Rehabilitation Protocol for Unilateral Laryngeal and Lingual Paralysis (Tapia Syndrome): Comment About "A Challenging Case of Tapia Syndrome After Total Thyroidectomy" By Ildem Deveci, Mehmet Surmeli, and Reyhan Surmeli.

Tapia syndrome is a rare complication after surgery, with ipsilateral paralysis of vocal cord and tongue due to extracranial involvement of recurrent laryngeal and hypoglossal nerves. Tapia's case report is extremely interesting for both the rarity of the reported cases and for the importance of an early rehabilitation. In a previous work, we reported a case of Tapia syndrome after cardiac surgery for aortic aneurysm, and the protocol of logopedic rehabilitation adopted. In the postoperative period, he developed severe dyspnea and dysphagia that required a tracheostomy and a logopedic rehabilitation therapy that led to a fast and efficient swallowing without aspiration after 47 sessions (less than 4 months). The progressive recovery of the function suggests aprassic nerve damage. However, the logopedic therapy is recommended to limit the possibility of permanent functional deficits and quickly recover swallowing and phonation.

Sporadic and NF2-associated vestibular schwannoma surgery and simultaneous cochlear implantation: a comparative systematic review.

PURPOSE: Cochlear implantation (CI) in patients with sensorineural hearing loss caused by a vestibular schwannoma (VS) represents a unique subtype of hearing rehabilitation, as the outcome may be compromised by vestibulocochlear nerve injury as part of the natural VS history or due to iatrogenic trauma induced by surgical tumor removal. This paper aims to review and report contemporary knowledge and practice regarding feasibility and outcomes of simultaneous vestibular schwannoma resection and cochlear implantation to serve as a reference and guide for future surgery and studies. METHODS: The current literature was searched systematically according to the PRISMA guidelines and after criteria-based selection, 29 studies were identified, including a total of 86 patients who had undergone surgical resection of a vestibular schwannoma and subsequent cochlear implantation in a single procedure. RESULTS: The postoperative outcomes were reported with a high degree of heterogeneity, hindering a proper meta-analysis. However, pooling those cases with reported speech discrimination outcomes demonstrated mean scores equivalent to moderate-to-high performance. A few cases had no audibility. A positive cochlear nerve test result was not a secure positive predictor of success. Complications were rare. CONCLUSION: NF2-associated and sporadic VS had good and comparable postoperative outcomes despite significant differences in tumor size, location and surgical approach.

Inhibition of the Adenosine A2A Receptor Mitigates Excitotoxic Injury in Organotypic Tissue Cultures of the Rat Cochlea.

The primary loss of cochlear glutamatergic afferent nerve synapses due to noise or ageing (cochlear neuropathy) often presents as difficulties in speech discrimination in noisy conditions (hidden hearing loss (HHL)). Currently, there is no treatment for this condition. Our previous studies in mice with genetic deletion of the adenosine A2A receptor (A2AR) have demonstrated better preservation of cochlear afferent synapses and spiral ganglion neurons after noise exposure compared to wildtype mice. This has informed our current targeted approach to cochlear neuroprotection based on pharmacological inhibition of the A2AR. Here, we have used organotypic tissue culture of the Wistar rat cochlea at postnatal day 6 (P6) to model excitotoxic injury induced by N-methyl-d-aspartate (NMDA)/kainic acid (NK) treatment for 2 h. The excitotoxic injury was characterised by a reduction in the density of neural processes immediately after NK treatment and loss of afferent synapses in the presence of intact sensory hair cells. The administration of istradefylline (a clinically approved A2AR antagonist) reduced deafferentation of inner hair cells and improved the survival of afferent synapses after excitotoxic injury. This study thus provides evidence that A2AR inhibition promotes cochlear recovery from excitotoxic injury, and may have implications for the treatment of cochlear neuropathy and prevention of HHL.

Traumatic Facial and Vestibulocochlear Nerve Injury in The Internal Acoustic Canal in The Absence of A Temporal Bone Fracture.

