Posts tagged hearing impaired
Single-sided deafness, or SSD, is a condition in which a person has good hearing in one ear, and non-functional hearing in the other ear. By ‘non-functional hearing’, it is meant that even with the help of some system of sound amplification, the bad ear cannot be made functional again. The most common reason for this is that a person with SSD has sustained damage to the inner ear, so amplification has no effect whatsoever on hearing ability in that ear.
Problems Presented by SSD
One of the most serious issues presented by single-sided deafness is the loss of spatial hearing. Spatial hearing allows a person to identify sounds both distant and nearby, in addition to all those that occur within 360° of the head area. Because our two-tiered auditory system is oriented to evaluate very specific information that can localize and pinpoint sounds, there is a big loss sustained when one ear is completely subtracted from that model.
It creates some difficulties for the brain, in terms of evaluating the information it receives and trying to assess what kind of information is missing. When the non-functional ear is in the acoustic shadow of the functional ear on the other side of the head, there can be significant difficulty with interpreting speech and other sounds, versus normal background noises.
This is especially true when speech or other distinctive sounds reach the non-functional ear first, and are not really ‘heard’ until the sound signal travels around to the other side of the head, to be received by the good ear. The net effects of this kind of sound reception are: a serious degradation in listening quality, difficulty with the interpretation of sounds and speech, and in a broader context, lowering of a person’s quality of life.
Another of the difficulties with single-sided deafness, alluded to above, is the condition known as ‘head shadow’ effect. What is meant by head shadow effect is a situation where sounds originating on the side of the head where the non-functioning ear is, are actually obstructed by the head itself in traveling to the other side of the head where the good ear is.
The main problem with this is that some kinds of sounds become very difficult to hear with the good ear. Low-frequency sounds are mostly unaffected in this scenario, because they have a long wavelength and they can move around the head more readily to the good ear. High-frequency sounds on the other hand, are characterized by much shorter wavelengths, and many of these are typically reflected by the head, and become altered before they reach the good ear.
Since consonant sounds occur largely in the high-frequency wavelengths, this can have a big impact on communication, because it is much more difficult to differentiate those sounds from background noises. Therefore, the biggest impact of this head shadow effect is on communication, and it causes a person with SSD to miss a great deal of what may have been said by someone, even if they’re standing close by.
Causes of SSD
One of the more common causes of single-sided deafness occurs is when surgery is necessary to remove a tumor growing in the ear. This kind of surgical removal sometimes causes such damage to the auditory nerve that a patient loses most or all hearing in that ear. If such tumors are not removed, they will continue to grow slowly, and will eventually cause damage to the ear anyway, including possible loss of hearing. However, surgical treatment can end up being just as harmful, if the auditory nerve becomes damaged.
A secondary cause of SSD is known as sudden idiopathic hearing loss, which is generally attributable to some kind of viral infection. In this scenario, a virus infects the cochlea, which eventually leads to swelling and permanent damage to the delicate structure of the cochlea. It happens fairly frequently that the ear cannot recover from this kind of damage, and the person is left with no hearing in that ear.
A third cause for SSD stems from some kind of blunt trauma to the head. In such cases, there can be a transverse fracture of the critical temporal bone, which has the effect of rendering the cochlea non-functional from that point forward. It is also possible for people to be born with hearing loss in one ear, while having perfectly good hearing in the other ear.
Solutions for SSD
One of the most effective solutions for SSD is known as a Contralateral Routing of Signal (CROS) configuration, in which a microphone is placed in the non-functioning ear, and transmits received sound signals over to a receptor in the good ear. The first of these configurations relied on a tiny wiring system for the transmission of sound between ears, but this has now been improved and refined with a wireless system that makes the whole arrangement less bulky and more effective.
There are now also two additional high-tech solutions which build upon the idea that sound received on the non-functioning side is somehow transported to the good side so that relatively normal hearing is possible. These two processes are known as bone conduction solutions and bone anchored solutions.
In the first, sound is actually transmitted through the bone of the skull to the other side of the head, and in the second, sound is transmitted by a subcutaneous implant which transmits sound through the skin to the good ear. As you might expect, these solutions can be relatively costly, but they can also be a very effective means of restoring normal hearing to someone who has completely lost hearing in one ear.
Imagine hearing a buzzing, clicking, or ringing sound that isn’t actually there. This nonexistent sound comes and goes as it pleases. This is tinnitus, a condition where a sound is only perceived by the affected individual. For millions of Americans, tinnitus is a pressing issue and an irritation. Tinnitus symptoms can be hard to live with and now it seems that the serotonin in a common antidepressant medication is making it worse.
