Weber & Rinne Test results Interpretation and Clinical Conclusion

 Weber and Rinne Test Interpretation

Weber & Rinne Test results Interpretation and Clinical Conclusion on the basis of both.

The Ear

Anatomy and Physiology. The ear has three compartments: the external ear, the middle ear, and the inner ear.

The External Ear. The external ear comprises the auricle and ear canal. The auricle consists chiefly of cartilage covered by skin and has a firm elastic consistency. Its prominent curved outer ridge is the helix. Parallel and anterior to the helix is another curved prominence, the anti helix. Inferiorly is the fleshy projection of the earlobe, or lobule. The ear canal opens behind the tragus, a nodular protrusion that points backward over the entrance to the canal. The ear canal curves inward and is approximately 24 mm long. Cartilage encases its outer two thirds. 

    In this segment, the skin is hairy and contains glands that produce cerumen (wax). The inner third of the canal is surrounded by bone and lined by thin, hairless skin. Pressure on this latter area causes pain—a point to remember when you examine the ear. At the end of the ear canal lies the lateral tympanic membrane, or eardrum, marking the medial limit of the external ear. The external ear captures sound waves for transmission into the middle and inner ear behind and below the ear canal is the mastoid portion of the temporal bone. The lowest portion of this bone, the mastoid process, is palpable behind the lobule.

The Middle Ear. In the air-filled middle ear, the ossicles the malleus, the incus , and the stapes transform sound vibrations into mechanical waves for the inner ear. The proximal end of the eustachian tube connects the middle ear to the nasopharynx. Two of the ossicles are visible through the tympanic membrane, and are angled obliquely and held inward at its center by the malleus Find the handle and the short process of the malleus, the two chief landmarks. 

    From the umbo, where the eardrum meets the tip of the malleus, a light reflection called the cone of light fans downward and anteriorly. Above the short process lies a small portion of the eardrum called the pars flaccida. The remainder of the drum is the pars tensa . Anterior and posterior malleolar folds, which extend obliquely upward from the short process, separate the pars flaccida from the pars tensa , but are usually invisible unless the eardrum is retracted. A second ossicle, the incus, can sometimes be seen through the drum.

The Inner Ear. Movements of the stapes vibrate the perilymph in the labyrinth of the semicircular canals and the hair cells and endolymph in the ducts of the cochlea, producing electrical nerve impulses transmitted by the auditory nerve to the brain. Much of the middle ear and all of the inner ear are inaccessible to direct examination. Assess their condition by testing auditory function.

Hearing Pathways. The first part of the hearing pathway, from the external ear through the middle ear, is known as the conductive phase. The second part of the pathway, involving the cochlea and cochlear nerve, is the sensorineural phase . Air conduction (AC) describes the normal first phase in the hearing pathway. An alternative pathway, known as bone conduction (BC), bypasses the external and middle ear and is used for testing purposes. A vibrating tuning fork, placed on the head, sets the bone of the skull into vibration and stimulates the cochlea directly. In those with normal hearing, AC is more sensitive than BC (AC > BC).

Equilibrium. The labyrinth of three semicircular canals in the inner ear senses the position and movements of the head and helps maintain balance.

Techniques of Examination

The Auricle. Inspect the auricle and surrounding tissue for deformities, lumps, or skin lesions. If ear pain, discharge, or inflammation is present, move the auricle up and down, press the tragus, and press firmly just behind the ear.

Ear Canal and Drum. To see the ear canal and drum, use an otoscope with the largest ear speculum that inserts easily into the canal. Position the patient's head so that you can see comfortably through the otoscope. To straighten the ear canal, grasp the auricle firmly but gently and pull it upward, backward, and slightly away from the head Holding the otoscope handle between your thumb and fingers, brace your hand against the patient's face. 

    Your hand and instrument can then follow unexpected movements by the patient. (If you are uncomfortable switching hands for the left ear, as shown in you may reach over that ear to pull it up and back with your left hand and hold the otoscope steady with your right hand as you gently insert the speculum.) Insert the speculum gently into the ear canal, directing it somewhat down and forward and through the hairs, if any

Whispered Voice Test or Rustling fingers test for Auditory Acuity

● Stand 2 feet behind the seated patient so that the patient cannot read your lips.

● Occlude the non test ear with a finger and gently rub the tragus in a circular motion to prevent transfer of sound to the non test ear.

● Exhale a full breath before whispering to ensure a quiet voice.

● Whisper a combination of three numbers and letters, such as 3-U-1. Use a

different number/letter combination for the other ear.

● Interpretation:

● Normal: Patient repeats initial sequence correctly.

● Normal: Patient responds incorrectly, so test a second time with a different number/letter combination; patient repeats at least three out of the possible six numbers and letters correctly.

● Abnormal: Four of the six possible numbers and letters are incorrect. Conduct further testing by audiometry. (The Weber and Rinne tests are less accurate and precise.)

Weber test

    Test for lateralization ( Weber test ). Place the base of the lightly vibrating tuning fork firmly on top of the patient's head or on the mid forehead. Ask where the patient hears the sound: on one side or both sides? Normally, the vibration is heard in the midline or equally in both ears. If nothing is heard, try again, pressing the fork more firmly on the head. Restrict this test to patients with unilateral hearing loss since patients with normal hearing may lateralize, and patients with bilateral conductive or sensorineural deficits will not lateralize.

Rinne: Compare AC and BC (Rinne test). Place the base of a lightly vibrating tuning fork on the mastoid bone, behind the ear and level with the canal. When the patient can no longer hear the sound, quickly place the fork close to the ear canal and ask if the patient hears a vibration. Here, the “U” of the fork should face forward, which maximizes sound transmission for the patient. Normally, the sound is heard longer through air than through bone (AC > BC).