Therapists working with families with young children with physical disabilities regularly make collaborative decisions about:

• which children might benefit from intervention,
• what types of interventions might be offered, and
• what outcomes of intervention might be anticipated (Magistro, 1989).

To assist with these decisions, assessments of impairment, ability, and activity are routinely conducted by teams of occupational therapists, physical therapists, and speech and language pathologists in the context of the diagnosis and the developmental domains of interest. Less frequently, however, do we explicitly consider and evaluate the role of inherent personality attributes that may be unrelated to the diagnosis in determining access to, and type and outcomes of rehabilitation services. The purpose of this brief communication is to provide an overview of what is known about the relationship between several inherent child attributes and developmental outcomes and to discuss how these attributes might influence decisions about intervention.

Determinants of change across developmental domains

More similar than different

In exploring child attributes influencing decisions for intervention, the acquisition of basic motor abilities generally will be used to illustrate aspects that therapists might need to consider in a broader context than movement acquisition. The concepts and determinants relating to the acquisition of early motor skills are also known to apply to change across many developmental domains (Thelen & Smith, 1994). For example, we know that severity of involvement is a major determinant of motor outcome among children with cerebral palsy (Palisano et al., 1997). In the broader context, severity of involvement ­ as captured by impairments related to the diagnosis and initial functional ability level in a variety of developmental domains ­ is also a major determinant of a variety of outcomes. Thus, aspects relating to impairments and initial functional status in different developmental domains should be considered in the assessment and intervention planning process... but is this enough?

More than impairment- and ability-level characteristics

In the past, general guidelines provided through frameworks such as the neuromaturational theory (e.g., McGraw, 1945) supported the idea that only physical features within the child explain the acquisition of new motor and other developmental abilities early in life. More recently, the dynamic systems framework proposes that the interaction of many elements in the child and environment contribute to motor, perceptual, and cognitive development (Thelen & Smith, 1994). This newer perspective suggests that we look beyond the physical elements within the child to explain the acquisition of new abilities. Although the central role of the family in early childhood development is clearly recognized (Law, 1998), the influence of inherent child attributes that may be unrelated to the diagnosis has not been adequately explored to date.

What are some of the inherent child attributes related to developmental change?

Inherent attributes are characteristic qualities that are generally stable within individuals over time while also being variable across individuals. For example, an easy-going infant will often become an easy-going toddler, but not all infants and toddlers can be described as "easy-going". In reviewing the literature, several personal attributes that may be related to motor and general development are temperament, motivation, and risk-taking tendencies.

The role of temperament has been best examined by Emmy Werner in her exemplary longitudinal study of high-risk infants exposed to perinatal trauma and chronic poverty on the island of Kauai (Werner, 1997). Although she did not investigate motor outcomes per se, the main "resiliency factors" that she identified as being related to optimal psychosocial outcomes were temperamental attributes that elicited positive responses from caregivers and other adults. Specifically, children with optimal outcomes were perceived by their mothers as active, affectionate, cuddly, good-natured, and easy to deal with. Although more rigorous measures of infant and child temperament have been constructed since the onset of this longitudinal study in 1955 (e.g., the Toddler Temperament Scale by Fullard, McDevitt and Carey, 1984), simple open-ended descriptions of caregivers' perceptions of their infants' temperament yielded important information.

In their comprehensive discussion about the development of both cognition and action, Thelen and Smith (1994) suggest that motivation is the key determinant of all developmental change. "Something has to motivate infants to look, to reach, to mouth, to seek out information about their worlds" (Thelen & Smith, 1994, p. 313). They suggest that infants come into the world with a rich set of adaptive predispositions which serve to motivate them to seek nourishment, warmth and social contact; in short, to seek out pleasure and avoid discomfort. These adaptive inclinations, which are manifested as preferences, are suggested as the primary determinants of early motor and general development. As with other personal attributes, motivation to explore the environment varies among infants and young children. Scrutton and Rosenbaum (1997) observed that "Some infants continuously explore, others are happy with the toy they have rather than the one just out of reach" (p.102). Infants who actively explore their environments ­ and take pleasure from exploration ­ may acquire motor and other developmental skills more readily than infants who are content to explore visually. Although this is a common clinical observation, this has not been empirically demonstrated.

