Sam J. Daniel

Can virtual reality improve anatomy education? A randomised controlled study of a computer‐generated three‐dimensional anatomical ear model

Introduction  The use of computer‐generated 3‐dimensional (3‐D) anatomical models to teach anatomy has proliferated. However, there is little evidence that these models are educationally effective. The purpose of this study was to test the educational effectiveness of a computer‐generated 3‐D model of the middle and inner ear.

Ototopical antifungals and otomycosis: A review

There has been an increase in the prevalence of otomycosis in recent years. This has been linked to the extensive use of antibiotic eardrops. Treatment of otomycosis is challenging, and requires a close follow-up. We present a review of the literature on otomycosis, the topical antifungals most commonly used, and discuss their ototoxic potential. Candida albicans and Aspergillus are the most commonly identified organisms. Antifungals from the Azole class seem to be the most effective, followed by Nystatin and Tolnaftate.

Diagnosis, monitoring, and treatment of primary ciliary dyskinesia: PCD foundation consensus recommendations based on state of the art review.

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, rare lung disease resulting in chronic oto‐sino‐pulmonary disease in both children and adults. Many physicians incorrectly diagnose PCD or eliminate PCD from their differential diagnosis due to inexperience with diagnostic testing methods. Thus far, all therapies used for PCD are unproven through large clinical trials. This review article outlines consensus recommendations from PCD physicians in North America who have been engaged in a PCD centered research consortium for the last 10 years. These recommendations have been adopted by the governing board of the PCD Foundation to provide guidance for PCD clinical centers for diagnostic testing, monitoring, and appropriate short and long‐term therapeutics in PCD patients. Pediatr Pulmonol. 2016;51:115–132.

Is type 2 diabetes mellitus associated with alterations in hearing? A systematic review and meta-analysis

The aim of this study was to systematically and quantitatively review the available evidence on the effects of type 2 diabetes mellitus on hearing function.

On the Coupling Between the Incus and the Stapes in the Cat

The connection between the long process and the lenticular process of the incus is extremely fine, so much so that some authors have treated the lenticular process as a separate bone. We review descriptions of the lenticular process that have appeared in the literature, and present some new histological observations. We discuss the dimensions and composition of the lenticular process and of the incudostapedial joint, and present estimates of the material properties for the bone, cartilage, and ligament of which they are composed. We present a preliminary finite-element model which includes the lenticular plate, the bony pedicle connecting the lenticular plate to the long process, the head of the stapes, and the incudostapedial joint. The model has a much simplified geometry. We present simulation results for ranges of values for the material properties. We then present simulation results for this model when it is incorporated into an overall model of the middle ear of the cat. For the geometries and material properties used here, the bony pedicle is found to contribute significant flexibility to the coupling between the incus and the stapes.

A nonlinear finite-element model of the newborn ear canal

A three-dimensional nonlinear finite-element model of a 22-day-old newborn ear canal is presented. The geometry is based on a clinical x-ray CT scan. A nonlinear hyperelastic constitutive law is applied to model large deformations. The Youngs modulus of the soft tissue is found to have a significant effect on the ear-canal volume change, which ranges from approximately 27% to 75% over the static-pressure range of +/-3kPa. The effects of Poissons ratio and of the ratio C10: C01 in the hyperelastic model are found to be small. The volume changes do not reach a plateau at high pressures, which implies that the newborn ear-canal wall would not be rigid in tympanometric measurements. The displacements and volume changes calculated from the model are compared with available experimental data.