We present a rare case of traumatic facial and vestibulocochlear nerve injury in the internal acoustic canal in the absence of a temporal bone fracture. A 2.5-year-old female presented with sudden-onset left-sided facial paralysis and ipsilateral total hearing loss after being hit by a falling television. High-resolution computed tomography revealed an occipital fracture line that spared the temporal bone and otic capsule. Diagnostic auditory brainstem response testing showed that wave V at 90-db normal hearing level was absent in the left ear. Needle electromyography revealed severe axonal injury. Facial paralysis regressed to House-Brackmann grade IV 9 months after the trauma, and no surgical intervention was scheduled. Traumatic facial and vestibulocochlear nerve injury can occur in the absence of a temporal bone fracture. Thus, careful evaluation of the internal acoustic canal is mandatory if concurrent 7th and 8th cranial nerve paralyses exist with no visible fracture line.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on Intraoperative Cranial Nerve Monitoring in Vestibular Schwannoma Surgery.

Question 1: Does intraoperative facial nerve monitoring during vestibular schwannoma surgery lead to better long-term facial nerve function? Target Population: This recommendation applies to adult patients undergoing vestibular schwannoma surgery regardless of tumor characteristics. Recommendation: Level 3: It is recommended that intraoperative facial nerve monitoring be routinely utilized during vestibular schwannoma surgery to improve long-term facial nerve function. Question 2: Can intraoperative facial nerve monitoring be used to accurately predict favorable long-term facial nerve function after vestibular schwannoma surgery? Target Population: This recommendation applies to adult patients undergoing vestibular schwannoma surgery. Recommendation: Level 3: Intraoperative facial nerve can be used to accurately predict favorable long-term facial nerve function after vestibular schwannoma surgery. Specifically, the presence of favorable testing reliably portends a good long-term facial nerve outcome. However, the absence of favorable testing in the setting of an anatomically intact facial nerve does not reliably predict poor long-term function and therefore cannot be used to direct decision-making regarding the need for early reinnervation procedures. Question 3: Does an anatomically intact facial nerve with poor electromyogram (EMG) electrical responses during intraoperative testing reliably predict poor long-term facial nerve function? Target Population: This recommendation applies to adult patients undergoing vestibular schwannoma surgery. Recommendation: Level 3: Poor intraoperative EMG electrical response of the facial nerve should not be used as a reliable predictor of poor long-term facial nerve function. Question 4: Should intraoperative eighth cranial nerve monitoring be used during vestibular schwannoma surgery? Target Population: This recommendation applies to adult patients undergoing vestibular schwannoma surgery with measurable preoperative hearing levels and tumors smaller than 1.5 cm. Recommendation: Level 3: Intraoperative eighth cranial nerve monitoring should be used during vestibular schwannoma surgery when hearing preservation is attempted. Question 5: Is direct monitoring of the eighth cranial nerve superior to the use of far-field auditory brain stem responses? Target Population: This recommendation applies to adult patients undergoing vestibular schwannoma surgery with measurable preoperative hearing levels and tumors smaller than 1.5 cm. Recommendation: Level 3: There is insufficient evidence to make a definitive recommendation. The full guideline can be found at: https://www.cns.org/guidelines/guidelines-manage-ment-patients-vestibular-schwannoma/chapter_4.

c-Jun N-Terminal Phosphorylation: Biomarker for Cellular Stress Rather than Cell Death in the Injured Cochlea.

Prevention of auditory hair cell death offers therapeutic potential to rescue hearing. Pharmacological blockade of JNK/c-Jun signaling attenuates injury-induced hair cell loss, but with unsolved mechanisms. We have characterized the c-Jun stress response in the mouse cochlea challenged with acoustic overstimulation and ototoxins, by studying the dynamics of c-Jun N-terminal phosphorylation. It occurred acutely in glial-like supporting cells, inner hair cells, and the cells of the cochlear ion trafficking route, and was rapidly downregulated after exposures. Notably, death-prone outer hair cells lacked c-Jun phosphorylation. As phosphorylation was triggered also by nontraumatic noise levels and none of the cells showing this activation were lost, c-Jun phosphorylation is a biomarker for cochlear stress rather than an indicator of a death-prone fate of hair cells. Preconditioning with a mild noise exposure before a stronger traumatizing noise exposure attenuated the cochlear c-Jun stress response, suggesting that the known protective effect of sound preconditioning on hearing is linked to suppression of c-Jun activation. Finally, mice with mutations in the c-Jun N-terminal phosphoacceptor sites showed partial, but significant, hair cell protection. These data identify the c-Jun stress response as a paracrine mechanism that mediates outer hair cell death.

