Biomedical subjects
Publications and source records attributed to H W Kortschot.
An extensive vestibular examination was conducted in 462 patients suffering from the after-effects of a cervical whiplash trauma. Vertigo and dizziness were mentioned by 318 (68%) of the subjects, among a variety of other complaints. The examination revealed the existence of central-vestibular lesions in 258 (56%) of the patients.
In human subjects the caloric vestibular test was conducted during parabolic flight. The ear irrigation was performed from 35 secs. till 5 secs. before the onset of microgravity. Nystagmography covered a 10-minutes period, including three parabolic manoeuvres of the aircraft. a. The slow phase velocity (SPV) of the caloric nystagmus increased proportionally with the value of the g-force. Introduction of microgravity induced an exponential decrease of the SPV decay. b. The nystagmus disappeared completely in microgravity, but SPV decay showed a specific time constant. c. The averaged time constant values of the caloric nystagmus SPV decay after sudden onset of microgravity and the averaged time constant of the SPV decay following a sudden stop after sustained rotation during 0-g appeared to be on the same level (10.2 s. and 10.6 s.). d. These two averaged time constant values obtained during short lasting microgravity proved to be on a lower level than those time constants (15.5 secs.; 15.9 secs.) found in ground-based conditions. e. Because of the similarities in the characteristics of both SPV decay's and their accompanying time constants, a common working mechanism of cupular stimulation is likely. Most probably a fluid movement (or pressure) provokes a cupula deflexion followed by a cupula reflexion, either caused by a sudden stop after a sustained rotation or by a sudden onset of microgravity after g-load calorization. The present results support the Barany convection theory with regard the endolymph stimulatory properties following the caloric test.
A group of 262 patients suffering from the after-effects of an acceleration trauma of the neck were subjected to an extensive vestibular examination. 85% of the patients complained of some type of vertigo. The visual suppression test conducted during rotation showed pathology in 37% of the cases. Visual pursuit movements were affected in 43% of the cases. In a group of 41 patients the results obtained respectively 1 and 2 years after the accident were compared. There was no significant improvement of the findings. No oculomotor system pathology was found in 99 cases (38%), and no electronystagmographic pathology at all in 55 cases (21%). The study emphasized the fact that nystagmographic examinations are able to detect central vestibular dysfunction and is therefore a suitable method to prove pathology.
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Several aircrew members of a Boeing 737 aircraft were referred to our department because they suffered from a barotrauma. The fast rate of pressure change during the descent of a Boeing 737 aircraft, as compared to the Boeing 747, DC-10 and Airbus 310 aircrafts, is most likely the cause of the development of the barotraumata.
A pilot suffering from Ménière's disease returned to flying status after a section of the vestibular nerve. The medical history proved to be quite unreliable. Ten years after the nerve section, hearing problems developed in the other ear. Only then was he grounded permanently.
In human subjects the caloric test was conducted during parabolic flight. The slow-phase velocity (SPV) of the caloric nystagmus increased proportionally to the value of the g-force. The nystagmus disappeared in microgravity, after an exponential SPV decay that showed a specific time constant (Tc). The average Tc value of this SPV decay is on a lower level than the one found after a sudden stop-test in the laboratory in a 1-g condition. Because of the exponential characteristics of the SPV decays and their Tc values, evoked in both conditions, a common working mechanism of cupular stimulation is likely. Most probably a fluid movement, caused either by a sudden stop in a 1-g condition or by weightlessness after a calorization, provokes a cupula flexion followed by a reflexion. The results support the Bárány convection theory with regard to the endolymph movement following the caloric test.