Roberto Bovo

Immune-mediated inner ear disease

The incidence of autoimmune inner ear disease (AIED) is difficult to determine: probably it is a rare disease, accounting for < 1% of all cases of hearing impairment or dizziness. Nevertheless, the diagnosis of AIED might be overlooked because of the lack of a specific diagnostic test. The hallmark of this clinically diagnosed condition is the presence of a rapidly progressive, often fluctuating, bilateral sensorineural hearing loss (SNHL) over a period of weeks to months. The progression of hearing loss is too rapid to be diagnostic for presbycusis and too slow to conclude a diagnosis of sudden SNHL. Vestibular symptoms, such as generalized imbalance, ataxia, positional vertigo and episodic vertigo may be present in almost 50% of patients. Occasionally only one ear is affected initially, but bilateral hearing loss occurs in most patients, with symmetric or asymmetric audiometric thresholds. Almost 25–50% of patients also have tinnitus and aural fullness, which can fluctuate. Systemic autoimmune diseases coexist in 15–30% of patients.

Environmental and genetic factors in age-related hearing impairment.

Age-related hearing impairment (ARHI), or presbycusis, is a complex disease with multifactorial etiology. It is the most prevalent sensory impairment in the elderly, and may have detrimental effects on their quality of life and psychological well-being. The aim of this paper is to give an overview of the current data on ARHI, focusing mainly on environmental agents and genetic predisposition in animal models and in humans. With improvement of our understanding of ARHI, treatment other than with amplification will be hopefully possible in the long term.

Tinnitus and cochlear implants

OBJECTIVE Several published studies seem to confirm the clinical observation that cochlear implants (CI) have a suppressive effect on tinnitus in most CI users. The aim of this paper is to present our personal experiences on tinnitus improvement after cochlear implantation. METHODS Before surgery, 51 post-lingually profoundly deaf adults, who underwent cochlear implantation between 2005 and 2007, filled out a questionnaire reporting tinnitus characteristics and the Italian version of the Tinnitus Handicap Inventory (THI-I). Moreover, they were asked to scale tinnitus loudness and annoyance. Six months after implant activation, patients repeated the same evaluations. Scores were statistically analysed by means of a Wilcoxon signed ranks test on the hypothesis that a CI could change the tinnitus magnitude and/or its annoyance. RESULTS In our series of 36 patients, 36.10% reported total loudness suppression and another 41.6% reported a reduction. Annoyance scores reduced in 75% of patients. THI reduced in 72.2% of patients. CONCLUSION Tinnitus reduction after CI may manifest as several mechanisms, such as habituation, acoustic masking, direct electrical nerve stimulation and cortical reorganization. Nevertheless, it is our opinion that data on CI benefits on tinnitus should be interpreted with caution and it seems reasonable to admit that further data is still necessary before considering CI as a treatment of tinnitus especially in unilateral deafness.

The diagnosis of autoimmune inner ear disease: evidence and critical pitfalls.

The purpose of this paper is to review the current diagnostic work-up for patients with suspected Autoimmune Inner Ear Disease (AIED). AIED is a rare disease accounting for less than 1% of all cases of hearing impairment or dizziness, characterized by a rapidly progressive, often fluctuating, bilateral SNHL over a period of weeks to months. While specific tests for autoimmunity to the inner ear would be valuable, at the time of writing, there are none that are both commercially available and proven to be useful. Thus far, most of the identified antigens lack a clear association with localized inner ear pathology and the diagnosis of AIED is based either on clinical criteria and/or on a positive response to steroids. For clinical practice, we recommend an antigen-non-specific test battery including blood test for autoimmune disorders and for conditions that resemble autoimmune disorders. Nevertheless, if financial resources are limited, a very restricted work-up study may have a similar efficiency.

Vertigo and autoimmunity

Autoimmune inner ear disease probably accounts for less than 1% of all cases of balance disorders, but its incidence is often overlooked due to the absence of a specific diagnostic test. Furthermore, in several systemic autoimmune diseases the vestibulo-cochlear system may be affected. Clinical features comprise generalized imbalance, ataxia, motion intolerance, episodic vertigo and positional vertigo. An autoimmune mechanism seems to be responsible for 6% of unilateral and 16% of bilateral forms of Ménière’s disease. Oscillopsia and disequilibrium secondary to a bilateral vestibular paresis are probably caused by an autoimmune response in 5% of cases. Balance disorders of central origin may be due to other immuno-mediated disorders such as multiple sclerosis, brainstem encephalitis and vasculitidis. Aim of this paper is to assess the clinical features of autoimmune vertigo disorders through a systematic literature review.

Aging, Cognitive Decline and Hearing Loss: Effects of Auditory Rehabilitation and Training with Hearing Aids and Cochlear Implants on Cognitive Function and Depression among Older Adults

A growing interest in cognitive effects associated with speech and hearing processes is spreading throughout the scientific community essentially guided by evidence that central and peripheral hearing loss is associated with cognitive decline. For the present research, 125 participants older than 65 years of age (105 with hearing impairment and 20 with normal hearing) were enrolled, divided into 6 groups according to their degree of hearing loss and assessed to determine the effects of the treatment applied. Patients in our research program routinely undergo an extensive audiological and cognitive evaluation protocol providing results from the Digit Span test, Stroop color-word test, Montreal Cognitive Assessment and Geriatric Depression Scale, before and after rehabilitation. Data analysis was performed for a cross-sectional and longitudinal study of the outcomes for the different treatment groups. Each group demonstrated improvement after auditory rehabilitation or training on short- and long-term memory tasks, level of depression and cognitive status scores. Auditory rehabilitation by cochlear implants or hearing aids is effective also among older adults (median age of 74 years) with different degrees of hearing loss, and enables positive improvements in terms of social isolation, depression and cognitive performance.

