online ML Comm Otology Korean J Otorhinolaryngol-Head Neck Surg 2014;57(8):511-7 / pissn / eissn

online ML Comm Otology Korean J Otorhinolaryngol-Head Neck Surg 2014;57(8):511-7 / pissn 2092-5859 / eissn 2092-6529 http://dx.doi.org/10.3342/kjorl-hns.2014.57.8.511 Clinical and Prognosis of Idiopathic Sudden Sensorineural Hearing Loss in Old Age Chang Ho Park, Yun Jae Lee, Moo Keon Kim, Jae Ho Chung, Chul Won Park, and Seung Hwan Lee Department of Otorhinolaryngology-Head and Neck Surgery, Hanyang University College of Medicine, Seoul, Korea 노인돌발성난청환자의임상적특징및예후인자에대한분석 박창호 이윤재 김무건 정재호 박철원 이승환 한양대학교의과대학이비인후 - 두경부외과학교실 Received April 10, 2014 Revised May 3, 2014 Accepted May 7, 2014 Address for correspondence Seung Hwan Lee, MD Department of Otorhinolaryngology- Head and Neck Surgery, Hanyang University College of Medicine, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-792, Korea Tel +82-31-560-2363 Fax +82-31-560-2894 E-mail shleemd@hanyang.ac.kr Background and ObjectivesZZIn aging society, interest in idiopathic sudden sensorineural hearing loss (ISSNHL) in elderly have been increased. However, as there has been little discussion about prognostic factors of ISSNHL in old age, this study aims to investigate clinical factors related with prognosis of ISSNHL in elderly and compare with that in adults. Subjects and MethodZZA retrospective medical chart review was performed in patients over 19 years old who diagnosed with ISSNHL from Jan. 2010 to Dec. 2012. Patients were categorized into the old age group (over 65 years old, n=62) and the control group (aged 19 to 64 years old, n=218). Clinical findings, audiological result and treatment outcomes were compared between two groups. And possible prognostic factors of SSNHL in elderly were also investigated. ResultsZZSignificant difference of hearing recovery was identified between the old age group (33.9%, 21/62) and control group (50.9%, 111/218) according to Siegel s criteria (p=0.021). Multivariate analysis concluded that delayed treatment and low speech discrimination score (SDS) might lead to poor prognosis in elderly. The presence of tinnitus or dizziness, audiometric configurations, hypertension and diabetes mellitus did not affect the treatment results of ISSNHL in the old age group. ConclusionZZOnset of treatment and initial SDS could be possible prognostic factors of ISSNHL in elderly. Early diagnosis and urgent treatment are more important in old age. Korean J Otorhinolaryngol-Head Neck Surg 2014;57(8):511-7 Key WordsZZOld age ㆍ Prognosis ㆍ Sudden sensorineural hearing loss. 