Posts tagged hearing loss
Acoustic neuromas are benign tumors that develop very slowly, on the eighth cranial nerve inside the ear, and they can have a major impact on a person. It is known that only about five individuals out of 100,000 actually have acoustic neuromas, but those who do have them may experience symptoms such as facial numbness, vertigo, a slow diminution of hearing in one or the other ear, problems with balance, and possibly tinnitus.
In extreme cases, the tumor itself can grow to a size where it actually becomes life-threatening, so its early detection is very important. The issue with early detection is that, as mentioned, the development of such a tumor is generally slow, which makes the symptoms experienced very gradual in nature.
In many cases, these symptoms are actually just attributed to normal aging and don’t attract any real attention because they’re thought to be a consequence of diminishing capability. Individuals who experience any of the symptoms referenced above should seek medical attention at the earliest opportunity. This is so that if there is an acoustic neuroma in progress, steps can be taken to have it treated before it gets critical.
How Acoustic Neuromas Develop
The cranial nerve where a neuroma begins to develop is the nerve which joins the inner ear and the brain, and it has a profound impact on both hearing and balance. This is why the symptoms of an acoustic neuroma include side effects that are both hearing-related and balance-related. It’s common for people with an acoustic neuroma to have problems with steadiness in their daily routine, even walking around the household.
Hearing can be impacted by the development of tinnitus, and possibly also a direct loss of hearing. As an acoustic neuroma grows larger and larger, it will begin to crowd the brain itself, as well as those nerves which manage facial expression and facial sensitivity. If an acoustic neuroma goes completely undetected and is allowed to continue growing, it can eventually put so much pressure on the cerebellum or brainstem, that a life-threatening situation can occur.
Causes of Acoustic Neuromas
There are two main causes of acoustic neuromas, the first of which is a sporadic form, and the second being related to a syndrome known as neurofibromatosis type II or NF2. Neurofibromatosis II is an inherited condition in which noncancerous tumors grow in the nervous system, and most of the time these noncancerous tumors are acoustic neuromas. For this inherited type of acoustic neuroma, it is fairly common for them to begin development in both of the patient’s ears, before the age of 30. This is a rare disorder that only makes up about 5% of all acoustic neuromas, meaning that the overwhelming majority of acoustic neuromas are of the sporadic form. Unfortunately, doctors and scientists do not yet understand what causes the sporadic form, although at least one risk factor has been identified as exposure to unusually high levels of radiation, primarily in the area of the neck and head.
Treatment for Acoustic Neuromas
There are three primary approaches to treatment of acoustic neuromas: radiation therapy, surgery, and observation. You can think of observation as ongoing monitoring or watchful waiting. Since acoustic neuromas are not cancerous and grow only slowly, there is usually not an immediate or urgent need for any more drastic form of treatment. What happens after the observation period will depend on how rapidly the acoustic neuroma grows, and what kind of impact it’s having on an individual.
Surgical procedures will take one of three tracks. Translabyrinthine surgery calls for an incision to be made behind the ear, so that a portion of the middle ear as well as the bone behind the ear can be removed, and this approach is generally used on tumors bigger than 3 cm. Sub-occipital surgery operates on the back of the head, and can be used for any sized tumors, and unlike translabyrinthine surgery which causes total hearing loss, sub-occipital surgery holds at least the potential for preserving your hearing. Middle fossa surgery also holds out hope for preserving a patient’s hearing, as it removes a small bone piece over the ear canal, so that tumors of a smaller size can be removed.
Radiation therapy is recognized as state-of-the-art treatment for acoustic neuromas, as it sends high radiation dosages directly at the tumor, while also limiting damage or exposure to all surrounding tissue. There are two types of radiation therapy which are generally used in the treatment of acoustic neuromas. The first of these is multi-session fractionated stereotactic radiotherapy (FRS). This delivers small doses of daily radiation over a period lasting several weeks, and is generally the more successful of the two radiation approaches. The second method for radiation therapy is known as single fraction stereotactic radiosurgery (SRS). In this approach, hundreds of small radiation beams are directed at the tumor in one comprehensive session. While this has the advantage of requiring only a single treatment session, it has historically been somewhat less effective than the FRS radiation therapy approach.
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.
Noise-induced hearing loss is a condition which currently affects about 10 million Americans. It is the most common preventable cause of hearing loss which is due to damage of the ear’s sensory nerve. The prevalence of noise-induced hearing loss and the number of people affected have steadily grown right along with the development of society—as more and more of man’s creations create noise pollution which damage a person’s hearing.