Endocochlear inflammation in cochlear implant users: Case report and literature review

OBJECTIVES Cochlear implantation is a relatively safe procedure with a low complication rate. The overall rate of complications among cochlear implant patients ranges from 6% to 20%. Major complications are those that are life-threatening or require surgery, whereas minor complications are those that can be medically treated. Nonetheless, certain complications, even if highly rare, may require specific investigations and treatments. Among these rare complications are those with endocochlear involvement, such as cochleitis or labyrinthitis, with fibrosis or ossification that could lead to explantation. The aims of the present study were to report a particular case of post-operative cochleitis and to review the rate of complications after cochlear implantation, emphasising those conditions with proven endocochlear involvement. METHODS We refer to the case of an eight-year-old Italian boy affected by the sudden onset of headache, ipsilateral otalgia and facial paresis, who presented to our clinic for inexplicable worsening of the performance of his implant and his residual hearing, six years after surgery. A complete investigation including (clinical history, routine, autoimmune and serological blood tests, electrophysiological measurements from the cochlear implant and neuroimaging) was performed and is herein described. Additionally, a comprehensive review of the literature was conducted using internet search engines; 274 papers were selected, 88 of which were best suited to our purposes. RESULTS In our case, the progression of the symptoms and the performance decrement required explantation, followed by a complete recovery. Reviewing the literature revealed only three reports concerning cases of proven endocochlear phlogosis that required revision surgery. Wound swelling/infection and vertigo remain the two most common complications of cochlear implantation. Failure of the device is the third most frequent complication (10.06% of all complications and 1.53% of cochlear implantations). Other rare conditions (such as granulating labyrinthitis with cochlear fibrosis, ossification and erosion, silicone allergy and the formation of a biofilm around the internal device) are possible and unpredictable. Although rare (approximately 1%), such cases may require explantation. CONCLUSIONS Despite efforts by both surgeons and manufacturers, device-related and surgical complications still occur. These and other rare conditions demand specific management, and their frequency may be underestimated. Further studies are needed to assess more realistic rates of complications and devise more efficient strategies for early diagnosis and treatment.

Cochlear implant in Cogan syndrome.

Abstract Conclusions: Despite the need for special fitting strategies, improvements in speech discrimination tests support the use of cochlear implantation (CI) for patients with Cogan syndrome. Adequate preimplant counselling is mandatory, to prevent high expectations and to stress the necessity for bilateral implantation. Objective: In 60% of patients with Cogan syndrome, CI remains the only treatment option. Literature data agree that once the electrode array is properly inserted, functional outcomes are very good. Nevertheless, results may deteriorate due to progressive cochlear ossification. A few studies have documented the outcomes of CI in these patients, but none have reported the long-term results. Methods: This was a retrospective study describing the outcomes of 3 implanted patients with Cogan syndrome – among 300 adult patients who received a cochlear implant, 3 had become deaf due to Cogan syndrome. Results: In one patient the cochlear ossification advanced and the speech perception abilities worsened from the highest category to identification of words in closed set. The second patient complained of an abrupt reduction of loudness at 18 months post-implant, which required an increased electrical stimulation. The third patient reached the identification category probably due to auditory dyssynchrony, as an atypical consequence of the syndrome.

Bilateral Sudden Profound Hearing Loss and Vertigo as a Unique Manifestation of Bilateral Symmetric Inferior Pontine Infarctions

Objectives: We present a case of sudden bilateral profound deafness and vertigo, without any accompanying neurologic signs, secondary to bilateral infarctions of the cochlear and vestibular nuclei. Methods: Vertigo, vomiting, tinnitus, and bilateral profound deafness suddenly developed in a 65-year-old woman without any accompanying neurologic signs. In particular, she did not present dysarthria, numbness, cranial nerve palsies, or visual or cerebellar signs. Results: Magnetic resonance imaging of the brain revealed 2 fresh infarctions of 8 to 10 mm symmetrically localized in the posterolateral bulbopontine junction. Angiography revealed a complete occlusion of the basilar artery, with a well-represented backward flow of its distal portion from the carotid artery via posterior communicating arteries. Excluding a transient ischemic attack that occurred 16 days after the acute episode, the patient had had no other neurologic events at 8 months of follow-up. Conclusions: Acute vertigo and sudden deafness in a patient with known cerebrovascular occlusive disease may represent the warning signs of an impending brain stem or cerebellar infarction, even when other neurologic signs are absent. These events are fortunately very rare, but should be considered by clinicians who see patients with vertigo.

Considerations on the physiopathological mechanism of inner ear damage induced by intravenous cocaine abuse: Cues from a case report

OBJECTIVE Aim of the following paper is to discuss about the possible etiopathogenetic mechanisms of inner ear damage induced by cocaine abuse. Unfortunately the data concerning this topic are very limited; the authors are then presenting a literature review, also discussing the clinical presentation and the possible therapeutical approach of a clinical case of bilateral sudden sensorineural hearing loss following i.v. injection of cocaine. PATIENTS Case report. INTERVENTION A strictly audiological evaluation has been performed, in order to identify the cochlear lesion site(s) and to provide the best medical treatment. CONCLUSIONS To our knowledge, this is the first report of acute cocaine intoxication with sudden bilateral hearing loss. Further studies are required in order to understand the effects of these substances on the inner ear cells and metabolism.