By Dr. Marcus Judge

OSCE

In an OSCE, you need to understand the pathology and the reasoning behind each sign and symptom you elicit. This is true even if the patient being examined is ‘normal’. This article explains how to perform an ear, otoscopy (looking into the ear canal with a handheld light and magnifier) and hearing examination. It covers the key findings to look for, what each sign means and which conditions it may indicate.

The ear is divided into three parts. The outer ear is the pinna (the visible part of the ear) and the external auditory meatus (the ear canal). The middle ear contains the tympanic membrane (the eardrum) and the ossicles (three tiny bones that carry sound). The inner ear contains the cochlea (the hearing organ) and the vestibular apparatus (the balance organs). Keeping this anatomy in mind helps you localise where a problem lies. That in turn tells you which of the two broad types of hearing loss is present: conductive (a problem of the outer or middle ear getting sound to the cochlea) or sensorineural (a problem of the cochlea or auditory nerve).

Anatomy of the Human Ear SimpleMed

Image - Cross-section of the ear. The outer ear (green), middle ear (red) and inner ear (purple). Conductive loss arises in the outer or middle ear, sensorineural loss in the inner ear or auditory nerve

Creative commons source by Lars Chittka and Axel Brockmann [CC BY 2.5 (https://creativecommons.org/licenses/by/2.5)]

Contents

  1. Introduction
  2. General Inspection
  3. Inspection of the Outer Ear
  4. Otoscopy
  5. Gross Hearing Assessment
  6. Tuning Fork Tests – Weber’s Test
  7. Tuning Fork Tests – Rinne’s Test
  8. Completing the Examination
  9. Quiz

Introduction

Wash your hands and put on personal protective equipment if appropriate, for example gloves if the ear is discharging.

Introduce yourself to the patient and make sure you mention your grade e.g. 3rd year medical student/junior doctor/consultant.

Confirm the patient’s details taking 3 points of identification, usually full name, date of birth and NHS or hospital number.

Obtain consent for the examination making sure you explain what the examination will entail, including that you will need to look inside both ears and carry out some simple hearing tests.

Position the patient sitting upright on a chair, with you able to access both ears from the side.

Ask whether the patient has any ear pain or discharge before you begin, as the examination of a painful ear should be performed gently and last.

Gather your equipment before you start so that the examination flows smoothly. You will need an otoscope (a handheld light with a magnifier for looking into the ear), disposable specula in different sizes (the small cone-shaped tips that fit on the otoscope), a 512 hertz (Hz) tuning fork for the Rinne and Weber tests (two tuning fork tests explained below), and alcohol gel for hand hygiene. Check the otoscope light works and is bright before you begin.

General Inspection

Begin by stepping back and observing the patient and their surroundings. Note whether the patient appears comfortable or in distress. Also note whether they turn a particular ear towards you or watch your lips closely, which can be subtle clues to hearing impairment.

Look for any hearing aids, which immediately suggest a degree of established hearing loss. Also look for a cochlear implant (a processor worn behind the ear with a magnetic disc on the scalp), which indicates severe to profound sensorineural loss.

Inspect for an obvious facial nerve palsy (weakness or paralysis of the facial muscles). The facial nerve (cranial nerve VII) runs through the temporal bone (the skull bone that houses the ear) in close relationship to the middle ear. It can be affected by middle ear disease, cholesteatoma (an expanding growth of skin cells in the middle ear that erodes bone) or surgery. Look at the bedside for any tissues, cotton buds, or evidence of discharge.

Facial Nerve Palsy SimpleMed

Image - A patient with left facial weakness attempting to show their teeth, with the mouth drawn towards the unaffected right side. The facial nerve’s course through the temporal bone means middle ear disease and ear surgery can cause facial weakness

Image source by Benjaminginterr [CC BY-SA 4.0]

Inspection of the Outer Ear

Inspect each pinna in turn, comparing both sides. Look at the front and behind the ear, and remember to lift the pinna forwards to inspect the post-auricular sulcus (the groove where the ear meets the skull) and the skin behind the ear.

Note the shape and size of each pinna. A deformity may be congenital (present from birth). Examples are microtia (a small pinna), anotia (an absent pinna) and low-set ears seen in some genetic syndromes. A deformity may also be acquired, such as the lumpy cauliflower ear that follows repeated trauma and an untreated auricular haematoma (a collection of blood under the skin of the pinna).

Look for scars. A post-auricular scar (a scar behind the ear) may indicate previous mastoid surgery (mastoidectomy, an operation on the bony lump behind the ear), while an endaural scar (a scar at the entrance to the ear canal) suggests previous middle ear surgery. Either scar points towards chronic ear disease such as cholesteatoma.

Inspect the skin for signs of inflammation, swelling or discharge. A red, swollen and tender pinna and canal with discharge suggests otitis externa (infection of the external ear canal). If the pinna itself is hot, red and extremely tender but the earlobe (the lobule, which contains no cartilage) is spared, consider perichondritis. This is an infection of the cartilage that can lead to permanent deformity if untreated.

