[Visual reinforcement audiometry with different sound stimuli in children].

Background: Hearing evaluation in children.

Aim: To verify the Minimum Response Levels (MRL) through the use of Visual Reinforcement Audiometry (VRA) in the sound field, in 50 normal hearing children and in 25 children with hearing loss, taking into account the following variables: side of sound presentation, gender, age and type of stimulus.

Method: VRA was performed using pure tone frequency modulation (warble) and the Sonar System. The modulated tones were produced by the Pediatric Audiometer, in the frequencies of 500, 1000, 2000 and 4000 Hz and at the intensities of 80, 60, 40 and 20 dBNA. The modulated tones were presented in a decreasing sequence of intensity and by using the stimulus-reply-visual reinforcement conditioning. The assessment procedure and analysis of response were the same when using the stimuli of the Sonar System. However, on this occasion, a sound amplification box was used. Each loudspeaker with the visual reinforcement was positioned approximately at 90 masculine azimuth to the right and the left of the child, and at a distance of approximately 50 cm. Visual reinforcement was an illuminated clown.

Results: No statistically significant difference was found between the MNL and the side of sound presentation. The MRL at 500 Hz and 2000 Hz, when using the Sonar System, were lower for normal hearing males. In this group, there was a decrease in the MRL with the increase in age for both stimuli. When comparing the MRL with two stimuli, there was a statistically significant difference in favor of the Sonar System, but only for the group of normal hearing children below two years of age.

Conclusion: The MRL decrease with age independently of the stimulus and are lower when using the Sonar System. For the group of children with hearing loss no significant difference was found for any of the studied variables.