Reduction of olfactory sensitivity during normobaric hypoxia.

Objective: Acute mountain sickness (AMS) is caused by a low partial pressure of oxygen and may occur above 2500m. The aim of this research was to evaluate olfactory and gustatory abilities of healthy subjects during baseline conditions and after seven hours of normobaric hypoxia.

Methods: Sixteen healthy subjects were assessed using the Sniffin' Sticks, as well as intensity and pleasantness ratings.

Susceptibility-weighted angiography visualizes hypoxia in cerebral veins.

Objectives: The objective of this study was to evaluate the influence of short- and long-term hypoxia on the depiction of cerebral veins in the susceptibility-weighted angiography (SWAN) sequence.

Materials And Methods: In the context of a study on brain adaptation mechanisms to hypoxia, 16 healthy men (aged 20-28 years) were studied through magnetic resonance imaging (MRI) under room air conditions, short-term-hypoxia (7 minutes before and during the MRI scan), and long-term hypoxia (8.5 hours before and during the MRI scan).

No evidence of intracranial hypertension in trekkers with acute mountain sickness when assessed noninvasively with distortion product otoacoustic emissions.

Aims: The role of intracranial hypertension in acute mountain sickness (AMS) is a matter of debate. Distortion product otoacoustic emissions (DPOAEs) can be used to monitor the intracranial pressure (ICP) noninvasively with a level decrease at the frequencies f2=1 and 1.5 kHz indicating elevated ICP.

Complex level alterations of the 2f(1)-f(2) distortion product due to hypoxia.

Objective: For diagnostic purposes and a better understanding of the pathophysiology of inner ear hearing disorders it would be of great interest to have parameters available that indicate inner ear hypoxia. In animal studies typical hypoxia-related alterations of the 2f1-f2 distortion product otoacoustic emissions (DPOAE) such as a reversible level decrease and destabilization could be demonstrated. The goal of this study was to investigate whether these hypoxia-associated alterations can also be observed in humans because this might help develop a new diagnostic tool for patients with inner ear disorders.

Level alterations of the 2f (1)-f (2) distortion product due to hypoxia in the guinea pig depend on the stimulus frequency.

Increased intracranial pressure (ICP) is known to affect the levels of distortion product otoacoustic emissions (DPOAEs) in a frequency-specific manner. DPOAEs might, therefore, be used for monitoring the ICP non-invasively. Hypoxia can also cause alterations of DPOAE levels, which can be distinguished from ICP-related changes only, when their characteristics, in particular frequency specificity, are known in detail.

Polygraphy of sleep at altitudes between 5300 m and 7500 m during an expedition to Mt. Everest (MedEx 2006).

Objectives: Sleep at extreme altitudes is characterized by the repetitive occurrence of central apneas that in some cases may lead to a marked decrease in arterial oxygen saturation. During the Ludwig Maximilians University Expedition to Mt. Everest (MedEx 2006), nocturnal polygraphic recordings were made at different altitudes and included the first recordings ever made at 7500 m, which were completed on 8 separate occasions during the expedition.

Complex level alterations of the 2f (1)-f (2) distortion product due to hypoxia in the guinea pig.

It is controversially discussed inasmuch acute hearing disorders might originate from impaired cochlear circulation. Hypoxia-specific alterations of inner ear parameters measurable in patients with acute sensorineural hearing loss would therefore be of great interest. Aim of this study was to characterize hypoxia-related alterations of the 2f (1)-f (2) distortion product.

Distortion product otoacoustic emissions for assessment of intracranial hypertension at extreme altitude?

The levels of distortion product otoacoustic emissions (DPOAEs) change at frequencies between 0.75 and 1.5 kHz along with intracranial pressure (ICP) and DPOAEs are suggested for monitoring ICP changes.

Round window application of D-methionine, sodium thiosulfate, brain-derived neurotrophic factor, and fibroblast growth factor-2 in cisplatin-induced ototoxicity.

Hypothesis: In this study we tested the effect of local administration of D-methionine, sodium thiosulfate, brain-derived neurotrophic factor, and fibroblast growth factor-2 on cisplatin ototoxicity in guinea pigs to the round window membrane.

Background: Cisplatin is an important antineoplastic agent in the therapy of many malignancies. Its clinical utility is limited by severe side effects, including ototoxicity.

Hyperfibrinogenemia as a risk factor for sudden hearing loss.

Objective: To clarify predisposing conditions for vascular events.

Setting: Vascular events, immunologic processes, and viral infections have to be considered as pathomechanisms for most cases of sudden hearing loss.

Study Design: Hemorrheologic parameters were studied in 53 patients with sudden hearing loss within 5 days of the onset.