Feel behind the ear for a tender, boggy swelling (soft and spongy to touch) that pushes the pinna forwards and outwards with loss of the post-auricular sulcus. This is the classic appearance of mastoiditis. It is a serious complication of middle ear infection, in which infection spreads into the air cells of the mastoid bone, and it requires urgent assessment.

Also note any obvious skin lesions on or around the ear (basal cell and squamous cell carcinomas, which are skin cancers, can arise on the sun-exposed pinna). Look too for a pre-auricular sinus, a small congenital pit in front of the ear that can become infected.

Palpate the regional lymph nodes that drain the ear. These are the pre-auricular nodes (in front of the ear), the post-auricular nodes (behind the ear) and the upper cervical chain (the lymph nodes in the upper neck). Enlarged, tender nodes accompany local infection such as otitis externa, while a hard, fixed node should raise concern about malignancy of the pinna or canal.

Finally, gently move the pinna and press on the tragus (the small flap of cartilage in front of the ear canal). Pain on moving the pinna or pushing the tragus (a positive tragal sign) is typical of otitis externa. Pain on this manoeuvre is usually absent in otitis media (infection of the middle ear), where the tenderness is felt deeper. This simple test helps distinguish outer ear from middle ear disease before you reach for the otoscope.

Otoscopy

Otoscopy allows you to inspect the external auditory meatus and the tympanic membrane (eardrum). Examine the normal (asymptomatic) ear first so that you do not transfer infection and so that you have a comparison for the affected side.

Select the largest speculum that comfortably fits the canal, as this gives the best view and the most light. Turn the otoscope light on. Hold the otoscope like a pen, in your right hand for the patient’s right ear and in your left hand for their left ear.

To straighten the naturally S-shaped ear canal in an adult, gently pull the pinna upwards and backwards. (In an infant or young child the canal is straightened by pulling the pinna downwards and backwards instead.) Brace the hand holding the otoscope against the patient’s cheek so that if they move suddenly the instrument moves with them, avoiding injury to the canal.

Advance the speculum under direct vision. Inspect the canal walls for wax, debris, discharge, swelling or foreign bodies. Wax (cerumen) is normal and protective but excessive wax may obscure the view and cause conductive hearing loss. Pus or debris in the canal suggests otitis externa, but pus can also come from the middle ear through a perforated eardrum (see below).

Now examine the tympanic membrane. A normal eardrum is pearly grey, translucent and slightly concave. You should identify the handle of the malleus (the first of the three ear bones, attached to the eardrum) running downwards and backwards, with the pars tensa (the large, tight part of the eardrum) below it. You should also see a cone of light (light reflex) radiating anteroinferiorly (forwards and downwards) from the tip of the malleus. It is classically at the 5 o’clock position in the right ear and the 7 o’clock position in the left ear. Above the malleus lies the smaller pars flaccida (the slack upper part of the eardrum).

Normal Tympanic Membrane SimpleMed

Image - A normal left tympanic membrane. It is pearly grey and translucent, with the handle of the malleus visible and a cone of light radiating anteroinferiorly

Creative commons source by Michael Hawke MD [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]

Look for the following abnormalities, each of which reflects a specific pathology:

  • A red, bulging eardrum with loss of the normal landmarks and light reflex suggests acute otitis media, where pus under pressure pushes the drum outwards.
  • A dull, retracted drum with a visible fluid level or bubbles behind it suggests otitis media with effusion (fluid in the middle ear, also called ‘glue ear’), caused by Eustachian tube dysfunction (poor working of the tube that links the middle ear to the back of the nose) and negative middle ear pressure. This is a common cause of conductive hearing loss in children.
  • A perforation appears as a defect in the drum. It may follow infection or trauma, and a persistent perforation causes conductive hearing loss.
  • A retraction pocket (an area where the drum is sucked inwards) or whitish keratin debris (flakes of a tough skin protein), classically in the attic (pars flaccida) at the top of the drum, raises suspicion of a cholesteatoma. This is an expanding collection of keratinising squamous epithelium (skin cells that produce keratin) that erodes bone and can cause serious complications.
  • Grommets (tympanostomy tubes) may be seen as small ventilation tubes inserted through the drum to drain the fluid and equalise pressure in children whose glue ear causes persistent hearing loss.

Gross Hearing Assessment

A bedside hearing screen assesses whether hearing is grossly intact and helps identify the worse ear. Test each ear separately, masking the non-test ear (blocking it so that it contributes less) by gently occluding its auditory canal and rubbing the tragus. This reduces the contribution of the opposite ear, but some sound may still reach its cochlea. Stand behind the patient so they cannot read your lips, and reach round behind their head to mask the opposite ear comfortably.

Position yourself about an arm’s length (60 cm) from the test ear, out of the patient’s line of sight so they cannot lip-read. Whisper a combination of numbers and letters (for example a two-digit number and a letter) and ask the patient to repeat it back. Use a different combination for each attempt so the patient cannot guess. If the patient repeats the first combination correctly, hearing is considered normal. If not, repeat with a different combination: the patient passes if they repeat at least three of the six items correctly across both attempts, which means hearing in that ear is broadly intact at that intensity.

