Functional Independence Measure (WeeFIM) for Chinese children: Hong Kong Cohort

The Functional Independence Measure (WeeFIM) for children is a simple-to-administer scale for assessing independence across 3 domains in American children. WeeFIM was based on a conceptual framework by the World Health Organization (1980) of pathology, impairment, disability and handicap, and the "burden of care." WeeFIM is useful in assessing functional independence in children aged 6 months to 7 years. It can be used for children with developmental disabilities aged 6 months to 21 years. Normative WeeFIM data had been validated for American children. Because of cultural and environmental differences among countries, normative data for the Chinese population are needed. With a normative database, the progression of independence at home and in the community can be evaluated. WeeFIM is an 18-item, 7-level ordinal scale instrument that measures a child's consistent performance in essential daily functional skills. Three main domains (self-care, mobility, and cognition) are assessed by interviewing or by observing a child's performance of a task to criterion standards. WeeFIM is categorized into 2 main functional streams: "Dependent" (ie, requires helper: scores 1-5) and "Independent" (ie, requires no helper: scores 6-7). Scores 1 (total assistance) and 2 (maximal assistance) belonged to the "Complete Dependence" category. Scores 3 (moderate assistance), 4 (minimal contact assistance), and 5 (supervision or set-up) belonged to the "Modified Dependence" category. Scores 6 (modified independence) and 7 (complete independence) belonged to the "Independent" category. The WeeFIM is a 7-level criterion-specific ordinal scale. Level 7 requires no assistance for the child and the child completes the task independently without requiring a device. During the task, there is no concern about safety or taking an inordinate amount of time. Level 6 reflects modified independence and includes use of an assistive device or not completing the task in a timely or safe manner.

To examine the utility of the WeeFIM in Chinese children and to create a normative WeeFIM profile suitable for Chinese children.

Direct interviews were conducted for 445 normal Chinese children, aged 6 months to 7 years, in the community.

1. WeeFIM total score and 3 domains subscores versus age. The total WeeFIM scores increased progressively with age, reaching a plateau at 72 months. There was a progressive increase in subscores of self-care, mobility, and cognition independence between 6 to 62 months, especially between 6 to 45 months. Similarly, the WeeFIM self-care subscores increased progressively with age, reaching a plateau at around 72 months. The WeeFIM mobility subscores increased progressively with age, reaching a plateau at around 54 months. The WeeFIM cognition subscores increased progressively with age, reaching a later plateau at around 80 months. 2. WeeFIM subtotal scores versus age. The total WeeFIM score and 3 domain subscores correlated significantly with age. We further classified the 18 items into 3 groups according to the degree of correlation with age. Most items had high correlation with Spearman's correlation coefficient of rho >0.8. Only 1 item (chair transfer) showed moderate correlation with rho = 0.7-0.8. The item "walk" had the lowest correlation with rho = 0.6-0.7. 3. Chronological order for achieving different items. The 50th percentile of age in months for achieving level 6 (modified independence) of the 18 items were compared and ranked according to the age of achieving level 6. In creating a developmental scale of achievement of level 6 (modified independence) for all 18 items, the developmental sequence clustered in the following order: chair transfer (order 1) and walk (order 2) were achieved much earlier (at 18 and 24 months, respectively). Thereafter, there was a clustering of 4 items achieved at around 45 months: toilet transfer (order 3), stair (order 4), expression (order 5), and social interaction (order 6). Then, 9 items were achieved at around 54 to 56 months: tub or shower transfer (order 7), eating (order 8), bathing (order 9), bowel management (order 10), dressing of lower body (order 11), comprehension (order 12), dressing of upper body (order 13), bladder management (order 14), and grooming (order 15). At 60 months, the following ranked in order: memory (order 16), problem-solving (order 17), and toileting (order 18). 4. Impact of sex factor. Girls aged 22 to 45 months had higher scores in self-care subscores and cognition subscores. From 63 months onwards, boys had statistically significant higher scores in mobility subscores. Otherwise, there was no statistically significant difference in WeeFIM scores for different age groups. 5. Impact of domestic helpers. There was also significant difference for self-care subscore with the presence of a maid at home. Those children with a maid at home obtained lower self-care subscores. However, the mobility and cognition subscores were not affected.

We have created a normative functional independence profile for Chinese children by adapting the American-based WeeFIM. There were cultural differences when compared with American children. Interestingly, Chinese children in Hong Kong scored better than their American counterparts in domain 1 (self-care) in all ages. This might be attributable to early attendance in preschool settings where children are taught to tend to their needs. Even for domain 2 (mobility), the higher scores in younger Chinese children in Hong King (<3 years) might be explained by earlier attendance in preschool settings. The American children did catch up after 3 years. As for domain 3 (cognition), the local educational system emphasized reading, writing, memorizing materials, and social interaction. Thus, Chinese children in Hong Kong had better cognition scores until 42 months, when their American counterparts caught up by attending preschool. There are definitely environmental and cultural practices affecting functional independence in both ethnic groups, especially in the upper age range (>4 years) both in America and Hong Kong. Thus, a locally validated WeeFIM instrument should be adopted for Chinese children. Our study demonstrated that WeeFIM could be used as a functional independence measure for Chinese children. Hong Kong has a different cultural background compared with America; thus, usage of WeeFIM with different age criteria for achieving independence should be adopted.