Mathematical modelling of the electric potential from cochlear implants for a new diagnosis tool

用于新诊断工具的人工耳蜗电势数学模型

• 批准号: EP/W018764/1
• 负责人: Tracey Newman
• 金额: $ 5.28万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW018764%2F1
• 关键词: Mathematical; modelling; electric; potential; cochlear

Cochlear implants restore hearing in people with hearing loss, by replacing damaged or missing sensors in the cochlea in the inner ear. However, some people experience persistent problems with their implant. Precise diagnosis of the cause of these problems is often not possible, resulting in people with poor hearing despite having an implant. Hearing loss is a significant risk factor for depression, dementia and disability-affected life-years with an estimated cost to the UK economy of >£40billion/annum. Cochlear implants could benefit many more deaf people and help to address a key societal challenge: a reduction in the burden of disability in later life. However, for this to happen, we need new diagnostic approaches to ensure lifelong good quality hearing for people with implants. This project will transform the diagnosis of problems in cochlear implants by applying mathematics to develop a diagnostic tool that is driven by and designed for use in the clinic, that is easy to administer and that is well tolerated by patients. A cochlear implant is a series of metal electrodes, which are inserted into the cochlea. Sound is captured by a unit on the ear that is connected to an internal stimulator on the skull. The stimulator causes the electrodes on the array in the cochlea to emit electric currents which activate the auditory nerve, sending signals to the brain which are recognised as sound. Problems can occur that disrupt the electric current and the signal relayed to the brain, causing poorer hearing or loss of sound. The current from the electrodes also causes voltages that can be detected on the scalp. We have measured these voltages in people with cochlear implants and found that they can identify problematic cases where the implant is no longer relaying sound as expected. Disruption to the electrical signals can also cause pain, or unpleasant sensations. These symptoms are distressing and hard to explain or treat, particularly when the underlying cause is not clear. We aim to build a mathematical model of cochlear implants operating in the human head using finite element methods: these methods are widely applied in many areas of medicine and industry. The model will predict the voltages on the scalp that are generated in response to each implant electrode producing a current in turn. We will compare these predictions to data from people with cochlear implants to validate the model, using existing data as well as collecting new data. To ensure the model can be applied to different people with differently shaped heads, we will study the effects of varying characteristics of the model head, such as its shape, capturing the right level of detail in our model. To diagnose problems, we will study the relationship between each electrode and the voltage at specific locations on the scalp. We will describe this relationship for fully functional implants, and will then incorporate common problems, such as misplaced implants or build-up of scar tissue, into our model. Preliminary results show that the relationship between which electrode produces the current and the voltage on the scalp changes significantly in the presence of such problems. This lays the foundation for using these relationships to diagnose problems. Our work focuses on the development of a clinical test that can be used on all patients, whereas prior work has generated detailed models of a few individuals. Cochlear implants have a lifespan of 20-25 years, and problems can reduce this lifespan or result in additional surgery being needed. This is detrimental both to the patient and health budgets. There is a clear need for a reliable diagnostic tool that is quick to run in a standard clinical environment and usable in adults and children, irrespective of language skills or cognitive abilities. This project paves the way for the development of a validated test that can be used in all cochlear implant clinics and ultimately, via telemedicine.

人工耳蜗通过替换内耳耳蜗中受损或缺失的传感器来恢复听力损失患者的听力。然而，有些人的植入物始终存在问题。通常无法准确诊断这些问题的原因，导致人们尽管植入了植入物，但听力仍很差。听力损失是抑郁症、痴呆症和残疾影响生命年的一个重要风险因素，估计每年给英国经济造成的损失超过 400 亿英镑。人工耳蜗可以使更多聋人受益，并有助于解决一个关键的社会挑战：减轻晚年残疾的负担。然而，要实现这一目标，我们需要新的诊断方法，以确保植入植入物的人终生拥有良好的听力质量。 该项目将通过应用数学开发一种诊断工具来改变人工耳蜗问题的诊断，该工具由临床驱动并设计用于临床，易于管理且患者耐受性良好。 人工耳蜗是一系列插入耳蜗的金属电极。声音由耳朵上的一个单元捕获，该单元连接到头骨上的内部刺激器。刺激器使耳蜗阵列上的电极发出电流，激活听觉神经，向大脑发送被识别为声音的信号。可能会出现问题，破坏电流和传递到大脑的信号，导致听力下降或失声。来自电极的电流也会产生可以在头皮上检测到的电压。我们测量了植入人工耳蜗的人的这些电压，发现他们可以识别植入物不再按预期传递声音的问题情况。电信号的干扰也会导致疼痛或不愉快的感觉。这些症状令人痛苦且难以解释或治疗，特别是当根本原因尚不清楚时。 我们的目标是使用有限元方法建立在人脑中运行的人工耳蜗的数学模型：这些方法广泛应用于医学和工业的许多领域。该模型将预测头皮上响应每个植入电极依次产生电流而产生的电压。我们将使用现有数据并收集新数据，将这些预测与人工耳蜗植入者的数据进行比较，以验证模型。为了确保模型可以应用于具有不同头部形状的不同人，我们将研究模型头部不同特征（例如其形状）的影响，捕获模型中正确的细节水平。 为了诊断问题，我们将研究每个电极与头皮特定位置的电压之间的关系。我们将描述功能齐全的植入物的这种关系，然后将常见问题（例如植入物错位或疤痕组织的堆积）纳入我们的模型中。初步结果表明，在存在此类问题时，哪个电极产生电流与头皮上的电压之间的关系会发生显着变化。这为利用这些关系来诊断问题奠定了基础。我们的工作重点是开发可用于所有患者的临床测试，而之前的工作已经生成了少数个体的详细模型。 人工耳蜗的使用寿命为 20-25 年，出现问题可能会缩短使用寿命或导致需要进行额外的手术。这对患者和健康预算都是有害的。显然需要一种可靠的诊断工具，该工具可以在标准临床环境中快速运行，并且适用于成人和儿童，无论语言技能或认知能力如何。该项目为开发经过验证的测试铺平了道路，该测试可用于所有人工耳蜗植入诊所，并最终通过远程医疗进行使用。

项目成果

Improving the sensitivity of cochlear implant integrity testing by recording electrode voltages with surface electrodes

通过表面电极记录电极电压提高人工耳蜗完整性测试的灵敏度

• DOI: 10.3389/fauot.2024.1342263
• 发表时间: 2024
• 期刊: Frontiers in Audiology and Otology
• 作者: Grasmeder M