Assessment of the Ears
The eye and the ear are sensory structures that connect us with the environment. They allow us to perceive our surroundings through sight and sound. Disorders of the eye and the ear can range from minor annoyances to life-threatening problems. Most problems do not result in acute illness; however, they may be associated with more serious neurological conditions such as brain tumor, stroke, or head injury.
No matter what the cause, visual and hearing problems can have a major impact on physiological functioning as well as psychological and social well-being. Early detection reduces the likelihood of problems related to social interaction.
Determining whether a patient has adequate vision and hearing is crucial before assessing mental status or providing instructions. The eyes and the ears are common sites of injury; they also exhibit structural variations as a result of age, cultural background, and genetic inﬂuences. Although, for the sake of clarity, the eyes and the ears are covered separately here, they are usually examined along with the head and neck because of their location.
A thorough assessment of the eyes and the ears includes vision and hearing screenings and examination of the external and internal structures.The assessment provides not only speciﬁc data about the eyes and the ears but also vital information on the health status of other systems.
Before you begin your assessment, an understanding of the anatomy and physiology of the eyes and the ears is essential. You need to be able to identify normal structures before you can identify abnormal ﬁndings, accurately perform the assessment, and correctly interpret your ﬁndings. This chapter covers assessment of the eyes ﬁrst and then assessment of the ears.
Anatomy and Physiology Review: The Ear
The main functions of the ears are hearing and equilibrium. Hearing requires an intact and unobstructed external canal, middle and inner ear, vestibulocochlear nerve (CN VIII), and temporal lobe (Figs. 12.14 and 12.15). Sound waves move through the external, middle, and inner ear,where they stimulate the vestibulocochlear nerve and transmit the impulses to the temporal lobe for interpretation. Maintaining normal equilibrium requires proper functioning of the structures in the inner ear.
Structures and Functions of the Ear. The three parts of the ear—external,middle, and inner—contain anatomical structures that work together to allow us to hear.
Understanding Sounds and Sound Waves. Hearing occurs by air conduction and bone conduction of sound waves. Sound waves are characterized by differences in pitch and loudness. Frequency, the number of sound waves per second, determines the pitch of the sound. Intensity or loudness is determined by the size of the sound waves. Sound waves can be classiﬁed on a continuum from high pitched to low pitched—for example, the high-pitched sounds of a whistle blowing or the screech of chalk on a chalkboard or the low-pitched sounds of a deep drum, thunder, or an explosion. The highness or lowness of pitch is a function of frequency or how fast or slow a sound wave vibrates.The frequency of a sound wave is measured in waves per second or Hertz (Hz). Low-frequency sound waves are interpreted by the brain as low-pitched sounds,and higher frequency waves are interpreted as high-pitched sounds.
The loudness of a sound wave is measured in a scale of units called decibels (dB). The structures of the inner ear are especially sensitive to loudness.Although we tolerate conversation,which is typically around 60 dB,exposure to excessive or repeated noise above 80 dB such as trafﬁc or machinery noise or exposure to rock music concerts at 120 dB or more can cause damage to the hearing structures and result in permanent hearing loss.
How We Hear. Air conduction is the primary mechanism of hearing; it involves carrying sound waves through the external auditory canal to the tympanic membrane (TM).There, the sound vibrations cause the TM and the malleus (hammer), incus (anvil), and stapes (stirrup) bones to move, thus transmitting the vibrations to the inner ear structures.
Bone conduction provides an additional pathway whereby sound waves vibrate the skull bones and transmit the vibrations to the inner ear structures.Both air and bone conduction use a common ﬁnal pathway involving transmission of the vibrations to the inner ear structures, then on to the cranial nerve and the temporal lobe (Fig. 12.16).
Interaction With Other Body Systems.
The Musculoskeletal System. Normal hearing involves proper functioning of certain skeletal structures.Hearing by air conduction involves the transmission of sound waves that vibrate the TM,which in turn transfers the vibrations to the three auditory ossicles. First, the malleus,which is in direct contact with the TM, receives the vibrations.The malleus then transfers the vibrations to the incus and then to the stapes,which transmits them directly to the oval window in the inner ear.