How Tinnitus Symptoms Occurs
There are actually two different types of tinnitus – subjective and objective. If a person is hearing sounds that nobody else can, that is classified as subjective tinnitus. This is both an auditory and neurological issue caused by hearing loss and it accounts for 99 percent of all reported tinnitus cases.
Objective tinnitus is a bit different and much rarer than subjective tinnitus. This form of the condition is when a patient hears sound generated by the body’s internal structures and circulatory system. This type of sound can be heard by another who is close enough to the affected individual.
How Serotonin Affects Tinnitus
The constant irritation caused by tinnitus can take its toll. In fact, the hearing condition has a close association to psychiatric disorders. Scientists have found that depression and anxiety are connected to the severity of tinnitus. With this link being so apparent, researchers at the Oregon Health and Science University decided to see how a common anti-depressant affect the condition.
The anti-depressant is called selective serotonin reuptake inhibitors. It is used to treat depression, anxiety, and social phobia. This drug prevents a neurotransmitter called serotonin from breaking down in the body. Serotonin is a known to boost mood and happiness.
Through the examination of brain tissue in mice, the researchers were able to find out that high serotonin levels make tinnitus worse. The dorsal cochlear nucleus (the part of the brain that the scientist examined) is responsible for sensory integration. It is also the area of the brain where tinnitus develops. As serotonin levels increased, the brain’s neurons become hyperactive and hypersensitive.
What Researchers Had to Say About the Study
“We saw that the activity of those neurons went through the roof,” said senior author Laurence Trussell, Ph.D., a professor of otolaryngology at the OHSU School of Medicine and scientist at the OHSU Vollum Institute.
While tinnitus may be the cause of depression, the medication for the mental disorder only seems to make it worse. This can lead to the mental illness becoming even more of a recurring condition.
“If you’re a physician treating a patient for depression who also has hearing loss or tinnitus, you may want to be careful about prescribing a drug that compounds their feelings of anxiety,” said Trussell. “The SSRI may be enhancing the thing you’re trying to fix.”
Unfortunately, there is no cure for tinnitus symptoms. New technologies are being developed every day and researchers are looking into other options. Dr. Trussell’s team hopes to find a way to develop an antidepressant that does not affect the severity of the condition.
Tinnitus stems from hearing loss, obstructions in the middle ear, head and neck trauma, and other conditions. If you want to prevent tinnitus, the simplest way is to avoid situations that may harm your hearing. Loud noises can cause severe trauma that leads to hearing loss. You’ll also want to keep your ears clean and clear of foreign objects. See a qualified otolaryngologist if you want to evaluate your hearing.
Cognitive issues usually accompany hearing loss. That’s because hearing impairment makes it difficult for some to understand what others are saying. As you can imagine, this makes it hard to hold a conversation. During moments where a person with hearing loss is in a crowded or noisy place, understanding speech becomes an increasingly taxing. In order to solve this issue, scientists are developing cognitive hearing aids. The hope is that these devices can filter background noise and enhance voice recognition to make it easier for people to understand speech.
How Hearing Aids Work
Hearing aids are the primary medical devices used to improve hearing. They are used by people who have hearing damage or have developed hearing loss at some point in their lives. Around 48 million Americans report having hearing loss. Unfortunately, only 20 percent of these people actually use hearing aids.
While these devices cannot fully correct hearing loss, they make is easier to understand and process sound. Some hearing aids can cancel noise and the wind, enhance your spatial region, and highlight voice. These devices still have a long way to go. While some hearing aids are capable of suppressing background noise, they have trouble focusing on the speech of a specific person.
Working on Cognitive Hearing Aids
The goal of creating cognitive hearing aids is to focus on hearing one speaker over voices of many others. Hearing aids that can focus on a singular person can make it easier to understand someone in a crowded place. The cognitive hearing aids would have to connect to the brain to understand where to focus. They would also be quite the achievement.
At the Columbia University School of Engineering and Applied Science, researchers came together to determine how they can achieve this kind of auditory focus with hearing aids. The scientists looked at deep neural network models, which helped them separate multiple voices and determine which one the brain is focusing on. The speaker is then amplified so the user can hear them better. Ultimately, this improves auditory attention decoding (AAD).
“This work combines the state-of-the-art from two disciplines: speech engineering and auditory attention decoding,” says Nima Mesgarani, associate professor of electrical engineering and lead of the study. “We were able to develop this system once we made the breakthrough in using deep neural network models to separate speech.”
