1. PREDICTION OF UNCOMFORTABLE LOUDNESS LEVELS IN NORMAL HEARING ADULTS FROM THE AUDITORY STEADY STATE RESPONSES Barajas de Prat, J.J. (1), Zenker Castro, F. (2), Mora Espino, R. (3) and Fernández Belda, R. (2) (1)Universidad de La Laguna (2) Clínica Barajas (3) Fundación Canaria Dr. Barajas para la Prevención e Investigación de la Sordera SANTA CRUZ DE TENERIFE - CANARY ISLANDS - SPAIN Universidad de La Laguna XXIX International Congress of Audiology, Hong Kong, June 8 - 12, 2008

2. Uncomfortable Loudness Levels Uncomfortable Loudness Level Amplified Speech Spectrum Threshold

3. ULL Measurement

4. ULL Objective estimation Kiessling, Audiology, 1980 Thornton, Scand Audiol, 1989 Acoustic Reflex Auditory Brainstem Response

5. ASSRs Recording Procedure Amplifier: Low Cut (A): 20 Hz High Cut (B): 300 Hz Gain: 100 000 Notch: On Electrode Arrangement: Non-inverted: Cz Inverted:1M Ground: forehead Impedance < 5k 500 Hz 3 kHz Acoustic Stimuli: AM Tones.5 & 3 kHz dB re ULL from -10 to -60

6. ULLs Measurement Procedure 500 Hz 3 kHz Acoustical Spectrum Electrical Waveform 500 Hz 3 kHz

7. Mean Threshold (dB HL) SD (dB) Frequency (Hz) Male Subjects Female Subjects Male Subjects Female Subjects 250 17.617.94.14.7 500 10.513.73.93.4 1000 9.17.14.73.8 2000 4.25.43.54.6 3000 4.92.14.45.0 4000 4.33.25.75.4 Characteristic of the study group Means and SDs audiometric thresholds (N=14)

8. ULL = 90 dB HL ULL 500 Hz Right ear Left ear ASSR Recordings

9. Subjective ULL (dB HL)

10. 3 kHz Amplitud-Intensity function (n = 14)

11. 500 Hz Amplitud-Intensity function (n = 14)

12. Inter subject average amplitude- intensity function (n = 14)

13. Objective ULLs predicted from the intensity-amplitude function

14. Conclusions High intersubject variabilty in the amplitude-intensity function was found. Higher correlations was found for the 3 kHz carrier frequency. In general a stepper amplitude - intensity function were found for the left ear than for the rigth ear. ULL prediction based solely on individual ASSR amplitude-intensity function proved to be problematic.

15. WELCOME! EFAS 2009 TENERIFESPAIN