Virtual simulations offer nearly unlimited training potential for naval aviation due to the wide array of scenarios that can be simulated in a safe, reliable, and cost-effective environment. This versatility has created substantial interest in using existing and emerging virtual technology to enhance training scenarios. However, the virtual simulations themselves may hinder training initiatives by inducing simulator sickness among the trainees, which is a series of symptoms similar to motion sickness that can arise from simulator use. Simulator sickness has been a problem for military aviation since the first simulators were introduced. The problem has also persisted despite the increasing fidelity and sense of immersion offered by new generations of simulators. As such, it is essential to understand the various problems so that trainers can ensure the best possible use of the simulators. This review will examine simulator sickness as it pertains to naval aviation training. Topics include: the prevailing theories on why symptoms develop, methods of measurement, contributing factors, effects on training, effects when used shipboard, aftereffects, countermeasures, and recommendations for future research involving virtual simulations in an aviation training environment.Geyer DJ, Biggs AT. The persistent issue of simulator sickness in naval aviation training. Aerosp Med Hum Perform. 2018; 89(4):396-405.

These results do not support postural instability as the primary causal factor in motion sickness; however, more research is needed to elucidate the mechanisms of motion sickness etiology.Pettijohn KA, Geyer D, Gomez J, Becker WJ, Biggs AT. Postural instability and simulator seasickness. Aerosp Med Hum Perform. 2018; 89(7):634-641.

This open-label, randomized study in 36 healthy postmenopausal women, investigated the pharmacokinetics of Fem7^® (an oestradiol matrix-type patch), at doses of 25, 50, 75 and 100 μg/24 h, applied once weekly. Maximum plasma concentrations of oestradiol and oestrone were observed 14–20 h after patch application, remaining within the therapeutic range until removal, and returning to baseline within 12 h thereafter. Plasma oestradiol concentrations increased in a dose-dependent manner for all four doses, and plasma oestrone increased for the three highest doses. Fem7 treatment was well tolerated at all four doses and no severe adverse reactions were reported. Fem7 is a convenient and well-tolerated form of hormone-replacement therapy that delivers oestradiol in a consistent and predictable manner.