title: Age-related change of the mean level and intraindividual variability of saccadic reaction time performance in persons with intellectual disabilities.
abstract: The current study examined age-related change of saccadic reaction time (SRT) in persons with intellectual disabilities (ID). Participants were 29 persons with intellectual disabilities aged between 14 and 34 years whose IQs were between 14 and 70. Participants were divided into Group I (IQ≧35) and Group II (IQ≦34). The mean and the standard deviation of SRT (SRTM and SRTSD, respectively) reduced through adolescence in both groups. This result suggests that the speed and stability of information processing develops during adolescence irrespective of the level of ID. Although SRTM and SRTSD of Group I stabilized after adolescence, those of Group II increased after their thirties. This outcome indicates that persons with severe ID may show signs of the aging process. The results of multiple regression analyses and path analyses indicated that SRTM was influenced by both the speed of information processing and the variability of the response. However, given that the extent of increase of SRTSD in Group II was smaller as compared with that of SRTM, this increase of SRTM after the thirties in Group II appears to be mainly affected by the slowness of information processing.
authors.affiliation: Joetsu University of Education, Joetsu, Japan. haishi@juen.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Haishi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okuzumi
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kokubun
mesh_terms: D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology; D000328:Adult; D000367:Age Factors; D053483:Eye Movement Measurements; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000503:physiopathology*; D008297:Male; D011930:Reaction Time / Q000502:physiology*; D012044:Regression Analysis; D012438:Saccades / Q000502:physiology*; D012720:Severity of Illness Index; D055815:Young Adult