Mohamed A. Hamid

Issues, indications, and controversies regarding intratympanic steroid perfusion

Purpose of reviewOffice-based intratympanic inner ear steroid perfusion (ITPs) treatment for Ménières disease, autoimmune inner ear disease, and sudden sensorineural hearing loss has been expanding over the past 10–15 years, yet remains controversial. The purpose of this review is to examine the current literature of basic science and human studies of ITPs treatment. Recent findingsAnimal studies exist regarding the delivery, distribution, biochemical, and microbiological changes in the inner ear post ITPs. However, few clinical studies exist on ITPs treatment in sudden sensorineural hearing loss and even less in treating Ménières disease. There are no consistent studies regarding drug delivery methods, type, and concentration of steroids. Moreover, there are no studies comparing ITPs results to the natural history of Ménières disease. SummaryITPs has impacted otology and neurotology practice due to increased utilization. A sound understanding of the basic science and clinical studies is needed to establish long-term efficacy of ITPs in controlling hearing loss in Ménières disease by comparison to its natural history, as well as, potential application to other disorders.

Autoimmune vestibular dysfunction: Preliminary report

Since 1981, 28 patients have been diagnosed with autoimmune inner ear disease. This preliminary, retrospective study reviews clinical and laboratory manifestations of autoimmune vestibular dysfunction.

Tinnitus and underlying brain mechanisms.

Purpose of reviewTinnitus is the sensation of hearing a sound when no external auditory stimulus is present. Most individuals experience tinnitus for brief, unobtrusive periods. However, chronic sensation of tinnitus affects approximately 17% (44 million people) of the general US population. Tinnitus, usually a benign symptom, can be constant, loud and annoying to the point that it causes significant emotional distress, poor sleep, less efficient activities of daily living, anxiety, depression and suicidal ideation/attempts. Tinnitus remains a major challenge to physicians because its pathophysiology is poorly understood and there are few management options to offer to patients. The purpose of this article is to describe the current understanding of central neural mechanisms in tinnitus and to summarize recent developments in clinical approaches to tinnitus patients. Recent findingsRecently developed animal models of tinnitus provide the possibility to determine neuronal mechanisms of tinnitus generation and to test the effects of various treatments. The latest research using animal models has identified a number of abnormal changes, in both auditory and nonauditory brain regions, that underlie tinnitus. Furthermore this research sheds light on cellular mechanisms that are responsible for development of these abnormal changes. SummaryTinnitus remains a challenging disorder for patients, physicians, audiologists and scientists studying tinnitus-related brain changes. This article reviews recent findings of brain changes in animal models associated with tinnitus and a brief review of clinical approach to tinnitus patients.

Determining side of vestibular dysfunction with rotatory chair testing.

Determining side of vestibular lesion remains a challenging task during neurotologic investigations, particularly if auditory laterallzing signs are absent. Traditionally, absent or decreased caloric response has been regarded as evidence of unilateral vestibular deficit. But, the inability of the chair test to detect side of lesion has been generally accepted because rotation stimulates both end organs. A retrospective study postulated and tested a hypothesis that low-frequency asymmetry of sinusoidal harmonic acceleration (SHA) testing can determine side of lesion when phase is abnormal. The present prospective, double-blind study was designed to further test the retrospective study hypothesis. Results showed that SHA asymmetry detects side of unilateral vestibular deficit when phase is abnormal in 97% of cases.

Medical management of common peripheral vestibular diseases.

Purpose of reviewReview of office-based medical management options for common vestibular diseases. Recent findingsBasic science studies have defined the ionic homeostasis of the inner ear stria vascularis as a central principle in the understanding of inner ear disorders. New molecular channels for water homeostasis have been identified in the inner ear structures. Office-based history, neurotological physical examination and judicial use of audiovestibular testing have increased our ability to manage vestibular patients more cost-effectively. Clinical studies supported the use of gentamicin and steroids intratympanic perfusion of the inner ear to augment traditional treatments of common vestibular disorders. SummaryThe molecular biology and ionic transport between the stria vascularis and endolymph provided further understanding to the pathology and treatment of inner ear disorders. The history, physical examination and judicial use of laboratory tests are very critical and cost-effective in managing patients with vestibular diseases. Treatments such as inner ear perfusion with gentamicin and steroids have helped control and stabilize vertigo and hearing loss in Menieres disease. Canalith repositioning treatments and home-based vestibular rehabilitation have improved our abilities to effectively manage patients with benign paroxysmal positional vertigo, uncompensated peripheral vestibular loss and multisensory deficit and age-related balance disorders.

