**2.1 Subjective evaluation (technology)**

Subjective hearing tests (Miller, 2006) are available for performing a rough estimate of the grade of hearing loss. These tests do not provide a quantitative report of the patient's hearing status, but rather comprise a method with practical clinical value for exploring the cochlea in order to determine location rather than intensity of the damage; results must be evaluated in conjunction with quantitative hearing evaluation. These include the following:

#### **2.1.1 Acumeter**

Instrumental acumetry (see Figure 1), which employs the diapason to assess hearing acuity, guarantees limited precision (Marullo et al., 1967). This instrument "tuning fork"produces sounds with frequencies between 16 and 4,096 Hz from octave to octave. This is a U-shaped acoustic resonator that resonates at a specific constant on a frequency-related scale when set to vibrate by striking it against a surface or with an object emitting a pure tone. There are three mean tests:

groups of receptor cells and their nerve fibers. The cochlear nerve innervates the organ of Corti; it possesses myelinized efferent fibers that carry spatial orientation information from the cochlea to the brain. Efferent signals are amplified and transmitted, frequency discrimination is increased, acoustic otoemissions originate, and mechanical changes

Hearing loss can occur at any age. Otorhinolaryngologists, surgeons, and audiologists with assistance technology are readily able to identify different degrees of hearing loss. Children and adults experiencing significant hearing loss suffer specific problems and may need special assistance. Early identification of hearing loss and its treatment is essential for successful speech development, the child's intellectual growth and the adult's social

Hearing impairment is caused by either loss in sensitivity (loss in perceived loudness), loss in the ability to discriminate different speech sounds, or both. Loss of loudness may be due to either increased mechanical impedance between the outer and inner ear or reduced sensitivity of the sensory hearing organ. Loss of the discrimination ability is basically associated with damage to the sensory organ, although other neural structures at higher

Several subjective and objective methods to assess hearing disorders are available, depending on the individual's age, hearing level and condition type. Among other things, evaluation must be conducted for cochlear integrity, acoustic impedance, and screening of

With ever changing technology and new methodologies in healthcare, available for addressing the specific needs of adult and pediatric populations, hearing technology represents not only devices for clinicians' practice, but also devices to meet the high level of need for diagnostic techniques, audiologic rehabilitation, treatment methodologies, and

Subjective hearing tests (Miller, 2006) are available for performing a rough estimate of the grade of hearing loss. These tests do not provide a quantitative report of the patient's hearing status, but rather comprise a method with practical clinical value for exploring the cochlea in order to determine location rather than intensity of the damage; results must be evaluated in conjunction with quantitative hearing evaluation. These include the following:

Instrumental acumetry (see Figure 1), which employs the diapason to assess hearing acuity, guarantees limited precision (Marullo et al., 1967). This instrument "tuning fork"produces sounds with frequencies between 16 and 4,096 Hz from octave to octave. This is a U-shaped acoustic resonator that resonates at a specific constant on a frequency-related scale when set to vibrate by striking it against a surface or with an object emitting a pure tone. There are

special issues in researching the needs of patients (Montano & Spitzer, 2009).

produced in the liquid medium of the sound waves are detected (Steele et al., 2000).

integration.

levels may also be involved.

hearing of newborns and infants.

**2. Audiologic evaluation technology** 

**2.1 Subjective evaluation (technology)** 

**2.1.1 Acumeter** 

three mean tests:

The Schwabach test determines BC duration. The instrument is placed on the anterosuperior region of the mastoid. Normal duration is 20 sec. The Schwabach test makes a comparison between bone conduction of the patient and the examiner. The diapason is placed between the patient and examiner and a sound is created. If the patient can no longer hear the sound even though the examiner can hear it, it is indicative of sensory neural loss; if the examiner stops hearing the sound and the patient continues to hear it, it suggests conductive loss. However, this test is completely dependent on the hearing powers of the examiner. In conduction hypoacusis – the duration is prolonged, while in sensory neural hypoacusis, the duration is shortened.

The Weber test utilizes the low frequency of the instrument (126 Hz), which is placed on vertex. Normally the vibration is heard equally in both ears. This is a common medical test conducted in the physician´s office in which a comparison is made between two hearings. In the first, the base of the tuning fork is applied to the bone and hearing is elicited after this. When the sound is completely inaudible, the vibrating top is brought near the external ear canal. If there is a positive value, it is considered that there is an air-bone gap due to which there is a conductive loss.

The Rinne test employs the diapason as initially placed near the ear to explore aerial conduction and after that, on the mastoid to explore bone conduction. Normally, air conduction is better than bone conduction. With BC/AC=½, the Rinne test is normally positive. In this test, a 512 Hz tuning fork is placed on the forehead of the patient. An ipsilateral conductive hearing loss is occurred if the sound appears to be louder on one side than on the other. A contralateral sensorineural hearing loss may also be determined by use of this test.

Fig. 1. Set of tuning fork

#### **2.1.2 Speech perception test**

This test uses words that the subject hears through headphones and he/she is required to identify them. This test depends on the knowledge of language; it must be adjusted to both

Technology for Hearing Evaluation 7

Welch-Allyn otoscope (Golfain et al., 2008), which is a small hand-held instrument. It has a light that is directed through a funnel-like tip to illuminate the ear canal for examination. The funnel-like tip is called speculum. The specula are disposable and come in sizes for average adult ear canals. The otoscope is powered by a rechargeable battery located in the handle; the handle is detachable and can be plugged into a standard wall outlet for recharging.

Diagnostic equipment can help to identify different degrees of hearing loss in a more quantitative fashion. There are several techniques that are implemented in medical equipment for screening of hearing. The most widely used initial screen involves a puretone, air-conduction hearing test or audiometry, followed by tympanometry, otoacoustic

Hearing testing is conducted in the audiometry testing chamber; a special sound booth is built into this room, which must be constructed based on testing guidance described in the ASTM E336 "Standard Test Method for measurement of Airborne Sound Insulation in Buildings" (ASTM E336–10, 2011). This triangular-shaped booth is designed to ensure that the sound levels inside are sufficiently quiet to permit accurate hearing-threshold measurements. In addition to the sound booth, the examination room possesses several other features designed to reduce sound levels in the room further, as shown in Figure 3. These include sound dampening materials on the interior walls of the examination room

emissions, multilingual speech audiometry, and stem cell evoked potentials.

**2.2 Objective evaluation (technology)** 

and a rubber seal on the exterior door.

Fig. 3. Anaechoic Chamber for audiometry test.

adult and pediatric populations. It is categorized according to whether the words are aimed at evaluating detection level ability, syllable, phoneme, word, or sentence perception (Australian Hearing Group, 2001). Additionally, it is designed to provide a useful overview of the key features (e.g., target hearing-impaired group, clinical application) of each of the tests and thereby assists the Audiologist in selecting the appropriate speech perception test/s for the individual patient and the specific clinical situation.