Probably most people understand the damage that can result from being close to a gunshot, but far fewer people are aware of potential damage from more mundane causes like leaf blowers, lawnmowers, traffic sounds, car alarms, music concerts, and even the stadium noise at a sporting event.
The truth is, any loud noises which are received by the ears over an extended period of time, no matter where they came from, can cause significant damage to the inner ear. Eventually this can lead to dizziness, ringing in the ears, some degree of hearing loss, and even issues unrelated to hearing, such as high blood pressure and an irregular heartbeat.
What is Noise-Induced Hearing Loss?
Noise-induced hearing loss is the condition which results from having an excess of sound energy reaching the inner ear. When the excess sound energy is temporary, any hearing loss is also likely to be temporary and reversible. A good example of this would be attending a loud rock concert where sound undergoes a great deal of amplification, and excess sound energy reaches every person in attendance, regardless of where they’re sitting.
It is fairly typical for someone attending a concert like this to completely recover within the next day or two, because the excess sound energy has dissipated. If that noise were to persist over a longer period of time, however, it is quite likely that the damage to the inner ear would be irreversible, and the listener would be subjected to a permanent loss of hearing.
It is also possible for excess sound energy to be so profound as to rupture a person’s eardrums, rendering them more or less deaf. Still more problems can be created if a person’s eardrums are shattered and he or she also develops severe dizziness, which is usually an sign that there is a perilymphatic fistula, i.e. an inner ear hole, created between the middle ear space and the inner ear fluid. Surgery in such cases may eliminate the dizziness, but the hearing loss is likely to remain permanent.
Prevention of Noise-Induced Hearing Loss
Two of the best kinds of protection for the inner ear are the simple devices we know as earplugs and earmuffs. Earplugs are small-sized devices made of various materials, which can easily fit into the outer ear canal to block sound reception. Since they come in many different shapes and sizes, earplugs can be fitted to virtually anyone’s ears, and the fit is very important because there must be an airtight seal in the ear canal to block excess sound energy from reaching the inner ear.
Earmuffs on the other hand, are devices fitted to the head, and they cover the entire outer ear to prevent sound energy from reaching the ear canal. These devices usually have an adjustable band which allows for a tight fit, and as in the case of earplugs, a tight fit is very important so as to make a good seal against excess sound energy.
The choice of which of these devices to use for any given situation is contingent upon which kinds of sounds need to be blocked. Earplugs are much more effective in providing protection from noises in the low frequency spectrum, whereas earmuffs offer better protection against noises on the high end of the spectrum. Either one will reduce the sound energy that reaches the inner ear by between 15 and 30 dB of sound, and when the two devices are used in tandem, a person wearing them can expect to have twice as much protection than by using either one alone.
Treatment for Noise-Induced Hearing Loss
Anyone who suspects that they may have sustained noise-induced hearing loss should seek professional advice from a doctor who has been trained in ear and hearing disorders. This kind of doctor will be able to diagnose the specific condition affecting a person’s hearing, and can recommend the most effective kind of treatment program.
Unfortunately, there is no real cure for noise-induced hearing loss, because damage to the inner ear is irreversible. There are various devices available which can help restore hearing if only one ear has been affected, and there are also amplification systems such as hearing aids, which can be used in certain situations.
There’s also a great deal of very promising research being conducted by such organizations as the National Institute on Deafness and Other Communication Disorders. One of the specific areas being researched now is how using antioxidants may be able to prevent hearing loss due to noise-induced causes, and may actually be able to restore relatively normal hearing.
Early results have already demonstrated that vitamin D and aspirin can reduce the effects of hearing loss when they are used prior to the event which produces excess sound energy. Other research conducted on laboratory animals has shown that exposure to loud noises does not result in hearing loss when the animals are provided with vitamins A, C, and E before being exposed to a loud noise.
With a name that confuses many, cholesteatoma is a delicate and troublesome problem within the ear. Describing an abnormal skin growth behind the eardrum, the middle ear, cholesteatoma is normally caused by multiple infections. However, there are other causes to note including a dysfunction in the eustachian tube.
What is the Eustachian Tube?