Hearing by bone conduction is much less precise and is dominant only when hearing by air conduction is not possible because of obstruction or perforation of the TM, ﬂuid behind the membrane, or otosclerosis of the auditory ossicles.Nevertheless,hearing by bone conduction also relies on an intact skeletal structure, the temporal bone, to transmit vibrations to the inner ear.Cooperation between the neurological and the skeletal systems is necessary to provide precise and accurate hearing.
The Neurological System. The primary functions of the ears, hearing and equilibrium, rely strongly on an intact and functioning neurological system.Whether hearing occurs solely by air conduction or bone conduction, the sound waves must eventually travel to the inner ear,where they are picked up by the organ of Corti, the sensory organ for hearing.Hair cells in the organ of Corti bend and mediate the vibrations into electrical impulses that are conducted to the vestibulocochlear nerve (CN VIII).The process of picking up sound waves, transmitting them,converting them to electrical impulses, and transmitting them to the brain represents only the ﬁrst of three levels of auditory functioning.
The second level involves the interaction of both ears and the brainstem in determining the location of the sound in space.When a sound is heard, the vestibulocochlear nerve from each ear sends electrical impulses to each side of the brainstem.The brainstem pinpoints the origin of the sound by evaluating factors such as head position, intensity, and timing of the information received from each ear.
The cortex of the brain, speciﬁcally the temporal lobe, is involved in the third level of auditory function, interpretation of the sound.Once sound waves have been converted to electrical impulses, they are received in the temporal lobe,where they are identiﬁed on the basis of past experience. Impulses are then sent to motor areas of the brain so that an appropriate response to the sound can be made.This level of response allows us to differentiate a telephone ring from a doorbell and take the action needed to either pick up the phone or answer the door.
As for maintaining equilibrium, the vestibule of the inner ear plays a crucial role.The vestibule is involved in sensing and perceiving how the body is moving in space.The vestibule also orients the body to maintain a vertical position, stabilizes the position of the head, and helps to maintain the center of gravity.
Disorders of equilibrium can result from two primary causes.The ﬁrst is chronic loss of vestibular information caused by CN VIII and vestibular hair cell degeneration related to aging or neurotoxicity.The second is distortion of information produced by disruption of the ﬂuid dynamics in the labyrinth of the inner ear. With chronic degeneration, problems with balance are more constant and the person can adapt to them to some degree if the terrain remains constant. However, persons with disorders involving disruption or distortion tend to have symptoms more intermittently and unpredictably, thus preventing the person from adapting as readily. In addition,movement of the head may trigger the vestibular receptors to signal the brain that the head and body are moving when in fact they are not.
Developmental, Cultural, and Ethnic Variations.
Infants and Children. The structures needed for hearing are predominantly developed in utero during the ﬁrst trimester. During this time, damage to the structures from genetic, congenital, and infectious processes can cause hearing problems.
Assessment of the ear is especially important in infancy. Observing the appearance of the external ear and noting behaviors that indicate intact hearing are important ways to screen for potential problems that can cause developmental delays or indicate genetic conditions.Abnormalities in the structure and positioning of the ears are more common in infants who have a hearing deﬁcit. Low-set ears, ears that are positioned at greater than a 15-degree angle, and malformed ears are often associated with genetic disorders and developmental delays.
Infants and children are more prone to inner ear infections than are adults.One reason is that the Eustachian tube, which opens from the nasopharynx to the middle ear, is shorter,wider, and more horizontal than in adults, making migration of bacteria from the nasopharynx common. Infants also have greater amounts of lymphoidal tissue surrounding the lumen of the eustachian tube,which can occlude and trap bacteria.By school age, the external auditory canal has assumed a straighter,more adult conﬁguration,which is less prone to infection (Fig. 12.17).
Young and Middle-Aged Adults. Hearing loss caused by excessive or chronic exposure to noise damages the cochlear structures of the inner ear that are involved in conduction of vibrations to CN VIII. Noise-induced hearing loss from exposure to loud music or machinery is the most common cause of hearing loss for the 20- to 40-year-old age group.
Older Adults. Hearing loss in older adults is extremely common and can be associated with sensorineural loss or conductive loss. Hearing loss associated with aging, referred to as presbycusis, occurs around the ﬁfth decade and gradually progresses. Typically, presbycusis involves hearing loss for high-pitched sounds, such as consonants, and affects men more often than women.
