When the Brain Can't Hear: Unraveling the Mystery of Auditory Processing Disorder

by Teri James Bellis

Writing letters backward (for example, b/d ) is quite common when children are just learning to write, but is much more pervasive and frequent when a child has a visual processing problem that affects the way he or she actually sees the symbols and words on the page.

To read fluently, we must be able to “sound out” the words on the page, a skill we refer to as decoding or word-attack abilities.

Phonological awareness essentially means our ability to understand how speech sounds are used in words.

Abilities that rely on phonological awareness include, but are not limited to, phonological manipulation, segmentation, and sound blending.

Difficulties in phonological awareness may be indicative of an APD.

Certainly, difficulties with the phonological representation of speech sounds such as those found in APD may affect a child's ability to perform phonological awareness activities; however, so might a deficit in attention, memory, organizational skills necessary for sequencing the response, and a host of other factors. Therefore, although formal assessment of phonological awareness abilities may provide insight into whether a child may have an APD, it certainly does not provide a definitive answer.

We begin to automatically recognize the overall pattern of the most frequently encountered words, an ability that is referred to as sight word reading.

For example, damage or dysfunction in the language-dominant (usually left) temporal lobe may impair word attack abilities, primarily because this portion of the brain assumes the greatest responsibility for speech-sound processing and phonological representation.

left hemisphere has been linked to the ability to analyze wholes into their constituent parts, something that is certainly required when one considers phonological awareness activities.

left-hemisphere dysfunction can be considered generally to impair the sound portion of...

dysfunction in the right hemisphere of the brain has been shown to affect the ability to engage in part-to-whole synthesis, or gestalt patterning.

Disorders of the right hemisphere can have an impact on the symbol portion of sound-symbol association, particularly as relates to the symbol formed by the combination of letters on the page.

As a result, sight word abilities may be affected significantly by right-...

disorders in the portion of the brain that connects the two hemispheres—the corpus callosum and related structures—can impair the association aspect of sound-symbol association.

these disorders, the problem can neither be identified precisely as either word attack or sight word difficulties, but rather as a generalized difficulty affecting both types of abilities.

one of the most frequent academic complaints is difficulty with reading or spelling.

Although not all reading disorders stem from auditory processing problems and not all cases of APD involve reading difficulties, the ability to read certainly involves an auditory component.

speech-sound-based APD is most often associated with word attack and phonological awareness difficulties, whereas sight word problems frequently accompany right-hemisphere-based APD.

general difficulties in associating the sound with the symbol can occur in APD involving interhemispheric integration, or communication between the two hemispheres of the brain.

nonsense words—words that do not mean anything in our language, but that would be pronounced similarly if not identically by most readers—and

Finally, when a child (or adult) is coping with an APD that impacts reading, so much time and effort may be spent trying to decode each letter, each word, that, by the end of the sentence, the reader has forgotten what the sentence is about. As a result, reading comprehension can be affected by APD, as well.

However, Harold continues to have great difficulty choosing the right words with which to express himself—what we call word retrieval abilities. He often goes around and around the topic rather than saying the word itself, a strategy known as circumlocution.

Aphasia can take many forms; sometimes the ability to understand is impaired although speech production may be preserved. Other forms may have exactly the opposite effect. Some may affect functioning in both receptive and expressive domains. Sometimes reading and writing are affected, but sometimes not. Different types are associated with damage in different portions of the language dominant hemisphere. In short, we refer to these disorders not as a single entity, but rather in the plural—the aphasias—and specify which type we are referring to. In Harold's case, aphasia is certainly a far more appropriate label than APD.

That hearing, auditory processing, and language are inextricably intertwined is obvious when one considers the impact hearing disorders or sensory deprivation have on the development of language.

The better a person's language skills, the more able he will be to compensate for an auditory processing deficit, as appeared to be the case with Harold.

auditory closure, the ability to fill in missing pieces of a message.

By age three, a child should be able to produce most of the sounds of English. Although the child may still make some articulation errors, his speech should be intelligible to strangers. Speech sounds that are acquired by age three include m, n, ng, p, f, h, and w.

By the age of three and a half, the y sound should be acquired (as in yes).

By age four, sounds such as k, b, d, g, and r should be produced accurately. More difficult sounds, such as s, sh, and ch, may not be acquired until slightly later,...

By age six, the child should be able to produce t, v, l, and ...

The most difficult sounds of English, which may not be acquired until age seven, include z, zh (as in meas...

Certainly, articulation errors that persist long after the normal age of acquisition of speech sounds suggest that a child may not be hearing the sounds of speech clearly.

By analyzing the type of speech-production errors a child makes, and comparing these to typical developmental errors or errors that arise from difficulties in planning or executing oral movements, we can begin to determine whether a young child may be exhibiting an APD that is affecting his or her speech production.

Many people with right-hemisphere-based dysfunction have difficulty with geometry because of the strong visual and calculation components.

The ability to identify the key words or main theme of a message may be difficult for many individuals with APD, especially those in which the right hemisphere is involved.

The JCIH “Year 2000 Position Statement” identifies the following neonatal and early-childhood factors that may place an infant or toddler at risk for hearing loss:

Any illness or condition that requires the baby to be admitted for forty-eight hours or more to a neonatal intensive care unit (NICU) • Physical signs of any of the many syndromes known to be associated with hearing loss, such as Down's syndrome or Treacher-Collins syndrome • History of permanent childhood hearing loss in the family

Any visible abnormality of the head or face, including even mild deformations of the ear • History of an infection in the mother during pregnancy such as rubella, herpes, toxoplasmosis, or cytomegalovirus (CMV) • History of an infection in the baby after birth that may be associated with hearing loss, such as bacterial meningitis • Infant conditions after birth such as severe jaundice (requiring blood transfusion) and breathing problems requiring the baby to be ass...

Presence of any neurological disorder that results in deterioration of motor or sensory function over time • History of head trauma • History of repeated or chronic ear infections with fluid in the middle ear for at least three months • Any concern on the part of parents, caregivers...

Although these high-risk factors have been shown to be associated with hearing loss in infants and children, many of them can affect development and functioning across a wide variety of sensory and cognitive domains.

We simply have not yet identified the high-risk factors for APD.

many of the children with clear high-risk factors do not, indeed, end up with hearing loss at all.

For this reason, we are now emphasizing the need for universal newborn hearing screening programs—or

The Newborn Hearing Screening and Intervention Act was passed by Congress in 1999, and the Children's Health Act of 2000, signed by President Clinton in May of 2000, extended the provisions of this act for another two years. The ultimate goal of this act is to provide hearing screening services to all infants born in the United States. The act also provides for follow-up and early intervention for all infants or children identified with hearing loss.

Passing a hearing screening or verification of normal hearing acuity does not mean that the child is processing what she hears adequately.

The finding of “normal hearing” by standard hearing tests refers only to what is heard, not how it is heard.

Although we have been referring to newborn “hearing” screening, it should be understood that we are not actually testing the infant's hearing. In other words, these tests tell us if certain parts of the auditory system appear to be functioning properly, but they give us no information about whether the infant can actually detect and process sound.

Finally, both OAEs and the ABR will be affected by conditions of the outer and middle ear that are medically treatable, such as ear infections or fluid or debris in the ear as a result of birth. Therefore, some infants who fail hearing screening by OAEs or ABR will not have permanent hearing problems.

It is possible that even relatively innocuous complications or problems during the pregnancy or birth may place the child at a higher risk for processing problems such as APD.

This initial assessment leads to an