The name of the test is the Listening in Spatialized Noise - Sentences test, or LiSN-S. It is available in English-speaking countries from Phonak. LiSN-S is used to diagnose a specific type of CAPD known as spatial processing disorder, or SPD. This is a reduced ability to selectively attend to sounds coming from one direction and suppress noise coming from other directions. You might expect a child to have SPD if they are having difficulty understanding speech in noisy situations, such as in the classroom. The cause of SPD is so far unknown, but it is more likely to be present in children who have had prolonged or repeated middle ear infections (otitis media) during early childhood, despite full recovery of their hearing thresholds. Research at NAL with the LiSN-S has also shown that all people with a sensorineural hearing loss experience some degree of SPD. As with any form of CAPD, children with SPD can have an FM system fitted to improve the signal-to-noise ratio. NAL has also developed the LiSN & Learn auditory training software to remediate this condition in children with normal hearing thresholds. Research and clinical trials have found, for all children who completed the training, no evidence of SPD remaining by the end of the training. The LiSN & Learn is available directly from the NAL website at http://shop.nal.

You often hear the little ones on flights crying, especially on descent because of ear pain associated with an inability to equalise air pressure. Problems with regulating ear pressure is common and can be as high as 25% in children and 5% in adults. People with upper respiratory infection, allergies causing congestion or middle ear problems are more likely to have trouble equalising their ears when flying because their pressure equalisation tubes (Eustachian tubes) are typically not functioning at their optimum. Every few minutes when we swallow, talk, chew or yawn, this closed tube opens and allows air in and out of the middle ear space. In a normal functioning ear, the pressure of the air behind the ear drum is equal to atmospheric pressure. For most people these tubes do a good job of keeping the pressure in the middle ear spaces equal to the atmospheric pressure inside the plane and they have little if any discomfort or prolonged hearing issues.Chewing, yawning or performing the Valsalva manoeuvre (blocking the nose and blowing into a closed mouth) can help to equalise the pressure and often a “popping” sensation is described when the Eustachian tube opens and the pressure is equalised. For others flying can be a painful experience. Their Eustachian tubes can be blocked and when the plane takes off the atmospheric pressure becomes lower than the pressure of the air behind the eardrum causing the eardrum to bulge outwards. On landing, the eardrum bulges inwards and often the Eustachian tube is “locked” up to the extent that even the Valsalva manoeuvre is ineffective. In extreme cases this pressure build up can result in a burst eardrum. In children, the Eustachian tubes often cannot regulate themselves as well as adults resulting in ear pain.Here are some suggestions that may assist in providing ear relief for travellers:1. Where possible never fly with an upper respiratory infection.2. Perform the Valsalva manoeuvre at ground level before take-off to check if your ears “pop”.3. If you consistently have ear issues when flying, consult your GP or audiologist to check if your eardrum appears normal and that your canals are clear of wax and debris. A tympanometer is used to assess the functioning of the middle ear system including the Eustachian tube.4. Your GP may recommend or prescribe nasal sprays for use prior, during or after a flight.5. During descent when the pressure change is greatest the Modern Medicine of Australia Journal recommends:- staying awake (Eustachian tubes do not open well during sleep)- yawn or make chewing movements (with or without food)- swallow fluids or suck a lolly (menthol or eucalyptus) and allow babies to suck on a breast/bottle- do the Valsalva manoeuvre6. Use special EarPlanes* earplugs during flight.7. In severe cases of middle ear problems or pain, grommets (tympanostomy tubes inserted in the ear drum) may be required.* EarPlanes are a type of earplug developed specifically for flying by the prestigious research centre the House Ear Institute. They are available for adults and children to help slow down the rate of pressure change. 

I was pleasantly surprised how effective they are when I used them recently. Typically I need to constantly chew, swallow and perform the Valsalva manoeuvre to reduce my ear discomfort and blocked hearing on flights but with the EarPlanes I experienced little pressure change. They are inserted into the ear canals when the seat belt sign goes on at take-off and removed at maximum altitude. The Ear Planes manufacturer recommends re-inserting their plugs an hour before landing rather than waiting for the seat belt sign to turn on and they can be removed again when the seat belt sign goes off.