Older adults are prone to stiffening of the cilia in the external canal. This impedes the transmission of sound waves to the TM and causes cerumen to accumulate more readily and obstruct the membrane. Excess accumulation of cerumen impairs hearing by air conduction and is one of the most common correctable causes of conductive hearing loss in older adults.
People of Different Cultures/Ethnic Groups. Several variations in ear structure and disorders of the ear are known to occur in certain ethnic groups.Otitis media, or middle ear infection, is a relatively common afﬂiction in infants as a result of bottle feeding and exposure to second-hand smoke. However, the incidence and severity of otitis media for Native American,Hispanic,and Alaskan infants is higher than for infants in the general population.
The characteristics of cerumen, or ear wax, also vary with different ethnic groups. Cerumen can be of two types—dry, white, and ﬂaky, as seen in the majority of Asians and Native Americans;or brown,wet,and sticky, as seen in the majority of blacks and whites.People living in highly industrialized communities are routinely exposed to sounds above 80 dB, such as trafﬁc and occupational machinery, and are more prone to hearing loss. In the United States, hearing loss caused by noise affects more than 1 million people and is one of the most prevalent occupational disorders.
Performing the Ear Assessment. Assessment of the ear involves obtaining a complete health history and performing a physical examination.As you perform the assessment, be alert for signs and symptoms of actual or potential problems in the various structures of the ear.
Health History. The health history identiﬁes any related symptoms or risk factors and the presence of diseases involving the ear. It must also detect any other disorders that may affect the ear.Your history will include obtaining biographical data and asking questions about the patient’s current health,past health, and family and psychosocial history. It also includes a review of systems and an ear history. If your patient has severe hearing problems, you may have to communicate by writing or have a family member answer questions. If you don’t have time to perform a complete health history, make sure to perform at least a focused health history of the ears.
Biographical Data. Review the patient’s biographical data to identify age, occupation, gender, and ethnic background. Use these patient characteristics to guide the types of health history questions that you ask and facilitate your interpretation of subsequent history and examination ﬁndings. For example, the techniques used to examine an infant’s ear differ from those used to inspect an adult’s ear.The types of assessments you perform for hearing acuity also vary greatly with the patient’s age.Knowledge of the patient’s cultural and ethnic heritage can provide information on potential language barriers and can facilitate the evaluation of physical examination ﬁndings that vary with different groups.
Knowing the patient’s occupation can provide information about environmental risk for ear trauma and can help identify areas for health promotion education.
Current Health Status. First, ask the patient to describe the chief complaint in his or her own words. Next, use the PQRST format to investigate further about any symptoms reported. If your patient reports an ear problem, focus your questions on the ear symptoms presented in the following section.
Hearing Loss. Hearing loss is a diminished ability to perceive sounds. It may be a result of problems that affect transmission of sound waves to the middle ear (conductive loss) or problems involving interpreting the sound and converting it to neurological impulses (sensorineural loss). Hearing loss may be sudden or gradual, unilateral or bilateral, and may be limited to sounds of certain frequencies or pitches.
Vertigo. Vertigo is a subjective feeling of the body moving or swaying in space or of stationary objects moving or spinning in space.Vertigo most often results from a disturbance of structures involved with equilibrium and balance, which includes the inner ear and central nervous system.
Tinnitus. Tinnitus is a subjective perception of a high-pitched ringing or buzzing sound in one or both ears. It occurs in certain disorders of the external, middle, and inner ear.
Ear Drainage (Otorrhea). Drainage from the ear is abnormal. Purulent drainage indicates infection; drainage that is clear or contains cerebral spinal ﬂuid or blood indicates trauma.
Earache (Otalgia). Ear pain, known as earache or otalgia, is a common symptom of ear disorders, particularly ear infections.
Past Health History. During this section of the health history interview, focus on gathering relevant information about the patient’s childhood illnesses and injuries,adult illness and injuries, and medication use as they relate to the ears.
Family History. When gathering information on your patient’s family history, consider the following familial conditions that may affect the ears.