Effect of cochlear nerve electrocautery on the adult cochlear nucleus.

HYPOTHESIS: Electrocauterization and subsequent transection of the cochlear nerve induce greater injury to the cochlear nucleus than sharp transection alone. BACKGROUND: Some studies show that neurofibromatosis Type 2 (NF2) patients fit with auditory brainstem implants (ABIs) fail to achieve speech perception abilities similar to ABI recipients without NF2. Reasons for these differences remain speculative. One hypothesis posits poorer performance to surgically induced trauma to the cochlear nucleus from electrocautery. Sustained electrosurgical depolarization of the cochlear nerve may cause excitotoxic-induced postsynaptic nuclear injury. Equally plausible is that cautery in the vicinity of the cochlear nucleus induces necrosis. METHODS: The cochlear nerve was transected in anesthetized adult gerbils sharply with or without bipolar electrocautery at varying intensities. Gerbils were perfused at 1, 3, 5, and 7 days postoperatively; their brainstem and cochleas were embedded in paraffin and sectioned at 10 µm. Alternate sections were stained with flourescent markers for neuronal injury or Nissl substance. In additional experiments, anterograde tracers were applied directly to a sectioned eighth nerve to verify that fluorescent-labeled profiles seen were terminating auditory nerve fibers. RESULTS: Cochlear nerve injury was observed from 72 hours postoperatively and was identical across cases regardless of surgical technique. Postsynaptic cochlear nucleus injury was not seen after distal transection of the nerve. By contrast, proximal transection was associated with trauma to the cochlear nucleus. CONCLUSION: Distal application of bipolar electrocautery seems safe for the cochlear nucleus. Application near the root entry zone must be used cautiously because this may compromise nuclear viability needed to support ABI stimulation.

Emprical factors associated with Brainstem auditory evoked potential monitoring during microvascular decompression for hemifacial spasm and its correlation to hearing loss.

BACKGROUND: Cranial nerve VIII is at risk during microvascular decompression (MVD) for hemifacial spasm (HFS). The primary aim of this study is to evaluate the empirical factors associated with brainstem auditory evoked potential monitoring and its correlation to post operative hearing loss (HL) after MVD for HFS. METHODS: Pre-operative and post-operative audiogram data and BAEP from ninety-four patients who underwent MVD for HFS were analyzed. Pure tone audiometry (PTA) and Speech Discrimination Score (SDS) were performed on all patients before and after surgery. Intraoperative neurophysiological data were reviewed independently. HL was assessed using the AAO-HNS classification system for non-serviceable hearing loss (Class C/D), defined as PTA >50 dB and/or SDS <50% within the speech range of frequencies. RESULTS: Patients with HL had higher rates of loss in the amplitude of wave V and prolongation in the interpeak latency of peak I-V latency during MVD. Gender, age, side, and MVD duration did not increase the risk of HL. There was no correlation between successive number of BAEP changes (reflective of the number of surgical attempts) and HL. There was no association between the speed of recovery of BAEPs and HL. CONCLUSIONS: Patients with new post-operative HL have a faster rate of change in the amplitude of wave V and the interpeak I-V latency during intraoperative BAEP monitoring for HFS. Our alarm criteria to inform the surgeon about impending nerve injury might have to be modified and prospectively tested to prevent rapid change in BAEPs.

Ouabain-induced cochlear nerve degeneration: synaptic loss and plasticity in a mouse model of auditory neuropathy.

