Impaired hearing (청력 장애)

The Root of Ambulatory Care (외래 진료 지침서) 전체 목록 보기
KEYWORDS: ..청력저하는 가장 흔한 감각장애이며 65세이상에서의 유병률은 35%에 이른다. ..감각신경성과 전음성 중 어느 곳에 속하는지 난청의 유형을 밝히는 것이 중 요하다. 전음성 난청은 가역적인 경우가 많기 때문이다. < Types of hearing loss > Impaired hearing Conductive - - 외이, 중이이상 Sensorineural - 내이, 청신경이상 Mixed Functional Otitis media with effusion (mc-especially in children) Impacted cerumen (or foreign body) External otitis - inflammation and exudates can lead to temporary loss of air conduction Perforation of TM Otosclerosis - produces fixation of the stapes over the oval window, preventing transmission of sound to the inner ear Exostoses - bony outgrowths in external auditory canal, 해녀처럼 차가운 물에 오래 노출된 경우 흔히 발생 Presbycusis(mc) - multifactorial etiology, typical high-frequency loss that is bilaterally symmetric and irreversible Noise induced - usually at a specific frequency loss (around 4000Hz) : Shearing forces caused by any sound have an impact on the stereocilia of the hair cells of the basilar membrane of the cochlea ; when excessive, these forces can cause cell death. Drug induced - aminoglycosides, loop diuretics, quinidine, salicylate (reversible), erythromycin Meniere’s disease - fluctuating hearing loss (usually unilateral) Acoustic neuroma Usually related with psychological factors without organic causes ..Sensorineural loss : patients may say that they think they hear fine, but they have difficulty understanding speech (or state that other people do not speak clearly) Noisy environments make hearing more difficult. ..Conductive loss : Patients complain of muffled hearing and may actually hear better than expected in a noisy room. ..손가락으로 딱 소리를 내거나 시계의 초침소리, 귀에 속삭이는 소리 등으로 청력을 측정하는 것은 정확하지 않으므로 피해야 한다. 1. Tuning fork test 95 The Root of ambulatory care Key tests ▶ Weber test. Holding a 512-Hz or 1,024- Hz tuning fork on the middle of the patient's forehead, the physician asks, “Where do you hear this loudest - left, right or in the middle?”The sound localizes toward the side with a conductive loss (toward the worse-hearing ear) or away from the side with a sensorineural loss (toward the betterhearing ear). The physician can clarify this test by performing the test on himself or herself, plugging one ear with a finger to simulate a conductive loss. The Weber test is only useful if there is an asymmetric hearing loss. If hearing is symmetric, the patient perceives the sound in the middle of the forehead. ▶ Rinne test. Holding a 512-Hz or 1,024-Hz vibrating tuning fork against the mastoid process, the physician asks the patient to indicate when the sound can no longer be heard. At this point, the physician places the tuning fork in front of the auditory meatus to determine whether the sound can be heard again. Normal hearing patients and patients with sensorineural hearing loss hear the sound longer through air than bone. The result is reported as“ AC > BC”(air conduction greater than bone conduction). In a conductive hearing loss, bone conduction becomes equal to or greater than air conduction. This result is reported as an“ abnormal Rinne”or“ reversed Rinne.” Impaired hearing Weber Rinne 정상 No lateralization + (AC > BC) Conductive Louder in the affected ear - (AC < BC) Sensorineural Louder in the unaffected ear + (AC > BC) 2. Audiometry ..난청의 객관적 증거가 보이는 환자들은 자세한 청력 검사를 위해 의뢰하는 것이 좋다. 더구나 갑작스런 청력저하(수분이나 수시간 이내에 발생)환자는 즉각 의뢰하여야 한다. 24시간이내에 치료를 시작하면 호전될 가능성이 있으 므로 지체하지 않도록 한다. 참고 문헌 Kenneth A. Weller : Impaired hearing, in Saunders Manual of Medical Practice, 2nd ed,Robert E. Rakel(ed). Philadelphia, Saunders, 2000, P 68-71 서상연 : 청력저하, in 가정의학 임상편. 서울, 계측문화사, 2002, P 533-538 Peter M. Rabinowitz, M.D., M.P.H. : Noise-Induced Hearing Loss.A journal of the American Family Physicains 2000 ; 61 : 2749-2756, 2759-2760 정재복 외 : 진단학. 서울, 군자출판사, 2004, P158