Review of Systems. Changes in the structure and function of the ear may relate to every other system of the body.The review of systems (ROS) will help you identify problems in other systems that directly affect the ear.Remember, the ROS allows you to pick up anything that you might have missed, and the ﬁndings will give meaning to the symptoms by relating them to the affected system.
Psychosocial Proﬁle. The psychosocial proﬁle includes asking questions about the patient’s lifestyle, including a typical day, personal habits, medications, sleep patterns, and home and work environment. These factors affect the patient’s overall health.
Anatomical Landmarks. Before beginning your physical examination of the ear, review the internal structures and normal positioning of the external ear (Figs. 12.18 and 12.19).
Physical Assessment. The health history has provided you with clues that will help direct your physical examination.When examining patients who have severe hearing deﬁcits, you may need to explain what you are doing by some other means,such as writing.
Approach. Physical assessment of the ear entails screening for hearing deﬁcits and examining the external ear and TM.Keep in mind that ear problems may relate to other body systems, so assess for signs in every system. Examination of the ear involves inspection and palpation of the external ear and external auditory canal, followed by tests for hearing and equilibrium. Examination of the auditory canal and TM are done early in the examination to ensure that structures for hearing are intact and unobstructed before testing hearing acuity.
The examination is usually performed with the person in a sitting position. However,when performing the otoscopic examination on a young child, it is better if the child is supine with the head turned to the side being examined.A quiet environment is essential when performing the hearing screening tests.
Performing a General Survey. Before assessing the ear, perform a general survey. Note the person’s overall appearance, including nutritional status, body habitus, and emotional status.Also take vital signs—temperature elevations may indicate an infection.
Be especially alert for signs that suggest problems with the ear. Ask yourself these questions:
■ Is the person guarding her or his ear? If the patient is a child, is she or he tugging or rubbing the ear? These are signs of an ear infection.
■ Is the patient attentive and responding appropriately? Inappropriate responses or inattentiveness may result in hearing deﬁcits.
■ Is the patient speaking loudly? People with hearing deﬁcits tend to speak louder.
■ Do you notice any problems with the patient’s ability to maintain balance? Balance problems are associated with inner ear problems.
Performing a Head-to-Toe Physical Assessment. Now scan your patient from head to toe.Check for more speciﬁc signs of diseases that involve other organ systems and that might affect the ears.
Performing Physical Assessment of the Ear. Now that you have completed your general survey and head-to-toe scan, you can focus on the ear. First, inspect and palpate the external structures of the ear. Then examine the internal ear with an otoscope. Finally, perform hearing acuity tests.
Otoscopic Examination. The otoscope illuminates and magniﬁes the auditory canal and the TM. The auditory canal is assessed for color, lesions, and foreign objects. The TM is assessed for color, intactness, appropriateness of landmarks, and mobility of the drum. Select the largest and shortest speculum that will ﬁt into the patient’s ear canal comfortably, and attach it to the head of the otoscope.Usually, a 4-,5-,or 6-mm, 1⁄2-inch speculum is appropriate for an adult ear canal.
Turn the otoscope light on.Have the patient tilt his or her head away from the side you are examining. Always look into the external canal before inserting the otoscope. Two insertion techniques may be used:
■ Technique #1: Hold the otoscope upside down like a pencil, with the magnifying lens facing the examiner. Pull the pinna of the ear up and back for adults and down for children under age 2. Brace your insertion hand on the patient’s head for stabilization. This technique is ideal for children, because if they move the head, your hand moves with it.
■ Technique #2: An alternative technique is to hold the otoscope handle upright and slowly and gently insert the scope along the axis of the external auditory canal (about 1⁄2 inch in an adult and 1⁄4 inch in a child). Be careful to enter only the outer third of the ear canal. With the scope inserted, put your eye up to the viewing lens. If you cannot visualize the TM, do not move the otoscope. Instead, apply more traction, pull on the ear, or carefully adjust the angle of the otoscope more toward the patient’s nose. Do not release the traction on the ear until the speculum of the otoscope has been removed from the ear. Remove the speculum in the same angle as it was inserted, and then release the traction to the pinna.
