. The rating values are as follows: 1 (very irrelevant), 2 (irrelevant), 3 (uncertain), 4 (relevant), and 5 (very relevant). and physical health characteristics of the subjects. The cohort had a mean age of 77.2 years, and 56% were women. The majority (90%) did not require physical assistance to walk outdoors, and only 13% had a history of at least 1 fall in the past 6 months. A large number (86%) routinely exercised at least 3 times per week. Informed consent was obtained from each subject in accordance with the 1964 Declaration of Helsinki, and the study commenced after approval from the local ethics committees. All subjects were assessed by using the ABC-C scale in an individual faceto-face interview. Fifty-six percent (n 56) were randomly selected by drawing lots for reassessment on the same instrument after 2 weeks. Of the 56 subjects, 44.6% (n 25) were reassessed to establish test-retest reliability, whereas the remaining (n 31) were to determine interrater reliability of the ABC-C scale (see table 1). A 2-week interval was used to minimize chances of subjects recall of contents from the previous assessment. This period was also considered optimal for avoiding potential occurrences of significant events or changes in their life circumstances that could also impact on their self-perceived balance confidence ratings. 25 Data Analysis All data collected were analyzed by using statistics software SPSS. a In phase 1, to determine whether an item (activity) was culturally relevant, mode calculations for each item and an interjudge percentage agreement were adopted. For an item to be considered culturally relevant, it had to be rated 4 (relevant) or 5 (highly relevant) with a 70% agreement achieved among panel experts. An item that failed to fulfill these criteria would require modification. In phase 2, internal consistency of the 16 item ABC-C scale was determined by using the Cronbach coefficient and item total correlations. Both test-retest and interrater reliabilities were established using the intraclass correlation (ICC) 1-way random model. Exploratory factor analysis was used to examine the structural coherence of the scale. Descriptive statistical analysis was performed to identify the level of self-perceived balance confidence of subjects. RESULTS Translation and Content Equivalence of ABC-C Scale Twelve of the 16 items on the ABC-C scale were found to be culturally relevant after reviews conducted by the expert panel and investigators of the study. The 4 items that were judged culturally irrelevant by the expert panel achieved a low interjudge agreement of 0% to 50% on 4 (relevant) and 5 (highly relevant) ratings assigned to these items. They comprised activities that all required some degree of dynamic balance (table 2, left-hand column). These activities were considered inappropriate because of considered differences in physical living environment, mode of transportation, and climate between Hong Kong and the ABC scale s place of origin, Canada. Specifically, in the original wording of item 3 concerned with the perceived level of competence a person has in bending and picking up a commonly used item (slipper) from the floor, the phrase...from the front of a closet floor was present, which implied that the slipper had to be retrieved from a storage cupboard. In Hong Kong, however, this is not a common practice because slippers are often placed in an open space rather than confined to a cupboard at home. In addition, the inclusion of such details would also add complexity and detract attention from the main purpose as described earlier. Hence, the phrase...from the front of the closet floor was removed. In items 8 and 9, car was adopted within these questions as the type of vehicle or transportation for determining balance confidence associated with their access. Car, however, is not a common mode of transportation among elderly people in Hong Kong because they tend to use a variety of public transports such as a bus, minibus, or taxi. It was, therefore, considered more appropriate to replace the word car with a broadly worded term transportation to allow for personal interpretations of the relevant mode by the respondents themselves. Finally, for item 16 concerned with perceived balance confidence in negotiating wet and slippery outdoor surfaces, the original wordings icy sidewalks were removed because the conditions do not apply in Hong Kong s climate. These wordings were instead replaced with wet and slippery pavement. The 4 modified questions are summarized in table 2 (right-hand column). Following Chinese translations performed on all items (the 4 modified and unchanged original items) of the ABC scale, they were all found to show conceptual, semantic, and technical equivalence. The Chinese translated items (appendix 1) were also found to be understood by the 3 older adults in the pilot test that were subsequently adopted in the next phase for validation testing. Slight modifications to the original testing instructions of the ABC scale were necessary with elderly respondents who were less educated to improve clarity. Reliability of the ABC-C Scale The items of the ABC-C scale showed high internal consistency with a Cronbach coefficient of.97 (table 3).

