DEAFNESS NURSING MANAGEMENT

  DEAFNESS NURSING MANAGEMENT

INTRODUCTION

   Sudden deafness is severe hearing loss, usually in only one or both ears that develop over a period of a few hours or less. Mechanical or nervous impediment to the transmission of sound waves can produce hearing loss, in this discussion, we shall look at the assessment of hearing, causes, types, prevention and rehabilitative measures.

               DEFINATION OF TERMS

1.     Deafness:- This is the partial or total inability to hear.

2.     Hearing Loss:- This exists when there is diminished sensitivity to the sounds normally heard.

3.     Hard of Hearing:- Having hearing impairment reaching to inability to hear own voice clearly or not able to learn or only occasionally use sign language.

                ASSESSMENT OF HEARING

   Hearing of an individual can be tested by clinical and audiometric test

a)     Clinical Tests of Hearing

·       Finger friction test

·       Watch test

·       Speech test

·       Tuning fork tests

Finger friction Test

    It is rough but quick method of screening and consists of rubbing or snapping the thumb and a finger close to patients’ ear.

Watch Test

    A clicking watch is brought close to the ear and the distance at which it is heard, is measured. It had been popular as a screening test before the audiometric era but is practically obsolete now.

Speech (voice) Tests

  Normally, a person hears conversational voice at 12 meters and whisper(with residual air after normal expiration) at 6 meters but for purposes of test,6 meters is taken as normal for both conversation and whisper.

   The test is conducted in reasonably quiet surroundings. The patient stands with his test ear towards the examiner at a distance of 6 meters. His eyes are shielded to prevent lip reading and the non-test ear is blocked by intermittent pressure on the tragus by an assistant. The examiner uses spondee words ( e.g black- night, football, day dream) or numbers with letters(X3B, 2AZ, M6D) and gradually walks towards the patient. The distance at which conversational voice and the whispered voice are heard is measured. Speech test lack standardization in intensity and pitch of voice used for testing and the level of ambient noise.

Tuning Fork Test

   These tests are performed with tuning forks of different frequencies such as 128, 256, 512, 1024, 2048 and 4096 Hertz (Hz), but for routine clinical practice, tuning fork of 512Hz is ideal. Forks of lower frequencies produce sense of bone vibration while those of higher frequency have a shorter decay time and thus not routinely preferred.

     A tuning fork is activated by striking it gently against the examiner’s elbow, heel of hand or the rubber heel of the shoe.

   To test air conduction (AC), a vibrating fork is placed vertically, about 2cm away from the opening of the external auditory meatus. The sound waves are transmitted through the tympanic membrane, middle ear and ossicles to the inner ear. Thus by air conduction test, the function of both the conducting mechanism and the cochlear are tested. Normally, hearing through air conduction is louder and head twice as long as through the bone conduction route.

    The test bone conduction (BC), the foot plate of   vibrating tuning fork is placed firmly on the mastoid bone. Cochlear is stimulated directly by vibrations conducted through the skull bones. Thus, BC is a measure of the cochlear function only. The clinically useful tuning fork test include: Rinnie test, Weber test, Absolute bone conduction (ABC) test, Schwa Bach’s test, Bing test and Gelle’s test. 

b)    Audiometric Tests

·       Pure Tone Audiometry

An audiometer is an electronic device which produces pure tones, the intensity of which can be increased or decreased in 5 decibel (dB) steps. Usually air conduction thresholds are measured for tones of 125, 250, 500, 1000, 2000 and 4000 and 8000Hz and bone conduction of thresholds for 250, 500, 1000 and 2000 and 4000Hz. The amount of intensity that has to be raised above the normal level is a measure of the degree of hearing impairment at that frequency. It is charted in the form of a graph called audiogram.

     Uses of pure tone audiogram

-        It is a measure of threshold of hearing by air and bone conduction and thus the degree and type of hearing loss.

-        A record can be kept for future reference.

-        Audiogram is essential for prescription of hearing aid.

-        Helps to find degree of handicap for medico legal purposes

-        Helps to predict speech reception threshold.

·       Speech Audiometry

In this test, the patient’s ability to hear and understand speech is measured. Two parameters are studied:

-        Speech reception threshold; it is the minimum intensity at which 50% of the words are repeated correctly by the patient.

-        Speech discrimination score; also called speech recognition or word recognition score is a measure of the patient’s ability to understand speech.

·       Bekesy Audiometry

It is self-recording audiometry where various pure tone frequencies automatically move from low to high while the patient controls through a butone. Two trainings, one with continuous and the other with pulsed tone are obtained. The trainings help to differentiate a cochlear from refrocochlear and an organic from a functional hearing loss.

·       Impedance Audiometry

It is an objective test, widely used in clinical practice and is particularly useful in children, it consists of:

-Tympanometry; It is based on a simple principle, e.g when sound strikes tympanic membrane, some of the sound energy is absorbed while the rest is reflected. A stiffer tympanic membrane would reflect more of sound energy than a complaint one. By changing the pressure in a sealed external auditory canal and then measuring the reflected sound energy, it is possible to find the compliance or stiffness of the tympanic ossicular system and thus find the health or diseased status of the middle ear.