A special form of motivation is mastery motivation which is defined as "a psychological force that originates without the need for extrinsic reward and leads an infant or young child to attempt to master tasks for the intrinsic feeling of efficacy rather than because of recurrent reward" (Morgan, MacTurk, & Hrncir, 1995, p.6). Implicit in the definition is that the child attempts a variety of developmental tasks independently, in a focused and persistent manner, to solve a problem or master a skill or task that is at least moderately challenging. A measurement tool entitled the "Dimensions of Mastery Questionnaire" is a parent report questionnaire designed to assess mastery motivation of children aged 1½ to 6 years (Morgan et al., 1997). Dimensions of the construct of mastery motivation cross developmental domains and include: object persistence at tasks, gross motor persistence, social persistence, and mastery pleasure. The key question regarding mastery motivation is "What factors enhance or depress mastery motivation in children?". Although 3½ and 4½ year old children with cerebral palsy and spina bifida with minimal physical and cognitive impairments have been found to have lower levels of mastery motivation than children with no physical disabilities, the severity of disability was not found to be related to the level of mastery motivation (Jennings, Connors, & Stegman, 1988). In order to determine whether some children with physical disabilities are intrinsically less motivated, subsequent investigators studied younger children. One and two year old children with physical disabilities were compared to cognitively age-matched children with general developmental delay and infants developing typically, and no differences in mastery motivation were detected (Hauser-Cram, 1996). When the relative contributions of preterm birth, presence of seizures, severity of cognitive delay and maternal didactic interaction in predicting mastery motivation were examined, only maternal didactic interaction revealed a significant effect. Thus, among children with physical disabilities, the caregiving environment has been shown to have a mediating effect on mastery motivation, which in turn may influence the acquisition of a range of developmental abilities.

Many children naturally engage in "moderately challenging tasks" that are required for mastery motivation. Further along this spectrum are the infants and young children who may regularly exhibit risk-taking tendencies during environmental exploration. Cintas (1992) has defined risk-taking behaviour as being accompanied by some element of danger such that the exploration may result in a fall. This attribute ­ as defined by Cintas ­ is typically observed during the emergence of independent standing and walking, and as such, may be more applicable to gross motor development than other developmental domains. Although the idea that infants or young children who are disposed to taking risks are likely to make more gains in the acquisition of motor abilities has some intuitive appeal, it has not been widely investigated.

Cintas (1992) developed an ordinal scale to measure the intensity of risk-taking when a young child explores a room with a variety of preschool gross motor equipment. The levels of the scale are:

1. child makes simple skin or clothing contact with the object;
2. weight bearing of at least one extremity on the object;
3. movement of the body in relation to the object or the body in relation to the object;
4. aggressive, moderate velocity body movements in relation to the object;
5. aggressive, high velocity body movements in relation to the object which require frequent brisk postural adjustments to maintain vertical stability.

She used a time-point sampling method and recorded each child's behaviour every 15 seconds for a half-hour interval after a 5-minute acclimatization period. A cumulative score, comprising the sum of the intensity of each event in relation to a gross motor object, was calculated. Cintas then investigated the relationship between the intensity of risk-taking and motor skill proficiency as measured by the Gross Motor Subscale of the Peabody Developmental Scales among children aged 12 to 24 months, and found a moderately strong, statistically significant correlation of .70. This cross-sectional design has limitations in that two competing inferences are possible. First, these results may infer that children with higher motor skill levels may take greater risks. Alternatively, children who take greater risks may develop higher levels of motor skills.

How might these attributes influence decision-making about intervention?

1) Which children might benefit from intervention?

As stated previously, Werner (1997) demonstrated that at-risk infants who were active, affectionate, cuddly, good-natured, and easy to deal with had the best psychosocial outcomes. Infants with these attributes may be successful in engaging caregivers and other adults to provide supportive care. In settings where therapists (together with families) determine the frequency, intensity, and duration of therapy services, an interesting related question is "Do infants and young children with personal attributes that elicit positive responses from adults get preferential care from health and education services?". Therapists who are responsible for the determination of the level of care provided for children with physical and developmental disabilities may consider being advocates for children who are perceived to be less affectionate and endearing, and more passive, fussy and difficult. These may be the children who benefit more from intervention; the good outcomes among the children with positive personal attributes may be self-fulfilling prophesies.

2) What types of interventions might be offered?