Intratympanic Dexamethasone to Prevent Cisplatin Ototoxicity: A Guinea Pig Model

Objective. To determine whether intratympanic administration of dexamethasone reduces ototoxicity from systemic cisplatin. Study Design. Prospective animal study. Setting. Cisplatin chemotherapy induces ototoxicity manifesting as irreversible, sensorineural hearing loss. This is due to damage to the inner ear structures by free radicals. Steroidal anti-inflammatories have been shown to reduce the formation of free radicals and protect hearing in animal models. Subjects and Methods. Pure tone auditory brainstem responses were obtained in 58 female albino guinea pigs before and 3 days after intraperitoneal (IP) cisplatin chemotherapy. Auditory brainstem responses were also taken up to 1 month after a low dose of cisplatin. Part I consisted of a dosing study to determine the optimal ototoxic dose of cisplatin. In part II, auditory brainstem response thresholds were compared after bilateral intratympanic dexamethasone doses to act as controls. For part III, the otoprotection of dexamethasone against cisplatin was tested in separate bilateral and unilateral studies. Results. IP injection of 12 mg/kg of cisplatin induced significant hearing loss (57.2 ± 4.4 dB, P < .01) with 0% mortality. Ears treated with intratympanic dexamethasone alone showed no significant threshold changes. Ears that received IP cisplatin and intratympanic dexamethasone showed reduced threshold shifts at 8 kHz when the greatest concentration of dexamethasone was administered. Conclusion. Modest intratympanic dexamethasone otoprotection of the guinea pig ear was greatest at the highest concentration tested and occurred in a frequency-dependent manner. Intratympanic dexamethasone presents as a safe, simple, and effective treatment modality to minimize cisplatin ototoxicity without interfering with the chemotherapeutic effects of cisplatin.

Is a plexiform neurofibroma pathognomonic of neurofibromatosis type I

Objectives/Hypothesis: Several prominent textbooks have claimed that a plexiform neurofibroma is pathognomonic for neurofibromatosis type I. This is not in agreement with the National Institutes of Health criteria, which require two signs to be present, one of which can be a plexiform neurofibroma. Is a plexiform neurofibroma pathognomonic for neurofibromatosis type I?

Cisplatin-induced ototoxicity: Transporters playing a role in cisplatin toxicity

Cisplatin is a potent antineoplastic agent widely used for a variety of cancer types. Unfortunately, its use leads to dose limiting side effects such as ototoxicity. Up to 93% of patients receiving cisplatin chemotherapy will develop progressive and irreversible sensorineural hearing loss which leads to a decreased quality of life in cancer survivors. No treatment is currently available for cisplatin-induced ototoxicity. It appears that cisplatin causes apoptosis by binding DNA, activating the inflammatory cascade as well as generating oxidative stress in the cell. Various studies have aimed to assess the potential protective effects of compounds such as antioxidants, anti-inflammatories, caspase inhibitors, anti-apoptotic agents and calcium channel blockers against the toxicity caused by cisplatin in the inner ear with variable degrees of protection. Nevertheless, the pathophysiology of cisplatin-induced ototoxicity remains unclear. This review summarizes all of the known transporters that could play a role in cisplatin influx, leading to cisplatin-induced ototoxicity. The following were evaluated: copper transporters, organic cation transporters, the transient receptor potential channel family, calcium channels, multidrug resistance associated proteins, mechanotransduction channels and chloride channels.

Otoacoustic emissions in newborn hearing screening: a systematic review of the effects of different protocols on test outcomes.

BACKGROUND AND OBJECTIVES Otoacoustic emission (OAE) tests are currently used to screen newborns for congenital hearing loss in many Universal Newborn Hearing Screening programs. However, there are concerns about high referral and false-positive rates. Various protocols have been used to address this problem. The main objective of this review is to determine the effects of different screening protocols on the referral rates and positive predictive values (PPV) of the OAE newborn screening test. METHODS Eligible studies published in English from January 1990 until August 2012 were identified through searches of MEDLINE, Medline In-Process, Embase, PubMed (NCBI), ISI Web of Science, and the Cochrane Central Register of clinical controlled trials. Two reviewers independently screened the data sources, using pre-defined inclusion criteria to generate a list of eligible articles. Data extracted included the number of newborns screened, age at screening, OAE pass criteria, frequencies screened, number of retests, referral rates, and the number of newborns identified with permanent congenital hearing loss. RESULTS Ten articles met the inclusion criteria, with a total of 119,714 newborn participants. The pooled referral rate was 5.5%. Individual referral rates ranged from 1.3% to 39%; the PPV from 2 to 40%. Increasing the age at initial screening and performing retests reduced the referral rate. Likewise, screenings involving higher frequencies had lower referral rates. CONCLUSION Delaying newborn hearing screening improves test results but may not be practical in all contexts. The use of higher frequencies and more sophisticated OAE devices may be useful approaches to ensure better performance of the OAE test in newborn hearing screening.