All Ears: Part II

All ears! Part II: The how and the why of hearing evaluation

In the first part of this article, we saw how complex and multi layered the process of hearing is. Owing to these multiple stages and levels, it is essential for hearing tests to rule out problems at all of these levels. In an adult, one can often reduce the number of tests to one or two because the adult can verbally describe symptoms in detail, which helps the clinician narrow down to the diagnostic tests required. In a baby, however, this cannot be done. Hearing evaluation for babies would therefore, consist of a battery of tests. Those used most often are listed below.

Hearing evaluation

Behavioral testing /audiometry

The child sits in a sound treated room, and sounds of different frequencies and loudness levels are presented through speakers or headphones. Responses to these are observed and noted.

Very young babies are observed during light sleep or while feeding.

Immitance / impedance testing

This is done to rule out any problems in the middle ear. This test requires the child to sit still, and takes no more than 5-10 minutes.

BERA testing (brainstem Evoked Response Audiometry)

This requires the child to sleep for about an hour. Electrodes are placed on the child’s head at various spots, and sounds are delivered through earphones. The electrodes pick up responses at the level of the brainstem. This test is usually done to confirm or add to behavioural observation findings, and arrive at a diagnosis as to the type of hearing loss (if present).

OAE testing (Oto Acoustic Emissions)

This test is used to detect the presence and function of the outer hair cells in the cochlea. It requires the child to be asleep and takes about 10 minutes. By itself, the test gives very little information, and should be combined with findings of other tests (at least BERA and/or audiometry).

Ideally, hearing should be screened (BERA, OAE) as soon as the baby is born. Based on this performance and other history (e.g. preterm, any complications during pregnancy, syndromes, etc.), the audiologist might call the baby for a re screening every 3-6 months. This is because some hearing losses might surface later, or are progressive. If a child does not pass screening, then the battery of diagnostic tests is done to determine the further course of action.

It is extremely important for a hearing problem to be detected as early as possible. Here’s why.

Importance of early intervention

As listed in the beginning of this article, one of the primary functions of the hearing mechanism is to detect and make sense of sounds around us. Even before a baby is born, it starts detecting sounds coming from outside the womb. After birth, these sounds become more meaningful. They come from somewhere, someone, or something. This marks the beginning of comprehension and learning.

When a baby hears speech, what it actually hears is a sequence of vowels and consonants. Each of these vowels and consonants has a definite frequency and intensity (loudness or strength). If the baby has a hearing loss, even partial, some of these frequencies are not heard at all. E.g. “Give me the shoes” is heard as “_i_   me __e __U.”

Such a child will have a gross delay in learning language and therefore speaking. Worse still, he may babble for a short period and because he can’t hear the sound of his own speech, he may cease to babble. Since he cannot make sense of or reproduce any of the words being said to him, he would start to communicate mostly using gestures or pointing.

Middle ear infections are very common in young children. A child who has a middle ear infection might cry incessantly, rub his ears and refuse to suckle. Even though conductive hearing losses are partial and reversible, they can cause the child to miss out on a lot of speech inputs, if not cured in time.

While the diagnosis of a sensorineural hearing loss might be difficult for parents to come to terms with, early detection and intervention can work wonders for these children. Introduction to hearing aids or cochlear implants before 6 months of age followed by regular auditory training and speech therapy might even allow the child to develop and achieve milestones like any normal hearing child.

It is therefore, extremely important to be as alert to the child’s hearing milestones as they are to their motor and speech milestones. Here’s a useful link:

http://www.asha.org/public/speech/development/chart/

If in doubt, always consult an audiologist and get the child’s hearing tested. Maybe it was a false alarm after all… maybe our baby just did not choose to attend to our incessant banter! Still, testing would only help us be sure, and at ease. And if in case it really is a hearing loss, we would be doing the best thing that we could possibly do as parents… giving our child the gift of sound as early as we can!

 

Written by Pallavi Kelkar, Speech language pathologist and audiologist

 

ALL EARS! How Hearing Works

Since the inception of ECDP, we have found parents reacting very anxiously whenever a hearing evaluation was recommended. We realized that this was not because they were not willing to face a potential problem, or that they were in denial. The reason for these reactions was that hearing has always been an enigma to the lay person, and we all have a fear of the unknown!

So the article that follows tries to describe in as simple words as possible, the hearing mechanism, its problems and their possible solutions. The article is in two parts- the first will cover how we hear, and the different types of hearing impairment. The second will go over the process of hearing evaluation, and underline why it is so important to intervene as early as possible.

