Electronic Stethoscopes
Western Electric "3A" Stethoscope, from around 1925. This portable device weighed 14 lbs and featured adjustable volume and filtering of auscultatory sounds through knobs on the amplifier panel. The photo displays the chest piece on the left side of the case, with Y attachment for a binaural earpiece on the right, allowing a second "consultant" to listen as well. Usage instructions for this electronic stethoscope were provided on a plate inside the cover, which is also depicted in the image.
Faraday "Sonoscope" in its wooden box which came with instructions and technical information, circa 1956.
The Littmann 2000 was the first 3M electronic stethoscope introduced in 1998.
Starting in the 1950s, when the idea was first proposed, many companies tried to produce a practical electronic stethoscope, but none were commercially successful. In 1995, 3M initiated their electronic stethoscope development program – one that would approach the problem from both a technological and a customer standpoint. The main goal was not simply to achieve practical amplified sound, but also to develop an instrument that looked, felt and operated as much as possible like a traditional, non-electronic stethoscope.
After three years of development and clinical trials, 3M launched the Littmann Electronic Stethoscope Model 2000 – in 1998. This was an analog, rather than a digital device, without any recording or communication features. All it did was amplify sound – but it did that very well.
The Littmann 3000, 3M electronic stethoscope was introduced in 2005.
3M partnered with Bang & Olufsen Medicom, who developed the ambient noise reduction technology that comprised the key feature of the Littmann Model 3000 stethoscope. With improved sound quality, the Littmann Model 3000 quickly became the best-selling electronic stethoscope in the world. Bang & Olufsen Medicom’s ambient noise reduction technology won an iF Product Design Award in 2006. The ambient noise reduction capability of the Model 3000 allowed clinicians to hear and diagnose heart sounds with greater confidence.
Stethee, circa 2018, and the accompanying blue-tooth earplugs to allow the physician to listen to the sounds and a using smartphone or smartwatch record and display AI assisted characteristics of the sounds.
The Littmann CORE Digital Stethoscope, circa 2020. It provides up to 40x the amplification at peak frequency, when compared with analog mode. Its innovating auscultation allows for toggling between analog and amplified modes. It feature two tunable diaphragms for adult and pediatric use, without repositioning to capture high and low frequency sounds. It also pairs with a variety of mobile devices, so the doctor can visualize, record and save sounds at the touch of a button.
Stethophone by Sparrow BioAcoustics, c. 2023 is an FDA-cleared medical software that allows your smartphone to be used as a digital stethoscope to listen to your heart and lungs. The Stethophone application utilizes the built-in microphone of a smartphone to capture chest sounds. It captures and amplifies sounds, incorporates AI for analysis and detection of conditions like murmurs and arrhythmias, and can record and share sounds securely that makes it valuable for telemedicine, allowing doctors to consult with patients remotely. Because it's software-based and uses an existing device (smartphone), it eliminates the need for additional hardware.