4 VALIDATION OF A BALANCE CONFIDENCE SCALE, Mak 499 Table 3: Internal Consistency of the ABC-C Scale Activity Corrected Item-Total Correlation Alpha if Item Deleted NOTE. Cronbach coefficient of ABC-C scale equal to.97. Further evidence contributing to such a favorable result consisted of moderately strong item-total correlations found for all 16 items that ranged from.71 to The value of.97 was further analyzed to determine if deletions of each item would have significant impact on this value. The result revealed a lack of such evidence supporting the retention of all 16 items of the instrument. Excellent test-retest reliability of the ABC-C scale was found as reflected in an ICC of.99 (95% confidence interval [CI], ) shown in table 4. The high ICC value (.75) indicated excellent stability and repeatability of the scale items across a 2-week interval. 25 Nunnally and Bernstein 26 further suggested that an ICC of about.95 should be considered as desirable if measures were to be used to monitor changes of individuals over time. For each item, the ICC value ranged from.73 to.98, with the highest as item 5 (stand on your tip toes and reach for something above your head) and the lowest as item 11 (walk up or down a ramp). A high ICC value of.85 (95% CI,.72.93) for interrater reliability of the scale was also revealed (see table 4). 25,26 This finding indicated very good agreement and high reproducibility of the instrument in assessments conducted by more than 1 rater. The ICC value of each activity ranged from.45 to.89, with the highest for item 15 (step onto or off an escalator while holding onto parcels such that you cannot hold onto the railing) and the lowest for activity item 10 (walk across a parking lot to the mall). Validity of the ABC-C Scale Factor analysis was performed by using a principal components analysis, followed by a varimax rotation. All the items were found to intercorrelate at greater than the recommended strength of 0.3, which confirmed the suitability of the data for factor analysis. Other assumptions were also met which included the generation of a Kaser-Meyer-Oklin value (.92) greater than the minimum recommended value of.60, 27 and the Barlett s test of sphericity also reached statistical significance at P less than The principal components analysis revealed the emergence of 1 factor with an eigenvalue exceeding 1 (see table 4). All 16 items displayed high loadings, which ranged from.75 to.90

5 500 VALIDATION OF A BALANCE CONFIDENCE SCALE, Mak Table 4: Test-Retest Reliability, Interrater Reliability, and Factor Analysis of ABC-C Scale Mean Test-Retest Reliability 95% CI Mean Interrater Reliability 95% CI Factor Analysis Activity 1st 2nd ICC Lower Upper 1st 2nd ICC Lower Upper Factor Loadings of 1 Factor Total ABC-C Score NA NOTE. For factor analysis, the eigenvalue equals and the cumulative percentage of variance explained is Abbreviation: NA, not applicable. with 69.66% of total variance explained. These findings reflect a coherent 1-factor structure. Self-Perceived Balance Confidence of Older Adults in Hong Kong The mean perceived balance confidence level standard deviation (SD) of community-dwelling older adults in Hong Kong as measured by the ABC-C scale was , with scores ranging from 48.4 to The highest level of confidence was found for balance associated with stepping on or off an escalator while holding onto parcels such that you cannot hold onto the railing (item 1), and the lowest was for walking around the house (item 15). DISCUSSION In the present study, the original version of the ABC scale was translated into Chinese (ABC-C scale), and its psychometric properties were examined. The translations involved a rigorous process that examined the equivalence of scale contents and also the use of an expert panel. The use of expert opinion is a conventional method used for development or validation of instruments because it is regarded as a simple, direct, and useful means for gathering content-related information about a concept. 29 The selection of this approach in the present study has enabled contents of the original ABC scale to undergo an extensive review and modifications were necessary, to ensure they were culturally appropriate for use within a Chinese community. Four items were modified, which predominantly involved changes in their wordings to becoming more generally phrased to accommodate for sociocultural differences identified between Hong Kong and Canada, where the original scale was developed. Forward and backward translations were also adopted in the study that contributed to rigor because such methods are acknowledged in the literature as one of the most adequate translation processes because it involves a number of independent reviews. 30 The validation results also found the ABC-C scale to display very good to excellent reliability and validity. High internal consistency (.97) (see table 3) was shown, which concurred with those of the original English ABC scale who reported values of and In addition, the fact that the 4 modified items of the scale did not result in reduced internal homogeneity of the instrument lend support to the high-quality translations performed in the present study. The ABC-C scale also showed excellent test-retest reliability with an ICC value of.99 (see table 4), which was also slightly higher than the and that were reported for the original scale. This study expands on the construct validity and interrater reliability of the original ABC described. The present study was the first to contribute new research evidence on these aspects. Results of a factor analysis conducted on the ABC-C scale showed a coherent 1-domain structure that supports the construct investigated (self-perceived balance confidence). An ICC value of.85 was also found that indicated very good interrater reliability of the instrument. Such positive findings could be explained by the face-to-face interview method adopted and clearer modified instructions achieved for administering the scale. This interview method was found effective with older adults, particularly with those who had low educational levels, because it allowed them the opportunity to clarify queries they had about the testing contents and procedure. There were, however, 2 items (items 4, 10) that showed lower levels of interrater reliability, with moderate ICC values of.54 and.45, respectively. For item 4 (reach for a small can off a shelf at eye level), this could have been because of differences in the modes of instruction delivered about the item between each interviewer, which resulted in discrepant assessment findings. With regard to this item,

