Alessandro Castiglione

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.

Association between idiopathic hearing loss and mitochondrial DNA mutations: a study on 169 hearing-impaired subjects.

Mutations in mitochondrial DNA (mtDNA) have been shown to be an important cause of sensorineural hearing loss (SNHL). In this study, we performed a clinical and genetic analysis of 169 hearing-impaired patients and some of their relatives suffering from idiopathic SNHL, both familial and sporadic. The analysis of four fragments of their mtDNA identified several polymorphisms, the well known pathogenic mutation, A1555G, and some novel mutations in different genes, implying changes in the aminoacidic sequence. A novel sporadic mutation in 12S rRNA (MT-RNR1), not previously reported in the literature, was found in a case of possible aminoglycoside-induced progressive deafness.

Novel mutations in the SLC26A4 gene

OBJECTIVES Mutations in the SLC26A4 gene (7q22.3-7q31.1) are considered one of the most common causes of genetic hearing loss. There are two clinical forms related to these mutations: syndromic and non-syndromic deafness. The first one is named Pendred Syndrome (PS) when deafness is associated with thyroid goiter; the second is called DFNB4, when no other symptoms are present. Both are transmitted as an autosomal recessive trait, but simple heterozygotes can develop both forms of deafness. Actually it is thought that Pendred Syndrome occurs when both alleles of SLC26A4 gene are mutated; DFNB4 seems due to monoallelic mutations. PS and DFNB4 can be associated with inner ear malformations. In most of the cases (around 80%), these consist in Enlarged Vestibular Aqueduct (EVA). EVA can also be present without SLC26A4 mutations. Understanding the role of new SLC26A4 variants should facilitate clinical assessment, as well as diagnostic and therapeutic approaches. This investigation aims to detect and report genetic causes of two unrelated Italian boys with hearing loss. METHODS Patients and family members underwent clinical, audiological and genetic evaluations. To identify genetic mutations, DNA sequencing of SLC26A4 gene (including all 21 exons, exon-intron boundaries and promoter region) was carried out. RESULTS Both probands were affected by congenital, progressive and fluctuating mixed hearing loss. Temporal bone imaging revealed a bilateral EVA with no other abnormalities in both cases. Probands were heterozygotes for previously undescribed mutations in the SLC26A4 gene: R409H/IVS2+1delG (proband 1) and L236P/K590X (proband 2). No other mutations were detected in GJB2, GJB6 genes or mitochondrial DNA (mit-DNA). CONCLUSIONS The IVS2+1delG and K590X mutations have not yet been described in literature but there is some evidence to suggest that they have a pathological role. The results underlined the importance of considering the complete DNA sequencing of the SLC26A4 gene for differential molecular diagnosis of deafness, especially in those patients affected by congenital, progressive and fluctuating mixed hearing loss with bilateral EVA.

Syndromic hearing loss: An update

Abstract Hearing impairment is one of the commonest clinical conditions. It has been estimated that approximately 1 in 10 persons has hearing concerns. Further epidemiological studies have found that the percentage of the general population with hearing loss greater than 45 dB HL and 65 dB HL is 1.3% and 0.3%, respectively, between 30 and 50 years of age; and 2.3% and 7.4% between 60 and 70 years of age. The prevalence of childhood and adolescent hearing loss is around 3%. At birth, between one and two out of 1000 newborns are affected by hearing loss of such a degree as to require treatment (auditory training and rehabilitation, hearing aids or cochlear implantation). To summarize, hearing impairment affects up to 30% of the international community and estimates indicate that 70 million persons are deaf. The causes of hearing loss differ and they can vary in severity and physiopathology. In many cases it is not possible to define a definite aetiology. Nevertheless, it is known that most are due to a genetic cause and among these the majority appear in a non-syndromic form. The aetiology of hearing loss in children is unknown in 40% of cases, genetic non-syndromic in 30%, and genetic syndromic in 3–5%. The two most common genes involved in hearing loss are GJB2 and SLC26A4. Mutations in these genes can be responsible for syndromic hearing loss, as keratitis ichthyosis deafness (KID) and Pendred syndromes, respectively, or non-syndromic hearing loss (as DFNB1 and DFNB4, respectively). DFNB1 with GJB2 mutations is the most common non-syndromic form and Pendred syndrome is the most common syndromic form. Neither of these last two is usually characterized by congenital macroscopic dysmorphic features, and affected children can be generally considered as well babies. Nonetheless, 2–4% of live births have congenital malformations, most commonly caused by multifactorial defects, followed by chromosomal disorders, single gene mutations and teratogens (alcohol, drugs). Some of these conditions could directly affect the auditory system and be responsible for sensorineural, conductive or mixed hearing loss. The London Dysmorphology Database lists approximately 400 syndromes that include hearing loss among the clinical features. Other conditions such as cystic fibrosis are not usually responsible for hearing loss but they can indirectly affect the auditory system as a consequence of the management of the disease. Other systemic disorders can lead to hearing impairment when the disease involves a part of the auditory system from the external ear to the auditory cortex. From this standpoint there are a huge number of syndromes or conditions that can directly or indirectly cause hearing impairment. They can be responsible for congenital or prelingual, progressive and post-lingual hearing loss, with sensorineural, mixed or conductive deficits. In this updating research we have focused on syndromic forms that are known to be associated with hearing loss or that directly affect the auditory system. Some conditions of particular interest, or with high incidence, are also included.

Karyotype-phenotype correlation in partial trisomies of the short arm of chromosome 6: a family case report and review of the literature.

The first child (proband) of nonconsanguineous Caucasian parents underwent genetic investigation because she was affected with congenital choanal atresia, heart defects and kidney hyposplasia with mild transient renal insufficiency. The direct DNA sequencing after PCR of the CHD7 gene, which is thought to be responsible for approximately 60-70% of the cases of CHARGE syndrome/association, found no mutations. The cytogenetic analysis (standard GTG banding karyotype) revealed the presence of extrachromosomal material on 10q. The chromosome analysis was completed with array CGH (30 kb resolution), MLPA and FISH, which allowed the identification of three 6p regions (6p.25.3p23 × 3): 2 of these regions are normally located on chromosome 6, and the third region is translocated to the long arm of chromosome 10. The same chromosomal rearrangement was subsequently found in the father, who was affected with congenital ptosis and progressive hearing loss, and in the probands sister, the second child, who presented at birth with choanal atresia and congenital heart defects. The mutated karyotypes, which were directly inherited, are thought to be responsible for a variable phenotype, including craniofacial dysmorphisms, choanal atresia, congenital ptosis, sensorineural hearing loss, heart defects, developmental delay, and renal dysfunction. Nevertheless, to achieve a complete audiological assessment of the father, he underwent further investigation that revealed an increased level of the coagulation factor XIII (300% increased activity), fluctuating levels of fibrin D-dimer degradation products (from 296 to 1,587 ng/ml) and a homoplasmic mitochondrial DNA mutation: T961G in the MTRNR1 (12S rRNA) gene. He was made a candidate for cochlear implantation. Preoperative high-resolution computed tomography and magnetic resonance imaging of the temporal bone revealed the presence of an Arnold-Chiari malformation type I. To the best of our knowledge, this study is the second report on partial 6p trisomy that involves the 10q terminal region. Furthermore, we report the first case of documented Arnold-Chiari malformation type I and increased factor XIII activity associated with 6p trisomy. We present a comprehensive report of the familial cases and an exhaustive literature review.

Audiological profiles and gjb2, gjb6 mutations: A retrospective study on genetic and clinical data from 2003 to 2008

