Hearing loss is an insidious problem in adults, but even more so in children. Adults who experience hearing loss generally deny it for years but they possess various coping mechanisms necessary to get through the day; the ability to predict where the conversation is going; the contextual vocabulary that fills in the blanks of missed or garbled words (auditory completion); the linguistic experience to know a question is being asked if the slight upward vocalization is missed to highlight just a few. Adults also have developed key evasive measures when they are asked specific questions that aren’t clearly understood such as a simple nod or a look of understanding. Very young children have not developed these skills. They can’t predict conversational direction or fill in the words that they missed. They can process the sounds they hear but might not be able to recognize, contextualize, or integrate those sounds into the current conversation.
Hearing Loss
There are many causative factors that may cause a person’s hearing loss and they fall into two major categories: congenital (at birth) or acquired (after birth). Congenital hearing loss may be genetic but it could also be caused by premature birth, an infection during pregnancy, a drug reaction, or an injury during the birthing process. Acquired hearing loss could be caused by frequent ear infections, contracting a disease such as meningitis or measles, a head injury, or exposure to very loud noises.
Hearing loss can then be classified as either conductive or sensorineural. Conductive loss can be the result of an object embedded in the ear canal, infections in the middle ear, damage to the ossicles, the three small bones in the middle ear, or any other condition that impedes the conduction of sound between the outer ear and the inner ear. While conductive hearing loss can be disturbing, almost all cases can be easily treated leaving no residual hearing loss. Sensorineural hearing loss is the result of damage to the cochlea, the cilia (the tiny hair-like structures within the cochlea) or the auditory nerves that are the conduit between the ears and the brain. Sensorineural hearing loss can be congenital in nature or caused by aging, exposure to loud noises, or the use of ototoxic drugs which may be prescribed or purchased over the counter. Unlike conductive hearing loss, sensorineural hearing loss generally results in a permanent disability.
Young Children
Young children are prone to ear infections with studies showing that five out of six children have at least one infection by their third birthday.
For those not involved in early childhood education, there is a tendency to discount the important education that occurs in these early years. According to the National Institute of Health:
The first 3 years of life, when the brain is developing and maturing, is the most intensive period for acquiring speech and language skills. These skills develop best in a world that is rich with sounds, sights, and consistent exposure to the speech and language of others.
It is through effective listening that a child learns to speak, read and then write. A hearing impairment can cause the child to miss many of the sounds around them which, in turn, can lead to delayed speech and language skills, learning and behavioral issues at home and at school, a feeling of confusion in listening intensive situations which can lead them feeling bad about themselves, trouble making friends, an unusual need for social isolation.
Ear infections is the most common reason that parents bring their child to the doctor. Aside from being painful, an ear infection is a major cause of temporary hearing loss at an age where hearing and listening are critical to language learning. The middle ear becomes filled with a viscus fluid that puts pressure on the rear (inside) of the ear drum–dampening its movement and reducing the transmissive amplitude (volume) of the sounds. The fluid also dampens the vibrations of the ossicles (the three small bones in the middle ear) which further reduces the sound volume and quality as it moves towards the cochlea via the oval window. These infections are usually very painful but with a course of antibiotics, the pain tends to go away within a few days. The problem is that the child can experience various degrees of hearing loss for up to a few weeks, even after the pain subsides.
Hearing Loss and Academic Achievement
It doesn’t take much of a hearing loss to impair a child’s academic experience. While the American Medical Association (AMA) defines hearing loss as being greater than 25 dB, a much smaller loss can have a major impact on a child’s education. A minimal hearing loss (MSHL), as low as 16 dB, can be a game changer for school-age children. Problems hearing faint or distant speech; problems hearing subtle conversational cues; problems in tracking fast-paced conversations and problems hearing the word-sound distinctions all contribute to problematic academic performance.
Dr. Fred H. Bess, a pioneer in the field of childhood deafness and family communication wrote in 1999:
The largest discrepancy between children with MSHL and children with normal hearing was on the subtest communication. The subset communication focuses on a student‘s understanding ability, vocabulary word usage skills, and storytelling abilities – all very important skills for learning in school. In fact, a child with MSHL is 4.3 times more likely to experience trouble in the area of communication than a child with normal hearing.
A study by Bess at a Middle Tennessee school district estimated that 5.4% – or more than one in twenty, roughly 2.5 million school-age children exhibit minimal hearing loss [2]. Add this number to the children who have been diagnosed with higher levels, mild, moderate or severe, hearing loss and it should be obvious that a problem in our schools exists.
The study went on by indicating that the children with a minimal hearing loss exhibited significantly lower scores on the psycho-educational tests and/or failed at least one grade as compared to children with normal hearing. “The study revealed that children with a minimal hearing loss clearly expend more effort in listening than children with normal hearing,” said Dr. Anne Marie Thorpe. “These findings suggest that class work may suffer if a child with hearing loss is expending extra mental or cognitive effort to listen to the teacher, take notes, and process what is being heard at the same time.”
