Cochlear implants (CIs), a revolutionary breakthrough in auditory technology, have profoundly impacted the lives of individuals with severe hearing impairment. Surgically implanted behind the ear and within the delicate cochlea, these devices represent a direct pathway to restoring the sense of hearing. Implanting hope alongside innovation, their captivating history unfolds through pivotal dates and transformative milestones. From the first human implantation by Drs. William House and John Doyle in 1961 to FDA approval in 1984, each step in their evolution mirrors a triumph of human ingenuity. The 1990s witnessed significant miniaturization, enhancing accessibility, while the 21st century brought about improvements in speech processing and electrode technology. These strides have elevated CIs beyond functional devices to life-changing instruments, enriching both auditory experiences and communication skills. This entry delves into the captivating history of CIs, spotlighting key dates that paint a vivid picture of challenges overcome and remarkable progress achieved. It explores the people and moments that defined their development, ultimately shaping these implants into indispensable tools that continually redefine the landscape of hearing assistance.

Auditory impairment stands as a pervasive global issue, exerting significant effects on individuals’ daily functioning and interpersonal engagements. Cochlear implants (CIs) have risen as a cutting-edge solution for severe to profound hearing loss, directly stimulating the auditory nerve with electrical signals. The success of CI procedures hinges on precise pre-operative planning and post-operative evaluation, highlighting the significance of advanced three-dimensional (3D) inner ear reconstruction software. Accurate pre-operative imaging is vital for identifying anatomical landmarks and assessing cochlear deformities. Tools like 3D Slicer, Amira and OTOPLAN provide detailed depictions of cochlear anatomy, aiding surgeons in simulating implantation scenarios and refining surgical approaches. Post-operative scans play a crucial role in detecting complications and ensuring CI longevity. Despite technological advancements, challenges such as standardization and optimization persist. This review explores the role of 3D inner ear reconstruction software in patient selection, surgical planning, and post-operative assessment, tracing its evolution and emphasizing features like image segmentation and virtual simulation. It addresses software limitations and proposes solutions, advocating for their integration into clinical practice. Ultimately, this review underscores the impact of 3D inner ear reconstruction software on cochlear implantation, connecting innovation with precision medicine.

Neonatal hearing screening (NHS) is a critical public health measure for early identification of hearing loss, ensuring timely access to interventions that can dramatically improve a child’s language development, cognitive abilities, and social inclusion. Beyond clinical benefits, NHS provides long-term advantages in education and quality of life. Given that congenital hearing loss affects approximately 1–2 in every 1000 newborns worldwide, the case for universal screening is clear. Countries like the United States and Australia have successfully implemented NHS, leading to earlier diagnoses, improved language development, and better educational outcomes. In Europe, while many nations have adopted NHS, consistency remains a challenge. Countries such as Norway and the United Kingdom stand out for their well-established systems, whereas others, like Greece, have made notable progress but have yet to mandate NHS nationwide. This highlights the need for cohesive national policies across Europe to ensure universal coverage. Screening methods such as Transient Evoked Otoacoustic Emissions (TEOAE) and Automated Auditory Brainstem Response (AABR) are established tools for detecting hearing impairments in neonates. Despite their demonstrated efficacy, NHS remains inconsistent globally, particularly in low- and middle-income regions that lack mandatory policies or access to reliable screening technologies. This perspective advocates for the urgent need to make NHS mandatory in all countries, emphasizing its societal benefits and cost-effectiveness. Early diagnosis supports prompt intervention, like hearing aids or cochlear implants, which are most effective when implemented before six months. It also empowers families to make informed decisions, fosters educational inclusion, and mitigates the social and emotional challenges of undiagnosed hearing loss. Policymakers, healthcare providers, and international organizations must prioritize universal NHS to ensure no child is left behind due to unaddressed hearing loss.

Leukemias and lymphomas, encompassing a spectrum of hematologic malignancies, often exhibit manifestations in various tissues and organs, including the ears, nose, and throat (ENT) region, extending beyond the typical sites of bone marrow and lymph nodes. This manuscript explores these interactions, considering disease-related symptoms and treatment effects. ENT symptoms, such as otalgia, hearing loss, and nasal obstruction, may arise from direct infiltration or treatment complications, with chemotherapy-induced ototoxicity being particularly characteristic. Furthermore, immunotherapy complications, including cytokine release syndrome and mucosal irritation, can also contribute to ENT symptoms. Additionally, targeted therapy and radiotherapy can lead to mucosal dryness, dysphonia, and radiation-induced otitis media. Patients with hematologic malignancies are especially vulnerable to various ENT infections, including bacterial, viral, and fungal infections, due to compromised immunity resulting from both the disease and its treatments. Conditions such as rhinosinusitis, otitis media, and pharyngitis pose significant management challenges. Moreover, patients undergoing hematopoietic stem cell transplantation (HSCT) face unique ENT considerations, including mucositis, opportunistic infections, and graft-versus-host disease in cases of allogeneic HSCT. These patients require specialized pre-transplant evaluations, meticulous post-transplant surveillance, and tailored assistance to mitigate complications. This manuscript underscores the importance of a multidisciplinary approach that integrates diagnostics, pharmacological interventions, and supportive care to address both disease-related and treatment-induced ENT manifestations. Further research is needed to refine management strategies and improve outcomes in this complex clinical population.

