Laterality of sudden sensorineural hearing loss.
It is known that sudden sensorineural hearing loss and other otoneurologic diseases, such as tinnitus or Meniere disease, occur more frequently in the left ear than in the right. We studied lateralization of sudden deafness in 489 patients treated at Radebeul Hospital from January 2004 to December 2009. The male-to-female ratio was 1:1.24; we found a predominance of the left side only in female patients. The cause for this predominance is unclear. The slight asymmetry might indicate a greater vulnerability of the left inner ear in women, suggesting hormonal factors in the genesis of sudden deafness.
Sudden sensorineural hearing loss is one of the most controversial, unsolved, and perplexing mysteries in otolaryngology. Most studies have found no seasonal, geographic, ethnic, racial, or sex predilection for sudden deafness. The etiology of sudden sensorineural hearing loss is still unknown. (1,2) Numerous theories are supported by some evidence, but these theories are conflicting and incomplete. The most promising possibilities include viral infections (particularly those involving herpes simplex), autoimmune attacks, and acute microvascular occlusion. (2,3)
Initial symptoms are a feeling of pressure in the ear followed by tinnitus, which in turn is followed by a loss of hearing within minutes. The lesion is almost always localized in the inner ear. Sudden sensorineural hearing loss may be a disorder of microcirculation or an autoimmune disorder. (1,2,4)
Generally, the disease is unilateral. We know that not only sudden hearing loss but also other unilateral disorders, such as tinnitus or Meniere disease, occur more frequently in the left ear than in the right. (5) Not all studies, however, have reported this difference between the right and the left side. (1,6) Bilateral sudden sensorineural hearing loss is very rare.
The purpose of the present study is to investigate the laterality of sudden sensorineural hearing loss in a population of patients.
Patients and methods
In this retrospective study, we recorded the side of the ear in which the hearing loss occurred. From January 2004 to December 2009,489 patients--218 male and 271 female; age range 10 to 91 years(mean: 55 years)--were treated for sudden sensorineural hearing loss at the Department of Otorhinolaryngology of the Hospital in Radebeul, Germany.
The table shows the distribution of sudden sensorineural hearing loss with respect to laterality in our sample. In 242 cases (49.5%), the hearing loss occurred on the left side, in 213 (43.6%) cases on the right side, and in 34 cases (6.9%) on both sides. The differences were not statistically significant ([chi square] = 2.3647; degree of freedom = 2). There was a predominance of the left side in women but not in men (47 vs 46%).
Statistics in the literature show sudden deafness, tinnitus, inner ear damage, and Meniere disease to be predominant in the left ear (10 to 20%). Other diseases, such as ischemic brain infarcts or diseases of the eyes, have the same incidence on both sides. (5)
In a meta-analysis of 17 studies (3,219 patients) exploring sudden deafness, Reiss found a distribution of 43.6% on the right side, 52.9% on the left side, and 3.5% on both sides (not all studies registered bilateral cases). (6) The nonsymmetrical distribution of this disease can point to a greater general vulnerability of the left side. (5,6)
In the present study, we found a predominance of the left side in female patients (right:left, 1:1.3) but not in male patients. The differences were not statistically significant. In most studies, no gender differences regarding possible right-left variation in sudden sensorineural hearing loss were noted. (4,7-10) In their study, Zastrow and Arndt indicated a predominance of the left side for men as well as women. (11) However, they discovered more women had left-sided sudden hearing loss (49/80; 61.3%) than men (57/103; 55.3%).
The female-to-male ratio was 1.29:1. This slight predominance suggests possible hormonal factors, as hormones might produce a more vulnerable ear on the left side in women.
In our meta-analysis, we found slightly more female patients with sudden deafness (male:female ratio 1:1.24), which is in line with other studies. (4) However, other studies found a reverse distribution, or a predominance of sudden deafness in male patients. (8,11)
Michel summarized 14 studies that included a total of 6,081 patients, and he noted a slight predominance of men affected by sudden sensorineural hearing loss (male:female ratio 1.17:1). (1) These differences in the distribution between the sexes should be considered but are not important in terms of the right-left differences.
Additional factors to consider are the relationships between degree and frequency of sudden hearing loss and its laterality. We did not take these factors into consideration because the other studies (4,7,9,10) did not investigate them and because our sample of patients was relatively small.
Our results indicate that further studies are necessary to investigate laterality in sudden sensorineural hearing loss, and particularly the differences between the sexes regarding sudden hearing loss.
(1.) Michel O. Der Horsturz. Stuttgart: Thieme; 1994:72-5.
(2.) Suckfull M. Perspectives on the pathophysiology and treatment of sudden idiopathic sensorineural hearing loss. Dtsch Arztebl Int 2009; 106(41):669-75.
(3.) Rauch SD. Clinical practice. Idiopathic sudden sensorineural hearing loss. N Engl J Med 2008;359(8):833-40.
(4.) Preyer S. Effect of weather on the incidence of sudden deafness [in German]. Laryngorhinootologie 1996;75(8):443-6.
(5.) Heermann J. Predominance of left ear in Meniere's disease, sudden deafness, inner ear damage, tinnitus and abnormally patent eustachian tube. Ear Nose Throat J 1993;72(3):205-8.
(6.) Reiss M. Physiologische und pathologische Funktionsasymmetrien des stato-akustischen Systems [unpublishedthesis]. Dresden, Germany: University of Dresden; 2003.
(7.) Becker A. Spatkontrollen nach Horsturz und akutem Vestibularisausfall [unpublished thesis]. Dresden, Germany: Medizinische Akademie; 1990.
(8.) Eichhorn T, Martin G. Course and prognosis in sudden deafness (in German], HNO 1984;32(8):341-5.
(9.) Klemm E. Die Bedeutung gestorter Mikrozirkulation in der Pathogenese des Horsturzes und akuten Vestibularisausfall [unpublished thesis], Dresden, Germany: Medizinische Akademie; 1986.
(10.) Wilhelm HJ, Schatzle D, Breyer D. Frtih- und Spatergebnisse sowie Rezidiv-quote behandelter Horsturze. Extracta Otorhinolaryngolica 1980;2:341-53.
(11.) Zastrow G, Arndt HJ. Clinical aspects and therapy of sudden deafness. Data of a patient sample of the ear, nose, throat clinic of the Wiesbaden City Clinic 1974-1982. Laryngol Rhinol Otol (Stuttg) 1987;66(5):237-41.
Michael Reiss, MD; Gilfe Reiss, MD
From the Department of Ear, Nose and Throat, Elblandkliniken Radebeul, Germany (Dr. M. Reiss); and the Department of Neurosurgery, University of Dresden, Germany (Dr. G. Reiss).
Corresponding author: Michael Reiss, MD, Department of Ear, Nose and Throat, Elblandklinikum Radebeul, Heinrich-Zille-Str. 13, D-01445 Radebeul, Germany. Email: firstname.lastname@example.org
Table. Laterality of sudden sensorineural hearing loss according to sex in the sample (N = 489) Male Female Total Right, n (%) 102 (20.9) 111 (22.7) 213 (43.6) Left, n (%) 100 (20.5) 142 (29.0) 242 (49.5) Bilateral, n (%) 16 (3.2) 18 (3.7) 34 (6.9) Total 218 (44.6) 271 (55.4) 489 (100)
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|Title Annotation:||ORIGINAL ARTICLE|
|Author:||Reiss, Michael; Reiss, Gilfe|
|Publication:||Ear, Nose and Throat Journal|
|Date:||Aug 1, 2014|
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