Quality of life related to symptomatic outcomes in patients with vestibular schwannomas: A Canadian Centre perspective.

Patients with vestibular schwannomas (VS) typically present with hearing loss and tinnitus as well as variable cranial nerve dysfunctions. Surgical resection, stereotactic radiotherapy and/or conservative management employing serial magnetic resonance or computed tomography imaging serve as the main treatment options. Quality of life (QoL) may be impacted by the extent of tumour burden and exacerbated or relieved by treatment. Subjective assessment and quality of life inventories provide valuable information in client centered approaches with important implications for treatment. The intention of QoL measurements affecting VS patients within a clinical setting is to facilitate discussions regarding treatment options and objectively evaluate patient- centered clinical outcomes in a naturalistic setting.

Vertigo and Dizziness: Understanding and Managing Fall Risk.

Vertigo and dizziness are common conditions among older adults. They are closely associated with fall risk and portend major implications for geriatric injury and disability. Management can be particularly challenging, because symptoms are often nonspecific and may reflect multiple etiologies. Chronic dizziness can reflect dysfunction in the vestibular, somatosensory, or visual systems or in their central integration. Systemic processes, such as postural hypotension, arrhythmias, heart failure, medication use, and lower extremity weakness or frailty, also contribute. Management of acute vestibular syndrome requires ruling out dangerous causes, such as stroke. This article reviews relevant definitions, epidemiology, pathophysiology, diagnosis, and clinical management.

The management of pediatric hearing loss caused by auditory neuropathy spectrum disorder.

PURPOSE OF REVIEW: Auditory neuropathy spectrum disorder (ANSD) is a condition in which auditory testing reveals normal otoacoustic emissions, but auditory brainstem testing is abnormal or absent and speech discrimination is poor. This constellation of findings ostensibly suggests that the cochlea is healthy and an abnormality of conduction or processing of sound occurs along the nerve fibers. As more is learned about this condition, it is becoming clear that ANSD describes heterogeneous, distinct clinical entities that must be taken into account when devising treatment modalities. RECENT FINDINGS: Modern auditory testing, genetic testing, and neuroimaging can allow for an accurate understanding of the location of the lesion causing ANSD in the auditory pathway. Contributing causes can include genetic mutations, absent or deficient cochlear nerve, hypoxia and jaundice among others. Hearing aids can be successful in the management of ANSD. Several studies suggest that cochlear implantation can lead to successful hearing outcomes in a subset of this patient population. SUMMARY: Auditory neuropathy spectrum disorder represents a relatively rare but important diagnosis for clinicians. Treatment for this condition includes hearing aids and FM systems in more mild cases, and cochlear implants in severe cases. Cochlear implantation for many patients can lead to a good hearing outcomes but the outcome can vary greatly depending on the underlying etiology of ANSD.

Contributions of Mouse and Human Hematopoietic Cells to Remodeling of the Adult Auditory Nerve After Neuron Loss.

The peripheral auditory nerve (AN) carries sound information from sensory hair cells to the brain. The present study investigated the contribution of mouse and human hematopoietic stem cells (HSCs) to cellular diversity in the AN following the destruction of neuron cell bodies, also known as spiral ganglion neurons (SGNs). Exposure of the adult mouse cochlea to ouabain selectively killed type I SGNs and disrupted the blood-labyrinth barrier. This procedure also resulted in the upregulation of genes associated with hematopoietic cell homing and differentiation, and provided an environment conducive to the tissue engraftment of circulating stem/progenitor cells into the AN. Experiments were performed using both a mouse-mouse bone marrow transplantation model and a severely immune-incompetent mouse model transplanted with human CD34+ cord blood cells. Quantitative immunohistochemical analysis of recipient mice demonstrated that ouabain injury promoted an increase in the number of both HSC-derived macrophages and HSC-derived nonmacrophages in the AN. Although rare, a few HSC-derived cells in the injured AN exhibited glial-like qualities. These results suggest that human hematopoietic cells participate in remodeling of the AN after neuron cell body loss and that hematopoietic cells can be an important resource for promoting AN repair/regeneration in the adult inner ear.