Background and Clinical Significance: Prader–Willi syndrome (PWS) is an imprinting disorder not typically associated with severe congenital sensorineural hearing loss (SNHL). When profound SNHL is present in an infant with a known syndrome, an independent monogenic etiology should be considered. We report the first molecularly confirmed case of PWS co-occurring with biallelic pathogenic TMC1 variants causing congenital SNHL, outlining diagnostic challenges, cochlear implant (CI) outcomes, and implications for blended phenotypes. Case Presentation: A male infant with PWS due to a paternal 15q11.2–q13 deletion failed newborn hearing screening. Diagnostic auditory brainstem response and auditory steady-state response confirmed bilateral severe-to-profound SNHL. Temporal bone CT/MRI were normal. Comprehensive genetic testing identified compound heterozygous TMC1 variants consistent with autosomal recessive DFNB7/11 hearing loss, plus two variants of uncertain significance in SERPINB6 and EPS8L2. Sequential bilateral cochlear implantation was performed (left ear at 14 months, right at 20 months), followed by auditory–verbal therapy. Over four years, the child showed steady improvements in hearing and early-speech development. Conclusions: Early genomic evaluation is essential when clinical features appear atypical for a known syndrome. Identifying TMC1-related deafness enabled timely cochlear implantation and measurable gains. This case highlights that severe congenital SNHL in a syndromic infant may reflect a distinct monogenic disorder rather than phenotypic expansion of the primary syndrome, emphasizing the importance of recognizing blended phenotypes to guide precision-care strategies in rare disorders.

Background and Clinical Significance: Warsaw Breakage Syndrome (WABS), also termed DDX11-related cohesinopathy, is an exceptionally rare autosomal recessive disorder caused by biallelic pathogenic variants in DDX11. Sensorineural hearing loss is a recurrent manifestation and has frequently been reported together with structural abnormalities of the cochlea or cochlear nerve. Published experience with cochlear implantation in WABS remains extremely limited. Case Presentation: A 2.5-year-old boy was referred because of absent spoken-language development and limited responses to environmental and speech sounds. Newborn hearing screening had not been performed. After treatment of bilateral middle-ear effusions, comprehensive audiological assessment showed absent transient-evoked otoacoustic emissions and cochlear microphonics, no reproducible auditory brainstem response waveforms at the maximum tested level of 90 dB nHL, and auditory steady-state response estimates in the severe-to-profound range bilaterally. Clinical examination revealed microcephaly, short stature, and global developmental delay, raising suspicion of an underlying syndromic disorder. High-resolution computed tomography demonstrated normal cochlear morphology, while magnetic resonance imaging showed bilaterally visualized cochlear nerves without aplasia or marked hypoplasia. Whole-exome sequencing identified a pathogenic frameshift variant in DDX11 in apparent homozygosity, supporting the molecular diagnosis of WABS. Simultaneous bilateral cochlear implantation was performed at 3 years of age without complications. Longitudinal auditory development, assessed with the LittlEARS Auditory Questionnaire, improved from 0/35 at activation to 10/35 at 8 months, 21/35 at 20 months, and 33/35 at 24 months of auditory age. At approximately 30 months of auditory age, structured language assessments demonstrated further receptive and expressive communication gains, although language development remained influenced by the underlying neurodevelopmental disorder. At 33 months of auditory age, functional auditory performance assessed with PEACH-GR was 90% in quiet, 80% in noise, and 85% overall, while Greek-standardized language testing demonstrated persistent language difficulties relative to chronological-age expectations. Conclusions: Severe-to-profound prelingual sensorineural hearing loss in WABS may occur despite normal cochlear morphology and bilaterally visualized cochlear nerves. In this patient, simultaneous bilateral cochlear implantation was technically uncomplicated. During subsequent bilateral device use, programming, rehabilitation, and maturation, quantitatively documented progressive auditory development and functional communication gains were observed. Comprehensive audiological, radiological, genetic and developmental assessment is essential for individualized implant candidacy and realistic family counseling.