Factors Predicting Intelligence Scores on the TONI in Individuals with Autism

• Published in: Focus on autism and other developmental disabilities Vol. 13; no. 1; pp. 17 - 26
• Main Authors: Goldberg, Meredyth, Timmons, Derenda, Edelson, Stephen M.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.02.1998; SAGE PUBLICATIONS, INC
• Subjects: Autism; Intellectual disabilities; Intelligence; Nonverbal Ability; Nonverbal Tests
• ISSN: 1088-3576; 1538-4829
• DOI: 10.1177/108835769801300102

Two hundred fifty-eight individuals with autism who ranged in age from 4 to 41 years were assessed with the Test of Nonverbal Intelligence-Second Edition (TONI-2). The purpose of the study was to determine whether the TONI-2 was appropriate for individuals with autism; to determine what factors such as verbal ability and degree of autism might have affected TONI-2 scores; and to compare our scores to those from a sample of individuals with mental retardation as well as to those from other special populations. Our results indicated that age, verbal ability, and lack of attention deficits were most predictive of TONI-2 scores in our sample. The presence of attention deficits and a moderate number of autistic symptoms predicted untestability on the TONI-2. The mean TONI-2 score for our sample was 88.99 with a standard deviation of 21.13. This mean most closely resembled means obtained for samples of non-English-speaking, head-injured, and dyslexic individuals rather than those from samples of individuals with mental retardation. Only 19% of our sample had scores that fell within the mentally retarded range. The implications of our findings are discussed with regard to the practice of intelligence assessment in persons with autism.