INTRODUCTION: Zero-G parabolic flight reproduces the weightlessness of space for short periods. However, motion sickness may affect some fliers. The aim was to assess the extent of this problem and to find possible predictors and modifying factors.METHODS: Airbus zero-G flights consist of 31 parabolas performed in blocks. Each parabola consisted of 20 s of 0 g sandwiched by 20 s of hypergravity of 1.5–1.8 g. The survey covered N = 246 person-flights (193 men, 53 women), ages (M ± SD) 36.0 ± 11.3 yr. An anonymous questionnaire included motion sickness rating (1 = OK to 6 = vomiting), Motion Sickness Susceptibility Questionnaire (MSSQ), antimotion sickness medication, prior zero-G experience, anxiety level, and other characteristics.RESULTS: Participants had lower MSSQ percentile scores (27.4 ± 28.0) than the population norm of 50. Motion sickness was experienced by 33% and 12% vomited. Less motion sickness was predicted by older age, greater prior zero-G flight experience, medication with scopolamine, lower MSSQ scores, but not gender or anxiety. Sickness ratings in fliers pretreated with scopolamine (1.81 ± 1.58) were lower than for nonmedicated fliers (2.93 ± 2.16), and incidence of vomiting in fliers using scopolamine treatment was reduced by half to a third. Possible confounding factors including age, sex, flight experience, and MSSQ could not account for this.CONCLUSION: Motion sickness affected one-third of zero-G fliers despite being intrinsically less motion sickness susceptible compared to the general population. Susceptible individuals probably try to avoid such a provocative environment. Risk factors for motion sickness included younger age and higher MSSQ scores. Protective factors included prior zero-G flight experience (habituation) and antimotion sickness medication.Golding JF, Paillard AC, Normand H, Besnard S, Denise P. Prevalence, predictors, and prevention of motion sickness in zero-G parabolic flights. Aerosp Med Hum Perform. 2017; 88(1):3–9.

BACKGROUND: More than half of astronauts develop ophthalmic changes during long-duration spaceflight consistent with an abnormal intraocular and intracranial pressure (IOP, ICP) difference. The aim of our study was to assess IOP and ICP during head-down tilt (HDT) and the additive or attenuating effects of 1% CO₂ and lower body negative pressure (LBNP).METHODS: In Experiment I, IOP and ICP were measured in nine healthy subjects after 3.5 h HDT in five conditions: -6°, -12°, and -18° HDT, -12° with 1% CO₂, and -12° with -20 mmHg LBNP. In Experiment II, IOP was measured in 16 healthy subjects after 5 min tilt at +12°, 0°, -6°, -12°, -18°, and -24°, with and without -40 mmHg LBNP.RESULTS: ICP was only found to increase from supine baseline during -18° HDT (9.2 ± 0.9 and 14.4 ± 1 mmHg, respectively), whereas IOP increased from 15.7 ± 0.3 mmHg at 0° to 17.9 ± 0.4 mmHg during -12° HDT and from 15.3 ± 0.4 mmHg at 0° to 18.7 ± 0.4 mmHg during -18° HDT. The addition of -20 mmHg LBNP or 1% CO₂ had no further effects on ICP or IOP. However, the use of -40 mmHg LBNP during HDT lowered IOP back to baseline values, except at −24° HDT.DISCUSSION: A small, posterior intraocular-intracranial pressure difference (IOP > ICP) is maintained during HDT, and a sustained or further decreased difference may lead to structural changes in the eye in real and simulated microgravity.Marshall-Goebel K, Mulder E, Bershad E, Laing C, Eklund A, Malm J, Stern C, Rittweger J. Intracranial and intraocular pressure during various degrees of head-down tilt. Aerosp Med Hum Perform. 2017; 88(1):10–16.

