HANDTRONIX
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HANDTRONIX
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What is Hearing Screening? Screening for hearing loss in the general population should be an important part of all physicals. The most common general populations for hearing loss are young children and aging adults. The most common types of hearing loss are:
As our exposure to noise increases with the many opportunities and changes in our world, so does the probability of some degree of hearing loss. In days gone by, one's environment had the sounds of nature. Now we enjoy concerts, sporting events, electronic games, and other leisure time activities with an increase in the loudness of what we hear. Our ears and their ability to hear are constantly challenged.The S-O-A-R Protocol was developed for the hearing health professional but is equally important for parents and other health care providers to utilize. It gives the very basic steps needed to quickly assess if a problem may exist.
For
Hearing Loss
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500 Hz |
1000 Hz |
2000 Hz |
4000 Hz |
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Children |
omit | 20dB | 20dB | 20 dB |
General Population |
may omit | 25 dB | 25 dB | 25 dB |
Geriatric |
omit | 40 dB | 40 dB | 40 dB |
OBSERVE . . . Look for signs of Hearing Loss
ASK . . . "Do you have any trouble with your hearing?"
REFER . . . All abnormal or questionable results for appropriate follow-up.
NOTE: A more complete version of the S-O-A-R Protocol is found in the Oto Screen I Users Manual.
 | Significant hearing loss is experienced by 20 to 30 million Americans. Presbycusis, or aging hearing loss is the most common type. At age 65, approximately one third of the population could benefit from amplification (use of a hearing aid). Aging causes abnormalities in the inner ear (cochlea) such as stiffening of membranes and loss of sensory cells (hair cells). There is typically no medical cure for aging hearing loss unless the cause is the outer or middle ear. An audiologist or otolarynologist (ear, nose and throat physician) should be consulted in all cases of hearing loss to determine the cause and possibilities for remedication (improvement in a patient's ability to hear). Hearing aids usually benefit aging hearing loss but should be applied early for better results. |
| Conductive hearing loss is due to abnormalities of the outer or middle ear where the eardrum and "ossicles" (hammer, anvil and stirrup) are located. Because these structures serve to merely conduct sound into the deeper neural structures of the cochlea, problems are more readily correctable than is the case with "sensorineural" hearing loss. |
| Common causes of "conductive" hearing loss are fluid in the middle ear, "cerumen" (ear wax) and stiffening of the middle ear bones (ossicles). All of these conditions lend themselves well to surgical or medical correction. Such procedures are usually very successful and effective since there is no neural damage or accompanying loss of clarity. If hearing aids are the preferred treatment, these are also nearly always successful. |
| This is the most common type of hearing loss and is the type found in most cases of aging loss (prebycusis), hereditary loss, noise damage as well as sequalai to certain medical conditions. It's cause is damage to the delicate sensory and/or nerve structures found in the snail-shaped "cochlea". This type of loss may occasionally be caused by more serious medical conditions such as tumors or neurological conditions. Because to cochlea is such a delicate structure, most mojor diseases have the capability of damaging it as is also true of many medicines. Fortunately, most cases of sensorineural hearing loss can be rehabilitated by use of hearing aids or other medical treatment. Audiological or medical consultation is always warranted prior to purchase of a hearing aid in order to determine need for alternative follow-up. Sensorineural loss may also be accompanied by tinnitus (ringing in the ear), vertigo (dizziness), or reduced clarity of words. Common complaints of persons with this type of loss are inability to hear in noisy places such as restaurants or at parties. The loss is so gradual in onset that the patient often accuses his family or friends of mumbling. "People just don't speak up these days" is a common theme. The loss is typically worse in the high frequencies, affecting mainly consonant's sounds, which give rise to the loss of clarity of words. |
| Hearing aids come in many forms and have generally been greatly improved over the last few years. Not only has size greatly decreased, but sound quality has been greatly improved due to a combination of advanced technology and knowledge concerning the "prescription methods". |
| Hearing aids, when properly fit by audiologists or other hearing professionals, ampligy only the frequencies corresponding to the patient's loss on the "audiogram". Though two hearing aids may look identical, internally their circuitry should differ according to the type of hearing loss of the individual. While hearing aids cannot cancel all background noise, there has been progress in this area. The greatest strides in noise reduction have come in the form of "directional" microphones, "completely-in-the-canal" (CIC) configurations in which the entire aid fits deep within the canal allowing for the natural amplification of the outer ear, "active filtering" circuits which change the amplification of certain sounds depending on the background noise conditions, and finally, true "digital" circuitry. Sometimes such innovations when first introduced are over prescribed as a panacea for all cases. In certain instances, sound processing of these types may actually degrade the signal. Proper consultation and a trial period are essential to choosing the right instrument. |
Lynn S. Alvord Ph.D.
There are two vast populations for which hearing loss is of major prevalence - young children and aging adults. It is estimated that between 30 and 50 percent of the population past 65 years of age is affected by significant hearing impairment (1), yet only 13 to 18 percent of the elderly hearing-impaired use a hearing aid (2, 3).
Though hearing loss is also very prevalent in young children, typical age of detection is not until between the ages of 3 and 7 years (4).
