hardofhearingchildren.com by PAM Candlish MLS
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What students hear impacts on what they learn

Researchers have repeatedly found that the quantity and quality of what students hear has a major impact on what they learn. Ross states this succinctly:

Ross states his surprise when intelligent, committed and sensitive child focused professionals have difficulty with this concept . This apparent enigma regarding the logical relationship between the individuals hearing acuity and the acoustical environment is evident when considering both classroom learning and classroom behaviour. The reason behind this may be because of the "...ambiguous, invisible, underestimated and often unidentified acoustic filter effect of hearing problems" . Flexer argues that the fact that children’s inability to hear in a classroom is underestimated, could be because many children appear to behave in a way that indicates they can hear, however these same children may not be able to hear an intelligible sound - instead they may "...be responding to the intonation patterns rather than to the specifics of an utterance .

Flexer reminds us that the inability to hear "well enough" becomes a significant educational problem because mainstream classrooms are auditory-verbal environments:

There are many factors affecting classroom communication, some of these concern the personal qualities that listeners bring to the classroom and other factors concern the classroom environment.

 increased difficulty when hearing-against-background-noise.

Certain personal qualities will put some children at greater risk of increased difficulty when hearing-against-background-noise. Crandell, Smaldino and Flexer assert that it is well recognised that listeners with sensorineural hearing loss have greater difficulty understanding speech in noise than do normal hearers. However, they also mention that researchers have identified a number of populations of children with ‘normal-hearing sensitivity’ who have also been found to experience greater speech perception difficulties in the classroom environment. These listeners include young children, children with attention problems and:

Several environmental factors affect classroom communication. These form part of the classroom acoustics. Included in classroom acoustics is the signal-to-noise ratio (or alternatively referred to as the speech-to-noise ratio), reverberation times and the distance the student is from the signal . Strict structural guidelines regarding acoustical building materials and classroom layout has resulted from research of the effects of classroom noise on learners, with the American Speech-Language-Hearing Association (ASHA) recommending unoccupied classroom noise levels to be equal to or less than 35 dBA. This organisation also recommend that the maximum average reverberation time in unoccupied learning spaces be between 0.4-0.6 of a second.

typical classroom noise levels far exceed this ASHA recommended level

Crandell & Smaldino reviewed the literature on average classroom noise levels and found that typical classroom noise levels far exceed this ASHA recommended level with a range from 41-51 dBA.. However, the most important environmental factor that affects classroom communication is the signal-to-noise ratio. The American Speech-Language-Hearing Association recommends a speech to noise ratio (SNR) of at least +15 dB in typical classrooms . Research has found that the range of SNRs for classrooms has been reported to be from -7 dB to +5 dB (Crandell & Smaldino, 2000 p364).

Children who cannot hear clearly, for whatever reason, may react to this by actively tuning out the distracting and confusing stimuli.

As can be seen from the above table links have been made between children’s inattentive behaviour and classroom noise. Children who cannot hear clearly, for whatever reason, may react to this by actively tuning out the distracting and confusing stimuli. Mussen makes the observation that "the effort of listening to half-heard signals is always great. The...child with partial hearing may not expend the energy required to attend selectively".

learned inattentiveness to sound

Other researchers have postulated that one of the possible consequences of fluctuating hearing loss in children is a "learned inattentiveness to sound" . Smaldino and Crandell suggest that

The relationship between hearing and attention deficit disorder has been made by some audiologists and ‘sound’ therapists . Table 1.2 below (Phonic Ear, 1996) reveals the behavioural similarities between mild hearing loss and Attention Deficit Disorder. With such similarities it is possible that some children are being misdiagnosed. However, I could not locate any research that specifically tested this hypothesis.

Current standard audiological assessments are conducted by either an audiologist or an audiometrist. They are conducted in sound proof rooms using air conduction and pure tones at different frequencies against a background of silence. The clinician may also test bone conduction, and speech stimuli in silence . Typically the frequencies measured are 500, 1000, 2000, 4000 and 8000 Hertz. Frequencies are a measure of the pitch or how high or low the sound is. The intensity of the sound is the loudness. This is measured in decibels (dB). The more decibels, the louder the sound .

pure-tone hearing assessments provide limited useful data

There is a growing body of research that provides evidence that pure-tone hearing assessments provide limited useful data regarding a child’s ability to listen in a classroom situation. As the following quote by Flexer states, many of the conditions that predispose children to having great difficulty hearing in a normal classroom situation remain undetected due to the problems with standard audiometry:

Once a hearing loss is detected the labels normal, minimal or mild are allocated to describe the severity of the loss. These labels can be misleading, as they are often used by different audiologists and researchers to describe different hearing levels. An example is provided in table 1.3 below.. This table demonstrates three slightly different classification schedules for children’s hearing.

pure-tone tests in silence been questioned.

In addition to the lack of uniformity of the labels used to describe hearing levels, the reliability of pure-tone tests in silence have also been questioned. Murray made the following comment to the Standing Committee on Employment, Education and Workplace Relations on the Education Of Boys:

There are many audiologists and researchers who question the validity of the use of the pure-tone audiogram for assessing real life listening situations. This is because the audiogram provides no information on the quality of audition present at these levels; it merely indicates the dividing line between hearing and not hearing .

