Noise-induced neurologic disturbances in divers exposed to intense water-borne sound: two case reports

Divers may be exposed to intense noise underwater. Two cases of neurologic disturbances during experimental exposures to 15 min of continuous underwater sound are described. Sound exposure in the first case consisted of a warble tone with center frequency of 240 Hz and a sound pressure level of 160 dB re 1 microPa. Symptoms during exposure consisted of somnolence, lightheadedness, and an inability to concentrate. No apparent effect on hearing was noted. In the second case, a center frequency of 1,000 Hz at 181 dB was used. Lightheadedness, inability to concentrate, agitation, and head vibrations were noted during the exposure. The diver also exhibited a temporary auditory threshold shift of 19.2 dB. In both cases, overt symptoms resolved within 30 min after exposure, but both divers reported recurrent symptoms days to weeks after the exposures. Medical histories and examinations, assessment of dive profiles, and breathing gas analysis failed to support a source other than the sound exposures to account for the symptoms observed. Potential mechanisms for the described symptoms are discussed.

Panic with a twist: an unusual presentation of combined psychiatric and neurologic symptoms in a tactical jet aviator

A 28-yr-old Naval F-14 aviator presented with complaints of flight-related anxiety occurring intermittently over an 18-mo period. Symptoms included sensation of strangeness, concern over the welfare of his radar intercept officer, flushing, nausea, and intense need to immediately land the aircraft. He also described a 6-mo history of episodes wherein he would see "shooting stars" in the periphery of his vision, accompanied by dizziness and disorientation. These latter attacks were always precipitated by head turning, usually in combination with positive Gz maneuvers, and were relieved by head straightening. The anxiety symptoms were consistent with a form of panic attack, but the neurological symptoms provoked further workup. Magnetic resonance cerebral angiogram demonstrated a dominant right vertebral artery and hypoplastic left vertebral artery. All symptoms resolved once the aviator was removed from flying the aircraft. After a year of follow-up with an aviation psychiatrist, he remained asymptomatic and was reassigned to maritime patrol aircraft. This case illustrates a difficult diagnostic, therapeutic, and disposition challenge. This aviator suffered from a complex interaction of neurologic and psychiatric manifestations having a common inciting stimulus, namely flying the F-14 Tomcat. A promising aviation career was preserved upon removal of that stimulus.

An aviator with an unusual gait: a rare disease teaches some everyday lessons

Muscular diseases including the dystrophies and myopathies are often incompatible with a variety of occupations including aviation and military duty. Many of these diseases present early in life, are readily diagnosable, and are therefore rare in the aviation community because of pre-screening and selection. Some forms, however, may not present until adulthood during an established aviation career. Furthermore, although initial presentations may be subtle and insidious, the potential occupational and aeromedical ramifications of these diseases can be profound. The following report describes the case of a subjectively asymptomatic career military aviation officer who presented with an unusual gait, and was subsequently determined to have one of the late-presenting muscle disease variants: Anterior compartment Distal Myopathy. The patient's presentation and progression, diagnostic evaluation, prognosis, aeromedical risk and disposition, and issues of occupational and aeromedical significance are discussed.

Role of the flight surgeon in fighter squadron Arctic deployments

Operational fighter squadrons frequently find themselves deployed to semi-isolated stations in the Arctic. This paper discusses the major issues necessary for flight surgeon consideration. In particular, the areas of pre-deployment planning, preparing for the worst, routine operations, and post deployment actions are discussed. A recent month-long deployment of a 12-ship squadron of F18s with support elements from Bagotvi le, Canada, to Evenes, Norway, is examined. A proposed kit list to support a similar deployment to a semi-isolated station is provided.

Stroke in the young aviator

A robustly healthy aviator experienced a sudden focal impairment in cerebral function from which he rapidly recovered in a manner consistent with the entity known as "spectacular shrinking deficit syndrome." Although brain imaging studies revealed a "lacunar" type lesion involving the caudate nucleus, the clinical picture was much more suggestive of a cardiogenic embolic event. Transthoracic echocardiography was required to demonstrate the probable cause of the stroke (an atrial septal defect). Following surgical repair of the atrial septal defect, the aviator was recommended for waiver to resume duties involving aviation as pilot in command.

LEAF-WRINKLE, A NUTRITIONAL DISORDER OF SOY BEAN

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