An Innovative Approach to Fair Evaluations for People with Cognitive Disabilities

Julie M. Tourigny and Lucy Jane Miller University of Colorado Health Sciences Center Departments of Rehabilitation Medicine and Pediatrics

Abstract The recent revision of the Leiter (Roid and Miller, 1997) has rendered the scale more comprehensive in domains assessed, and has greatly improved its psychometric characteristics. The Leiter-R assesses the global intelligence of children and adolescents who cannot be tested using traditional methods. Specifically, the new assessment targets individuals diagnosed with all types of cognitive disorders including communication disorders, hearing impairments, motor impairments, traumatic brain injury, attention deficit disorder, and some forms of learning disability.

Abstract (cont’d.) This assessment tool is made up of two subdivisions comprised of 10 subtests each: the Visualization and Reasoning (VR) subdivision, and the Attention and Memory (AM) subdivision. Administration of the VR and AM Batteries provides clinicians, teachers and families with a comprehensive understanding of a child or adolescent’s cognitive functioning regardless of language or motor ability. The Leiter-R battery of 20 subtests plus four rating scales (parent, teacher, examiner and self-rating) are specifically designed to detect small changes in cognitive ability, such as those that might be seen after interventions, because the scaling is based on item response theory.

Abstract (cont’d.) Since the scales are detailed, they can aid in early detection of cognitive deficits or delays, as well as accurate treatment and program planning. Another unique feature and a major advance over previous intelligence scales, is that the Leiter-R is culturally fair and focuses on cognitive strengths rather than cognitive limitations.

Construct Validity with Children with Disabilities As an integral part of the standardization of the Leiter-R, comparison samles of a variety of children in the following atypical and clinical categories (N = number of subjects in the VR Standardization sample) were identified.

Adaptation of Administrative Procedures for Exceptional Population As it relates to the Leiter-R, any person between the ages of 2 and 20 years, who may not obtain an accurate evaluation from traditional, verbally loaded cognitive measures, is included in the term “Exceptional Population” as used here. Since the Leiter-R is a nonverbal and relatively nonmotor ability scale, most of the instructions are applicable for administration of the scale to children with special needs.

Adaptation of Administrative Procedures for Exceptional Population (cont’d.) Examiners are encouraged to be creative in demonstrating or explaining the tasks and employing any method that can help the child to understand the task. It may be necessary to create unusual methods by which the child can communicate his/her answers to test items within the capabilities they have. ** Note: Caution should be exercised in using normative scores if standardization administration instructions are radically changed in the adaptation process.

Use and Interpretation of Growth Scores For children who function at a low level of ability and any child who is expected to be retested on the Leiter- R, the Growth Scores provide an excellent source of information. The Growth Scores were designed using item response theory so that small increments of growth could be measured. Growth between two testing occasions are more clearly seen from Growth Scores and growth scale item values than from the normative scaled scores or IQ scores. Refer to the example below of Julieta, a 12-year-old girl who was retested on the Leiter-R. Please note Growth Score changes that occurred from past to present performance on each subtest.

Classification Accuracy of Identification of Cognitive Delay Using Cutpoints

Classification Accuracy of Identification of Cognitive Delay Using Cutpoints (cont’d.)

Correlation with Weschler Intelligence Scale (WISC-III) A sample of 126 children, ages 6 to 16, were given both the Leiter-R and the WISC-III. The sample included 57% male, 57% Caucasian, 15% African- American, 25% Hispanic, and 3% other ethnic backgrounds. Testing was conducted predominantly in the Midwest (35%) and South (44%), with some subjects from the Northeast (17%) and West (3%). The sample included normative cases (47%), cognitive delay (18%), gifted (9%) and ESL-Spanish (23%).

Classification Accuracy of Leiter-R with WISC For Children with Cognitive Delays