BEHAVIORAL COMPETITION IN A CASE OF RETT-SYNDROME

Major behavioral features of Rett syndrome are the loss of instrumenta l reaching and grasping and the presentation of some variant of hand-h and or hand-mouth stereotypy. As part of on experimental home interven tion program, a 3-year-old girl with Rett syndrome was exposed to four types of contingency games designed to elicit instrumental reaching, kicking, vocalization, and eye movement, respectively. Parent and subj ect performance were videorecorded on seven occasions over the initial 2-month period. Evaluation of these records provided evidence of cont ingency learning in all but the vocalization games. Stereotypic hand c lasping was examined in relation to the performance of instrumental be havior (reaching, kicking, looking). Coincidental (short-term mutual i nhibition arising by chance co-occurrence), associative (shalt-term mu tual inhibition arising by having elicitor in common), and foundationo l (long-term mutual inhibition arising by having neural network in com mon) forms of specific behavioral competition were defined and examine d. Evidence for coincidental and foundational competition was found in the relation between reaching and hand clasping. Implications for the support of functional hand use are discussed.