Previous studies helped the research team develop this new method. “Translating these findings to real-world applications poses many challenges,” notes James O’Sullivan, a postdoctoral research scientist working with Mesgarani and lead author of the study.
“Our study takes a significant step towards automatically separating an attended speaker from the mixture,” O’Sullivan continues. “To do so, we built deep neural network models that can automatically separate specific speakers from a mixture. We then compare each of these separated speakers with the neural signals to determine which voice the subject is listening to, and then amplify that specific voice for the listener.”
Final Thoughts on the Study
“Our system demonstrates a significant improvement in both subjective and objective speech quality measures — almost all of our subjects said they wanted to continue to use it,” Mesgarani says. “Our novel framework for AAD bridges the gap between the most recent advancements in speech processing technologies and speech prosthesis research and moves us closer to the development of realistic hearing aid devices that can automatically and dynamically track a user’s direction of attention and amplify an attended speaker.”
Hopefully, the cognitive hearing aids will convince those with hearing loss to use these devices. Hearing impairment can occur around the age of 65 years old. Using these devices can significantly improve their quality of life.
Unfortunately, there are many cases of infants with significant hearing loss. This loss of sound can occur at birth. Other times, hearing loss in infants develop slowly, becoming worse over time. It can be hard to pinpoint the cause of damage to the middle and outer ear. A loss of sound may occur due to birth defects, a buildup of fluid and ear wax, or because of a rupture to the eardrum. Researchers at the University of Colorado made a recent discovery, showing that early intervention of hearing loss can help your child later in life.
Early Intervention for Hearing Loss
Lead author Christine Yoshinaga-Itano is an audiologist and research professor in the Institute of Cognitive Science. With funding from the Centers for Disease Control (CDC), Yoshinaga-Itano’s team worked to assess the impact of Early Hearing Detection Intervention (EHDI) 1-3-6 guidelines. The Joint Committee on Infant Hearing developed these guidelines 17 years ago. These guidelines suggest that the following steps should be taken:
- All newborns should be screened for hearing loss within the first month.
- If the test is positive for hearing loss, parents should see a specialist within three months for an evaluated.
- Within six months, parents should start early interventions based on their child’s diagnosis.
About 96% of U.S. infants undergo the screening process. For one reason or another, some parents only go through with the first step. Several difficulties prevent parents from affording or meeting the requirements to improve their child’s hearing.
In a previous study, Yoshinaga-Itano looked at children with hearing loss in Colorado. The state has done well to promote early intervention for hearing loss.
Yoshinaga-Itano notes that “We showed that failure to diagnose hearing loss early can create an environmentally induced and preventable secondary disability, making children function much like children with cognitive delay.”
How Intervention Affects Speech
The research team at the University of Colorado at Boulder looked at 448 infants with hearing loss in both ears. The age of these children ranged from 8 to 39 months. Almost 58 percent of the kids have met the EDHI 1-3-6 guidelines.
To measure the impact of meeting these guidelines, the researchers how well these children learn vocabulary and language. The team measured the number of words the kids used when either speaking or using sign language via the Vocabulary Quotient (VQ) score. The difference was startling. Children who met the guidelines score significantly better than those who didn’t.
“We can’t change how much hearing a child has at birth or the educational background of a parent, but we can develop better systems,” says Yoshinaga-Itano. “Policymakers need to do whatever they can to make transitions from one step to another as seamless as possible so parents can meet the 1,3,6. And parents should know that there is an urgency to assuring that children who are deaf or hard of hearing have access to language as quickly as possible.”
Hopefully, the new study can show the need for parents to seek early intervention for their child. Like most diseases, the earlier you catch it, the easier it is to treat.
As we grow older the risk of developing debilitating conditions increases. As a result, staying healthy becomes more and more of a pressing concern for older adults. The truth is that the body doesn’t work as well as it used to and some of our functions may potentially fail as we age. Thankfully, scientists and researchers are always looking into how to treat and detect these situations before they arise.
Take dementia for instance. There are several causes of this degenerative disorder, including neurological diseases, vascular disorders, brain injuries, and more. However, there is one commonality that patients with these diseases share – their age. Approximately 5 percent to 8 percent of adults over 65 have some form of dementia. Even worse, that risk doubles every five years after people reach the age of 65.
One important aspect of treating this disease is detecting it early. Researchers have found a new way to determine if patients are affected by the disease.
Symptoms of Dementia
Dementia comes in two different forms. The first is cortical dementias, which usually shows up in the form of Alzheimer’s or Creutzfeldt-Jakob disease. This form of dementia can cause server memory loss, cognitive issues and may impair your ability to remember words.
