Focusing on Function

Rehabilitation services for infants, children, and youth are all about function, but what is function all about? In professional educational program curricula, occupational therapy, and physical therapy students are encouraged to articulate functional, measurable goals. The students learn about functional measures and treatment approaches to optimize function, and they read literature about functional gains in children with disabilities. The term “function” is often used, in many cases without elucidation of its boundaries or precise connotation.

Function (noun) is defined as an assigned duty or activity; an occupation or role. To function (verb) is to perform or execute a specified action or activity; to work or to operate (www.dictionary.com, accessed March 1, 2009). Functions may involve a group of related actions contributing to a larger action (www.merriam-webster.com, accessed March 1, 2009). Links can readily be made to activity (actions, occupations) and participation (group of actions contributing to a larger action, roles), terms used in the International Classification of Functioning, Disability and Health (ICF).

In my view, function from a pediatric perspective includes everyday tasks and activities that are expected or valued for a child of the same age, gender, and cultural background. A similar definition of “functional status” was put forth by Saigal and Tyson (2008, p. 59): “The level of ability to perform age-appropriate activities of daily living and socially allocated roles.” Disability is defined as the restricted capability or inability to pursue or perform an occupation as a consequence of a physical or mental impairment (www.merriam-webster.com), and may be viewed as the converse of functioning.

What is sometimes confusing is the difference between functional and developmental outcomes, and similarly, functional and developmental assessment tools. From my perspective, developmental outcomes would include description of motor, cognitive, sensory, behavioral, perceptual, speech, and social–emotional abilities, with a focus on identifying delays in these developmental domains. Although we may use “tasks,” such as stringing beads, building block towers, or copying block designs as part of developmental assessments, these tasks are utilized to ascertain whether there are delays in development in particular domains, with careful clinical observation of why (e.g., diminished visual-motor coordination, decreased attention span, and poor balance) these children cannot adequately perform particular items on the test battery. Whether or not norm-referenced assessments of development, such as the Peabody Developmental Motor Scales and the Bayley Scales of Infant Development, are measures of “body function” or “activity and participation” (as defined by the ICF) remains a point of controversy.

Norm-referenced developmental assessments are used to identify whether a child has a delay, establish eligibility for a service or intervention program, and may be helpful in elucidating the underlying impairments that may guide strategies for intervention. In my view, items on norm-referenced developmental assessments are not necessarily ecologically meaningful. This view is supported by Long, Blackman, Farrell, Smolkin, and Conaway (2005) in a recent article comparing developmental and functional assessments used in pediatric rehabilitation. Developmental testing is deficit oriented, but does not determine the impact of delays on real-life situations and roles.

Functional assessments are used to document what the child actually does do in his or her natural environment, and therefore are helpful in developing individualized goals, treatment plans, and for monitoring change over time. Functional outcome domains may include, for example, mobility, self-care, communication, social relationships, leisure/play, education, domestic chores, and community integration. The emphasis is on groups of activities within a domain and is evaluated in a real-life environmental context. This may be differentiated from “capability,” or what the child can do (but may or may not do) in his or her natural environment (Morris, 2009). Functional assessments, such as the WeeFIM, Vineland Adaptive Behavior Scale, Pediatric Evaluation of Disability Inventory, Activity Scale for Kids, and Life Habits, provide an indication of the potential impact of functional limitations in daily life, but do not address the cause of functional limitations. Clearly, both developmental and functional assessments are needed, providing complementary information regarding a child's performance (Long et al., 2005).

The ICF-CY (children and youth version) conceptualizes “developmental delay” using descriptors within body functions and structures, as well as activity and participation. It is argued that this broad outlook allows for full documentation of the magnitude of delays. Similarly, “functioning” within the ICF is considered as an umbrella term that includes body functions and structures, and activity and participation. Therefore the ICF endorses a much more all-encompassing designation to the term “function” (ICF-CY, 2007). This serves to emphasize the importance of functioning to all individuals, but may not be sufficiently focused as a clinical descriptor term for practitioners.

Pediatric rehabilitation aims to enhance a child's abilities to participate in everyday meaningful activities in the child's home, school, and community environments. Whether by improving performance, adapting activities, modifying environments, educating and supporting families, or preventing disability, ultimately therapists strive to optimize children's functions (Case-Smith, 2005). The meaning of “function” remains somewhat controversial, therefore it is imperative that we clarify the terms we choose to use to ensure that our communications, whether in clinical practice or in research, are appropriately interpreted and not misconstrued.