The need to identify the optimal intervention strategies for different subgroups of children has long been recognized. Typically, therapists consider subgroups of children based on impairment level attributes such as type and distribution of motor involvement in cerebral palsy or level of lesion among children with spina bifida. Rarely, however, are intervention strategies explicitly selected based on inherent child attributes. Greater attention to determining the optimal match between personality attributes and type of intervention may result in better outcomes. For example, cognitive strategies may have a greater impact on children with easy-going temperaments and high levels of mastery motivation. In contrast, a facilitation approach may be more beneficial ­ at least initially ­ for children who are more passive, with lower levels of mastery motivation and risk-taking tendencies.

While acknowledging that the attributes of temperament, motivation, and risk-taking tendencies are generally stable, we need to recognize that they may be modified somewhat as a function of environmental influences. For example, a young child with spastic quadriplegia who shows no interest in exploration may exhibit greater interest and curiosity if regularly provided with opportunities to participate in activities with peers. Thus, optimization of the expression of these personal attributes through specific strategies may facilitate the acquisition of a variety of developmental abilities. Conversely, it may be important to recognize how intervention may adversely influence these attributes. Palmer and associates (1988) speculated about the results of their randomized controlled trial comparing 12 months of neurodevelopmental therapy with 6 months of infant stimulation plus 6 months of similar therapy on a sample of children with spastic diplegia. They proposed that the greater motor gains in the group receiving infant stimulation may be attributable to the encouragement the children received to explore their environments. An alternative explanation is that neurodevelopmental therapy may inhibit exploration and therefore gains in motor development. We need to be vigilant about documenting both the beneficial and harmful effects of our interventions.

Mastery motivation has been identified to be a fundamental substrate for learning and an important prognostic indicator across multiple developmental domains; thus it ought to be a key focus for many intervention efforts (Hauser-Cram & Shonkoff, 1995). Interventions may have better outcomes if mastery motivation is facilitated. For example, parents could be encouraged to provide safe access for exploring the physical environment and to reinforce their child's independent exploration and mastery attempts through attention to and praise of these behaviours. In this context, it is important to note that while unobtrusive help is known to promote mastery attempts and motivation, both rewarding dependency behaviours and being overly helpful have been found to impede the development of mastery motivation (Jennings & MacTurk, 1995). Although these suggestions may have been components of many intervention programs in the past, children might benefit from more systematic implementation of guidelines arising from the mastery motivation literature (Busch-Rossnagel, 1997).

If the second interpretation of Cintas' results holds ­ that is, that children who take greater risks may develop higher motor skills ­ the incorporation of risk-taking activities (within the limits of safety) into intervention programs might result in greater motor gains. For example, she suggests that the systematic introduction of activities such as stepping over chasms of increasing width may have a positive impact on motor skill level. Alternatively, a child might be encouraged to make different degrees of physical contact in a variety of speeds with pieces of preschool gross motor equipment such as a slide, trampoline, tire, inclined wedges, tilt board, and balance beam.

3) What outcomes of intervention might be anticipated?

Finally, if inherent child attributes are fundamental determinants of developmental outcomes, it may be important to measure the changes over time. That is, they may be important intermediate outcomes that warrant more systematic measurement. Inherent temperamental attributes and intensity of risk-taking may not be particularly malleable. In contrast, we do have evidence that the level of mastery motivation may change over time, particularly among children with physical and developmental disabilities, as discussed above. Mastery motivation may be one such important intermediate outcome. If different levels or magnitude of change in mastery motivation are found to be associated with a change in motor abilities, ongoing monitoring of this construct using a measure such as the "Dimensions of Mastery Questionnaire" (Morgan et al., 1997) may be important for both intervention decisions and outcome evaluation.

Summary

Clearly, child attributes relating to primary and secondary impairments and functional abilities will continue to comprise the major focus in assessment and intervention planning. In the future, however, greater knowledge of the inherent child attributes associated with change in abilities may also contribute to optimal assessment and intervention decisions for each child.

Specifically,

Perception of child temperament might be important to consider when making decisions about access to services (i.e., we need to be vigilant about the possibility of preferentially offering services to children with positive personal attributes) and type of intervention to offer;

Motivation might be important to consider when planning intervention programs and determining the target outcomes; and

Risk-taking - within the limits of safety ­ might be introduced as an effective determinant of motor outcomes.

Further investigation of the role of these inherent child attributes in the acquisition of different developmental abilities among children with physical disabilities is warranted. Although risk-taking behaviours might be limited in use to motor development, the other two attributes are likely to have an impact on a variety of developmental domains. These are only a few of the personality attributes that appear in the research literature. Consideration of these and other personality attributes may influence clinical decision-making and optimize a variety of outcomes among children with physical disabilities.

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