서론 돌발성난청은확실한원인없이갑자기발생하는감각신경성난청으로이명과현훈등의증상을동반하기도하며, 수시간내지수일만에청력소실을유발할수있는이과적응급질환이다. 발병원인에대해서는명확히밝혀진것은없으나바이러스감염, 내이질환, 혈관장애등이원인으로제시된바있다. 1) 대부분이청 장년층에서발병하며, 연령별발생빈도는 30~50대가가장높고, 유 소아또는노인의발생률은상대적으로낮 은것으로알려져있다. 2) 2013년도보건복지부통계연보에의하면 1990년 5.1% 이던 65세이상인구가 2000년도에는 7.2%, 2013 년도에는 12.2% 로점차늘어나고있으며, 이에따라노인돌발성난청환자의증가가예상되면서이들의예후에대한관심도커지고있다. 돌발성난청의임상증상과예후에관한연구는전통적으로매우활발하게이루어지고있다. 일반적으로, 치료를하지않는경우 32~65% 의청력회복률을보이는것으로보고된바있으며, 3,4) 소아, 40세이상의고령, 현훈, 고음역대의청력손실, 어음명료도의저하등이동반된경우예후가불량한것으로 Copyright 2014 Korean Society of Otorhinolaryngology-Head and Neck Surgery 511

Korean J Otorhinolaryngol-Head Neck Surg 2014;57(8):511-7 알려져있는데, 3,5,6) 노인돌발성난청의임상적특징이나예후에관하여는알려진바가많이없다. 그리고, 노인에서는퇴행성변화에의해이미난청을지닌경우가있어청력회복을판단할때는이를고려하는것이중요하다. 본연구에서는노인돌발성난청환자들의임상양상및청력상태를조사하고, 청력회복에관여하는인자들에대하여알아보고자하였다. 대상및방법 2010년 1월부터 2012년 12월까지본원이비인후과에서특발성돌발성난청으로진단받고치료받은성인환자를대상으로후향적의무기록조사를시행하였다. 노인의경우기존의감각신경성난청이동반되어있는경우가많아, 자세한병력청취를통해갑자기발생한난청인지, 기존의난청이갑자기악화된경우인지를확인하였으며, 돌발성난청진단시반대측청력상황을고려하였다. 노인환자군은 65세이상의돌발성난청환자로 62명이었으며, 19세부터 64세까지의성인환자 218 명을대조군으로정하여노인돌발성난청환자와의임상양상, 치료결과등을비교분석하였다. 모든환자들은입원하여치료받았으며, 전신적스테로이드제 (prednisolone) 를 1일최대 60 mg(1 mg/kg/day) 부터시작하여 1주투약후감량하였고, 저분자량혈량증량제 (Dextran R, Daihan Pharm. Co., Korea) 및혈관확장제, 비타민제를함께사용하였다. 특히기저질환으로당뇨병이있었던환자들은스테로이드복용이혈당의상승을유발할수있으므로, 내분비내과와협진을통해인슐린으로혈당을조절하였다. 치료시작 2주일이내에청력회복을보이지않는경우, 동의한환자에한하여고실내스테로이드주입술을 1주에 2회씩, 2주간총 4회시행하였다. 청력검사는순음청력검사로내원당시의기도, 골도청력을측정하였으며, 어음역치검사, 어음명료도검사를시행하였고, 기능성난청을감별하기위해청성뇌간유발반응검사등의객관적청력검사를시행하였다. 청력소실은순음청력검사상 4분법으로 0.5, 1, 2, 3 khz에서의기도청력역치의평균을기준으로평가하였고, 청력도유형은순음청력검사에따라옥타브당 5 db 이상청력역치가올라가는경우는하강형 (descending), 옥타브당 5 db 이상청력역치가낮아지는경우는상승형 (ascending), 옥타브당청력의변화가 5 db 이하인경우는수평형 (flat), 전음역에서청력역치가 91 db 이상인경우를농형 (profound) 으로구분하였다. 반대측귀의청력에대한평가는순음청력검사상 40 db 이상의역치를보이는경우난청이있다고판단하였다. 청력회복은치료시작 2달이후의청력역치를청력개선율 과 Siegel 7) 의분류를이용하여판단하였다. 청력개선율은내원당시병변측과반대측의청력역치의차이를기준으로호전된청력역치가차지하는비율로계산하였으며, 50% 이상개선된경우를회복으로정하였다. Siegel 의분류는완전회복군, 부분회복군, 경도회복군, 불변군으로분류하였고, 회복을평가할때는부분회복이상의호전을보인경우로정하였다. 통계분석은 SPSS version 21(SPSS Inc., Chicago, IL, USA) 을이용하여 chi-square test, Student s t-test 및 binary logistic regression analysis의방법으로분석하였으며, 통계적유의수준은 95% 이상 (p value<0.05) 으로하였다. 결과 총 280명의평균연령은 52.2(±13.8) 세였고, 연령별분포는 40대에서가장많았으며, 그중 65세이상노인환자는 62명 (22.1%) 이었다 (Fig. 1). 전체환자에서, 나이가증가함에따라남성발병률은증가하는양상을보였으나통계적으로유의하지는않았다 (p=0.811). 반대측난청의비율은나이가들수록유의하게증가하였다 (p<0.001). 