Clinical studyWhite matter lesions and sudden sensorineural hearing loss
Introduction
Sudden sensorineural hearing loss (SSNHL) is defined as a acute hearing loss, of at least 30 dB, involving at least three contiguous frequencies and developing over a period of 72 h [1]. Reported annual incidence ranges between 5 and 20 cases/100,000 [2]. Usually SSNHL is unilateral and can be associated to tinnitus and vertigo.
Although its etiology is not well understood, microvascular injury and viral infections have been claimed to be involved in SSNHL pathogenesis by many investigators [3], [4]. A microvascular damage can be related to microembolic and/or thrombotic events, increased plasma viscosity, vasospasm endothelial dysfunction or hypotension [5], [6], [7], [8]. Magnetic Resonance Imaging (MRI) has been recommended by many investigators and by several scientific societies, in order to rule out retrocochlear pathology or central causes of SSNHL [9], and therefore is usually performed in all patients affected by SSNHL.
Hyperintense on T2-weighted MRI spots are commonly referred as white matter lesion (WMLs); several Authors provided evidence that WMLs are a consequence of, and indicative for, brain small vessel disease [10], [11]. In the literature, the presence of WMLs has been associated to a greater risk of developing a future stroke and dementia [12], [13]. In the field of audiology, recently, a relationship between WMLs and dizziness has also been investigated [14].
Aim of this paper is to investigate the presence of WMLs in subjects affected by SSNHL and possibly to evaluate the significance of WMLs in SSNHL patients.
Section snippets
Subjects and methods
Case-control study: A total of 64 patients (29 males and 35 females), aged between 16 and 82 years (mean age 58,25 ± 14,91) affected by SSNHL have been included. Patients were referred to the Audiology Department of the University Hospital of Ferrara between January 1st 2012 to June 30th 2017. All patients underwent clinical history taking, complete audiological evaluation, including tonal audiometry and speech audiometry. Hearing tests were performed at SSNHL onset, after 7 days and after
Results
Among 64 participants (mean age 58,25 ± 14,9), 29 were males and 35 were females. The initial average hearing threshold (500–1000 Hz) was 60,8 dB and the final hearing threshold was 48,3 dB. 41 patients complained also unilateral tinnitus.
At onset 56,3% of patients were affected by moderate SSNHL, 26,6% of patients by severe SSNHL and 17,2% of patients by profound SSNHL, according to Clark criteria. There was a positive and statistically significant correlation between the initial average
Discussion
In the literature, White Matter Lesions (WMLs) have been described as abnormalities of the cerebral tissue architecture detected by neuroimaging; they have been defined as rounded areas of decreased attenuation at the cerebral CT scan, increased signal on T2-weighted and FLAIR, often decreased at T1-weighted MR imaging. It has been reported that, these lesions can occur as a result of cerebral small vessel disease, and therefore are a usual finding in subjects with common cardiovascular risk
Conclusion
The present findings suggest that, (i) MRI could have a prognostic role in the management of SSNHL patients, since the presence of WMLs can be linked to a poorer hearing recovery rate. Furthermore, (ii) the assessment of WMLs can be performed using Fazekas scale, which is faster and has a similar reliability to the Wahlund scale.
Acknowledgement
The Authors would like to thanks Monica Rosignoli for her help with the statistical analysis.
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