Running to the middle of the ear from the back of the nose, this tube is essential for our hearing. Since it allows air to reach the ear, ear pressure is equalized efficiently and our hearing works as expected. Sadly, an issue can occur with a simple cold along with allergies, sinus infections, and chronic ear infections.
With a failure in the eustachian tube, the middle ear can experience a partial vacuum and, in turn, the eardrum, or certain sections of the eardrum, is pulled out of position. As you can see, each step of the process causes another problem and it ends with a growth or cyst in the middle ear.
When left untreated, willingly or unknowingly, the size of the cholesteatoma can change while causing severe damage to the delicate bones located in the middle ear. If left for too long, hearing loss is experienced and surgery becomes one of just a few select options. Fortunately, there aren’t any serious side effects when the issue is treated which means that permanent hearing loss and muscle paralysis in the face are both unlikely. This being said, there has been cases of all three when the cholesteatoma is allowed to keep growing.
Causes of Cholesteatoma
As we’ve seen, the main causes are problems with the eustachian tube and chronic infections but there are also small numbers of people who are born with a cholesteatoma. Ultimately, this is seen as a birth defect and should be picked up on soon after birth. If children experience numerous ear infections, cholesteatoma can also become a problem at a young age.
Symptoms of Cholesteatoma
With any health issue such as this, the key information comes in knowing the symptoms so it can be recognized early. With cholesteatoma, many are actually drawn to a foul odor before anything else and this is where the ear drains fluids. After this, you might feel building pressure or a sense of fullness in the ear where the sac enlarges over time.
As with ear infections themselves, cholesteatoma will cause discomfort whether it comes through an ache in the ear, a difficulty to fall asleep at night, or a slight loss of hearing. Finally, there may be muscle weakness on the side of the cyst in addition to dizziness. If you experience any of these symptoms, we advise you to visit your doctor as soon as possible. Even if it turns out to be a simple ear infection, this will still need treatment.
As you visit your doctor, they’ll examine the inside of the ear because the signs of a cyst can often be seen early whether it’s a congregation of blood vessels or excess skin cells. If they don’t find anything but are still a little worried, they may ask for you to attend a CT scan which will show the cyst or whatever it may be causing your discomfort.
As with any other cyst, a cholesteatoma is something that needs surgery for removal. Unfortunately, cysts don’t just go away on their own; in fact, they do the opposite and grow. While you’re waiting for surgery, your doctor might suggest ear drops, antibiotics, careful cleaning, and other forms of light therapy.
During surgery, most cases are completed under a general anesthesia with the main aim of removing the cyst. If the cyst is removed, this is great news but it might not be the end of the problem depending on how serious the issue was and the state of your ear now. Typically, a second surgery will be planned at the very least to check the cyst has gone. However, you may also require a reconstruction of the damaged bones in the middle ear; this will improve your hearing and reverse other symptoms experienced. Of course, this will be judged on a case-by-case basis as not all patients would benefit from reconstruction if the damage is too severe.
In terms of the logistics, you’ll be an outpatient and a certain percentage will stay in the facility overnight as a precaution. If the cholesteatoma was extremely damaging, you might be required to stay in hospital for a few days with a course of antibiotics. On the whole, you can expect to need one or two weeks away from work. In the months ahead, check-ups and evaluations will ensure the problem has gone for good.
Although we can’t provide any prevention tips for congenital cholesteatomas, we do advise visiting the doctor as soon as you notice any of the symptoms we’ve listed. Whether it’s yourself or your child, quick action is the best way to remove the problem and ensure the middle ear bones aren’t damaged. Despite cholesteatoma being a serious ear condition, it is treatable with the right steps.
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.
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.
Hearing aids are enough to combat mild-to-moderate damage. While this option works for a majority of people with hearing loss, it simply isn’t enough for those who have suffered trauma to their hearing nerve. In the case of nerve deafness, a cochlear implant is necessary for hearing preservation.
People with this severe degree of deafness need as much help as they can get. That’s why scientists strive to improve the technology that returns hearing to normal. Let’s look at the latest study from the Mount Sinai Hospital, which narrows down the best practice for cochlear implants.
Hearing Preservation: Finding the Better Option
Cochlear implants are medical devices that connect directly to the auditory ear. By bypassing the damaged structures of the inner ear, the implant can improve the hearing of people with severe hearing loss. They help more than 188,000 people worldwide.