All Ears! Part I: How we hear, and when we don’t

We wake up to an alarm. We often stumble but don’t fall. We speak clearly. We enjoy the birds chirping, come spring. We slow down at a sharp turn when we know there is a car approaching.

Wondering what these completely unrelated sentences are all about? Well, they have one indispensable factor in common….our sense of hearing.

While vision, taste and touch are easily tangible, hearing is a sense that a lot of us don’t know completely about. Our ears really serve all of the above purposes. First off, they help us hear our own speech and thus act as a feedback mechanism. The next, most obvious function is that of hearing the sounds around us. By virtue of this, ears often act as a signal or warning mechanism, to alert us (alarms) or protect us from danger (fire alarms, car horns). In addition to this, ears also have a parallel sub system for balance, which prevents us from falling, or sometimes makes us sick if it is overstimulated (too much time on an adventure park ride)!

How we hear

The ears that we see on either side of our head are, in fact, only a small part of the hearing mechanism, called the “outer ear”. The hearing mechanism is, in reality, extremely complex. An attempt has been made to simplify the process of hearing. It must be noted however that the descriptions given below are extremely basic, just for the purpose of easy understanding.

Outer ear

The outer ear mainly collects sounds and “funnels” them into the ear canal (the one ENT doctors clean for us). The ear canal ends at the eardrum, a thin membrane which vibrates when sound waves reach it.

Middle ear

The middle ear is beyond the eardrum, and is grossly shaped like a box. Ear cleaning devices cannot (or rather should not!) reach this part of the ear. It consists of three small bones, which form a chain connected to the ear drum at one end and the inner ear at the other. When the eardrum vibrates, so does the chain of bones and conducts the vibrations to the inner ear.

Inner ear

The inner ear has two parts- the cochlea, for hearing; and the vestibule, for balance.

These are both filled with fluids. The cochlea also has specialized cells for hearing, called the hair cells. The vestibule, similarly, has hair cells specialized for balance. These in turn, are connected to nerves.

When vibrations from the middle ear reach the cochlea, the fluids in the cochlea vibrate. This causes the hair cells to move, leading to hearing sensations being produced in the nerves. These then travel to the brain where they are recognized as sounds.

This entire process needs to take place for each and every shred of sound that we hear. No wonder then, that hearing problems are much more common than we think!

Types of hearing loss

While the causes could be as many as the number of steps in our hearing mechanism, hearing losses can broadly be classified into three types.

Conductive hearing loss

When the cause of the damage lies in the outer or middle ears, which “conduct” sound, it results in a conductive hearing loss. This type is often reversible (to some extent at least) through medicines or surgery.

Sensorineural hearing loss

When the cause lies in the inner ear, the loss of hearing is called a sensorineural hearing loss. The cause lies either at the level of the hair cells (sensory) or the auditory nerve (neural). This type is not reversible. However, with the advent of good hearing aids and cochlear implants, timely intervention can greatly minimize repercussions of this hearing loss.

Mixed hearing loss

As is evident from the name, mixed losses are those resulting in a combination of causes, in the outer/ middle and inner ears. Middle ear problems when ignored over a long period might also result in mixed hearing loss.

While all this information might be a bit intimidating for some, it must be mentioned that the ear is a very robust organ. It can protect itself from many causes of hearing loss, like from debris building up in the ear, or from sudden exposure to a loud sound. However there are certain causes of hearing loss which can strike before birth, and are beyond our control. This makes it extremely essential to assess babies’ hearing, and if there is a problem, act in time.

The next part of this article dwells upon what these assessments are, and why we need to get them done, as early as possible.

 

Written by Pallavi Kelkar M.A.S.L.P,  Speech Language Pathologist 

Parent Story: Cri-Du-Chat Awareness Week

This is World Cri-Du-Chat awareness week.

Cri-Du-Chat or 5P- syndrome. It means 5p gene of Chromosome is missing or part of it is missing.  The most distinctive symptom of CDC us “cat like cry” or “cri du chat” in French.
Some of the common traits are-

They have close set of eyes
Low nasal bridge
Low set of ears, wide mouth.
Usually born hypotonia(low muscle tone).

My son was born with Cri Du Chat. I had a normal pregnancy, but at 5th month we were told that my son has bilateral clubfoot. A good doctor would have advised to take a Genetic test but my doctor didn’t. We did everything right within our reach so that our baby does not have any other complication. I ate right, exercised, did yoga and was leading a healthy life. I delivered my angel on Valentine’s day 2014. A perfect day and a perfect baby.