The second form of dementia is subcortical. The diseases that are most commonly associated with this are Parkinson’s disease, Huntington’s disease, and HIV. Patients with these diseases are very likely to difficulty thinking quickly or starting a task.
Detecting the Disorder
The hard part about detecting dementia is that these changes may not appear at first or can develop slowly over time. This can lead to some people not detecting signs of the disorder until it is too late. The biggest indicator of the condition in its early stages is memory and thinking problems. Now, scientists at the Baycrest-University of Memphis are saying that hearing and communication issues are a sign as well.
The brainstem and the auditory cortex are the regions of the brain known to process speech. Once thought to resistant to dementia’s effects, the region has shown trouble processing speech from sound to words. In order to look more into this change, researchers used an electroencephalogram (EEG) to measure the brain’s electrical activity in the brainstem and auditory cortex. With 80 percent accuracy, they were able to predict mild cognitive impairment (MCI), a condition that can develop into Alzheimer’s.
“This opens a new door in identifying biological markers for dementia since we might consider using the brain’s processing of speech sounds as a new way to detect the disease earlier,” says Dr. Claude Alain, the study’s senior author and senior scientist at Baycrest’s Rotman Research Institute (RRI) and professor at the University of Toronto’s psychology department.
Dr. Alain continues, stating that “Losing the ability to communicate is devastating and this finding could lead to the development of targeted treatments or interventions to maintain this capability and slow progression of the disease.”
There is no cure for dementia but with continued study, scientists can find new and innovative ways to help people with the disease live normally.
Sometimes, hearing loss occurs because of damage to the tiny hair cells within the inner ear. Using a cochlear implant device allows deaf patients to bypass the effects of inner ear damage, giving them the ability to hear some form of sound. A cochlear implantation requires drilling a hole behind the ear, through the skull bone, and to the inner ear. Researchers may have found another way to perform this procedure.
Using Robotics for Cochlear Implantation
During a cochlear implantation, the hole is drilled to allow the device access to the inner ear. To improve the drilling procedure, scientists at the University of Bern turned to robotics. They developed a high-precision surgical robot to create the entryway for the cochlear device. Their hope is that it provides better hearing outcomes.
The surgical robot would make the hole about 2.5mm in diameter. In order to perform a task of such magnitude, the robot has the do the surgery by itself and without any hands-on interaction or visual from a surgeon. This obviously presents concerns. Surgeons need to be able to track the drill’s progress to make sure in is on track and just in case there is an error.
The researchers built the robot with interlocking safety components. This allows the drill to avoid damaging key areas like the nerves and inner ears.
Prof Weber of the University of Bern, explains: “The robot relies on a number of sensors which are a high-accuracy, optical tracking system, a sensor for resistance that can “feel” the texture of the bone while drilling, and a radar-like nerve stimulation probe that sends small electric pulses into the bone from which the robot can compute whether or not it is on the preplanned track.”
This may be the next major development in cochlear implantation. It has proven effective for one patient and hopefully, it will prove helpful for future patients.
If you often hear a sound that isn’t there, then you may have tinnitus. This condition affects millions of Americans. In fact, the CDC estimates over 50 million Americans are dealing with this troubling health condition. Of those 50 million, 2 million suffer from severe tinnitus. There is no cure, but new technology seems to be helping patients.
The Brain Fitness Program – Tinnitus (BRP-T)
Unfortunately, tinnitus comes with cognitive issues. This causes a decline in reaction times and the ability to pay attention. It can even interfere with a patient’s ability to process and remember certain situations. Researchers believe that the answer to this problem is to strengthen the brain. Through neuroplasticity, they hope to heal the mind by forming new neural connections.
One attempt at “working out” the brain is a training program called the Brain Fitness Program – Tinnitus (BRP-T). Through an online interface, the program uses 11 interactive exercises. It seeks to improve simple acoustic stimuli, continuous speech, and visual stimuli.
Fixing Severe Tinnitus
Through testing a group with severe tinnitus and a control group, researchers at the Washington University School of Medicine in St. Louis were able to find out if the BRP-T actually worked. Randomly selected individuals from both groups used the program an hour every day, five days a week for two months.
As predicted, the tinnitus patients showed improvements. After thorough testing, their perception, memory, attention, and concentration showed better results than those who did not undergo the training.
Researchers say this about the results: “We believe that continued research into the role of cognitive training rehabilitation programs is supported by the findings of this study, and the role of neuroplasticity seems to hold a prominent place in the future treatments for tinnitus,” the researchers write. “On the basis of our broad recruitment and enrollment strategies, we believe the results of this study are applicable to most patients with tinnitus who seek medical attention.”