노인군 62명을살펴보면, 평균나이는 70.6(±4.5) 세로, 남녀비는 1:1.1 이었고, 측별분포는우측 32예 (51.6%), 좌측 30예 (48.4%) 로차이가없었다. 노인환자들은증상발생시점부터치료시작까지평균 5.1(±4.8) 일경과하였고, 동반증상으로현훈 (25.8%), 이명 (56.5%), 이충만감 (19.4%) 등이있었다. 돌발성난청에동반된만성질환으로당뇨병은 21예 (33.9%), 고혈압은 36예 (58.1%) 에서동반되었다. 청력도유형은수평형이 38예 (61.3%) 로가장많이나타났으며, 그다음으로농형 (19.4%), 하강형 (11.3%), 상승형 (8.1%) 순으로나타났고, 내원당시순음청력역치의평균은 72.8(±19.9) db, 어음명료도는평균 37.6% 를보였다. 청력개선율기준으로는 45.2%, Siegel 의분류기준으로는 33.9% 의노인환자에서청력회복을확인하였다. 노인군과대조군을비교하였을때, 노인군에서반대측난청이많았고, 당뇨병, 고혈압의유병률이높았다. 이는일반적인노인의특성을반영한다. 청력도유형에서는노인군에서대조 Percentage (%) 30 25 20 15 10 5 0 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 Age group Fig. 1. Age distribution of sudden sensorineural hearing loss patients. 512

Sudden Sensorineural Hearing Loss in Old Age Park CH, et al. 군에비해수평형의청력도가많았고, 상승형은적었다. 청력회복은청력개선율로계산하였을때는노인군에서대조군에비해낮은회복률을나타냈으나, 의미있는차이는확인되지않았다. 그러나 Siegel 의분류를이용하였을때는노인군에서유의하게회복률이낮음을알수있었다 (Table 1). 노인환자에서청력회복에관여하는요인을살펴보기위해, 청력이회복된군과회복되지않은군을비교하여분석한결과, 청력개선율을이용한분석에서는청력이회복되지않은군에서통계적으로유의하게치료시작시기가늦었고, 어음명료도가낮았으며 (Table 2), Siegel의분류를이용한분석에서는청력이회복되지않은군에서통계학적으로유의하게치료시작시기가늦었다 (Table 3). 일반성인, 즉대조군에서청력개선율을이용한분석에서는청력이회복되지않은군에서반대측난청비율이높았고, 이명이적었으며, 초기난청의정도가크고, 어음명료도가낮았으며, 상승형의청력도는적었고, 농형이많았다 (Table 4). Siegel 의분류를이용한분석에서는청력이회복되지않은군에서통계학적으로유의하게치료시작시기가늦었고, 당뇨병의유병률이높았으며, 이명이적었고, 어음명료도가낮았고, 청력도유형에서상승형이적었다 (Table 5). 노인군내에서치료시작 2주경에청력회복을보이지않은경우는 42예 (67.7%) 로, 그중 30예에서고실내스테로이드주입술을시행하였으며, 그결과청력개선율기준으로는 8예 (26.7%) 에서, Siegel 의분류기준으로는 7예 (23.3%) 에서청력회복을보였다. 고실내스테로이드주입술을동의하지않았거나시행하지못하였던 12예중청력개선율기준으로는 3예 (25.0%) 에서, Siegel의분류기준으로는 2예 (16.7%) 에서만최종청력이회복되었다. 노인에서치료시작 2주일이내청력회복이없었던환자들중고실내스테로이드주입술을시행한경우는시행하지않은경우에비해청력개선율과 Siegel의분류모두에서청력회복률은높았으나, 통계적으로유의하지않았다 (p=1.000, 0.707). 본연구에서전신적스테로이드제사용에의한부신억제나간기능장애, 위장관염, 피하출혈, 비출혈, 고혈당증등의합병증은발생하지않았다. 고찰 돌발성난청이란명확한원인없이 72 시간이내에급격히진 Table 1. Clinical characteristics of patients Aged group (n=62) Control group (n=218) Age (year) 70.6 (±4.5) 46.9 (±10.8) <0.001* Gender (male:female) 30:32 96:122 0.565 Side of SNHL (right:left) 32:30 108:110 0.886 Opposite side SNHL 20 (32.3%) 25 (11.5%) <0.001 Onset of treatment (day) 5.1 (±4.8) 4.4 (±4.1) 0.285* Diabetes 21 (33.9%) 26 (11.9%) <0.001 Hypertension 36 (58.1%) 43 (19.7%) <0.001 Vertigo 16 (25.8%) 51 (23.4%) 0.736 Tinnitus 35 (56.5%) 113 (51.8%) 0.566 Ear fullness 12 (19.4%) 49 (22.5%) 0.610 Initial hearing level (db) 72.8 (±19.9) 67.9 (±24.0) 0.143* Speech discrimination score (%) 37.6 (±38.2) 44.8 (±40.7) 0.213* Opposite sidehearing level (db) 36.1 (±15.1) 22.1 (±15.6) <0.001* Ascending 5 (8.1%) 58 (26.6%) 0.003 Flat 38 (61.3%) 91 (41.7%) 0.009 Descending 7 (11.3%) 23 (10.6%) 1.000 Profound 12 (19.4%) 46 (21.1%) 0.860 Hearing recovery Recovery rate 28 (45.2%) 114 (52.3%) 0.388 Siegel s criteria 21 (33.9%) 111 (50.9%) 0.021 *Student s t-test, chi-square test. SNHL: sensorineural hearing loss, db: decibel www.jkorl.org 513

Korean J Otorhinolaryngol-Head Neck Surg 2014;57(8):511-7 행하는난청으로, 순음청력검사에서 3개의연속된주파수에서 30 db 이상의감각신경성난청이발생한경우로정의된다. 8) 돌발성난청의원인은명확히규명된것은없는데, 여러연구에서감염, 종양, 외상, 약물부작용, 면역학적이상, 혈관질환등 다양한병인을제시한바있으며, 1,9-11) 특히노인에서는혈관경색이나혈전등과같은혈관질환의증가가돌발성난청의위험을증가시킨다고보고된바있다. 12) 돌발성난청의발병률은 1년에 10만명당 5~77 명정도로알 Table 2. Clinical factors related with hearing improvement by the recovery rate in old age Table 3. Clinical factors related with hearing improvement by the Siegel s criteria in old age 514 (n=21) (n=41) Gender (male) 11 (52.4%) 19 (46.3%) 0.789 Opposite side SNHL 4 (19.0%) 16 (39.0%) 0.154 Onset of treatment (day) 3.1 (±1.5) 6.1 (±5.6) 0.002* 0.034 Diabetes 8 (38.1%) 13 (31.7%) 0.777 Hypertension 12 (57.1%) 24 (58.5%) 1.000 Vertigo 4 (19.0%) 12 (29.3%) 0.542 Tinnitus 12 (57.1%) 23 (56.1%) 1.000 Ear fullness 6 (28.6%) 6 (14.6%) 0.308 Initial hearing level (db) 65.9 (±17.9) 76.4 (±20.1) 0.048* 0.773 Speech discrimination score (%) 52.2 (±37.6) 30.1 (±36.7) 0.029* 0.180 (n=28) (n=34) Gender (male) 16 (57.1%) 14 (41.2%) 0.307 Opposite side SNHL 6 (21.4%) 14 (41.2%) 0.112 Ascending 3 (14.3%) 2 (4.9%) 0.325 Flat 15 (71.4%) 23 (56.1%) 0.282 Descending 1 (4.8%) 6 (14.6%) 0.406 Profound 2 (9.5%) 10 (24.4%) 0.195 Onset of treatment (day) 3.3 (±1.5) 6.6 (±6.0) 0.004* 0.008 Diabetes 12 (42.9%) 9 (26.5%) 0.191 Hypertension 14 (50.0%) 22 (64.7%) 0.305 Vertigo 4 (14.3%) 12 (35.3%) 0.082 Tinnitus 18 (64.3%) 17 (50.0%) 0.309 Ear fullness 8 (28.6%) 4 (11.8%) 0.117 Initial hearing level (db) 68.5 (±19.3) 76.4 (±19.9) 0.122* Speech discrimination score (%) 50.5 (±36.3) 27.0 (±36.9) 0.015* 0.003 Ascending 3 (10.7%) 2 (5.9%) 0.650 Flat 17 (60.7%) 21 (61.8%) 1.000 Descending 4 (14.3%) 3 (8.8%) 0.691 Profound 4 (14.3%) 8 (23.5%) 0.521