As soon as he was born he cried “miaow miaow”. We thought he is so cute, cries like a Kitten. Our parents consoled us that it must be because boys don’t cry loudly. We didn’t notice much. I was really tired with the delivery; we came back to our room and we tried to feed. He could not latch. I thought being a first time mother, I am facing what all mothers face. We tried a lot, and after a while he latched. He latched fine but he was not swallowing. Sometimes he would and sometimes he won’t. Sometimes milk would flow from sides and he wouldn’t react.

After a week we put on a cast on his legs. From groin till toes. He was treated with Ponseti method. He was so irritated and was not drinking milk properly. We thought it must be the pain and irritation. His feeding pattern only got worst from there. He was 5 weeks and still at his birth weight. We started bottle and he could not suck from bottle either. We were struggling a lot with reflux, colic, constipation.

He was out of casts and in the brace. To keep him comfortable we kept him on bed, comfortable pillows. All these only added to the delay. His head was not set, even by 6 months. He was still crying like a cat. No doctor tried to find out why baby has such a shrill voice. No one advised any test. Even when head was not set, we were not asked to meet a developmental specialist.

We did some research, and a lot of help and encouragement from this group, my husband and I decided to take an opinion from a developmental specialist. Aparna Bhat and Puja Padbidri helped us look at the bigger picture. Till that time we were thinking it should be the clubfoot but they made us realize that clubfoot has no relation with delay. They helped us understand the importance of each milestone and how skipping a milestone is not normal. They gave us plenty of references. We had a lot of questions from our family. We had people telling us not to worry and give it time. We were given examples of xyz’s son or daughter did this or achieved this milestone at so and so age. But they made us understand the importance of early intervention. They gave us the courage to go beyond all the advice and do what is best for our child.

Just to convince our family we consulted our family pediatrician. He immediately referred us to a Pediatric Physiotherapist. We started therapy when he was 7 months old. We also met a developmental specialist. She pointed out a lot of things. I was so angry and that is when I realized, as a parent I don’t want to see what she is saying. But whatever she pointed out was true. She was blessing in disguise. She referred us to one of the best neurologists in Mumbai. Being form India, hearing the word “neurologist” gives a chill down the spine. We still went ahead. By the time we met this neurologist, he was much better thanks to our physiotherapist. We met her and she suggested tests and asked us to meet after 3 months. She didn’t show any urgency maybe because baby was already improving with physiotherapy. She asked us to continue.

We conducted tests as per the neurologist. The tests were genetic test, Brain MRI and a few more. These were huge for us. First of all we were unaware of levels and degrees of these genetic problems. For us it means only one thing which every parent is scared of. Second was Brain MRI. It had to be done under general anesthesia. Vedhanth have already had one general anaesthesia at the age of one month and we were scared of put him under another one. We took the genetic test first thinking we would take MRI right before we meet her. The CGH array genetic test takes about 3 months for the workup and result. It was a long wait but we never thought it could be a problem. When he was 11 months old we did a brain MRI and found that he did not have any issues. Two weeks before his appointment we got the CGH test results.

It had 5P- written on it. We were totally devastated. We don’t know much about this syndrome so we started researching and things were not looking good. We stopped everything and thought that we will put our faith on our doctor. We will follow what she says. They were the hardest two weeks of our lives. Life was not going to be the same but at least we were in peace because we know what he is suffering from and we were prepared. Since then, he has been only progressing because of all the therapies. I am with him 24/7 and so is my husband once he is back from office.He is improving because of our personal attention.

 

Every year, there are children that are born with Cri Du Chat syndrome and due to the rarity of the syndrome and the lack of information, these children slip through the cracks and are not diagnosed, or are misdiagnosed. Every year, there are families that are presented with information, from the 1970’s, about their child’s syndrome. These studies state that their child will not walk, talk, and may die at an early age. This information is not necessarily true, and something needs to be done about it. There is very less awareness regarding genetic disorders.

Please spread awareness on early intervention. Trust your doctors and follow up on the tests they recommend. It is not necessary that all genetic problems necessarily mean inability for life. Proper help can make a huge difference.

 We want to thank Revathy and her husband for being so courageous and sharing this powerful story. She has been a source of inspiration to many parents who get the “wait and watch” advice from other people. She is one of the motivators and now a strong advocate for our milestone screening program- Babyshastra.