Performance of High Frequency Impaired Listeners with Conventional and Extended High Frequency Amplification

Abstract

This study sought to determine if a high-pass hearing aid can provide increased improvement in word recognition and consonant discrimination over that of a conventional high frequency emphasis hearing aid in listeners with hearing loss limited to frequencies above 1 000 Hz. Word and consonant discrimination were assessed in quiet and in the presence of 12 talker speech babble for 10 subjects under three listening conditions: (1) unaided; (2) wearing a conventional high frequency emphasis hearing aid, and (3) wearing an experimental high-pass instrument. The speech testing materials included: (1) Northwestern University Auditory Test No. 6; (2) California Consonant Test, and (3) eight voiceless English consonants. Results suggested that both instruments provided similar benefit in quiet for improving word recognition and resolving consonant errors. For the noise condition, however, the experimental high-pass aid provided a considerable advantage in both word recognition and consonant identification and was particularly sensitive to reducing within- and between-manner voiceless consonant confusions. Furthermore, measurements of real-ear gain revealed that the high-pass aid afforded considerably greater acoustic gain above 4 000 Hz than that shown for the conventional high frequency emphasis hearing aid.

Nous avons, chez 10 sujets atteints d'une pertc d'audition pour les fréquences supérieures à 1 kHz, cherché à établir si un appareil expérimental de correction auditive passe-haut peut, davantage qu'un appareil classique à amplification préférentielle pour les fréquences hautes et dont le gain chute après 4 kHz, améliorer la discrimination de mots et de consonnes dans le calme et aussi en présence d'un bruit de conversation de 12 personnes. Les deux appareils se sont révélés identiques pour la discrimination dans le calme; mais dans le bruit, l'appareil expérimental s'est révélé etre nettement plus efficace.

Key Words:

• Hearing aids
• Extended high frequency response
• Functional gain
• Consonant confusion
• Manner-of-articulation