-Acoustic reflex measurement; it is based on the fact that loud sound,70-100dB above the threshold of hearing of a particular ear, causes bilateral contraction of the stapedial muscles which can be detected by tympanometry. Tone can be delivered on one ear and the reflex picked from the same or the contralateral ear. The reflex arc involved is ipsilateral: CN viii-ventral cochlear nucleus-CN. Vii nucleus – ipsilateral stapedius muscle.

                            Nursing care

                   Aims.

-to provide psychological care

-to provide knowledge and understanding of the condition

-to prevent depression

                         Psychological care .

     These patients are treated as outpatients. Therefore psychological care will be of much help, before any procedure (examination) is done, we will explain as to each procedure is to be done to gain co-operation. We will explain the benefits and importance of the examination to gain cooperation and allay anxiety, this will assist to obtain an informed consent.

      The causes of hearing loss are explained to the client as well as to the relatives so as to impact knowledge and gain understanding. The patient and family shall be encouraged to ask question to help allay their anxiety and relieve their fears. The patient and relatives shall be talked to in a calmly manner to gain their trust and cooperation. It will be explained that some assistance will be needed and that it is available in places like speech and hearing centers to prevent depression and to assist the patient to live a normal life as possible.

  CAUSES OF HEARING LOSS

Viral infection- such as measles, mumps influenza and herpes zoster cause primary labyrinthitis and hence cause perceptive deafness and congenital cytomegalovirus.

Drugs- this may include streptomycin which when given in doses of more than 3 grams daily may cause damage of the vestibular labyrinth. In addition it can also cause high frequency deafness.

Senile- with advanced age, gradual perceptive deafness occurs in several people, the condition is caused by atrophy and degeneration of the labyrinth, predominantly the cochlear portion.

Very loud noise – Loud noise is known to be a major cause of hearing loss in people of all ages, continuous exposure to very loud noise for example continuous employment in a potentially noise hazardous environment for 10 to 15 years may cause hearing loss or bombing and loud music that teenagers are exposed to.

Accumulation of ear wax- when ear wax accumulates in the ear, it plugs the acoustic meatus hence causing hearing loss.

Otosclerosis- This is due to hearing loss related condition and can be treated with surgery.

Temporal mandibular joint disorder- This disorder affects the jaw and can hearing loss.

Cholesteatoma- these are growths in the ear that can cause hearing loss.

     In children common causes may include:

Prenatal; diseases like rubella, diabetes mellitus and drugs that can be taken during pregnancy such as streptomycin or quinine can cause deafness.

Perinatal; prematurity, haemolytic diseases such as kernictus can cause hearing loss.

Postnatal; infectious diseases such as measles, meningitis and trauma may cause hearing loss.

                   TYPES OF HEARING LOSS

      Hearing loss can be categorized by which part of the auditory system is damaged. There are basically four types of hearing loss, which include conductive hearing loss, sensorineural hearing loss, mixed hearing loss and single sided hearing loss.

Conductive hearing loss

     It can be acquired or congenital, it occurs when sound is not conducted efficiently through the ear drum and the tiny bones (ossicles) of the middle ear. Conductive hearing loss usually involves a reduction in sound level or the ability to hear faint sounds. This type of hearing loss can be corrected surgically or medically. Possible causes of conductive hearing loss may include;

·       Ear infection (otitis media)

·       Perforated ear drum

·       Impacted ear wax

·       Presence of foreign bodies

·       Benign tumors

Sensorineural hearing loss (SNHL)

     It occurs when there is damage to the inner ear (cochlear) or to the nerve pathway from the inner ear to the brain, it cannot be medically or surgically corrected and it is the most common type of permanent hearing loss, sensorineural hearing loss reduces the ability to hear faint sounds even when speech is loud enough to hear. Possible causes include;

·       Prolonged illness

·       Aging

·       Head trauma

·       Malformation of the inner ear

·       Exposure to loud noise

Mixed hearing loss

      This refers to a combination of conductive hearing loss and sensorineural hearing loss, this means that there may be damage to the outer or middle ear and in the inner ear (cochlear).

Single sided hearing loss

      This refers to no hearing or very little hearing in only one ear and normal hearing in the the other ear. possible causes of single sided hearing loss are;

·       Physical trauma

·       Mastoditis

                      PREVENTION OF DEAFNESS AND HARD OF HEARING

        Half of all cases of hearing loss are avoidable through primary prevention. Some simple strategies for prevention include;

·       Immunizing children against childhood diseases, including rubella, measles, meningitis and mumps.

·       Immunizing adolescent girls and women of reproductive age against rubella before pregnancy.

·       Screening for and treating of syphilis and other infections in pregnant women.

·       Improving of antenatal and perinatal care, including promotion of safe childbirth.

·       Avoiding the use ototoxic drugs, unless prescribed by qualified physician.