Flexer (1994,p 36) states that

A child may appear to hear well in a soundproof audiological test room or a quiet one-to-one communicative situation, but not hear equally well in a relatively noisy home or school setting.

Auditory System analyses the complex sound waves arising from this ‘noise

Plomp , questions the validity of the physics behind testing ‘pure tones in silence’. He notes that there is no such thing as pure-tones in real life listening. The auditory system usually operates in noise and that one of its main functions is to analyse the complex sound waves arising from this ‘noise’. Plomp states that processes involved in the perception and analysis of such complex mixtures cannot be revealed by the study of simple stimuli under silent and unimodal conditions. Plomp proposes that this "microscopic" approach has provided interesting but also inaccurate results and needs to be combined with the "macroscopic" information gathered by more ‘realistic’ hearing indicators.

 otitis media with effusion before their first birthday,

Other studies have found that pure tone tests overlook children who have difficulty hearing against background noise. Gravel, Wallace and Ruben (1996) have found that children who experienced otitis media with effusion before their first birthday, had greater difficulty hearing against background noise than children who did not suffer otitis media with effusion at such a young age, and yet they found no differences between the groups when tested on the audiological pure tone tests.

Fatigue not included

Hicks and Tharpe (2002) point out that even hearing assessments that test word recognition against background noise, a more valid test of educational hearing ability than pure-tone tests, fail to capture the children who fatigue in the process of listening. Therefore, any currently used hearing assessments will miss many of the children who need a better signal-to-noise ratio in order to reduce fatigue.

boys process speech sounds more slowly

In addition recent research undertaken at National Acoustic Laboratories (NAL) using otoacoustic emissions indicates that from the age of four years, boys have significantly reduced physiological capacity to process auditory ‘streams’ of sound such as speech. That is, compared with girls, boys process speech sounds more slowly . It is evident from this research that otoacoustic emissions provide a more sensitive assessment of hearing than pure-tone tests.

Considering the above criticisms, and the fact that it is well established that standard audiometry procedures using pure tone tests do not test for hearing acuity against background noise , raises the question of how this ‘real life’ listening ability is tested and who conducts these tests and who has access to this assessment.

central auditory function

The ability to hear against background noise has been considered a central auditory function rather than a sensory function, thus audiologists who assess central auditory processing deficits use some specific tests for this purpose. Ferre and Bellis include the detection of children with difficulty hearing against background noise as part of their Central Auditory Processing Disorder (CAPD) testing battery. Central Auditory Processing tests are used to test children thought to have difficulty understanding the meaning of incoming sounds Central auditory processing is not considered an impairment of hearing reception or reduced hearing sensitivity, as children are screened so that only the children with ‘normal’ hearing sensitivity are given CAPD tests. This means that in current practice a child is only screened for their ability to hear-against-background-noise when they have a CAPD test. This anomaly between the availability of standard audiological testing compared to the more ‘realistic’ (and therefore more informative) tests of hearing ability formed part of the motivation for conducting the present study.

question the validity of audiological results in regard to their valid extrapolation into the students educational environment.

The present study was undertaken due to my interest in the controversies, mentioned above, surrounding audiological tests, classroom acoustics and the hearing abilities each individual brings to the classroom. My initial interest was stimulated from the experience of my son, whom was 6 years old and in Grade 1, when he was described by his teacher as underachieving academically. In addition to other observations, his teacher complained that when the whole class was given instructions, he would wait for other students to get the right books for him, and to tell him what to do. During the following 10 months, I had the opportunity to witness seven different audiological assessments. These experiences led me to question the validity of the audiological procedures, including the subjectivity of the audiological examination and the use of the ‘pure-tone’ test in silence as the adjudicator of ‘hearing ability’. In particular this led me to question the validity of audiological results in regard to their valid extrapolation into the students educational environment. Through my studies in Literacy, I learned of the Goldman-Fristoe-Woodcock Test of Auditory Discrimination (1970) (G-F-W), which did not require an audiologist to assess hearing acuity against background noise.

The participants were obtained from a school population which was selected from a lower socio-economic area of Adelaide. There was a possible population of 127 children enrolled in grade 1 and 2 at this school, with all 127 given the opportunity to participate, through an addressed package to the parent(s)/caregiver(s) of each child. Contained in this package (see appendix B) were two letters of introduction about the study along with the parent(s)/caregiver(s) questionnaire and consent form. An initial total of 65 completed questionnaires and consent forms were returned within a few weeks of the initial ‘distribution’. A second distribution of the same package was sent in the same manner to the remaining 64 children and a further 39 children returned their consent forms and the completed parent(s)/caregiver(s) questionnaire. By the end of the study 103 children were administered the Goldman-Fristoe-Woodcock Test of Auditory Discrimination.

The Goldman-Fristoe-Woodcock Test of Auditory Discrimination (G-F-W) was used in the present research project because of its design, construct validity, concurrent validity, internal-consistency, and test-retest reliability as purported in their manual that comes with the test (Goldman et al, 1970; pp15-31). Another reason for using this test was because it has been reported to be used extensively with children aged 4 years and over .

Because of the tests design, the authors state that

Controlling for factors other than auditory discrimination is a major concern for test developers, and the G-F-W (Goldman et al.,1970, p 7) test minimizes these by: