A nurse is assessing a 70-year-old client with suspected mixed hearing loss. Which assessment finding would be most characteristic of mixed hearing loss?
The nurse is conducting a comprehensive hearing assessment on a client who reports progressive hearing difficulties over the past two years.
1Bone conduction is better than air conduction on Weber test
2Sound lateralizes to the unaffected ear on Weber test
3Both air and bone conduction are reduced, with air conduction more affected✓ 정답
4Normal tympanic membrane with clear visualization of landmarks
해설
Mixed hearing loss shows reduced air and bone conduction, with air conduction more affected, indicating combined conductive and sensorineural components. Other options describe findings for conductive or sensorineural loss alone.
Clinical Judgment
This question assesses the ability to identify the characteristic audiometry findings of mixed hearing loss. The key is understanding the pattern of air conduction (AC) and bone conduction (BC) thresholds that occurs when conductive and sensorineural components are combined. In mixed hearing loss, both types of loss are present, so both AC and BC thresholds are elevated (worse) than normal. The critical distinction is that, due to the conductive component, AC is more severely impaired than BC. This differentiates it from pure sensorineural hearing loss, where AC and BC are equally impaired.
Memory Tip: Think of mixed hearing loss as All Conductions Bad, Air is Worse (ACBW). All conductions (AC, BC) are bad, but air conduction (AC) is worse.
KR vs US: In Korea, the interpretation of pure tone audiometry results and clinical judgment are key. In the US NGN, questions assessing a nurse's Clinical Judgment based on the basic principles and result patterns of these hearing tests are frequently seen.
Clinical Practice Guide
When assessing a patient suspected of having mixed hearing loss, carefully review the hearing test results (pure tone audiogram). Compare the AC and BC curves to check for an AC-BC Gap (difference) (conductive component) and whether the BC curve itself falls outside the normal range (sensorineural component).
Caution: Do not fall into the trap of trying to diagnose mixed hearing loss based solely on the Weber test result. The Weber test is primarily a screening test to differentiate the type of impairment in unilateral hearing loss, and the characteristic that best demonstrates mixed hearing loss is the AC and BC pattern on pure tone audiometry. Options 1 and 2 are distractors that focus only on the Weber test result.
Mixed Hearing Loss (혼합성 난청) — Hearing loss that combines conductive and sensorineural elements. There are simultaneous issues with sound conduction in the outer/middle ear and sensory/neural problems in the inner ear/auditory nerve.
Air Conduction (AC, 기도 전도) — Sound is transmitted through the external auditory canal, via the tympanic membrane and ossicles, to the cochlea (inner ear) — this is the normal pathway. Disruption of this pathway causes conductive hearing loss.
Bone Conduction (BC, 골도 전도) — A pathway where a vibrator applies vibrations to the skull, directly stimulating the cochlea (inner ear) to transmit sound. Since this pathway bypasses the middle ear, middle ear problems do not affect it. BC damage suggests inner ear abnormalities.
Weber Test (베버 검사) — A vibrating tuning fork is placed on the patient's forehead or the midline of the skull, and the test evaluates whether the sound is heard equally in both ears or lateralizes to one side. It helps differentiate the cause of unilateral hearing loss.
Sensorineural Hearing Loss (감음신경성 난청) — Hearing loss due to damage to the sensory cells of the inner ear (cochlea) or the auditory nerve pathway. It is characterized by equal impairment of AC and BC. Presbycusis is a typical example.