STEREOTYPED BEHAVIOR IN DEVELOPMENTALLY DELAYED OR AUTISTIC POPULATIONS - RHYTHMIC OR NONRHYTHMIC

Stereotypies are high-frequency, highly repetitive, nonfunctional beha viors that are also often characterized as rhythmic. Rhythmicity sugge sts that the behavior is periodic, occurring at fixed intervals, Few s tudies, however, have rigorously demonstrated periodicity in stereotyp y. This study examined various topographies of stereotypy in 9 partici pants and used spectral methods to detect existence of periodicities. Two general patterns emerged in the spectral analysis. Participants wh o engaged in stereotypic rocking showed peaks in their power spectra; participants who engaged in other topographies of stereotypy did not s how peaks. Thus, it appears that although some stereotypies-notably, r ocking-have a periodic component, rhythmicity does not appear to be a characteristic of stereotypy in general.