Acute Unilateral Vestibulopathy.

Normal vestibular end organs generate an equal resting-firing frequency of the axons, which is the same on both sides under static conditions. An acute unilateral vestibulopathy leads to a vestibular tone imbalance. Acute unilateral vestibulopathy is defined by the patient history and the clinical examination and, in unclear cases, laboratory examinations. Key signs and symptoms are an acute onset of spinning vertigo, postural imbalance and nausea as well as a horizontal rotatory nystagmus beating towards the non-affected side, a pathological head-impulse test and no evidence for central vestibular or ocular motor dysfunction. The so-called big five allow a differentiation between a peripheral and central lesion by the bedside examination. The differential diagnosis of peripheral labyrinthine and vestibular nerve disorders mimicking acute unilateral vestibulopathy includes central vestibular disorders, in particular "vestibular pseudoneuritis" and other peripheral vestibular disorders, such as beginning Menière's disease. The management of acute unilateral vestibulopathy involves (1) symptomatic treatment with antivertiginous drugs, (2) causal treatment with corticosteroids, and (3) physical therapy.

Atypical teratoid/rhabdoid tumor (AT/RT) arising from the acoustic nerve in a young adult: a case report and a review of literature.

Atypical teratoid/rhabdoid tumors (AT/RTs) are rare, highly malignant central nervous system tumors that predominantly occur in young children. A 22-year-old woman presented with a 4-year history of relapsing tinnitus and gradual hearing loss. Neuroimaging revealed an enhanced intrinsic left internal auditory canal mass. The patient underwent radiotherapy treatment. Three years later, the tumor size continued to increase, as observed by imaging, and ultimately evolved into the left cerebellopontine angle. As a consequence, a total tumor resection was performed, and a pathological diagnosis of AT/RT was made. Aggressive radiotherapy and chemotherapy treatment continued; however, the tumor recurred within 11 months after the total tumor resection. The patient died within 4 months of the second operation. Histopathologically, the tumor contained characteristic rhabdoid cells with areas that resembled a classical primitive neuroectodermal tumor. Immunostaining showed loss of INI1 protein expression in tumor cells, and fluorescence in situ hybridization showed a hemizygous deletion of the hSNF5/INI1 gene region on 22q11.2. This is the first report of an AT/RT that arised from the acoustic nerve in a young adult. Despite manifold diagnostic and therapeutic advances, the prognosis of patients with AT/RT remains poor.

Tinnitus: diagnostic approach leading to treatment.

Optimal care for a patient with tinnitus begins with identifying the cause of the tinnitus. Once the cause has been identified then an appropriate treatment plan can be initiated. In this article, the author reviews how to identify the tinnitus etiology and its treatment.The workup begins with the patient's description of the percept because in some cases, the quality of the tinnitus will make the diagnosis (e.g., clicking, which is readily suppressed pharmacologically); in other cases, it will give direction in the diagnostic evaluation (e.g., pulsatile). With the exception of a small dural arteriovenous malformation, the source of objective pulsatile tinnitus can be determined without conventional cerebral angiography. If the diagnostic workup is unrevealing and the pulsations are not suppressed with somatic testing, then eighth nerve vascular compression becomes the likely etiology, especially if there is some clicking also heard, no matter how minor.The two major causes of tinnitus are hearing loss and myofascial disorders of the head and neck. Moreover, the two can combine and cause tinnitus even though either condition alone would not have caused tinnitus. Although the tinnitus of hearing loss is not easily treatable, the tinnitus from myofascial disorders is often responsive to an optimized myofascial treatment program. Hyperacusis, a frequent accompaniment of tinnitus, and its treatment are discussed.

Stimulation rate reduction and auditory development in poorly performing cochlear implant users with auditory neuropathy.