·       Referring babies with high risk factors (such as those with a family history of deafness, those born with low birth weight, birth asphyxia, jaundice or meningitis) for early assessment of hearing, prompt diagnosis and appropriate management as required.

·       Reducing exposure (both occupational and recreational) to loud noise by creating awareness, using personal protective devices and implementing suitable legislations.

·       Hearing loss due to otitis media can be prevented by healthy ear and hearing practices, it can be suitably dealt through early detection, followed by appropriate medical or surgical intervention.

·       Avoid sticking cotton swabs, hair pin or other foreign objects in the ear when trying to remove ear wax or scratching in the ear as this may damage the ear hence causing hearing loss.

              REHABILITATIVE MEASURES OF THE DEAF

           Hearing Aid

A hearing aid is a device used to amplify sounds reaching the ear, it consists of 3 parts: (a) a microphone, which picks up sound and converts them into electrical impulses, (b)an amplifier, which magnifies electrical impulses, and (c) a receiver, which converts electrical impulses back to sound, this amplified sound is then carried out through the ear mould to the tympanic membrane. Hearing aid is indicated for deaf children, conductive deafness and sensorineural hearing loss.

 Speech reading

  Earlier called lip-reading, it is an integrated process to understand speech by studying movements of lips, facial expressions, gestures and the probable context of conversations. Speech reading is not only useful for the totally deaf but also useful for those hearing-impaired individuals who have high frequency loss and difficult hearing in noisy surroundings.

  Implantable Hearing Aid

  To avoid the objection of cosmetically visible aids, attempts are being made to develop implantable hearing devices which can be totally or partially concealed under the tissues round the ear. The transducer of the aid is coupled directly to the ossicular chain (malleus or stapes). These devices which are still in their developmental stage and are being evaluated, offer better acoustic gain, no feedback and low battery consumption. They are particularly useful in conductive hearing loss, congenital or acquired, which are not amenable to surgery correction. They are also used for sensorineural hearing loss.       

 Bone Anchored Hearing Aid

 This is a new advance over the conventional bone conduction hearing aids. In bone anchored hearing aid, an osseointegrated implant with atitanium abutment is fixed to the skull. The hearing aid is then coupled to the abutment to carry sound directly to the cochlear via bone conduction eliminating the soft tissues between the skull bone and the bone vibrator of the conventional bone aid. It also eliminates the pressure, pain and local irritation of the skin which are caused by conventional bone aids as they had to be applied with pressure for a snugly fit with a head band. Bone anchored hearing aid also had the advantage of providing better efficiency and fidelity.

        Auditory Training

    It enhances listening skills and is used with speech reading. The patient is exposed to various listening situations with different degrees of difficult and taught selectively to concentrate on speech sounds. Auditory training is useful for those using hearing aids and cochlear implants.

     Assistive Devices

      These devices are needed to help the patient listen in special difficult situations. These devices are divided into groups such as:

-        Assistive listening device and systems;-  These are devices which help the hearing impaired to listen efficiently in the presence of background noise, over the telephone, in auditoriums or theatres. They may be used by person, individuals or are meant for a group.

    According to the technology used, they are grouped as hard wire system, induction loops (amplified modulation) frequency modulation or infra-red signals.

-        Alerting devices;- A hearing impaired person may not hear a telephone or a door bell, a baby crying in another room, an alarm clock or noise of a smoke detector. Alerting device are used in such situations. They produce an extra loud sound signal or relay the signal to area close to the individual. The dog is trained to bark loudly at the sound of a door bell, crying of a baby.

      For people with severe to profound of total deafness, even these devices which produce extra loud sound may not be useful. They need assistive signaling devices where the found (as of doorbell, telephone, alarm clock, baby crying) is changed into a light signal or vibrations. Alarm clock with flashing lights or those devices which produce strong vibrations to awaken the individual or even shaking his bed are also available. 

 Health education.

        The client and his relatives are educated on how to keep the ear after any procedure done on him. For example, not to put anything in the ears, like oils or herbal drugs, to prevent further damage of the inner lining of the ear.

The client is introduced to the rehabilitative centers where he could be taught sign language to assist him to live a normal life.

The client is encouraged to keep appointment dates (review dates), to the health facility as ordered for further assessment and treatment if applicable.

The relatives are advised not to refer to the client’s hearing loss to help prevent the client from getting depressed.

The client is advised to be mixing with others, like the family members or friends for interaction and to prevent boredom. And his family should accept him as any other normal person, to promote sense of belonging.

  CONCLUSION

       In conclusion, we can simply say it it’s important for us nurses to have enough knowledge about management of clients with deafness and hard of hearing in order to be able to apply nursing skills in their management. This is to enhance their quick recovery and adaption to normal function.

  REFFERENCES .

1. Loeb S. et al (1993), Diseases, spring house, Bethlehem.

2. Berkow R. et al (1997), The Merck Manual of Medical Information, white House

station, USA.

3. Soanes C. (2008), Oxford English dictionary, Oxford University Press, New York.

4. David S. et al, (2007), Hole’s Human Anatomy and Physiology, McGraw Hill, Boston Burr Ridge.