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Universidad de La Laguna. 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).
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Universidad de La Laguna 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) • 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 XXIX International Congress of Audiology, Hong Kong, June 8 - 12, 2008
Uncomfortable Loudness Levels Uncomfortable Loudness Level Amplified Speech Spectrum Threshold
ULL Objective estimation Acoustic Reflex Auditory Brainstem Response Thornton, Scand Audiol, 1989 Kiessling, Audiology, 1980
ASSRs Recording Procedure 500 Hz 3 kHz Acoustic Stimuli: AM Tones .5 & 3 kHz dB re ULL from -10 to -60 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
ULLs Measurement Procedure Electrical Waveform 500 Hz 3 kHz Acoustical Spectrum 500 Hz 3 kHz
Characteristic of the study group Means and SDs audiometric thresholds (N=14)
ASSR Recordings ULL 500 Hz Right ear ULL = 90 dB HL Left ear ULL = 90 dB HL
Objective ULLs predicted from the intensity-amplitude function
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.
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