OBJECTIVE: Patients with auditory neuropathy spectrum disorder (ANSD) exhibit altered neural synchrony in response to auditory stimuli. It has been hypothesized that a slower rate of electrical stimulation in programming strategies for cochlear implant (CI) users with ANSD may enhance development of neural synchrony and speech perception abilities. STUDY DESIGN: Retrospective case series. SETTING: Tertiary otologic practice. PATIENTS: Twenty-two patients with ANSD underwent CI. Patients with complete postoperative audiometric data and at least 2 years of follow-up were included in further analysis. INTERVENTION: Thirteen patients patients met inclusion criteria. Five "poorly performing" CI recipients with ANSD who had not developed closed-set speech perception abilities despite at least 2 years of implant use underwent implant programming to lower the neural stimulation rate. MAIN OUTCOME MEASURES: Speech perception abilities over time using parent questionnaire, closed-set testing, and open-set measures. RESULTS: A high incidence of comorbid conditions was present in the poor performers, including cognitive delay (n = 2), motor delay (n = 3), and autism spectrum disorder (n = 1). The median time to rate slowing in 5 poor performers was 29 months after implant activation. Three of 5 patients achieved closed-set speech perception scores higher than 60% after 6 to 16 months of implant use at the slower rates. At last follow-up (median, 42 mo), no poor performer had yet achieved open-set speech perception abilities. Of all CI recipients with ANSD included in analysis, open-set speech perception abilities developed in 46% (6/13). CONCLUSION: In CI recipients with ANSD who demonstrate limited auditory skills development despite prolonged implant use, lowering the stimulation rate may facilitate acquisition of closed-set speech perception abilities. Further efforts on the study of programming parameters in ANSD patients with CIs are necessary to maximize auditory development in this patient population.

Electrophysiologic and behavioral outcomes of cochlear implantation in children with auditory nerve hypoplasia.

OBJECTIVES: Hypoplasia of the auditory nerve (AN) refers to significant narrowing of the VIIIth cranial nerve which could compromise stimulation of the nerve by electrical pulses delivered from a cochlear implant (CI), thereby hindering activity in other parts of the auditory pathways. To compensate, high current levels or increased charge may be required to elicit auditory perception causing current to spread to other cranial nerves and potentially resulting in unwanted myogenic responses. Deficits in central auditory activity could reduce perception of speech and language. In the present study, we measured auditory brainstem responses in children with and without hypoplasia of the AN to answer the following questions. In children with hypoplastic ANs, (a) can CI stimulation evoke typical patterns of activity from the AN and brainstem?, (b) do brainstem responses change with CI experience?, (c) are evoked responses dependent on the size of the AN pathway?, and (d) does auditory development measured by behavioral tests of speech perception develop more slowly than in peers with normal AN diameter? DESIGN: Of 807 children using CIs in our program, 20 (2.5%) were identified as having AN hypoplasia using high-resolution computed tomographic scan and/or magnetic resonance imaging. An age-matched control group of children using CIs with normal AN diameter were recruited to compare electrophysiological and behavioral measures. Radiologic imaging was used to measure the diameter of the internal auditory canal (IAC), auditory nerve canal (ANC), and AN. Electrophysiological testing of the evoked compound action potential and auditory brainstem response was performed at CI activation and every 3 mo after initial testing up to 2 yr. Peak latency and waveform morphology were compared between study and control groups. Tests of speech perception and discrimination were attempted every 12 mo after device activation up to 10 yr. RESULTS: : Hypoplastic AN was identified as moderate to critical stenosis of the IAC, ANC, and AN. Initial electrically evoked compound action potential responses were mostly absent in children with AN hypoplasia. In the time window when electrically evoked auditory brainstem responses would be expected, some responses included single amplitude peaks at normal wave eV latencies, but the majority were abnormal, with peaks at atypical latencies or with no observable wave peaks. All evoked responses were inconsistent over time and did not reflect a typical pattern of auditory brainstem development. Speech perception scores were significantly poorer in the study group compared with controls and did not improve with CI experience. The type of abnormal evoked waveform response was independent of IAC, ANC, or AN diameter and also independent of behavioral outcome measures. CONCLUSIONS: : Evoked responses recorded in CI children with AN hypoplasia indicate a high incidence of nonauditory activity with CI use. The range of abnormal responses was not predicted by the severity of the hypoplastic AN or associated structures. This, along with poorer auditory development compared with peers with normal AN diameters, suggests that children with hypoplasia of the AN are poor candidates for cochlear implantation.

Malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem: multimodality treatment with survival of 27 months. A case report and review of the literature.

BACKGROUND AND IMPORTANCE: Malignant peripheral nerve sheath tumors are the most common malignant mesenchymal tumors of soft tissues, but they are very rare when found to arise from a cranial nerve and when not in association with neurofibromatosis. These tumors are highly malignant and carry a poor prognosis with survival usually less than 6 months. CLINICAL PRESENTATION: The authors report the case of a 23-year-old female with no history of phakomatoses, previous irradiation, or known genetic disorders, who presented with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem. Multiple staged skull base approaches were carried out with maximal possible resection. Adjunctive therapies including standard radiation therapy, intensity-modulated radiation therapy, and stereotactic gamma knife radiosurgery were used with an ultimate patient survival of 27 months. CONCLUSION: To our knowledge, this is the first report describing a patient with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem treated with staged surgical approaches in conjunction with multiple forms of radiotherapy and having a significant survival of more than 2 years.

A review of treatment modalities for vestibular schwannoma.

Vestibular schwannomas are benign intracranial tumors arising from the vestibular nerve. Treatment options include observation, stereotactic radiosurgery, fractionated radiotherapy, and microsurgery. We review the evidence describing efficacy and side-effect profiles of each of these modalities. This was accomplished by outlining the results of published meta-analyses and performing a systematic search of the literature for individual studies published between 2004 and June 2009. Without intervention, 29-54% of tumors will grow and 16-26% of patients require additional treatment, with 54-63% preserving functional hearing. With radiosurgery, only 2-4% require additional treatment and hearing preservation is accomplished in 44-66% of cases. Reviewing contemporary studies, it appears that reduced marginal doses may have decreased morbidity risks associated with radiosurgery without sacrificing efficacy. With fractionated radiotherapy, 3-7% will require additional treatment and hearing preservation is reported at 59-94% of patients, although long-term outcomes are not known. Microsurgery is an alternative for eligible patients, with fewer than 2% requiring additional treatment; however, the risk of hearing loss, facial neuropathy, and other morbidities is relatively high. There are significant limitations with comparing the efficacy and morbidity rates across interventions because of selection bias and confounding factors. Additional prospective comparative trials and randomized studies are needed to improve our understanding of the relative benefits of each modality.

Cochlear implantation in children with auditory neuropathy spectrum disorder.

OBJECTIVE: To report the patient's characteristics, preoperative audiological profiles, surgical outcomes, and postoperative performance for children with auditory neuropathy spectrum disorder (ANSD) who ultimately received cochlear implants (CIs). DESIGN: Prospective, longitudinal study of children with ANSD who received CIs after a stepwise management protocol that included electrophysiologic and medical assessment, documentation of behavioral audiometric thresholds and subsequent fitting of amplification according to Desired Sensation Level targets, auditory-based intervention with careful monitoring of skills development and communication milestones, and finally implantation when progress with the use of acoustic amplification was insufficient. RESULTS: Of 140 children with ANSD, 52 (37%) received CIs in their affected ears (mean duration of use of 41 mos). Many of these children were born prematurely (42%) and impacted by a variety of medical comorbidities. More than one third (38%) had abnormal findings on preoperative magnetic resonance imaging of the brain and inner ear, and 81% had a greater than severe (>70 dB HL) degree of hearing loss before implantation. Although 50% of the implanted children with ANSD demonstrated open-set speech perception abilities after implantation, nearly 30% of them with >6 months of implant experience were unable to participate in this type of testing because of their young age or developmental delays. No child with cochlear nerve deficiency (CND) in their implanted ear achieved open-set speech perception abilities. In a subgroup of children, good open-set speech perception skills were associated with robust responses elicited on electrical-evoked intracochlear compound action potential testing when this assessment was possible. CONCLUSIONS: This report shows that children with ANSD who receive CIs are a heterogeneous group with a wide variety of impairments. Although many of these children may ultimately benefit from implantation, some will not, presumably because of a lack of electrical-induced neural synchronization, the detrimental effects of their other associated conditions, or a combination of factors. When preoperative magnetic resonance imaging reveals central nervous system pathology, this portends a poor prognosis for the development of open-set speech perception, particularly when CND is evident. These results also show that electrical-evoked intracochlear compound action potential testing may help identify those children who will develop good open-set speech perception. Instead of recommending CI for all children with electrophysiologic evidence of ANSD, the stepwise management procedure described herein allows for the identification of children who may benefit from amplification, those who are appropriate candidates for cochlear implantation, and those who, because of bilateral CND, may not be appropriate candidates for either intervention.