Lead investigator and researcher at Mount Sinai, George Wanna, MD, Site Chair, Department of Otolaryngology-Head and Neck Surgery at New York Eye and Ear Infirmary of Mount Sinai (NYEE) and Mount Sinai Beth Israel, found that a certain design of cochlear implants worked better than others. After examining 230 patients with every type of cochlear implant, Dr. Wanna’s team of researchers discovered that implants without wires in the electrode worked best.
These implants are called lateral wall electrodes. Not only do they provide better hearing for those wearing them but they do less damage to the ear. The device is less likely to cause internal fractures to the inner ear, making it less traumatic. In order to prove this point even further, the team tested several different brands of the same cochlear implant, finding the same results.
Dr. Wanna had this to say about the study, “”This is the largest clinical study done in the world on conventional electrodes and will have major implications for doctors and their patients who need their long-term hearing restored. This study is a breakthrough for patients with hearing loss, and improvements in practice and techniques will allow them to enjoy many hearing benefits such as music enjoyment, listening in complex environments, and sound localization.”
The research team at Mount Sinai also made another important discovery – the best surgical approach to inserting the cochlear implant. Most implants are surgically inserted under the skin and behind the ear by drilling through the bone. What the research team found was that other options, without drilling through the bone were better.
The two surgical approaches the team examined are called the “round window” and “cochleostomy.” The round window approach involves surgeons opening the membrane without removing the bone or drilling into the inner ear. On the other hand, the cochleostomy approach does drill into the bone.
“The cochleostomy approach causes fibrosis and scarring, leading to hearing loss over time,” said Dr. Wanna. “Our results also revealed that using oral steroids also helped in the long term to preserve hearing by preventing inflammation.”
Dr. Wanna and his team hope surgeons will put this information to good. This research can help by giving patients the best implants available for hearing preservation. “This is an exciting time in this field, and the advancement in hearing technology and continued improvements in techniques and outcomes will benefit patients and their families,” said Dr. Wanna.
As adults grow older, they become more likely to develop hearing and balance disorders. Hearing loss can result from a multitude of factors, including bacterial and viral infections, environmental and work-related noise exposure, genetics, medication toxicity and trauma.
Some of these conditions affect the cochlea, which is the inner ear. As the innermost part of the vertebrate ear, this section of the body is responsible for sound detection and balance. If this part of the body is damaged, your ability to hear suffers greatly.
New research at the Indiana University School of Medicine has developed a way to grow inner ear tissue from human stem cells. The researchers’ findings may lead to better methods of treating hearing loss. Find out how they were able to achieve this success and what it means for the those with hearing impairments.
Research Into the Inner Ear
“The inner ear is only one of few organs with which biopsy is not performed and because of this, human inner ear tissues are scarce for research purposes,” said Eri Hashino, Ph.D., Ruth C. Holton Professor of Otolaryngology at IU School of Medicine. “Dish-grown human inner ear tissues offer unprecedented opportunities to develop and test new therapies for various inner ear disorders.”
In the past, researchers have had difficulties growing inner ear tissue. Traditionally, scientists cultivate human stem cells in a flat layer on a culture dish. However, this method proved unsuccessful in producing viable tissue. Research leads, Karl R. Koehler and Dr. Hashino, instead tested a different culturing technique called three-dimensional culture.
The three-dimensional culture is a technique that grows stem cells in a floating ball-shaped aggregate. This method allows the cells to grow more naturally. They incubate in an environment similar to the body. Through expert guidance, the scientists were able to create structures called “organoids.” These structures contain sensory and supporting cells akin to the ones in the inner ear.
What Does This Research Mean for the Future?
“This is essentially a recipe for how to make human inner ears from stem cells,” said Dr. Koehler, lead author of the study and whose research lab works on modeling human development. “After tweaking our recipe for about a year, we were shocked to discover that we could make multiple inner ear organoids in each pea-sized cell aggregate.”
“We also found neurons, like those that transmit signals from the ear to the brain, forming connections with sensory cells,” Dr. Koehler said. “This is an exciting feature of these organoids because both cell types are critical for proper hearing and balance.”
Dr. Hashino and his colleagues hope to use this new knowledge to study diseases and disorders that affect hearing. In addition to learning more about the ear, the scientists hope to develop new therapies and drugs.
“We hope to discover new drugs capable of helping regenerate the sound – sending hair cells in the inner ear of those who have severe hearing problems,” Dr. Hashino said. If successful, then this is another step towards healing people with hearing impairments.
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.