Bess went on to say that, in one school district, 37% of children with MSHL failed at least one grade compared to a district norm of about 3%. This not only affected the children’s academics in a very negative way, but also placed a huge financial burden on the school district. As mentioned earlier, there are almost almost 2.5 million children that exhibit MSHL. Of these, 37%, or almost 1 million, can be projected to fail at least one grade. If one assumes that the average cost to educate a child for one year is $6,000, the total expenditure for grade repetition would be close to $6 billion.
McFadden and Pittman wrote that there is a growing body of evidence that children with minimal hearing losses are at an increased risk for speech and language delays, poor academic performance, and social dysfunction compared to their normally hearing peers. The focus of their study was to determine how children with MSHL manage multiple demands on their attention; such as attending to written assignments or taking notes while listening to verbal instructions. Adults, when faced with competing tasks, reduce their performance on one task to maintain their performance on another task. Children with minimal hearing loss have difficulty attending to multiple tasks if one of those tasks involves listening. They concluded that children with minimal hearing loss may be unable to respond to a difficult listening task by drawing resources from other tasks to compensate. They added:
Unfortunately there remains a prevailing perception among physicians, parents, and teachers that the consequences of minimal hearing loss in childhood are likewise minimal. Therefore, research to reveal the many consequences of minimal hearing loss in children is warranted.
Unless a child has a significant loss, the chances of it being detected early is, unfortunately quite low. Most states require a hearing test to be administered at birth, but for the most part, infants have to have a hearing loss greater than 35 – 40 dB before they are identified. The in-school hearing tests have been eliminated in almost one-third of the states, and even in those where children are tested, the testing fails to identify the milder forms of hearing loss.
Hearing – the Gateway to Listening and Understanding
Our ability to hear is the gateway to our ability to listen, or to understand what we hear. School children spend upward of 75% of their school day engaged in some type of listening activity – and its through listening, that a child learns to speak, read, and write – the other three communication modalities.
A child with even a minimal loss of hearing acuity often presents symptoms similar to that of ADD/ADHD – inappropriate responses, difficulty following directions or sustaining attention during presentations, impulsiveness and more – and if often diagnosed as ADD/ADHD rather than having hearing loss or auditory processing issues. It is not until after various courses of medication – taking months – if not years – that failed to solve the child‘s problem, that their hearing and understanding levels are examined.
These children can miss more than 25% of classroom instruction, not only due to their hearing loss, but also the additional cognitive stress that poor classroom acoustics and noise puts on them. Additionally, they often miss the more subtle conversational cues which causes them to respond inappropriately to questions or within a conversation. This can be a source of taunting, ridicule or even bullying by their classmates, especially in the early grades. To their parents and teachers they may appear to be a little immature and more fatigued than their better hearing peers because of the high level of cognitive effort that they exert as they work hard at listening more effectively.
Many of the morphological markers that indicate plurality, tense and possessiveness occur with low energy (soft) sounds at higher frequencies. While the vowel sounds carry much of the volume of a conversation, the consonants carry most of the information. Acoustic engineers have found that if you filter out everything below 500 Hz, you will only have a 5% reduction in speech intelligibility even though most of the speech energy (volume) is lost. However, if you reduce the volume of the sounds above 1,000 Hz by 30 dB, intelligibility is reduced over 40%.
The audiogram in Figure 3 shows that many of the key consonant sounds – /th/, /f/, /s/, and /h/ are at the high frequency end of our tested hearing and at very low intensity. The /th/ sound lies at roughly 5,000 Hz at 20 dB, meaning that an individual with a hearing loss of just 20 dBHL will begin to lose, or at least confuse this with other sounds in the same range – /s/ and /f/ especially. It is the final /s/ sound that indicates plurality and possessiveness in many English language words. The confusion of these four consonant sounds can affect the understandability of many words and lead to miscommunication.
It is critical that teachers have an awareness of the issues faced by those students with even a minimal hearing loss because the classroom environment only exacerbates the problem.
Classrooms are rarely designed for listening. School architects spend many hours insuring that the classroom’s lighting is both sufficient and glare-free, yet, in general, spend little time on the noise and echo reduction necessary for better speech intelligibility.
Classroom size is also an issue because the laws of physics are not often broken. In a classroom that is 30 feet deep, the teacher‘s voice volume differs by almost 75% from the front rows to the rear rows of seats. Since sound intensity halves as the distance from the sound source is doubled, a teacher speaking at 60 dB HL (normal speech intensity) to the students in the front row (6 feet from the teacher), the intensity drops to 54 dB HL (half) for those students only 6 feet back (12 feet from the teacher) and down to 48 dB HL (half again) for those 24 feet from the teacher. This is roughly the sound level of a quiet street or whispered speech – not at all conducive to accurately perceiving speech in a learning environment. And this does not take into account a child‘s hearing loss! Add in the overall noise level in a typical classroom along with the soft echoes (reverberation) and the problems multiply for those children with any level of hearing loss.
