ABSTRACT
Background: Exposure to high-performance flight stresses the vestibular system and may lead to adaptive changes in the vestibular responses of pilots. We investigated the vestibular-ocular reflex of pilots with different histories of flight exposure both with respect to hours of flight and flight conditions (tactical, high-performance vs. non-high-performance) to evaluate if and how adaptative changes are observable. Methods: We evaluated the vestibular-ocular reflex of aircraft pilots using the video Head Impulse Test. In study 1, we assessed three groups of military pilots: Group 1 had 68 pilots with few hours of flight experience (<300 h) in non-high-performance flight conditions; Group 2 had 15 pilots with many hours of flight (>3,000 h) and regularly flying tactical, high-performance flight conditions; Group 3 had eight pilots with many hours of flight (>3,000 h) but not exposed to tactical, high-performance flight conditions. In study 2, four trainee pilots were followed up and tested three times over a 4-year period: (1) <300 h of flight on civil aircraft; (2) shortly after exposure to aerobatic training and with <2,000 h of overall flight; and (3) after training on tactical, high-performance aircraft (F/A 18) and for more than 2,000 h of flight. Results: Study 1: Pilots of tactical, high-performance aircrafts (Group 2) had significantly lower gain values (p < 0.05) as compared to Groups 1 and 3, selectively for the vertical semicircular canals. They also had a statistically (p = 0.022) higher proportion (0.53) of pathological values in at least one vertical semicircular canal as compared to the other groups. Study 2: A statistically significant (p < 0.05) decrease in the rVOR gains of all vertical semicircular canals, but not of the horizontal canals, was observed. Two pilots had a pathological value in at least one vertical semicircular canal in the third test. Discussion: The results evidence a decrease in the gain of the vestibular-ocular reflex as measured with the video head impulse test for the vertical canals. This decrease appears to be associated with the exposure to tactical, high-performance flight rather than with the overall flight experience.
ABSTRACT
OBJECTIVE: To describe a unique case of definite neuroborreliosis presenting with bilateral vestibulopathy (BV) due to simultaneous involvement of both vestibular systems highlighted by a complete assessment for all five vestibular receptors. PATIENT: A 72-year-old woman presented with disabling disequilibrium arisen about 4 weeks earlier and history of erythema migrans developing about 45 days before. INTERVENTIONS: Assessing all five vestibular receptors with the video-head impulse test (vHIT), the suppression head impulse paradigm (SHIMP) and vestibular evoked myogenic potentials (VEMPs), a severe bilateral vestibulopathy was diagnosed. IgG and IgM Borrelia-specific antibodies on patient serum and cerebrospinal fluid analysis confirmed the diagnosis of neuroborreliosis. Following diagnosis, a course of doxycycline was started and the patients received an individualized vestibular rehabilitation program. RESULTS: The patient exhibited slowly progressive improvements for disabling symptoms and the improving function of all five vestibular receptors was monitored with vHIT, SHIMP, and VEMPs over time. CONCLUSIONS: This is the first case report of bilateral vestibulopathy likely caused by neuroborreliosis. Although neurotologic involvement is an uncommon complication in this condition, clinicians should consider a vestibular testing battery when addressed by patient's history and bedside vestibular findings.
