3D印刷超低成本助听器

The ultra-low-cost proof-of-concept device known as LoCHAid is designed to be easily manufactured and repaired in locations where conventional hearing aids are priced beyond the reach of most citizens. The minimalist device is expected to meet most of the World Health Organization's targets for hearing aids aimed at mild-to-moderate age-related hearing loss. The prototypes built so far look like wearable music players instead of a traditional behind-the-ear hearing aids.

“我们为自己设定的挑战是建立一个简约的助听器，确定它有多好，并询问可以使用它的数百万人有用如何有用，”助手教授M. Saad Bhamla说道。佐治亚理工学院化学与生物分子工程学院。“需求是显而易见的，因为传统的助听器花费了很多，只有需要他们可以访问的人的一小部分。”

Age-related hearing loss affects more than 200 million adults over the age of 65 worldwide. Hearing aid adoption remains relatively low, particularly in low-and-middle income countries where fewer than 3 percent of adults use the devices—compared to 20 percent in wealthier countries. Cost is a significant limitation, with the average hearing aid pair costing $4,700 in the United States and even low-cost personal sound amplification devices—which don't meet the criteria for sale as hearing aids—priced at hundreds of dollars globally.

高成本的部分原因是，有效的助听器提供了远远超过声音放大。听力损失往往会在不同的频率下不均匀发生，因此促进所有声音实际上可以使言语理解更加困难。因为解码语音对于人类大脑如此复杂，所以设备还必须避免扭曲声音或增加可能妨碍用户理解能力的噪音。

Bhamla和他的团队选择专注于与年龄相关的听力损失，因为老年人倾向于在更高频率下丢失。专注于具有类似听力损失的大型组，通过缩小所需的声频放大范围来简化设计。

Modern hearing aids use digital signal processors to adjust sound, but these components were too expensive and power hungry for the team's goal. The team therefore decided to build their device using electronic filters to shape the frequency response, a less expensive approach that was standard on hearing aids before the processors became widely available. "Taking a standard such as linear gain response and shaping it using filters dramatically reduces the cost and the effort required for programming," said Soham Sinha, the paper's first author, who was born in semi-rural India and is a long-term user of hearing aid technology.

"I was born with hearing loss and didn't get hearing aids until I was in high school," said Sinha, who worked on the project while a Georgia Tech undergraduate and is now a Ph.D. student at Stanford University. "This project represented for me an opportunity to learn what I could do to help others who may be in the same situation as me but not have the resources to obtain hearing aids."

The ability to hear makes a critical quality-of-life difference, especially to older people who may have less access to social relationships, said Vinaya Manchaiah, professor of speech and hearing sciences at Lamar University and another member of the research team. "Hearing has a direct impact on how we feel and how we behave," he said. "For older adults, losing the ability to hear can result in a quicker and larger cognitive decline."

The inexpensive hearing aid developed by Bhamla's team can obviously not do everything that the more expensive devices can do, an issue Manchaiah compares to "purchasing a basic car versus a luxury car. If you ask most users, a basic car is all you need is to be able to get from Point A to Point B. But in the hearing aid world, not many companies make basic cars."

对于Manchaiah，问题是原型设备是否为成本提供了足够的值。研究人员已经广泛地研究了它们的装置的电声性能，但实际测试将进入临床和用户试验，这将在可以作为医疗设备认证之前。“当我们谈论助听器时，即使是世界上许多地方的人的最低技术也非常高，”他说。“我们可能不需要拥有最好的技术或最好的设备，以便提供价值和良好的听证体验。”

The electronic components of the LoCHAid cost less than a dollar if purchased in bulk, but that doesn't include assembly or distribution costs. Its relatively large size allows for low-tech assembly and even do-it-yourself production and repair. The prototype uses a 3-D-printed case and is powered by common AA or lithium ion coin-cell batteries designed to keep costs as low as possible. With its focus on older adults, the device could be sold online or over-the-counter, Bhamla said. "We have shown that it is possible to build a hearing aid for less than the price of a cup of coffee," he said. "This is a first step, a platform technology, and we've shown that low cost doesn't have to mean low quality."

在该设备的缺点中是其大尺寸，无法调节频率范围，并且只有一年半的预期寿命。电池的成本通常是助听器用户隐患，AA电池预计最长可达三周，这仍然是当前助听器中普通锌空气电池的4-5天预期寿命的改善。

研究人员现在正在进行更小版本的设备，将散装成本提高到七美元，并需要一个复杂的制造商可以组装。“我们将无法再能够在实验室中焊接他们，”Bhamla说，他们的研究侧重于节俭科学。“这是对我们的爱的劳动，所以我们会错过。”

该项目的详细信息描述于PLOS ONE。