|
Previous research in developmental psychology has found that the ability to move about independently is a critical facilitator in a child's development and can impact cognitive, social, and communication skills. Due to limited availability of clinical assessment instruments, it is often difficult to determine when a young child with mobility impairments may be developmentally ready to operate a powered wheelchair functionally. A study is currently being completed that investigates cognitive readiness for powered mobility in young children with orthopedic disabilities. The goals of the study were to develop an assessment battery that evaluates cognitive developmental skills that are influential in powered mobility and to develop an age-appropriate powered mobility program which introduces and evaluates powered mobility skills. The development, components, and preliminary reliability results of the assessment tool are described in this paper. For information on the powered mobility program, refer to Pediatric Powered Mobility: Readiness to Learn in these proceedings. APPROACH Participants Twenty-six children participated in the study, consisting of twenty males and six females. In order to minimize the influence of sensorimotor integration problems on powered mobility, children with diagnoses that impair primarily physical abilities only were included. Table 1 presents the frequency of diagnoses. Diagnoses classified as 'other' include polio, burn/amputee, spinal bifida, femur hyplasis syndrome, osteogenesis imperfecta. The ages of the children ranged from 20 months to 36 months, with the average age of 28.3 months. |
TABLE 1. PARTICIPANT DIAGNOSES
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Assessment Battery Development
The cognitive assessment battery was a Piagetian-based tool consisting
of five scales evaluating the different skill domains of cause/effect,
object permanence, problem solving, spatial relations, and symbolic play.
This approach was selected as Piaget's theory of sequential stage development
within distinctly different skill domains is a well researched, validated
theory of early childhood development, and has been found to be appropriate
for children with a diverse range of disabilities (1). Another reason for
selection of a Piagetian-based tool was that this type of assessment renders
scores for each specific domain of development. This would allow a comparison
of scores on specific domains to wheelchair performance. An assessment battery was developed since no single existing assessment
tool met the study's requirements (i.e., Piagetian-based, appropriate for
ages 18-36 months, does not penalize children with physical limitations).
The assessment battery incorporated tasks from several standardized developmental
batteries.(1,2,3,4,5) This battery was then pilot-tested on three children
and further revisions were made. The final battery included eighty-three
tasks (See Table 2 for example items). |
TABLE 2. SAMPLE COGNITIVE TEST ITEMS
| Cognitive Domain |
|
Test Items |
| Cause/Effect |
|
Searches for causal mechanism needed to activate a mechanical toy. |
| Object Permanence |
|
Searches for and obtains object hidden invisibly under the last of three screens. |
| Problem Solving |
|
Shows foresight by NOT stacking solid ring on pole. |
| Spatial Relations |
|
Able to nest 4 cups. |
| Symbolic Play |
|
Demonstrates sequenced events with familiar toys. |
|
Since the battery was to be administered to children with physical limitation, it was essential that the response requirements not penalize the children. Items were modified to accommodate a child's functional limitations; however, care was taken to insure that the basic task premise always remained the same. For example, the spatial relations task of nesting cups, which evaluated a child's awareness of size differences, required children to lift and nest commercially available plastic cups of various sizes. During the assessment of children too weak or with poor grasp to lift the cups, miniature cups were created and substituted. For a problem solving task that required children to stack large plastic rings on a long plastic stick, small styrofoam rings and a shorter dowel rod were substituted. Administration Information from family and professionals was reviewed prior to assessment to determine appropriate positioning supports or requirements and need for modification of toys. Generally, all items on one scale were administered before beginning the next scale. However, the battery allowed deviation from this protocol as necessary to maintain the child's attention. The battery also allowed a variety of toys to be used to maintain a child's interest. Each item was administered one or more times, depending upon the number of correct responses required to score a task as 'successfully completed'. Items were scored on a 3-point scale, ranging from ‘successfully completed’, to ‘emerging’, to ‘not successfully completed’. Final scores in each scale indicated the highest developmental level that a child consistently demonstrated in that scale. The test was administered over one to three sessions, depending upon the child's attention span. All sessions were completed within a two week time period. Sessions were videotaped and later reviewed and scored. RESULTS Data from 10 children were scored independently by two raters to establish an index of interrater agreement on the cognitive assessment battery. In addition, the responses made by 9 children were rescored 8 to 12 months later to determine 'drift' in ratings. To assess test-retest reliability, three children were re-evaluated two weeks after the initial testing. Interrater agreement The Kappa statistic was used to determine the proportion of agreement between raters.(6) Kappa scores ranged from .64 to .86 across the five scales (see Table 3). Scores were then tested against the hypothesis that the agreement is only that predicted by chance. Scores for all five domains were found to have significant agreement above chance. Kappa scores of .75 and above represent excellent interrater agreement above chance, and scores between .40 and .75 represent fair to good agreement above chance.(7) TABLE 3. INTERRATER AGREEMENT ACROSS DEVELOPMENTAL DOMAINS
|