Nitta Yoshihiro, Sano Hajime, Furuki Shogo, Umehara Sachie, Hara Yuki, Yamashita Taku
Department of Otorhinolaryngology and Head and Neck Surgery, Kitasato University School of Medicine, Kanagawa, Japan.
Department of Rehabilitation, Kitasato University School of Allied Health Sciences, Kanagawa, Japan.
J Int Adv Otol. 2024 Nov 25;20(6):502-506. doi: 10.5152/iao.2024.241565.
During hearing aid (HA) fitting, individuals may experience better speech discrimination at normal speech levels and worse discrimination at loud speech levels than without an HA. Therefore, we investigated factors that worsen speech discrimination when the speech sound level increases.
Speech discrimination was measured in patients aged >20 years who had average hearing thresholds <90 dB on pure-tone audiometry. An insufficient benefit was defined as speech discrimination being better at 65 dB sound pressure level (SPL) with HAs than without HAs and worse at 80 dB SPL.
Of the 251 participants (296 ears), 229 and 25 had sufficient benefit and insufficient benefit, respectively. Functional gains (FGs) of sufficient benefit were approximately 1/3 gain (1/3 G) at 500 and 4000 Hz and slightly larger at 1000 and 2000 Hz. Functional gains of insufficient benefit were approximately 1/2 G at 1000 and 2000 Hz, smaller at 500 and 4000 Hz, and approximately 1/3 G at 250 Hz. Moreover, the difference between 1/2 G and FG was significantly larger in the sufficient benefit group at 250 500, and 4000 Hz than in the insufficient benefit group. Additionally, the average compression ratio at 50-80 dB SPL in the insufficient benefit group was approximately 1.1 to 1.2, slightly lower than the standard values.
Adjusting the compression ratio and lowering the FG to approximately 1.5 and 1/3 G, respectively, may help improve speech discrimination if it worsens with increasing sound levels during HA fitting.
在助听器（HA）验配过程中，与未佩戴HA时相比，个体在正常言语水平下可能会有更好的言语辨别能力，但在大声言语水平下辨别能力会更差。因此，我们研究了言语声级增加时会使言语辨别能力变差的因素。
对年龄大于20岁、纯音听力计平均听阈<90dB的患者进行言语辨别能力测量。益处不足定义为佩戴HA时在65dB声压级（SPL）下的言语辨别能力比未佩戴HA时好，而在80dB SPL下更差。
在251名参与者（296只耳）中，分别有229名和25名有足够益处和益处不足。有足够益处者的功能增益（FG）在500和4000Hz时约为1/3增益（1/3G），在1000和2000Hz时稍大。益处不足者的功能增益在1000和2000Hz时约为1/2G，在500和4000Hz时较小，在250Hz时约为1/3G。此外，在250、500和4000Hz时，有足够益处组的1/2G与FG之间的差异明显大于益处不足组。此外，益处不足组在50 - 80dB SPL时的平均压缩比约为1.1至1.2，略低于标准值。
在HA验配过程中，如果言语辨别能力随声级增加而变差，分别将压缩比调整至约1.5和将FG降低至约1/3G可能有助于改善言语辨别能力。