Advances in auditory and vestibular medicine

Abstract Auditory and vestibular medicine is becoming more accepted as a specialty in its own right. Recent advances in the field have been instrumental in the understanding of the scientific foundations, pathophysiology, clinical approach and management of patients with hearing and vestibular disorders. This paper will review these advances.

ENG-MRI Correlates in Cerebellar Oculomotor Dysfunction

This study correlates ENG and MRI findings in six patients with cerebellar eye movements. For each subject, both tests independently support the presence of a cerebellar tract abnormality. In two patients, MRI studies confirmed the site of cerebellar dysfunction previously demonstrated by ENG. Although the number of patients is small, the strong correlation (100%) indicates that ENG remains a sensitive method for detection and localization of the origin of cerebellar eye movements. The physiologic information provided by ENG is supported anatomically by MRI. The cerebellar eye movement abnormalities are briefly reviewed.

Advances and challenges in inner ear medicine.

Recent advances in basic science, technology and treatments have increased our abilities to manage hearing and balance diseases more effectively. Advances in molecular genetics, particularly recessive DFNB1 gene (Connexin 26,30), have allowed better understanding and early detection and management of congenital and hereditary hearing loss. The molecular biology and ionic transport between the stria vascularis and endolymph allowed further understanding of endolymphatic hydrops and provided support for ‘old’ and ‘new’ treatments of Meniere’s disease. The use of ultrasensitive histologic examination of the inner ear allowed better visualization of hair cell behavior in health and disease. High-resolution computed tomography scans, three-dimensional MRI, diffusion weighted imaging, functional MRI and diffusion tensor imaging of the temporal bone and the brain allowed better visualization of inner ear structures and anomalies, and brain lesions and pathways that were undetectable with traditional imaging. Refinement of clinical vestibular exam using videoelectronystagmography and advanced testing like stress electrocochleography and vestibular evoked myogenic potentials have improved clinical diagnosis of inner ear disorders. New clinical entities such as vestibular migraine, autoimmune inner ear disease, superior canal dehiscence, benign intracranial hypertension, and auditory neuropathy have been identified and managed more effectively. Relatively new treatments such as inner ear perfusion with gentamicin, dexamethasone and neurotrophins (such as insulin-like growth factor-1) have allowed better management of Meniere’s disease and sudden sensorineural hearing loss. Advances in hearing aids, cochlear implants and implantable middle ear devices have provided effective management of hearing loss, particularly in the pediatric population. The more recent use of cochlear implants to deliver both electrical stimulation and neurotrophins to the inner ear holds promise in improving cochlear implant speech performance and restoring

Vestibular and postural findings in the motion sickness syndrome

The motion sickness syndrome constitutes varying degrees of subjective motion intolerance and three objective findings: hyperactive VOR (79%), hip sway strategy (60%), and positional nystagmus (42%). It is present in subjects who have a strong history of motion sickness. Vestibular rehabilitation appears to help control symptoms. The study also suggests an inheritance pattern, but a structured pedigree could not be constructed. Prospective studies are warranted to further establish the patterns of the motion sickness syndrome.

An Approach to Quantify Central Vestibular Compensation

Central vestibular compensation is the ultimate goal for the dizzy patient. Monitoring spontaneous nystagmus and caloric responses are not usually correlated with the patient progress and cannot be objectively documented. On the other hand, Temporal Asymmetry Shift (TAS) is a more accurate and objective measure of central vestibular compensation. Furthermore, its dynamic pattern offers a reliable indicator to differentiate between peripheral and central vestibular dysfunctions.