Hearing examination

Hearing examination Weber’s test • • • Tap a 512Hz tuning fork and place in the midline of the forehead. - The tuning fork should be set in motion by drinking the table. Ask the patient where they hear the sound. These results should be assessed in context with the result of Rinne’s test before any diagnostic assumptions are made: - Normal: sound is equal in both years. - Sensorineural deafness: sound is heard louder on the side of the intact year. - Conductive deafness: sound is heard louder on the side of the affected year. Rinne’s Test • • • • • Place a vibrating 512 Hz turning firmly on the mastoid process (apply pressure to the opposite head to make sure the contact firm) -> this will test the bone conduction. Confirm the patient can hear the sound of the turning fork and then ask them to tell you when they can no longer hear it. When the patient can no longer heat the sound, move the turning folk in front of the external auditory meatus to test air conduction. Ask the patient if they can now hear the sound again. - If they hear the sound, it suggests air conduction is better than the bone -> this is expected in a healthy individual -> positive Rinne’s positive test. Test results should be assessed in the contest with the results of weber’s test before any diagnostic assumptions are made: - Normal result: air conduction -> bone conduction. - Sensorineural deafness: air conduction -> bone conduction -> due to both air and bone conduction being equally reduced. - Conduction deafness: bone conduction -> air conduction. Conductive vs sensorineural hearing loss • Conductive hearing loss: - Inability for sound waves to reach the inner ear. - Causes: excess ear was, otitis externa, otitis media, perforated tympanic membrane and otosclerosis. ✓ Abnormal bone growth of the bony labyrinth, primary the oval window -> manifests at the stapes -> become increasingly fixated to the oval window -> ossicles ability vibrate becomes increasingly less -> conductive hearing loss. ✓ Direct blow, penetrating trauma, acute otitis media, foreign bodies -> tympanic membrane perforation. - • Pathophysiology: external or middle ear pathology that disrupts the conduction of sound into the middle ear. - Clinical features: sound improves in noisy environment; volume of voice remains intact because the inner ear and the auditory nerve are intact. Sensorineural hearing loss: - Dysfunction of the cochlea or the vestibulocochlear nerve. - Causes: increasing age (presbycusis), excessive noise exposure, genetic mutations, viral infections e.g. CMV and ototoxic agents e.g. gentamicin, platinum-based chemotherapy, traumatic (e.g. induced due to hearing loss). - Clinical features: worsens in noisy environments, impaired volume of voice, tend to lose higher frequencies preferentially -> such sounds may be distorted, tinnitus, features of external auditory canal are absent. External Ear Assessment Pinnae • • • • • • Asymmetry -> unilateral pathology Deformity: - Acquired -> cauliflower ear - Congenital -> microtia, low-set ears Ear piecing -> potential source of infection, allergen and a cause of trauma Erythema and oedema -> typically associated with otitis externa Scars: look for evidence of previous surgery Skin lesions: - pre-malignant -> actinic keratosis - Malignant -> basal cell carcinoma, squamous cell carcinoma Mastoid • • Erythema and swelling -> mastoiditis Scars: previous surgery e.g. mastoidectomy Pre-auricular region • • Lymphadenopathy: associated with ear infection e.g. otitis media, otitis externa Pre-auricular sinus/pit: a common congenital deformity that appears as a dimple in the pre-auricular region. - These sinuses can sometimes become infected and require surgery. Conceal Bowl • Look for signs of active infection such as erythema and purulent discharge Palpation • • Pre-auricular lymph nodes Post-auricular lymph nodes