Assistive listening devices are a useful supplement to many wearing hearing aids and / or cochlear implants. The most well known “wireless” assistive listening device is the FM (frequency Modulated) system. An FM system consists of a microphone, a receiver and a transmitter. The microphone is used by a speaker or teacher (when an FM system is used in the classroom) and is positioned very close to the speaker’s mouth.This signal is then transmitted to the hearing impaired person via radio waves to a receiver either worn on the body or connected directly to the hearing aid/cochlear implant. This analogue wireless transmission of a signal is fairly robust and the Australian Government has put aside an FM frequency for low power assistive listening systems to minimise interference from other radio users. FM systems help a hearing impaired person overcome:1. Distance effects2. Listening to speech in the presence of background noise, and3. Listening challenges in reverberant (echoey) listening environments. Most hearing impaired people would benefit from an FM system in some specific listening situations. FM systems are used for nearly all hearing impaired children here in Australia and Australian Hearing funds these devices. FM systems are compatible with nearly all hearing aid systems and all cochlear implant systems.Blue-tooth is a digital wireless solution which allows for direct communication between hearing aids and external devices that are blue-tooth compatible ie. Phones, TV’s, MP3 players and also from one hearing aid to another. Blue-tooth allows communication between different devices without the need for cords and wires through the use of short wavelength radio signals. This communication between aids could potentially result in better hearing outcomes and allows users to change volume and programme settings simultaneously in both right and left worn hearing aids. While many hearing aid systems can give users connectivity to bluetooth enabled devices, no cochlear implant or middle ear implant system has blue-tooth compatibility.

Auditory neuropathy was once thought to be rare but it may be quite common and account for up to 10% of childhood cases of hearing loss, and can also be seen in older children and adults. It is an unusual cause of hearing loss. The understanding of how it occurs is still changing and is a source of some controversy amongst hearing specialists, as is its diagnosis and treatment. The most common progressive and severe hearing losses involve hair cell failure within the cochlea while leaving the auditory nerve intact and working well. This is why a cochlear implant usually works so well for most profound hearing losses. It stimulates a nerve which is still functioning. In Auditory Neuropathy Spectrum Disorder (ANSD) some of the hair cells (or at least the outer hair cells) may be functioning well but inner hair cells and/or the junction with the auditory nerve (the synapse) along with the auditory nerve itself seems to have failed. ANSD seems to occur in several clusters of patients. One cluster involves infants who are born preterm and spend some time in the neonatal intensive care. They may have been affected by some degree of birth trauma (hypoxia), high levels of jaundice and exposure to a variety of medications during their treatment. A second group generally develops later onset symptoms during childhood, adolescence or early adulthood. This group (the minority) often have associated neurological disorders with neuropathy affecting other parts of the body. Disorders such as Charcot- Marie-Tooth disease fit this category. Genetic defects with failure of the otoferlin gene, which is required for normal inner hair cell function, may also be underlying factors. As one can imagine, the diagnosis of such a variable and complex condition requires several sophisticated hearing test. This involves an audiogram (and speech perception test in older children or adults), otoacoustic emission studies (a test of outer hair cell function) and an auditory brain stem response test (ABR). The classical test results in ANSD are a variable degree of hearing loss on the audiogram, but poor speech discrimination, particularly in background noise; poor or absent ABR wave forms and intact otoacoustic emission. The problem with ANSD is that the outcomes of children and adults with the disorder is highly variable. The long term outcomes range from normal hearing, speech and language development, to such disordered hearing that a cochlear implant is considered. The response to hearing aids and cochlear implantation is also highly variable. At this stage of our understanding, patients with disorders limited to the cochlea (hair cell failure) may have good outcomes, while those involving poor auditory nerve function have outcomes which are more varied and difficult to predict. Much work is being done in furthering the understanding and diagnosis of ANSD as well as more strongly predicting the outcomes of treatments. 


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