If they cannot hear the whisper, you can repeat at a normal conversational volume and then a loud voice. The louder you have to go before the patient responds, the greater the loss is likely to be, but this is only a rough guide: the whispered voice test is a pass or fail screen and does not measure how severe the loss is. Inability to hear a whispered voice at arm’s length suggests hearing loss in that ear and prompts more formal testing.

The gross test only tells you that hearing is reduced. It does not tell you why. To distinguish conductive from sensorineural loss you need the tuning fork tests.

Tuning Fork Tests – Weber’s Test

Tuning fork tests use a 512 Hz fork. This frequency is chosen because it gives the best balance between an audible tone and a long enough decay time (how long the sound lasts before it fades). Lower-frequency forks are felt as vibration more than heard, and higher-frequency forks decay too quickly.

To set the fork in motion, strike it against your knee or elbow (a soft surface), never a hard table, which produces unwanted overtones (extra notes that distort the tone).

For Weber’s test, place the base of the vibrating fork in the midline of the forehead (or on the vertex, the top of the head). Ask the patient: “Where do you hear the sound: in the middle, the left ear or the right ear?”

  • Normal: the sound is heard equally in the midline, in both ears.
  • Conductive hearing loss: the sound localises to the affected (worse) ear. This is because the absence of competing background (air-conducted) sound in the blocked ear allows bone-conducted sound to be perceived more clearly on that side.
  • Sensorineural hearing loss: the sound localises to the unaffected (better) ear, because the damaged cochlea on the affected side perceives the bone-conducted tone less well.

Weber’s test alone cannot tell you which ear is abnormal. It only tells you that the sound has lateralised (shifted to one side). It must always be interpreted together with Rinne’s test.

Tuning Fork Tests – Rinne’s Test

Rinne’s test compares air conduction (AC) with bone conduction (BC) in each ear. In a healthy ear the entire conducting apparatus (canal, drum and ossicles) amplifies sound, so air conduction is normally better than bone conduction.

Strike the fork and place its base firmly on the mastoid process (the bony lump behind the ear) to test bone conduction. Steady the patient’s head with your other hand. Ask the patient to tell you when they can no longer hear the tone. As soon as they say so, move the still-vibrating prongs to sit just in front of the external auditory meatus (without touching it) to test air conduction. Ask whether they can now hear it again.

  • Rinne’s positive (normal): air conduction is better than bone conduction (AC > BC), so the patient still hears the fork at the ear after it has faded at the mastoid. This is the normal result and is also seen in sensorineural hearing loss, where both AC and BC are reduced but their normal relationship is preserved. Tuning fork tests are imperfect and can miss a conductive loss, so do not rely on Rinne’s test alone.
  • Rinne’s negative (abnormal): bone conduction is better than air conduction (BC > AC), so the patient does not hear the fork when it is moved to the ear. This indicates a conductive hearing loss in that ear, because the damaged conducting apparatus can no longer amplify air-conducted sound, while the cochlea still detects vibration delivered directly through bone.

Beware the false-negative Rinne: in a severe unilateral sensorineural loss, the bone-conducted tone applied to the ‘deaf’ mastoid may actually be heard by the opposite, healthy cochlea, mimicking a conductive picture. Combining Rinne with Weber, and ultimately with pure tone audiometry (a hearing test using headphones and tones of different pitches), resolves this.

Putting the two tests together gives you a quick way to characterise the loss. This is exactly what an examiner wants to hear you interpret out loud:

  • Normal hearing: Weber central; Rinne positive (AC > BC) in both ears.
  • Conductive loss (e.g. wax, effusion, perforation, or otosclerosis, which is abnormal bone growth that stops the middle ear bones moving): Weber lateralises to the affected ear; Rinne negative (BC > AC) in the affected ear.
  • Sensorineural loss (e.g. presbycusis, which is age-related hearing loss, noise damage, or ototoxicity, which is ear damage caused by drugs): Weber lateralises to the better ear; Rinne positive (AC > BC) in both ears.

If the results do not fit one of these patterns, for example a Rinne that appears negative in a profoundly deaf ear, suspect a false-negative from cross-hearing (sound travelling through the skull to the opposite cochlea). Rely on Weber and formal audiometry to clarify.

Completing the Examination

Thank the patient and wash your hands.

Summarise your findings, stating whether hearing appeared normal or reduced and, if reduced, whether the tuning fork tests suggest a conductive or sensorineural pattern and in which ear.

To complete the examination, suggest performing a full examination of the cranial nerves (particularly the facial nerve, given its course through the temporal bone). If the patient reports dizziness or balance problems, also suggest an examination of the vestibular system (the balance system), including the Romberg test (standing with feet together and eyes closed to test balance), the head impulse test (a quick head turn to test the balance reflex) and assessment for nystagmus (involuntary jerking movements of the eyes).

Suggest examining the nose and throat, as Eustachian tube dysfunction and nasopharyngeal pathology (disease at the back of the nose) can cause middle ear disease. Also suggest tympanometry (a test of how well the eardrum moves) to assess middle ear function and pure tone audiometry to formally quantify and characterise any hearing loss.

Quiz

Preview the Ear, Otoscopy and Hearing OSCE Examination quiz

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