6 VALIDATION OF A BALANCE CONFIDENCE SCALE, Mak 501 Table 5: Comparison of ABC-C Score (present study) and the Original English-Version ABC Score 21 ABC-C Score (N 100) Original ABC Score 21 (N 60) Activity Mean SD Mean Total score SD some respondents had required only verbal explanations, whereas others required additional demonstrations of the action involved of the mentioned activity. As for item 10 (walk across a parking lot to the mall), the level of difficulty associated with performing such activity could have been opened to multiple interpretations by different respondents because this could vary in accordance with perceptions of different geographic locations in Hong Kong. These 2 items would benefit from further review in future studies. A mean level of self-perceived balance confidence of 71.6 (table 5) was identified with the 100 elderly participants in the study. This was higher than the ABC score (59.6) reported in an earlier study 21 conducted on 60 older Canadian adults. Such difference might be explained by the higher mobility functions of respondents in the present study because 63% to 83% were able to walk indoors and outdoors without aids, with 86% able to maintain regular exercise. Because the Hong Kong sample were relatively well community-dwelling elderly people, it will be useful to replicate this study on those who are older or more frail in future investigations to enhance generalization of our current findings to the broader elderly population. It is interesting to note that for the modified item 16 (walk outside on wet and slippery ground), the score of 57.2 derived in the present study was much higher than that found (20.7) in an earlier study 21 for the same item from the original ABC scale (walk outside on icy sidewalk). The differences might be explained by differences in perceived levels of difficulty associated with maintaining balance in these 2 activities. Specifically, walk outside on icy sidewalk in the original version would appear to require a higher level of balance function than walking on wet and slippery surface in the present Chinesetranslated scale. The results of a study conducted with 475 participants 31 showed that an ABC score of 67 or below could predict future fall. Because the Hong Kong population in the present study had an ABC-C score higher than this cutoff score, this may suggest that older adults in Hong Kong are less prone to having a fall. Further study is necessary to verify this and determine the cutoff score for fall prediction in Chinese older adults by using the ABC-C scale. CONCLUSIONS The contents of the ABC-C showed good conceptual and cultural relevancy for measuring self-perceived balance confidence in Chinese older adults who are living in Hong Kong. This is supported by found evidence of good validity and reliability of the instrument. It will be useful as a screening tool in clinical and research work for advising appropriate fall preventions and other useful interventions. Future research can address the sensitivity, predictive, and discriminative validity of the ABC-C scale. Results of the current study will also provide useful grounding for future validation work and intended use of this tool with Chinese older adults who are living in other countries or cultures. We thank Peggo Lam for the statistical ad- Acknowledgment: vice.

7 502 VALIDATION OF A BALANCE CONFIDENCE SCALE, Mak APPENDIX 1: CHINESE VERSION OF ACTIVITIES-SPECIFIC BALANCE CONFIDENCE SCALE ABC 0% %

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