Ouabain application to the round window can selectively destroy type-I spiral ganglion cells, producing an animal model of auditory neuropathy. To assess the long-term effects of this deafferentation on synaptic organization in the organ of Corti and cochlear nucleus, and to ask whether surviving cochlear neurons show any post-injury plasticity in the adult, we quantified the peripheral and central synapses of type-I neurons at posttreatment times ranging from 1 to 3 months. Measures of normal DPOAEs and greatly reduced auditory brainstem responses (ABRs) confirmed the neuropathy phenotype. Counts of presynaptic ribbons and postsynaptic glutamate receptor patches in the inner hair cell area decreased with post-exposure time, as did counts of cochlear nerve terminals in the cochlear nucleus. Although these counts provided no evidence of new synapse formation via branching from surviving neurons, the regular appearance of ectopic neurons in the inner hair cell area suggested that neurite extension is not uncommon. Correlations between pathophysiology and histopathology showed that ABR thresholds are very insensitive to even massive neural degeneration, whereas the amplitude of ABR wave 1 is a better metric of synaptic degeneration.

Analysis of interpeak latencies of brainstem auditory evoked potential waveforms during microvascular decompression of cranial nerve VII for hemifacial spasm.

OBJECT: Microvascular decompression (MVD) of the facial nerve is an effective treatment for patients with hemifacial spasm. Intraoperative monitoring of brainstem auditory evoked potentials (BAEPs) during MVD can reduce the incidence of hearing loss. In this study the authors' goal was to evaluate changes in interpeak latencies (IPLs) of Waves I-V, Waves III-V, and Waves I-III of BAEP Waveforms I, III, and V during MVD and correlate them with postoperative hearing loss. To date, no such study has been performed. Hearing loss is defined as nonuseful hearing (Class C/D), which is a pure tone average of more than 50 dB and/or speech discrimination score of less than 50%. METHODS: The authors performed a retrospective analysis of IPLs of BAEPs in 93 patients who underwent intraoperative BAEP monitoring during MVD. Patients who did not have hearing loss were in Class A/B and those who had hearing loss were in Class C/D. RESULTS: Binary logistic regression analysis of independent IPL variables was performed. A maximum change in IPLs of Waves I-III and Waves I-V and on-skin change in IPLs of Waves I-V increases the odds of hearing loss. However, on adjusting the same variables for loss of response, change in IPLs did not increase the odds of hearing loss. CONCLUSIONS: Changes in IPL measurements did not increase the odds of postoperative hearing loss. This information might be helpful in evaluating the value of IPLs as alarm criteria during MVD to prevent hearing loss.

Desarrollo de una hoja de cálculo del impedimento auditivo usando Microsoft EXCEL / Developement of a spreadsheet for hearing impairment using Microsoft Excel

En nuestra actividad profesional diaria es habitual que necesitemos calcular el impedimento auditivo, para realizar informes médicos o para informar a nuestros pacientes. Hasta ahora hemos utilizado tablas y sistemas de cálculo manual que lo facilitan. Para simplificar y hacer más preciso este cálculo hemos desarrollado un sistema utilizando el programa Microsoft Excel y las fórmulas de cálculo de la American Academy of Otolaryngology. Respecto a otros sistemas, el programa de cálculo que describimos aporta 2 ventajas. La primera es su capacidad para corregir el error asociado a la aplicación directa de la fórmula de cálculo del impedimento monoaural, que con valores audiométricos normales (<25dB)da resultados negativos y en caso de hipoacusia profunda (>90dB), resultados superiores al 100%. La segunda ventaja es que no se tiene que indicar cuál es el oído mejor antes de realizar el cálculo binaural hecho que evita la introducción de los valores de «oído mejor» «oído peor» en 2 celdas y supone el ahorro de alrededor de un 20% de tiempo total de cálculo. En conclusión, consideramos que en nuestras especialidades, la hoja de cálculo de Excel adaptada para la valoración del impedimento auditivo, resulta muy adecuada, reproduce los resultados de cualquier sistema de cálculo manual y minimiza la posibilidad de error, por lo que puede aportar un ahorro de tiempo y una mayor seguridad (AU)

In daily clinical practice, the results of audiometric tests often need to be converted into the percentage of hearing impairment in order to prepare health reports or to provide information requested by patients. Until now, manual systems have been used to calculate this percentage. To simplify and add precision to this calculation, we developed a spreadsheet using Microsoft Excel software and the American Academy of Otolaryngology's formula to determine hearing handicap. Compared with other systems, our spreadsheet provides two main advantages. First, it corrects the intrinsic problem of the original formula, which gives negative results in the presence of normal audiometries (values under 25dB) or results over 100 in the case of severe hypoacusis (values over 90dB). The second advantage is that there is no need to specify the best ear in order to calculate the global hearing handicap, thus avoiding the introduction of two values and saving 20% of the overall calculation time. In conclusion, we consider that the Excel spreadsheet, adapted for the evaluation of hearing handicap, could save time and be more accurate than manual methods, thus reducing the possibility of making mistakes (AU)

The efficacy of N-acetylcysteine to protect the human cochlea from subclinical hearing loss caused by impulse noise: a controlled trial.