With little help in the form of auditory testing for low level hearing loss, it is important for both parents and teachers to be aware of the signs and symptoms of minimal and mild hearing loss and request that a child have a comprehensive auditory evaluation by a pediatric audiologist if the child exhibits any of the following symptoms. It is too easy for hearing loss to be overlooked with a quick diagnosis of ADD/ADHD, but this misdiagnosis could be the beginning of a lifetime of academic underachievement.
Some of the signs of hearing loss in children are:
- Delayed speech.
- Speech is not clear (articulation issues).
- Does not follow directions.
- Difficulty paying attention or behaving.
- Often says “Huh?”
- Turns up the volume of the TV, music player, game console, too high.
- Respond inappropriately to questions.
- Not replying when called.
- Watches others to imitate what they are doing.
- Complain of earaches, ear pain, or head noises.
- Have difficulty understanding what people are saying.
- Seems to speak differently from other children of the same age group.
- Difficulty with academic performance.
- Intently watches the faces of those speaking.
- Difficulty understanding speech when there is background noise.
- Not responding to voices over the telephone or continually switching ears when on the phone.
- Not ‘jumping‘ or becoming startled by sudden, loud noises.
- Unable to accurately determine where a sound is coming from.
References
[1] ASHA. Even minimal, undetected hearing loss hurts academic performance. Science Daily, November 2004.
[2] Fred H Bess. School-aged children with minimal sensorineural hearing loss. The Hearing Journal, 52(5):10–14, May 1999.
[3] Fred H Bess, Jeanne Dodd-Murphy, and Robert A Parker. Children with minimal sensorineural hearing loss: prevalence, educational performance, and functional status. Ear and hearing, 19(5):339–354, 1998.
[4] BHI.org. Causes of hearing loss in children. http://www.betterhearing.org/hearing-losschildren/understanding-your-child’s-hearing-loss.
[5] James C Blair et al. The effects of mild sensorineural hearing loss on academic performance of young school-age children. Volta Review, 87(2):87–93, 1985.
[6] E. B. Brixen. Speech intelligibility and bodyworn microphones. http://dpamicrophones.com/mic-university/factsabout-speech-intelligibility.
[7] CDC.gov. Facts – what is hearing loss? http://www.cdc.gov/ncbddd/hearingloss/facts.html, 2015.
[8] Julia M Davis, Jill Elfenbein, Robert Schum, and Ruth A Bentler. Effects of mild and moderate hearing impairments on language, educational, and psychosocial behavior of children. Journal of speech and hearing disorders, 51(1):5362, 1986.
[9] Carol Flexer. Commonly asked questions about children with minimal hearing loss in the classroom. Hearing Loss, Jan/Feb 1997.
[10] OT Kenworthy, Thomas Klee, and Anne Marie Tharpe. Speech recognition ability of children with unilateral sensorineural hearing loss as a function of amplification, speech stimuli and listening condition. Ear and hearing, 11(4):264270, 1990.
[11] Brittany McFadden and Andrea Pittman. Effect of minimal hearing loss on children’s ability to multitask in quiet and in noise. Language, speech, and hearing services in schools, 39(3):342–351, 2008.
[12] PAMR.org. Hearing loss in children.
http://www.pamf.org/hearinghealth/facts/children.html, 2015.
[13] A. M. Tharpe. Minimal hearing loss in children: the facts and the fiction. https://www.phonakpro.com/content/dam/phonak/b2b/Pediatrics/webcasts/pediatric/com_31_p61899_pho_kapitel_18.pdf.
footnote: Clinicians measure sound intensity in dBHL (decibels Hearing Level). 0 dB HL is considered to be the quietest sounds that a young, healthy individual should be able to hear and 140 dBHL is the threshold of pain. An audiologist will test an individual’s ability to hear sounds at various frequencies between 250 Hz and 8000 Hz by presenting pure tones at varying levels between 0dB and 80 dB to each ear. By indicating when a tone is heard, the clinician can determine the amount of hearing loss at each of the frequencies. If the softer tones, between 0dB and 25dB are heard, the person is considered in the normal hearing range. Thresholds at and above 25 dB are considered diagnostic for mild, moderate, severe, or profound hearing loss.
Hearing tests check one’s ability to hear but even those with excellent hearing can have listening-related learning issues. Hearing is one part of the listening process but other functional issues – listening disorders – can k
Even when pure-tone testing does not test any of the cognitive functions necessary for effective listening.