The effect of changes in perilymphatic K+ on the vestibular evoked potential in the guinea pig

To investigate the effect on the functioning of the vestibular system of a rupture of Reissner’s membrane, artificial endolymph was injected in scala media of ten guinea pigs and vestibular evoked potentials (VsEPs), evoked by vertical acceleration pulses, were measured. Directly after injection of a sufficient volume to cause rupture, all ears showed a complete disappearance of VsEP, followed by partial recovery. To investigate the effect of perilymphatic potassium concentration on the vestibular sensory and neural structures, different concentrations of KCl were injected directly into the vestibule. The KCl injections resulted in a dose-dependent decrease of VsEP, followed by a dose-dependent slow recovery. This animal model clearly shows a disturbing effect of a higher than normal K+ concentration in perilymph on the vestibular and neural structures in the inner ear. Potassium intoxication is the most probable explanation for the observed effects. It is one of the explanations for Menière attacks

Alternatives for OSAHS treatment: selection of patients for upper airway surgery and oral appliances

Although continuous positive airway pressure (CPAP) is considered to represent the standard treatment for patients with moderate-to-severe obstructive sleep apnoea/hypopnoea syndrome (OSAHS), poor treatment compliance and/or refusal is an issue in 20–30% of these patients. As an alternative to life-long CPAP treatment, conservative procedures exist with dental appliances for mandibular advancement, as well as curative surgical techniques. Surgical treatment of OSAHS can be divided into the following two main groups: 1) upper airway surgery by soft tissue resection (uvulopalatopharyngoplasty, etc.), and 2) skeletal procedures, such as maxillo-mandibular advancement. Proper selection of patients for the different treatment modalities is the key for full treatment success. Patient-related factors, such as the site of upper airway collapse, craniofacial characteristics, dental health, obesity, age, profession and positional dependence, as well as treatment-related factors, should be evaluated before a final proposal for these treatment alternatives is formulated

Unilateral congenital hearing loss in children: challenges and potentials

The estimated incidence of sensorineural hearing impairment (>40 dB HL) at birth is 1.86 per 1000 newborns in developed countries and 30-40% of these are unilateral. Profound sensorineural unilateral hearing impairment or single sided deafness (SSD) can be treated with a cochlear implant. However, this treatment is costly and invasive and unnecessary in the eyes of many. Very young children with SSD often do not exhibit language and cognitive delays and it is hard to imagine that neurocognitive skills will present difficulties with one good ear. In the current paper we review the most recent evidence on the consequences of unilateral hearing impairment for auditory and neurocognitive factors. While data of both adults and children are discussed, we focus on developmental factors, congenital deafness and a window of opportunity for intervention. We discuss which etiologies qualify for a cochlear implant and present our multi-center prospective study on cochlear implants in infants with one deaf ear. The large, state-of-the art body of research allows for evidence-based decisions regarding management of unilateral hearing loss in children.status: publishe