Ear and Facial Nerve (inc. Free Field Hearing)

sGross hearing using free field voice testing 

 

    1. Test the better hearing ear first.
    2. Stand to one side of the patient
    3. Use one hand to shield the patient’s eyes and the other to pass behind their head and continuously rub the opposite non-test ear’s tragus. This is called masking. 
    4. Stand at arms length away from the patient
    5. Whisper a combination of alphanumeric syllables (e.g. 6-H-G). Bisyllabic words may be used for children (e.g. football)
    6. Ask the patient to repeat what they heard back to you.

The patient has passed the test if they can accurately repeat >50% of the alphanumeric combinations back to you. This person should have hearing thresholds of ≈ 12dB.

 

If they fail then repeat steps 1-3. Then perform the following in order until the patient is able to accurately repeat >50% of the alphanumeric combinations back to you:

  1. Arms length away – conversational voice ≈ 48dB
  2. Arms length away – loud voice ≈ 76dB
  3. Half-arms length away – whispering ≈ 34dB
  4. Half-arms length away – conversational voice ≈ 56dB
  5. Half-arms length away – loud voice ≈ >90dB

There is some overlap, but essentially this test can be used to divide patients into mild (PTA <30dB), moderate (PTA 30-70dB) and severe (PTA >70d) hearing loss. 

Facial nerve

The facial nerve has motor, sensory and parasympathetic functions. 

 

Motor function

  • Examine the face at rest for asymmetry

  • “Raise your eyebrows” – frontalis muscle

  • “Close your eyes as tight as you can, don’t let me open them” – orbicularis oculi muscle

  • “Open your eyes”

  • “Puff out your cheeks” – Orbicularis oris, buccinator muscle.

  • “Show me all your teeth” – platysma

Sensory function

  • Ask about dysgeusia (altered taste) 

  • Offer formal taste testing

 

Parasympathetic function

  • Ask about dry eyes, mouth and nose (parasympathetic supply to lacrimal gland, submandibular gland and nasal mucosa)

  • Offer to do corneal reflex (the efferent arm of the corneal reflex is via the facial nerve, the afferent arm is via the trigeminal nerve)

 

To complete examination 

Suggest further examinations

  • Thank patient for examination

  • Wash your hands

  • Present findings

  • Full head and neck examination

  • Facial nerve and cranial nerve examination

  • Audiometry and tympanometry

  • Suggest that you would document your findings in the patient’s notes

 

Possible investigations that may subsequently be requested:

 

  • Pure tone audiometry 

  • Tympanometry 

  • MRI internal auditory meatus

  • CT temporal bone

  • Vestibular function tests

 

Post a comment

Leave a Comment

Your email address will not be published. Required fields are marked *