As we get older, we begin to worry more and more about our bodies. What is ailing us and what will fail next? These are the questions that many of us have. For that very reason, scientists look into how our bodies operate to get not only a better understand but to fix our illnesses. The American Physiological Society performed a recent study examining the causes of age-related hearing loss and difficulties processing speech. Here is what they found.
Processing Speech Deteriorates
Processing speech is important. It helps us communicate effectively with others, especially when the volume changes in an area. Your hearing adapts to understand what someone is saying in noisy or quiet areas. A lot of what controls your hearing has to do with the brain. And when the brain malfunctions, your senses go as well.
The scientists at the American Physiological Society suspected that a decline in midbrain and cortical activity are responsible for hearing loss. So, they tested two groups using an electroencephalogram to measure mid-brain activity, and a magnetoencephalogram to measure the cortical activity. A group of younger adults around the age of 22 and another group of older individuals around the age of 65.
As expected, the older groups experienced difficulties processing speech. The environments noise level did not matter. Whether it was loud or quiet, the older group had trouble while the younger group took less time processing cues and speech. And these results show in the same in their brains.
The activity in the midbrain and cortex was low, showing that the health of these key areas is necessary to function. They help us process speech and understand others effectively. Hopefully, further research can tell us more. Aging can be difficult but it doesn’t have to stop us from living life. Maybe, it will be a sign to older adults to seek alternate options to hear from their physician.
Our senses are crucial aspects of our body, with each serving a specific purpose. However, it turns our senses do not work alone. In a coordinated effort, they work together to function properly. According to a recent study by NYU Langone Medical Center, our sense of hearing collaborates with some of our other senses to better interpret sound.
“What the brain ‘hears’ depends on what is ‘seen’ in addition to specific sounds, as the brain calculates how to respond,” says study senior investigator and neuroscientist Robert Froemke, Ph.D., an assistant professor at NYU Langone and its Skirball Institute of Biomolecular Medicine.
The nerve cells that are responsible for hearing also use the other senses. As Dr. Froemke stated, sight plays a big role in providing context. When you can see your surroundings, your brain knows how to properly react to certain sounds. Think of sights relationship to hearing as a form of confirmation, helping the brain determine what the origin of a certain sound is.
“Our study shows how the same sound can mean different things inside the brain depending on the situation,” says Froemke. “We know, for instance, that people learn to respond without alarm to the honk of a car horn if heard from the safety of their homes, but are startled to hear the same honk while crossing a busy street.”
NYU Langone’s team used mice and treats to look into how the nerve cells work. What they found is that depending on the context, the brain will adjust hearing accordingly. Surprisingly, when the mice expected a treat, these nerve cells weren’t as active. However, when they expected a reward based on a sound, some of these nerves were highly active.
Further research needs to be done. What scientists should look into is how these nerves react in a person without sight or poor sight. Hopefully, it can help them understand cognitive issues.
Those who deal with hearing damage suffer from a series of issues. These issues include hearing loss, difficulties understanding others, poor speech, and other communication problems. A cochlear implant is a tools used to combat this type of hearing loss. Every year, scientists research the effectiveness of this surgical implant.
Their research helps them discover new ways to make the device work better. One study found that the level of hearing damage a person has suffered does not determine how well a cochlear implant works. Another study discovered that the benefits were significant.
Why Is the Cochlear Implant Effective?
A cochlear implant is a small electronic device that is surgically inserted into person’s ear. Using a microphone, the device converts external noise to digital signals. These signals are sent to the auditory nerve and processed by the brain as sound.
The cochlear implant is very different from a hearing aid. The aid amplifies sound for damaged ears, while the implant works around the damage and directly stimulates the auditory nerve.
Researchers at the Johns Hopkins Medical Institute tested individuals with significant, little, and no residual hearing prior to their cochlear implant surgery. What they found is that those who had the worse hearing damage experienced substantial improvements in hearing. They were able to interpret speech in loud spaces and speech patterns better.
Another study discovered that adults over the age of 65, with profound hearing loss, greatly benefited from cochlear implants. After surgery, their speech perception and cognitive function improved drastically. The brain’s cognitive function is its ability to reason, recall, pay attention, and understand language. The better you can hear, the more this function works.
Scientists believe that cochlear implants work well. Both its ability to send electrical signal directly to the auditory nerve, and the brain’s ability to properly interpret these signals improves hearing. This spells good news for those with significant hearing loss. It helps them to communicate better others around them.