Connectivity to TV, cellphones, iPods, computers.

More and more hearing aid manufacturers are providing hearing aids that provide a clearer and more convenient connection to external electronic sound sources such as TVs, phones, cell phones, iPods, computers, stereos, etc. This is typically achieved by using a small device that hangs around the hearing aid wearer's neck that acts as a wireless interface between the hearing aids and the electronic sound input. Cellphone calls can be routed through this device and to the hearing aids using wireless Bluetooth technology, making cell phone conversations hands free and much clearer. TV sound (or any other audio signal) can be input directly to the hearing aids aids via the device, giving the wearer much clearer and effortless sound reception. Some interface devices, like Phonak's iCom, also accept an FM receiver allowing access to conversation being sent via a remote microphone and transmitter.

'Open Fit' receiver in the ear technology. 

Open fit hearing aids have been around for at least 5 years now, so they are not exactly emerging technology, but there continues to be significant developments worth mentioning. 'Open fit' technology refers to hearing aids that do not plug up the ear canal. Typically they are a behind-the-ear style hearing aid - often quite small in size - that have a thin tube or wire that disappears into the ear canal to deliver the sound. At the end of the tube or wire is a small soft rubber dome that helps to keep it in the ear canal. This dome does not stop the natural flow of air and sound going in and out of the ear, and so the wearer receives a mix of 'natural' sound and amplified sound. Many manufacturers now make open fit hearing aids that place the receiver (speaker) in the ear canal, bypassing the problem of forcing sound through a thin sound tube. Receiver in the ear hearing aids tend to output a wider bandwidth (think more notes on a piano), are slightly more discrete because the thin sound tube is replaced by a thinner wire, and have a smoother sound response because sound is not being forced through a narrow sound tube. Some hearing aids, such as the Phonak Audeo YES and Siemens Pure, allow different power receivers to be used, giving the wearer the flexibility to simply change the receivers if their hearing changes significantly, rather than buying new hearing aids.

Frequency Compression

Hearing aids have limited ability to give people useful amplification of very high frequency (think 'high pitch') sounds, due to technical limitations and the typical user's poor high frequency hearing.  For most people this means that very high frequency sounds are simply not heard, no matter what hearing aid they buy.  This is unfortunate because these very high frequency sounds can play a significant role in hearing speech sounds like "s" and "sh".  Phonak recently has included a feature, called SoundRecover, in some of their hearing aids that moves these inaudible very high frequency sounds into lower frequency regions where people typically have better hearing.  This allows the user make use of speech information in these high frequency regions that otherwise would have been lost.  Frequency compression is an exciting area of research, and many Phonak hearing aid wearers using SoundRecover say it's the feature they love the most.  Phonak Audeo YES, Naida and Exelia ART hearing aid models all have SoundRecover.