Hearing Tests. Examination of the ear includes conducting hearing tests for high-tone, low-tone, sensorineural, and conductive hearing loss. Typical tests include the following:
■ Watch tick test: This test determines the patient’s ability to hear high-pitched sounds and screen for hightone hearing loss.To do this test, have the patient obstruct one ear at a time by placing her or his index ﬁnger in the external canal.Using a ticking watch,hold it close to the unobstructed ear and slowly move it away until the patient says that she or he can hear the watch tick (usually about 5 inches [13 cm]).Repeat the test on the other ear.
■ Whisper test: This test assesses low-pitch or low-tone hearing loss.Again, have the patient obstruct one ear with the index ﬁnger. Then stand 1 to 2 feet behind and to the side of the patient’s unobstructed ear and whisper three or four unrelated words. Have the patient repeat the words heard. Test the other ear in a similar fashion.
■ Tuning-fork tests: These tests check for intact sensorineural and conductive hearing. The Weber test assesses lateralization of sound. Sound transmission with the Weber test is both through bone conduction (BC) and air conduction (AC). To perform the test, place a vibrating tuning fork firmly on top of your patient’s head or forehead.
Ask the patient if the vibration sounds the same in both ears or different. Normally, the vibration is heard equally in both ears. If the vibration is louder or more distinct in one ear than in the other, it has lateralized to that ear (positive lateralization). If there is conductive hearing loss, the sound lateralizes to the impaired ear; if there is sensorineural hearing loss, the sound lateralizes to the unaffected or good ear. Conductive hearing loss is usually caused by a problem with the external or middle ear, such as acute otitis media, perforated eardrum, or a blocked canal with cerumen. Sensorineural hearing loss is usually caused by a problem in the inner ear, such as acoustic nerve damage from ototoxic drugs.
Having a conductive loss in the lateralizing ear (e.g., as a result of accumulation of cerumen or a perforated eardrum) means that sound waves are not conducted effectively by AC to the inner ear. Thus, limited or no sound waves are received by AC. The only mechanism remaining for sound wave conduction in the lateralizing ear is by BC.But without competing AC, sound waves will be interpreted by the patient as sounding louder.To test this yourself, create a temporary conductive hearing loss by occluding the external auditory canal and placing the vibrating tuning fork as described. In a person with normal hearing, sound will lateralize to the obstructed ear because you have blocked any competing AC sounds from being transmitted.
With a sensorineural hearing loss, the sound lateralizes to the good ear. The ear with sensorineural deafness is unable to transmit sound waves by AC or BC to the acoustic nerve to the brain. Consequently, the sounds transmitted to the opposite ear will be interpreted as louder, or lateralizing.
The Weber test can detect lateralization, but it cannot differentiate the cause. So if lateralization occurs, you will need to perform the Rinne test to establish if the problem is caused by a conductive hearing loss.
The Rinne test is a timed tuning-fork test used to compare AC and BC. To perform this test, place a vibrating tuning fork on your patient’s mastoid process. When it is on the mastoid process, sound transmission is through BC to the inner ear. Ask the patient to tell you when he or she no longer hears the vibrations. Record the amount of time the patient heard the sound in seconds.When the sound is no longer heard, immediately place the vibrating fork about 1 inch in front of the external auditory canal and continue to time until your patient can no longer hear the sound.When in front of the ear, sound transmission is through AC through the auditory canal, to the TM, middle ear, and inner ear. Avoid touching hairs in front of the ear with the vibrating tuning fork because this may provide a clue that the tuning fork is vibrating. Record the amount of time the patient hears the vibrating tuning fork in seconds. Normally, sound transmission through air is twice as long as sound transmission through bone. If AC time is less than twice as long as BC time, it generally indicates hearing loss by AC. Inability to hear the tuning fork during BC indicates sensorineural hearing loss.
■ A thorough health history provides direction for the physical examination to include exploration of factors that may be related to ear health. Information from both the history and the physical examination is then analyzed to determine appropriate nursing diagnoses.
■ The ears are complex sensory organs that provide specialized functions crucial to neurosensory development in infancy and to the development of psychosocial, motor, and cognitive skills in childhood and the maintenance of those skills in adulthood.
■ A comprehensive history and physical examination enables early detection and treatment of hearing problems.