The effect of initial stimulus type for visual reinforcement audiometry

Abstract

Visual reinforcement audiometry (VRA) is routinely used with infants to assess hearing level. It is an operant procedure based on the association of auditory and visual stimuli. There are several recommended test procedures for VRA. One clinical VRA procedure involves presenting the initial auditory stimulus without activation of the visual reward. If the infant generates a head orientation response, the visual reward is then activated. The aim of this study was to investigate the unconditioned response rates (head orientation towards loudspeaker) to two different sound-field-presented stimuli, 1000–Hz narrowband noise (NBN) and 1000–Hz frequency-modulated tones (FMTs), using this VRA procedure. For each stimulus type, 100 infants presenting for VRA were assessed (age range 6–30 months, mean age 13 months). Of the infants presented with NBN, 69% responded, compared to 25% of infants presented with FMTs. Chi-squared analysis revealed a highly significant statistical difference in favour of NBN. In conclusion, this study demonstrated the effectiveness of using a 1000–Hz NBN stimulus over a 1000–Hz FMT stimulus in securing an unconditioned head orientation response in infants presenting for VRA.