PubMed Health⌕ Search

Biomedical subjects

O I Molvaer

Publications and source records attributed to O I Molvaer.

At least 19 recordsLinked to original sources
PubMed1991

[The Norwegian Antarctic expedition 1989-1990--medical contingency, work and research].

Antarctica is the world's coldest, driest, highest and most windy continent. The ice may reach a thickness of nearly five km, and the greater part of the world's fresh water is bound in this ice cap. The lowest temperature ever measured is -90 degrees C. The weather during this summer expedition was pleasant, and the temperature seldom fell below -30 degrees C. The 35 persons in the land party included two physicians and one nurse. No serious injury or disease occurred. The participants seemed experience an increase in lean body weight and loss of fat during five weeks in tents. Extensive data were collected for medical-psychological projects on immunology, adaptation to cold, exhaustion from cold and stress. Some results have been published in separate reports.

Adaptation, Physiological↗
PubMed1991

Vestibular problems in diving and in space.

On firm ground our sense of balance is supplied by super abundant input from several sensoric sources. In other environments insufficient or conflicting input may cause vestibular problems. In diving, vertigo may be caused by a variety of influences, like sensory deprivation, optokinetic illusion, asymmetric vestibular stimulation, inner ear barotrauma, decompression sickness, breathing gas toxicity, high pressure neurological syndrome, sea sickness and intense noise. During space flight some of the mentioned mechanisms may contribute to vestibular problems, although space motion sickness being the main cause of concern in this connection.

Barotrauma↗
PubMed1990

Functional capacity of neutrophil granulocytes in deep-sea divers.

Neutrophil granulocytes (PMN) are main defenders against invading microbes. We evaluated the adaptive response of PMN from divers exposed for weeks to high total and oxygen pressures. Under these conditions PMN could be primed to give a heightened respiratory burst upon stimulation with the bacterial peptide analogue, formyl-methionyl-leucyl-phenylalanine (FMLP): blood PMN sampled both shortly after operational saturation dives offshore and during an onshore test-dive gave larger responses than control pre- or post-dive PMN from the same subjects and PMN from laboratory personnel. The assays used measured oxygen consumption, intracellular H2O2 availability, and chemiluminescence. The submaximal responses provoked by the non-metabolizable diacylglycerol analogue phorbol myristate acetate (PMA) were less and less often increased. Such enhanced PMN responsiveness may possibly decrease resistance to skin and other infections that are encountered in divers, if PMN thereby failed to localize correctly to inflamed tissues.

Adult↗
PubMed1990

Hearing deterioration in professional divers: an epidemiologic study.

Hearing acuity was measured in 116 professional divers. After approximately 6 yr they were retested. At most frequencies, the divers had higher hearing thresholds than otologically normal subjects at the same age, both at the first and at the final examination. The divers' hearing deteriorated faster than that of the otologically normal subjects. The young divers' hearing thresholds were lower than in unscreened nondivers at comparable age, but the gap closed gradually with increasing age. Accordingly, the divers' hearing deteriorated faster than that of unscreened nondivers. Some of the divers had suffered permanent hearing loss from acute barotrauma. Considering the regular noise exposure during commercial diving, this must have contributed significantly to the observed hearing deterioration.

Adult↗
PubMed1989

Immediate neurological effects of diving to a depth of 360 metres.

Eighteen divers performed a simulated dive to a depth of 360 metres of seawater breathing a mixture of helium and oxygen. Clinical neurological examinations and neurophysiological tests were performed before and after the dives. Two divers had mild ataxic signs and changed electronystagmography after the dive, and one had impaired vibration sense in one lower extremity. Abnormal EEGs with slow waves and sharp potentials, seen primarily in the temporal regions, occurred in 2 divers. No changes were found in the magnetic resonance imaging brain scans. The divers with evidence of previous central nervous system injury, or a history of unconsciousness or previous decompression sickness seemed more likely to develop neurological signs after these deep dives. This study shows that deep diving may induce immediate neurological changes. We recommend that future deep divers have a neurological examination and 2 separate EEGs included in their medical examinations.

Adult↗
PubMed1988

Alternobaric vertigo in professional divers.