In military outdoor shooting training, with safety measures enforced, the risk of a permanent, noise-induced hearing loss is very small. But urban warfare training performed indoors, with reflections from walls, might increase the risk. A question is whether antioxidants can reduce the negative effects of noise on human hearing as it does on research animals. Hearing tests were performed on a control group of 23 military officers before and after a shooting session in a bunker-like room. The experiments were repeated on another group of 11 officers with peroral adminstration of N-acetyl-cysteine (NAC), directly after the shooting. The measurements performed were tone thresholds; transient-evoked otoacoustic emissions, with and without contralateral noise; and psycho-acoustical modulation transfer function (PMTF), thresholds for brief tones in modulated noise. Effects from shooting on hearing thresholds were small, but threshold behavior supports use of NAC treatment. On the PMTF, shooting without NAC gave strong effects. Those effects were like those from continuous noise, which means that strict safety measures should be enforced. The most striking finding was that the non-linearity of the cochlea, that was strongly reduced in the group without NAC, as manifested by the PMTF-results, was practically unchanged in the NAC-group throughout the study. NAC treatment directly after shooting in a bunkerlike room seems to give some protection of the cochlea.

Role of stromal cell-derived factor-1 expression in the injured mouse auditory nerve.

OBJECTIVE: The degeneration of hair cells and spiral ganglion neurons (SGNs) is an important pathologic process in the development of sensorineural hearing loss. In a murine model, predictable and reproducible damage to SGNs occurs through the application of ouabain to the round window. Recent evidence has shown that the chemokine stromal cell-derived factor-1 (SDF-1) is a potent chemoattractant of hematopoietic stem cells (HSCs) and provides trophic support to injured tissues during development and maturation. The hypothesis for the current study is that expression of SDF-1 plays an important role in protecting SGNs and preventing further degeneration in the setting of cochlear injury. STUDY DESIGN: Prospective, controlled. SETTING: Academic research laboratory. SUBJECT AND METHODS: Auditory brainstem response (ABR) and the expression of SDF-1 mRNA and protein were examined 1, 3, 7, 14, and 30 days after application of ouabain in 35 adult mice. RESULTS: Following ouabain application, real-time reverse-transcription polymerase chain reaction for SDF demonstrates increased mRNA expression following ouabain injury in nontransplanted mice. A significant increase in SDF protein expression was also observed using immunolabeling techniques and Western blot analysis. CONCLUSIONS: SDF-1 expression is increased in the auditory nerve following cochlear injury. Further knowledge about the cochlear microenvironment, including SDF-1, is critical to maximizing HSC engraftment in the injured cochlea and providing a therapeutic option for sensorineural hearing loss.

Facial and vestibulocochlear nerve avulsion at the fundus of the internal auditory canal in a child without a temporal bone fracture.

OBJECTIVE: To describe a case of facial, vestibular, and cochlear nerve avulsion secondary to blunt trauma without an associated temporal bone fracture. STUDY DESIGN: Clinical capsule report. SETTING: University hospital. PATIENT: A 3.5-year-old girl presented with immediate facial nerve paralysis and complete deafness after being struck by an automobile. High-resolution computed tomography demonstrated a depressed occipital bone fracture with no visible fracture of the temporal bone. Magnetic resonance imaging sequence raised the question of VIIth nerve bundle discontinuity at the distal end of the internal auditory canal. INTERVENTION: The patient underwent a posterior fossa craniotomy via a translabyrinthine approach 9 months after the initial injury, and facial and auditory nerve avulsion at the fundus was confirmed at the time of surgery. The proximal segment of the facial nerve had formed a traumatic neuroma, which was resected, and primarily anastomosed to the rerouted distal segment. MAIN OUTCOME MEASURES: Facial nerve function. RESULTS: Patient has regained facial function to Grade III/VI House-Brackmann with no asymmetry at rest. CONCLUSION: An unusual pattern of injury is described. We suggest that in patients presenting with facial nerve paralysis secondary to blunt trauma, without an associated temporal bone fracture, high-resolution magnetic resonance imaging is recommended to evaluate internal auditory canal discontinuity of the VIIth and VIIIth nerve complexes. A potential mechanism of avulsion is explained.

