Current cochlear implants are partially implanted and require external components, limiting patient options. A new development, a microphone placed directly in the ear cavity, will allow people with hearing impairments to lead more active lifestyles.
Made from biocompatible piezoelectric material, the microphone picks up the smallest vibrations in the eardrum. Piezoelectric materials produce an electric charge when compressed or stretched. To improve the device’s performance, the scientists also created a low-noise amplifier that boosts the signal while minimizing noise from electronics.
Scientists say there are still a number of issues that need to be resolved before the microphone can be used with a cochlear implant, but the prototype, which is based on more than a decade of work, shows great promise.
Fully implantable microphones offer a number of advantages. For example, they take into account natural noise filtering and sound localization due to the structure of the outer ear, which is not found in external microphones.
The new microphone is attached to a vibrating section of the eardrum. Measuring such microscopic vibrations required careful engineering.
Additionally, any implantable sensor must be biocompatible and able to withstand the body’s wet environment without damage.
Researchers created the UmboMic, a 3 x 3 millimeter triangular motion sensor made from two layers of biocompatible piezoelectric material.
About the size of a grain of rice and 200 micrometers thick (twice as thick as a human hair), the microphone fits with its narrow tip into the umbilical cord. Vibrations in a section of the eardrum cause electrical charges that are measured by electrodes on a circuit board.
The team used a two-layer PVDF (piezoelectric material) design to reduce noise. When the sensor is bent, one layer of PVDF creates a positive charge while the other creates a negative charge. Noise affects both layers equally, so removing the charges eliminates the noise.
Source: Ferra
I am a professional journalist and content creator with extensive experience writing for news websites. I currently work as an author at Gadget Onus, where I specialize in covering hot news topics. My written pieces have been published on some of the biggest media outlets around the world, including The Guardian and BBC News.
