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Ultimate Hearing Aid Guide.
CROS and BiCROS
CROS and BiCROS Hearing Aids
CROS hearing aids (where CROS stands for "Contralateral Routing of Signal") are generally intended for use by individuals who suffer from unilateral hearing loss. That is, they have some degree of hearing loss in a single ear, causing them difficulties in everyday conversations and potential issues regarding distance perception. BiCROS hearing aids are slightly different, and are intended for use by people who have almost total hearing loss in one ear, and partial hearing loss in the other. So, the two are related, but are suitable for very different patients.
In both BiCROS and CROS hearing aids, the aim of the device is to recreate the sensation of binaural hearing (even auditory perception in both ears). How do they do this? The system that hearing aid engineers have arrived it is fairly simple. In CROS systems, the poorly functioning ear is fitted with a microphone, while the ear with relatively functional hearing is fitted with a receiver unit. When sounds are detected by the microphone at the poorly functioning ear, they are automatically transmitted to the receiver on the other side, allowing the wearer to achieve the sensation of binaural hearing.
In BiCROS systems, the setup is similar. The ear with the lowest quality hearing is fitted with a microphone, which detects noises in the local area, and beams them wirelessly to a hearing aid attached to the other ear. This hearing aid than functions like a normal BTE or ITE device, helping to adjust for the poor auditory abilities of the ear with better hearing quality. Because of this, the hearing aid component of effective BiCROS devices needs to be precisely balanced to account for the difference between the two ears - something that modern hearing aids make relatively easy with smartphone apps and hearing aid processors.
One question that arises for some people suffering from unilateral hearing problems is why systems like this would be preferable to simply using a hearing aid in the ear with poor auditory performance? Well, CROS/BiCROS devices are suitable when one ear has little to no hearing ability, or when the difference between the two ears is so large that it affects the quality of life of the individual concerned.
The benefits can be huge, including restoring the ability to have normal conversations, to listen to music on standard stereo systems, or enjoy the experience of attending movie shows. But these benefits are amplified when CROS/BiCROS devices are fully-equipped with technology which supplements their core elements. For instance, they may come with settings to minimize feedback and whistling, and sophisticated directional microphones which can pinpoint specific sources of noise and focus on them - making life much easier in very noisy environments.
CROS/BiCROS hearing aids depend on having reliable ear-to-ear streaming technology on place. Without this, their efficacy is drastically reduced, although older models do still manage to replicate binaural hearing using wires passed behind the hearer's head. With reliable streaming, these products can make things like telephone conversations or listening to audio players much easier, convenient, and more enjoyable.
This type of hearing aid is really a variant of the other types we have already discussed. In fact, it's possible to purchase CROS/BiCROS devices in both BTE and RIC versions, depending on which one feels most comfortable for the user concerned.
If they have a drawback, it's that CROS/BiCROS devices often require larger units to accommodate extra battery capacity. However, given their specific benefits for patients with unilateral hearing loss, this is often a price worth paying. As with BTE hearing aids, any extra visibility can be compensated for by customizing the look of CROS/BiCROS hearing aids, so that they harmonize with skin or hair tone, and ensuring an attractive cosmetic profile.
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