Atypic geniculate neuralgia: atypic anatomic correlation of cranial nerve roots and AICA.

Geniculate neuralgia is a rare cause of craniofacial pains. The anterior inferior cerebellar artery is the offending vessel which compress nervus intermedius in the patients with typical geniculate neuralgia. We report a patient whose pain was atypical for either geniculate neuralgia and trigeminal neuralgia. At operation the anterior inferior cerebellar artery was coursing with the nerves and was separated. After the decompression the pain resolved immediately.

Remote tentorium meningioma causing sudden sensorineural deafness.

BACKGROUND: Sudden sensorineural deafness is a well-known symptom mostly of unknown etiology. CASE DESCRIPTION: A case of sudden sensorineural deafness is reported to be caused by a small, remote, ipsilateral tentorial meningioma not compressing the vestibulocochlear nerve or auditory tract. Surgical resection of the meningioma immediately restored the patient's hearing. CONCLUSION: The authors hypothesize that the sudden sensorineural deafness resulted from a growing meningioma inducing a neurovascular compression of the vestibulocochlear nerve, the vertebral artery already being in close relationship with the vestibulocochlear nerve in the premorbid phase. Resection of the meningioma allows for an autodecompression of this vascular conflict resulting in hearing restoration.

Short-term pathophysiologic changes and histopathologic findings of the auditory pathway after closed head injury, using a rabbit model.

Hearing impairment is a well-known consequence of closed head injury (CHI). The aim of this study was to elucidate the pathogenesis of CHI-induced hearing loss, using a rabbit model. Twelve New Zealand white rabbits were divided into two groups of 6. In the first group, CHI was induced mechanically, whereas the rabbits of the second group served as controls. Baseline distortion product otoacoustic emissions (DPOAEs), contralateral suppression (CS) of the DPOAEs and auditory brainstem response (ABR) were obtained. The same measurements were performed in the first group after CHI. Three hours later, the animals were sacrificed and their brain was excised and subjected to histopathologic examination. Mean I-III ABR latencies were increased and DPOAE amplitudes and CS values were reduced in the trauma group after CHI, at a statistically significant level. Histopathologic examination of the temporal lobe and brainstem showed multiple hemorrhagic and necrotic areas, with edema in the surrounding region. The vestibulocochlear nerve was severely damaged at its emerging site at the brainstem. In conclusion, both peripheral and central involvement of the auditory pathway was found after CHI. Otoacoustic emissions in conjunction with ABR may provide significant information on both peripheral and central auditory function.

Extracellular matrix molecules and their possible roles in the regeneration of frog nervous system.

Recent biochemical and histochemical analyses explored different components of the extracellular matrix (ECM) in the nervous system, and either permissive or non-permissive roles in neuronal development and regeneration were suggested. The aim of this study was to detect the distribution pattern of a few of these molecules in the nervous system of intact frogs and during nerve regeneration. The hyaluronan (HA) and tenascin C reactions were negative in the peripheral nerves, but appeared in their entry zones. In the CNS, different populations of neurons were surrounded with HA and tenascin C-positive material, forming a perineuronal net (PN). The phosphacan reaction was weakly positive in the PNS, and a moderate intensity was detected in the entry zone and in the PN. Laminin and fibronectin immunoreactivity was strong in the PNS, but laminin could not be detected in the CNS. In animals with cut and regenerating vestibulocochlear nerve, the distribution of the ECM molecules in the CNS and PNS characteristically changed from that of the normal pattern. Our results showed a non-homogenous distribution of ECM components in the frog nervous system that could be associated with their different roles in physiological and pathological processes.