Cochlear implantation in 3 adults with auditory neuropathy/auditory dys-synchrony.

We describe 3 adult patients with auditory neuropathy/auditory dys-synchrony (AN/AD) who underwent cochlear implantation. All patients had absent or poorly formed auditory brainstem responses (ABRs) in combination with preserved otoacoustic emissions (OAEs). They exhibited various aetiologies and a large variation in clinical features known to be consistent with AN/AD. Cochlear implantation was successful in 2 out of 3 cases. We conclude that AN/AD implantee candidates should be counselled with care.

Vestibular paroxysmia: diagnostic features and medical treatment.

BACKGROUND: Vestibular paroxysmia (VP), which is attributed to neurovascular cross-compression (NVCC), leads to vertiginous spells. Although VP was described more than 30 years ago by Jannetta and colleagues, we still need more reliable data on its diagnostic features and the efficacy of medical treatment. METHODS: A follow-up study of 32 patients with recurrent short spells of vertigo and with diagnosis of VP by published criteria was performed using medical records and patient consultation (mean follow-up time 31.3 months). RESULTS: In 28% of patients the attacks occurred exclusively when at rest, whereas in 22% they were regularly precipitated by a certain action, most frequently a head turn (60%). The most common accompanying symptom was unsteadiness of stance or gait (75%). Constructive interference in steady state magnetic resonance imaging (n = 23) demonstrated at least one site of NVCC in all but one patient. Caloric testing disclosed a mild increase in vestibular deficit over time, and a hyperventilation-induced nystagmus was found in 70% of the tested patients (n = 23). The majority of patients were treated with carbamazepine (mean dose 568 mg/d) or oxcarbazepine (mean dose 870 mg/d). Treatment led to a significant reduction in the attack frequency to 10% of baseline (95% CI 6.69-14.96%), in attack intensity to 15% (95% CI 11.57-19.63%), and a reduction in attack duration to 11% (95% CI 6.72-17.40), after adjusting for time effects. CONCLUSION: This follow-up proves the usefulness of the diagnostic criteria, especially constructive interference in steady state magnetic resonance imaging, and the therapeutic efficacy of medical treatment.

Dystrophic epidermolysis bullosa with one dominant and one recessive mutation of the COL7A1 gene in a child with deafness.

Dystrophic epidermolysis bullosa can be inherited in autosomal dominant and recessive forms, the former usually expressed as a milder phenotype, although mild forms of recessive dystrophic epidermolysis bullosa can occur. We present a patient who was found to be a compound heterozygote, inheriting a dominant mutation from his father and a recessive mutation from his mother, resulting in a clinically severe case of dystrophic epidermolysis bullosa. Mutations in the gene for collagen VII (COL7A1) have been documented in both types of dystrophic epidermolysis bullosa. Our patient has also been diagnosed with bilateral auditory neuropathy, a disorder coincidentally also mapped to a nearby gene on chromosome 3p21 (the transmembrane inner ear expressed gene, TMIE).