Three Methodologies for Measuring the Acoustic Startle Response in Early Infancy

The present study investigated whether three methodologies currently used in animal as well as human adult startle research could be adapted for measuring the startle response in 5-month-old infants. The three methods performed: an automated and computerized recording of the infants’ whole-body motor reactions (Automated Infant Motor Movement Startle Seat, AIMMSS); a coding of the infants’ facial muscular contractions involved in the startle response (FACS, Baby FACS); an analysis of the infants’ eyeblink intensity in response to the startle probes (Eye-Blink Strength scale). The results showed that these methods accurately registered the latency and intensity parameters of the reactions to acoustic startle stimuli. A correlational analysis showed, also, that the three methods registered the same motor reaction measuring the infant acoustic startle response in a consistent way.