The benefit of bilateral cochlear implants in adults with bilateral sensorineural hearing loss: a systematic review and meta-analysis

To perform a systematic literature review (SLR) on hearing and quality-of-life (QoL) benefits of bilateral versus unilateral cochlear implants (CIs) in adults with sensorineural hearing loss (SNHL), and to quantify benefits through a meta-analysis when feasible. Embase, MEDLINE, and Cochrane were searched from January 2005–June 2022. Eligible studies presented effectiveness of CIs and/or QoL of adult CI users. Articles that presented numerical point estimates for, or numerical difference between, bilateral and unilateral CI, and measures of uncertainty were considered for meta-analysis, with data analyzed using fixed- and random-effects models. Thirty-five articles were included. There was a trend of significant improvement with bilateral CIs in sound localization and binaural redundancy. A meta-analysis confirmed statistically significant benefits in speech perception (in quiet, 12.6 percentage point [95% confidence interval: 7.1, 18.1] improvement; in noise, improvement in speech reception threshold of 1.5 dB signal-to-noise ratio [–1.5 dB; 95% confidence interval: −2.5, −0.4]). There were beneficial trends of bilateral CIs regarding head-shadow effect and binaural release from masking. Significant improvements in hearing-specific QoL were observed; generic QoL was mostly unchanged. Bilateral CIs provide audiological benefit over unilateral CI, resulting in hearing-specific QoL improvements. Lack of changes in generic QoL may reflect that instrument domains are insensitive to hearing-related changes when going from unilateral to bilateral CIs. Meta-analyses could not be performed for all hearing and QoL outcomes owing to variability in methodologies across studies. These findings should be used to inform clinical decision-making to ensure the best outcomes for adults with bilateral SNHL.

开展关于双侧与单侧人工耳蜗（CI）对感音神经性听力损失（SNHL）成人患者的听觉及生活质量（QoL）获益的系统文献综述（SLR），并在可行时通过元分析量化其获益。检索了Embase、MEDLINE及Cochrane数据库2005年1月至2022年6月期间的文献。纳入标准为报告人工耳蜗有效性和/或成人人工耳蜗使用者生活质量的研究。对于报告双侧与单侧人工耳蜗的数值点估计值或数值差异，并提供不确定性度量的文章，纳入元分析范围，数据采用固定效应与随机效应模型进行分析。共纳入35篇文章。双侧人工耳蜗在声音定位及双耳冗余方面呈现显著改善趋势。元分析证实，双侧人工耳蜗在言语感知方面具有统计学显著获益：安静环境下，改善幅度为12.6个百分点（95%置信区间：7.1~18.1）；嘈杂环境下，言语接收阈值改善1.5 dB信噪比（即-1.5 dB；95%置信区间：-2.5~-0.4）。双侧人工耳蜗在头影效应及双耳掩蔽释放方面亦呈现获益趋势。观察到听觉特异性生活质量显著改善，而普适性生活质量大多无变化。双侧人工耳蜗相较于单侧人工耳蜗具有听觉获益，可带来听觉特异性生活质量的改善。普适性生活质量无变化可能反映出，从单侧转为双侧人工耳蜗时，相关量表维度对听觉相关变化不敏感。由于各研究方法学存在差异，无法对所有听觉及生活质量结局指标进行元分析。这些发现可为临床决策提供参考，以确保双侧感音神经性听力损失成人患者获得最佳结局。