Sudden Sensorineural Hearing Loss in Old Age Park CH, et al. 려져있으며, 5,13) 일반적으로나이가증가할수록발병률이높아진다고하나, 13) 50대에서발병률이가장높다는보고도있다. 2,5) 전체돌발성난청환자중 60세이상이차지하는비율은 11~15% 정도로알려져있으며, 고령에서는남성의발병률이 더높다고한다. 13) 본연구에서는 40대에서발병률이가장높았으며, 19세이상성인환자중 65세이상이차지하는비율은 22.1% 였고, 나이가증가할수록남성에서발병률이높아지는경향을보였으나통계적으로유의하지는않았다 (p=0.811). 양측성돌 Table 4. Clinical factors related with hearing improvement by therecovery rate in control group (n=114) (n=104) Gender (male) 47 (41.2%) 49 (47.1%) 0.414 Opposite side SNHL 7 (6.1%) 18 (17.3%) 0.011 0.008 Onset of treatment (day) 4.2 (±3.2) 4.8 (±4.9) 0.282* Diabetes 10 (8.8%) 16 (15.4%) 0.148 Hypertension 19 (16.7%) 24 (23.1%) 0.307 Vertigo 17 (14.9%) 34 (32.7%) 0.002 0.059 Tinnitus 68 (59.6%) 45 (43.3%) 0.021 0.025 Ear fullness 28 (24.6%) 21 (20.2%) 0.517 Initial hearing level (db) 64.1 (±22.7) 72.2 (±24.8) 0.012* 0.004 Speech discrimination score (%) 54.2 (±39.2) 34.5 (±40.0) <0.001* 0.002 Ascending 45 (39.5%) 13 (12.5%) <0.001 <0.001 Flat 47 (41.2%) 44 (42.3%) 0.891 Descending 8 (7.0%) 15 (14.4%) 0.082 Profound 14 (12.3%) 32 (30.8%) 0.001 0.031 Table 5. Clinical factors related with hearing improvement by the Siegel s criteria in control group (n=111) (n=107) Gender (male) 43 (38.7%) 53 (49.5%) 0.133 Opposite side SNHL 8 (7.2%) 17 (15.9%) 0.056 Onset of treatment (day) 3.8 (±2.9) 5.1 (±4.9) 0.015* 0.001 Diabetes 8 (7.2%) 18 (16.8%) 0.036 0.008 Hypertension 22 (19.8%) 21 (19.6%) 1.000 Vertigo 16 (14.4%) 35 (32.7%) 0.002 0.061 Tinnitus 68 (61.3%) 45 (42.1%) 0.007 0.003 Ear fullness 27 (24.3%) 22 (20.6%) 0.521 Initial hearing level (db) 61.5 (±23.2) 74.6 (±23.1) <0.001* 0.096 Speech discrimination score (%) 57.0 (±38.7) 32.2 (±38.9) <0.001* 0.001 Ascending 47 (42.3%) 11 (10.3%) <0.001 0.001 Flat 46 (41.4%) 45 (42.1%) 1.000 Descending 7 (6.3%) 16 (15.0%) 0.047 0.096 Profound 11 (9.9%) 35 (32.7%) <0.001 0.072 www.jkorl.org 515

Korean J Otorhinolaryngol-Head Neck Surg 2014;57(8):511-7 발성난청은매우드물게발생하는것으로알려져있는데, 10) 고령환자에서는난청의유병률이높기때문에돌발성난청의발생시기를확인하여양측성돌발성난청과구별하는것이필요하다. 고령에서는고혈압, 당뇨병, 고지혈증등의만성질환의유병률이높다. 만성질환은미세혈관에손상을주고, 혈관경색이나혈전및혈액점도의갑작스러운증가를일으킴으로내이순환장애를유발하여돌발성난청이발생할수있는것으로알려져있다. 12) 이러한만성질환은돌발성난청외에도점진적인청력저하를유발할수있는데, 이들대부분은서서히진행하는좌우대칭적인고도하강형의감각신경성난청이많아, 돌발성난청과구별할수있다. 노인돌발성난청환자에서고혈압, 당뇨, 고지혈증등의만성질환은청력회복을떨어뜨릴수있다는보고도있으나, 14) 아직명확히규명되지는않았다. 15) 본연구에서도고혈압과당뇨병은노인돌발성난청환자의청력회복에영향을주지않았다. 돌발성난청에동반되는증상으로는두통, 이폐쇄감, 현훈및이명등이알려져있는데, 6) Chon 등 16) 은노인환자의 75.5% 에서이명이, 23.5% 에서현훈이동반되었다고보고하였다. 본연구에서는노인환자에서이명은 56.5%, 현훈은 25.8% 에서동반되었는데, 대조군에비해다소높았으나통계적으로유의하지는않았다. 정확한진단을위해서는난청의발생시기를확인하여야하는데, 노인의경우이를정확하게기억하지못하는경우가많아자세한병력청취가필요하며, 반대측청력의상태를고려하여종합적으로판단하여야한다. 치료는전신적스테로이드제와함께혈액점도를감소시키기위한저분자량혈량증량제, 혈관확장제, 비타민제등을함께사용하는것이일반적이며, 8,17) 전신적스테로이드제의부작용및와우영역에국소적으로작용하지못하는단점을보완하기위해고실내스테로이드주입술을시행하기도한다. 18) 고실내스테로이드주입술을전신적스테로이드제와병용하여시행할경우청력회복에도움을준다고알려져있으나, 19) 차이가없다는보고도있다. 