The present investigation was part of a project performed to detect possible effects of diving on the cochleovestibular system. A group of 194 professional divers were interviewed, examined otologically, and their hearing was tested audiometrically. Caloric vestibular tests were performed in 48 subjects. The interview reviewed age, diving experience, previous ear disease or injury, head trauma, noise exposure during diving and during spare-time activities, eye color, tobacco habits, and the occurrence of vertigo during diving. Useful information regarding vertigo was obtained from 193. Of the 76 (39%) who had experienced vertigo, 64 (33%) were classified as alternobaric vertigo (AV), a type of vertigo caused by asymmetric middle ear pressure. A stepwise multiple logistic regression analysis was performed to detect variables contributing to the presence of AV. Variables having a statistically significant association with AV were previous barotrauma of the ear (P less than 0.05) and noise exposure during diving (less than 0.05). AV was most frequently encountered when diving during a common cold. In this sample of divers, AV did not lead to any serious or critical situations.

Adult↗
PubMed1987

Facial baroparesis: a review.

If impaired eustachian tube function causes an overpressure to remain in the middle ear after ascent in diving or aviation in a subject with a defect in the wall of the facial canal, an ischemic neurapraxia of the seventh cranial nerve may occur. This type of facial palsy is designated facial baroparesis, baroparesis facialis, or alternobaric facial palsy. If the middle ear pressure is asymmetric the subject may also have alternobaric vertigo. A causative relationship between middle ear overpressure and facial palsy is supported by the palsy's rapid onset following a reduction in ambient pressure and by its quick disappearance after either an increase in ambient pressure or release of the middle ear overpressure. Transient compression-induced ischemic neurapraxia of the facial nerve is also demonstrated in animal experiments. A similar palsy, ischemic neurapraxia of the fifth cranial nerve due to compression in the maxillary sinus, has been reported in divers. Although it is under-reported, facial baroparesis occurs infrequently, with 23 subjects mentioned in the available literature. Nevertheless, it is important to be aware of its existence, because misdiagnosis as type II DCS or air embolism results in unnecessarily long recompression treatments and pointless delay of resumption of diving. In the worst case, a misdiagnosis might cause a diving license to be revoked.

Animals↗
PubMed1985

Hearing acuity in professional divers.

Pure tone audiograms and relevant history were recorded in 164 professional divers aged 19 to 66 yr, mean 30.9. A close correlation exists between hearing impairment and increasing age, increasing diving experience, and acoustic trauma. A statistically significant elevation (P = 0.01) of the high-frequency hearing threshold is demonstrated in smokers as compared to those who had never smoked. The divers' hearing threshold was elevated in the high frequencies in all age groups as compared to ISO normality curves. It was, however, lower than that of a Norwegian standard population at a young age, but in their fourth decade of life, the divers' high frequency hearing was at the same level as that of the standard population. We conclude that professional diving may cause a more rapid deterioration of high-frequency hearing than seen in a standard population and that smoking may be an additional hazard to high-frequency hearing.

Adult↗
PubMed1985

Facial baroparesis: a report of five cases.

Six episodes of facial baroparesis in 5 divers are reported. Three of the divers experienced left-sided paresis and 2 right-sided. In 2 of the subjects (3 episodes) the paresis disappeared spontaneously when the relative middle ear overpressure cleared, and in the remaining 3 subjects the paresis disappeared on recompression to less than 2 m. No residual effects were found, but the subject who experienced 2 episodes stopped diving. Available evidence favors the theory of ischemic compression neurapraxia.

Adolescent↗
PubMed1979

Ear damage due to diving.

Diving injury may affect all parts of the ear during all types of diving. Divers are regularly exposed to noise and 120 dB(A) is measured during ventilation of a hyperbaric chamber. Ear canal squeeze, possibly with drum perforation, may give a transient conductive hearing loss. Middle ear squeeze, possibly with drum perforation, also gives a transient conductive loss. Inner ear barotrauma, possibly with perilymph fistula, most often results in transient vertigo and lasting sensorineural high tone loss, often resembling a noise-induced loss. Decompression sickness and gas embolism can also damage the inner ear. A change of breathing gas during deep diving has damaged the labyrinth, most likely due to counter diffusion. The authors have seen two cases of over window perilymph fistula resulting from diving. One of them also suffered a burst ear drum on the same side. His hearing returned to normal after surgical repair.

Barotrauma↗
PubMedDate not supplied

The size of the middle ear and the mastoid air cell.

The total volume for the middle ear and mastoid air cells was measured in 55 temporal bones with normal ear drums from a Norwegian post-mortem material. The measurements were made by an acoustic method and checked by means of fluid filling induced by vacuum pumping. As a measuring fluid X-ray contrast medium was employed so that the degree of filling could be examined by X-ray. The volume varied between approximately 2--22 cm3 with an average round 6,5 cm3.

Aged↗