For the elderly, hearing loss causes many psychosocial and emotional changes. Many authors have reported the value of communication to a person's social, intellectual and emotional well-being (5). The isolation caused by communication disorders may be unbearable, health may be affected and mental state deteriorates at a more rapid degree.
The hearing impaired often withdraw socially, not wishing to draw attention to their disorder, and may be mistakenly categorized as less intelligent, shy, learning disabled or lacking in motivation.
For the young child, language, reading and general learning is delayed, even for mild hearing losses (6).
Late or delayed identification is the major stumbling block to remediation. Possible causes for such delays are:
Evidence of these factors is born out by the experience of many who undergo a complete physical examination without consideration for hearing loss.
Although blood pressure, reflexes and vision (eye chart) are often screened, hearing is rarely checked by physicians. The often stated excuse is that the patient will likely point out a hearing loss to the physician. Considering the slow, insidious nature of the disorder, this is unlikely.
Children are often screened at school but not typically before kindergarten and then only every other year. since peak age for learning language is 2 1/2 years and most ear infections occur prior to age 4 (6), such a screening scenario is far from adequate.
Studies were undertaken to assess the adequacy of newer miniature screening devices and noise environments under which screenings may be performed. Ambient noise was measured in physicians' offices and compared to recommended background levels for screening. Accuracy of a miniature hand-held audiometer was compared to that of standard full-scale equipment used in a sound proof booth.
Background noise was monitored in 20 physician offices in the Salt Lake City area. Two 20 minute averaged measurements were taken using a Larson-Davis sound level meter and Hewlett Packard microcomputer (71B). Next, the hearing of 50 patients was tested both with a small hand-held audiometer (Handtronix-OtoScreener) and standard audiometer and test booth. Sensitivity and specificity of the small screener was judged based upon comparison to the "true" test utilizing standard equipment. Hearing was screened at a level of 20 dB HL (re: 1969 ANSI) (7).
Table 1 shows agreement between the small and standard audiometer. "Sensitivity" refers to ability of the screener to correctly detect hearing loss (93%). "Specificity" or ability to correctly pass those without loss was 85.7%. False positives, those without loss but shown to be abnormal by the screener was 14.3%, while false negatives, those with true losses missed by the screener, was 6.9%.
Noise measurements in physicians' offices are shown in Table 2, and then compared to allowable levels for screening at 20 dB (Table 3). According to the guidelines of the American Speech-Language-Hearing Association (ASHA) the following octave band room noise levels are allowable for screening at 20 dB: 41.5 dB at 500 Hz, 49.5 dB at 1000 Hz, 54.5 dB at 2000 Hz, and 62.0 dB and 4000 Hz (dB SPL re.0002 dynes/cm2 ) (8). The ASHA recommendations call for screening at 20 dB for children (500, 1000, 2000, and 4000 Hz) (9). Ventry and Weinstein recommend screening the geriatric population at 40 dB (1000 and 2000 Hz only) (10), however, other authors feel the aging population should be screened at the same criteria as a younger population (11)
According to these results, noise is sufficiently low to allow screening at all but 500 Hz in virtually all offices tested. The inclusion of 500 Hz is considered less than necessary since the latest ASHA proposal will omit 500 Hz from the protocol. also, results show accuracy of the smaller hand-held audiometer to be quite high (93% sensitivity).
These results lead to the conclusion that screening may be performed easily, accurately and inexpensively in nearly any typical (quiet) environment such as a physician's examination room. Therefore, expensive equipment such as a sound treated booth is not necessarily a prerequisite for accurate screening provided precautions are taken to maintain quiet.
The implications of early detection of hearing loss are far reaching. For the child, adequate hearing is a essential to normal language development and classroom learning. For the aging adult, prompt identification of impairment can lead to remediation through hearing aids and other rehabilitation processes.
As stated in the introduction, hearing loss extremely prevalent among the very young and aging populations. The high numbers of individuals possessing this disorder necessitates a growing awareness and willingness to deal with the problem. Since screening is a simple procedure, programs may be initiated and executed by non-health professionals. An audiologist is the professional best qualified to oversee and administer such programs. Early identification of hearing loss through screening will lead to more effective and timely remediation of this pervasive social problem.
Table 1: Accuracy of Miniature Screener
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Result
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Number | % |
Recommendation
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False Negative
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4
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6.9%
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Underreferral |
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False Positive
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6
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14.3%
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Overreferral |
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True Negative
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36
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85.7%
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Specificity |
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True Positive
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54
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93.1%
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Sensitivity |
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Total
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100
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Table 2: Average dB (SPL) Background Noise of
Physician's Offices at Various Octave Bands
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Frequency
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500 HZ | 1000 Hz | 2000 Hz | 4000 Hz |
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Mean
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39.5 | 36.2 | 32.4 | 30.8 |
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Standard Deviation
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4.9 | 5.5 | 8.9 | 8.8 |
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Range
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26.9-47.7 | 27.5-47.4 | 14.1-49.5 | 19.8-50.6 |
Table 3: Number of Offices and Percent of Total Sample with Adequate Noise for Screening at Various Frequencies
| Frequency | 500 Hz | 1000 Hz | 2000 Hz | 4000 Hz | ||||
| n | % | n | % | n | % | n | % | |
| 13 | (65) | 20 | (100) | 20 | (100) | 20 | (100) | |
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