20) 본연구에서는노인군에서고실내스테로이드주입술을병용사용한경우청력회복이보다높았으나, 통계적으로유의하지는않았다 (p>0.05). 돌발성난청의예후인자로는고도난청, 고음역대난청, 전주파수대역난청, 어음명료도저하, 현훈, 소아, 40세이상, 지연된치료, 양측돌발성난청등이알려져있다. 21-23) 많은연구에서 65세이상노인의경우예후가좋지않다고보고하고있으며, 24,25) 노인돌발성난청환자의경우고혈압과당뇨병이동반되었거나, 치료시작시농의청력손실, 농형의청력도유형, 지연된치료시작등이불량한예후인자로보고된바있다. 16) 본 연구에서는노인에서발생한돌발성난청환자의청력회복률 은 Siegel 의분류를이용한경우대조군에비해통계적으로 유의하게낮았고, 치료시작이지연되거나어음명료도가낮을 수록청력회복이좋지않음을알수있었다 (p<0.05). 청력회복의기준에는 Wilson 등 8) 이제안한최초청력에서 50% 이상의호전된것을치료성공으로정의하는청력개선율 방법이나, Siegel 의분류법 7) 등이있다. 청력개선율은발병전 청력을고려하기때문에노인성난청비율이높은노인돌발성 난청에서적합할수있으나, 반대측청력이정상이아닐시사 용하기어려운단점이있고, Siegel 의분류는가장널리사용되 고있으나환자의발병전청력상태를반영하지않고개선된 청력으로만평가하는단점이있다. 본연구의노인돌발성난 청환자에서예후는청력개선율을이용한경우치료시작시 기와어음명료도가, Siegel 의분류를이용한경우치료시작 시기와관련되어있었고, 공통적으로치료시작시기가중요한 예후인자임을알수있었다. 그러나, 이러한방법들은어음명료 도에대한평가가이루어지지않았기때문에, 보청기등을이 용한청각재활혹은보청기착용의적합성을판정하는데어려 움이발생할수있으며, 향후어음명료도를포함한청력회복 분류법을이용한추가연구가필요할것으로생각된다. 노인돌발성난청환자에서고혈압, 당뇨병등의만성질환 의유병률은높은것으로알려져있지만, 이는돌발성난청의 회복에는많은영향을미치지않는것으로생각된다. 노인환 자에서는치료시작시기와초기어음명료도가청력의중요한 예후인자로생각되며, 따라서노인돌발성난청에서청력의회 복을위해서는빠른진단과치료가필수적이다. REFERENCES 1) Chau JK, Lin JR, Atashband S, Irvine RA, Westerberg BD. Systematic review of the evidence for the etiology of adult sudden sensorineural hearing loss. Laryngoscope 2010;120(5):1011-21. 2) Chon KM. Clinical practice of sudden hearing loss. 1st ed. Busan: Jung Myung Dang Co;1995. 3) Mattox DE, Simmons FB. Natural history of sudden sensorineural hearing loss. Ann Otol Rhinol Laryngol 1977;86(4 Pt 1):463-80. 4) Conlin AE, Parnes LS. Treatment of sudden sensorineural hearing loss: II. A Meta-analysis. Arch Otolaryngol Head Neck Surg 2007; 133(6):582-6. 5) Byl FM Jr. Sudden hearing loss: eight years experience and suggested prognostic table. Laryngoscope 1984;94(5 Pt 1):647-61. 6) Mattox DE, Lyles CA. Idiopathic sudden sensorineural hearing loss. Am J Otol 1989;10(3):242-7. 7) Siegel LG. The treatment of idiopathic sudden sensorineural hearing loss. Otolaryngol Clin North Am 1975;8(2):467-73. 8) Wilson WR, Byl FM, Laird N. The efficacy of steroids in the treatment of idiopathic sudden hearing loss. A double-blind clinical study. Arch Otolaryngol 1980;106(12):772-6. 9) Schuknecht HF, Donovan ED. The pathology of idiopathic sudden sensorineural hearing loss. Arch Otorhinolaryngol 1986;243(1):1-15. 10) Shaia FT, Sheehy JL. Sudden sensori-neural hearing impairment: a report of 1,220 cases. Laryngoscope 1976;86(3):389-98. 516

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