Simple Reaction Times and Timing of Serial Reactions of Adolescents with Mental Retardation, Autism, and down Syndrome

Abstract

The purpose of this study was to examine the serial information processing in adolescents with mental retardation, autism, and Down syndrome by using a serially patterned tracking task. Analyses indicated that 7 adolescents with mental retardation, 8 with autism, and 3 with Down syndrome had significantly slower and more variable simple reaction times than did 10 college students. Also, the autistic adolescents had significantly faster mean simple reaction time than those with Down syndrome. On a task of tracking serial light stimulation, mentally retarded adolescents had significantly faster reaction time than college students. The autistic subjects excessively had faster anticipatory reaction time than did the subjects in the other three groups. On the other hand, adolescents with Down syndrome had markedly slower and more variable reaction time than did adolescents with non-Down-syndrome mental retardation. As for motor organization of keystrokes on the tracking task, mentally retarded adolescents responded with six movements, in which these individuals pressed a series of keys 1, 2, 3, 4, 5, and 6, as a chunk, as exhibited by college students. Adolescents with autism and Down syndrome, however, did not produce this movement-output chunking.

Muscle Activation and Movement Responses in Youth with and without Mental Retardation

“…Consistently, researchers have shown that individuals with mental retardation have longer and more variable reaction times than those without mental retardation (see Anson & Mawston, 2000;Nettlebeck, 1980). Differences in reaction times have often been associated with central and peripheral processing components (Davis, Sparrow, & Ward, 1991;Inui,Yamanishi, & Tada, 1995;LeClair & Elliott, 1995;Un & Erbahceci, 2000) as well as structural alterations within the central nervous system (CNS; LeClair, Pollock, & Eiliot, 1993;Saccuzzo & Michael, 1984).…”

A note on motor skill acquisition in mild and moderate Down syndrome individuals

“…The mild group did not show this speed-accuracy trade-off. Down syndrome individuals have problems to structure spatially motor sequences also due to limitations associated with memory problems and selective attention (Reid 1980;Horgan 1983;Inui et al 1995;Lanfranchi et al 2015). These difficulties would be associated not only with information storage but also with an inability to recognize stimuli and determine strategies for information storage.…”

“…Rather than being a defect, this is an adaptive strategy to deal with some limitations to plan ahead and also to pre-program motor units into one-single and detailed motor program. These limitations have been pointed out before by a number of authors (e.g., Wade et al 1978;Seyfort and Spreen 1979;Anwar 1981;Kerr and Blais 1985;1987;Dummer 1985;Inui et al 1995;Jarrold et al 2009). DS individuals would show some diverse structural organization in regions involved in motor planning (the pre-frontal lobe) and programming (the cerebellum and basal ganglia) (cf.…”

Muscle reaction function of individuals with intellectual disabilities may be improved through therapeutic use of a horse

“…Nevertheless, the underlying mechanisms for these differences have not been extensively studied (Inui, Yamanishi, & Tada, 1995;LeClair & Elliott, 1995;Un & Erbahçeci, 2001). Davis (1987) suggested that muscle activation and EMG variability could be the reason for the movement delays observed in this population.…”