In many world populations, mutations in the GJB2 gene (codifying for Connexin 26) are the most common causes of autosomal recessive non-syndromic hearing loss and account for approximately 50% of cases. To date, more than 100 (dominant or recessive) mutations have been identified (The Connexin Deafness Homepage, 2009) and differences in frequency and distribution across the world are significant. In European and American Caucasian populations, the 35delG is the most common mutation found to account for nearly 70% of the pathological alleles. Mutations in the GJB6 gene (codifying for Connexin 30) can co-occur in some cases (we refer to the 342-kb truncating deletion, named as GJB6-D13S1830). Thus, these mutations have been associated with autosomal recessive and non-syndromic hearing loss, mostly as biallelic/digenic inheritance of the Cx26 and/or Cx30. Our objective in this study was to describe audiological features and genotypes in patients with GJB2 and/or GJB6 mutations. We performed a retrospective study on a deaf cohort of 566 patients who underwent specific genetic tests for Connexin 26 and 30; the latter was investigated in 385 cases. GJB2 mutations were found in 162 patients and GJB6 mutations in five. The most common mutation of GJB2 was 35delG, a truncating (T) mutation, although we also found other types of truncating (nine genotypes) and non-truncating (NT) (11 genotypes) mutations, such as M34T, L90P, R184P, IVS1 + 1G→A, V37I, and E47X. Even if more than 70% of patients with biallelic/digenic mutations exhibit a severe/profound hearing impairment (even between the simple heterozygotes), mild/moderate deafness is also possible. Other interesting clinical data, such as atypical history or phenotype, were considered. In accordance with the literature, all categories of HL were found. The severe-profound HL was predominant especially in T/T, T/NT forms. The 35delG is the most common mutation that we found, especially in profound hearing impairment. Mild-moderate HL was identified overall among NT/NT forms. Our findings confirm the importance of newborn screening, and the evaluation of genetic mutations to define genotype/phenotype correlation and clinical or audiological features useful to early diagnosis and improvement of therapeutic protocols.

Sudden sensorineural hearing loss and polymorphisms in iron homeostasis genes: new insights from a case-control study.

Background. Even if various pathophysiological events have been proposed as explanations, the putative cause of sudden hearing loss remains unclear. Objectives. To investigate and to reveal associations (if any) between the main iron-related gene variants and idiopathic sudden sensorineural hearing loss. Study Design. Case-control study. Materials and Methods. A total of 200 sudden sensorineural hearing loss patients (median age 63.65 years; range 10–92) were compared with 400 healthy control subjects. The following genetic variants were investigated: the polymorphism c.−8CG in the promoter of the ferroportin gene (FPN1; SLC40A1), the two isoforms C1 and C2 (p.P570S) of the transferrin protein (TF), the amino acidic substitutions p.H63D and p.C282Y in the hereditary hemochromatosis protein (HFE), and the polymorphism c.–582AG in the promoter of the HEPC gene, which encodes the protein hepcidin (HAMP). Results. The homozygous genotype c.−8GG of the SLC40A1 gene revealed an OR for ISSNHL risk of 4.27 (CI 95%, 2.65–6.89; P = 0.001), being overrepresented among cases. Conclusions. Our study indicates that the homozygous genotype FPN1 −8GG was significantly associated with increased risk of developing sudden hearing loss. These findings suggest new research should be conducted in the field of iron homeostasis in the inner ear.

EYA1-related disorders: Two clinical cases and a literature review

OBJECTIVES To delineate the diagnostic and rehabilitative aspects of syndromes that have overlapping features, we present the cases of two unrelated Caucasian males affected by hearing impairment, preauricular pits and cervical fistulae. Specific findings that are helpful in the diagnosis and management of EYA1-related disorders are highlighted. METHODS Genetic, otologic, imaging, eye and renal evaluations were conducted to achieve a detailed and comprehensive assessment, leading to the most accurate diagnosis and appropriate treatment. A literature review was also carried out. RESULTS Diagnostic criteria indicated that the two patients were affected by BOS1 (Branchio-Otic Syndrome 1). We also identified a novel sporadic missense mutation in the EYA1 gene: p.G533R (c.1597G>A, NM_000503.4), a highly conserved, heterozygotic amino acid substitution. In the other case, we identified the p.X593QextX6 (c.1777T>A, NM_000503.4) substitution. Both variants lead to isoform 1 (EYA1B and EYA1C) which is composed of 592 amino acids. Clinical and in silico evidence suggests a pathogenic role for the new mutations. Imaging evaluation revealed a complex pathology, characterized by external, inner and middle ear malformations, without renal anomalies. CONCLUSIONS Our results demonstrate the importance of considering the imaging evaluation and the complete DNA sequencing of the EYA1 gene for the differential diagnosis of deafness and related branchio-oto-renal disorders.