BACKGROUND: Health incapacitation is a serious threat to flight safety. Therefore, a study conducted 10 yr ago examined the incidents of ear-nose-throat (ENT) barotrauma and upper respiratory infection (URI) among commercial pilots and found that a large number continued to carry out their duties despite the risk of incapacitation. Now, 10 yr later, this new study examines if the attention to URIs has improved.METHOD: This study was conducted at the Danish Aeromedical Centre over the course of 1 yr with 463 valid respondents to a questionnaire on URIs and ENT barotrauma. These respondents were compared to 940 respondents answering the same questionnaire 10 yr prior in the same setting.RESULTS: This study shows a significant increase in the number of pilots flying despite signs of an URI from 42.8 to 50.1% and in the number of pilots using decongestant medicine from 43.3 to 59.5%. The proportion of pilots experiencing one or more ENT barotraumas has also increased from 37.4 to 55.5% for barotitis media and from 19.5 to 27.9% for barosinusitis.CONCLUSION: Half of all pilots in this study fly despite signs of an URI. This is a significant increase and shows that after 10 yr an URI is still not considered a valid reason for reporting in sick despite international aeromedical recommendation. Based on these findings, the study recommends that awareness of the risk of flying with an URI be increased.Boel NM, Klokker M. Upper respiratory infections and barotrauma among commercial pilots. Aerosp Med Hum Perform. 2017; 88(1):17–22.

BACKGROUND: The clinical experience and preferred learning style of U.S. Air Force flight nurses and aeromedical evacuation technicians are unknown.METHODS: Using a cross-sectional survey design, we gathered data regarding the clinical experience, level of comfort providing clinical care, and preferred learning style of 77 active duty (AD), Air Force Reserve (AFR), and Air National Guard (ANG) nurses enrolled in the U.S. Air Force School of Aerospace Medicine Flight Nurse course, and 121 AD, AFR, and ANG medical technicians enrolled in the Aeromedical Evacuation Technician course.RESULTS: Nurses and medical technicians reported 7.6 ± 5.5 and 3.9 ± 4.5 yr of experience, respectively. AD, AFR, and ANG nurses had comparable years of experience: 5.8 ± 3.2, 8.3 ± 6.6, and 7.9 ± 4.2 yr, respectively; however, AD medical technicians had more years of experience (5.6 ± 4.4 yr) than AFR (3.1 ± 4.8 yr) and ANG (1.9 ± 2.8 yr) medical technicians. Both nurses and medical technicians reported infrequently caring for patients with various disease processes and managing equipment or devices that they will routinely encounter when transporting patients as an aeromedical evacuation clinician. Nurses and medical technicians preferred a kinesthetic learning style or a multimodal learning style that included kinesthetic learning. Nearly all (99%) nurses and 97% of medical technicians identified simulation as their preferred teaching method.DISCUSSION: These findings confirm faculty concerns regarding the clinical experience of flight nurse and aerospace evacuation technician students.De Jong MJ, Dukes SF, Dufour KM, Mortimer DL. Clinical experience and learning style of flight nurse and aeromedical evacuation technician students. Aerosp Med Hum Perform. 2017; 88(1):23–29.

BACKGROUND: Myasthenia gravis is an autoimmune condition where antibodies form against the acetylcholine receptors at the neuromuscular junction, eventually causing damage to the motor end plate. The clinical features include muscle fatigability as well as ocular, bulbar, and limb weakness, which can have implications on the role of a pilot or air traffic controller. This retrospective study reviewed the United Kingdom Civil Aviation Authority (UK CAA) experience of myasthenia gravis.METHODS: A search of the United Kingdom Civil Aviation Authority medical records database from 1990 to 2016 identified 11 individuals with a diagnosis of myasthenia gravis. Data were extracted for the class of medical certificate, age at diagnosis, symptoms, acetylcholine receptor antibody status, treatment, the time from diagnosis to loss of medical certification, and the reasons for loss of certification.RESULTS: There were two Class 1 certificate holders (for professional flying) and six Class 2 certificate holders (for private pilot flying) and three air traffic controllers. The mean and median ages at diagnosis were 53 and 57 yr, respectively, with a range of 28–67 yr. The mean and median intervals from diagnosis to loss of certification were 22 and 11 mo, respectively, with a range of 0 to 108 mo.CONCLUSION: The aeromedical implications of myasthenia gravis, including complications, types of treatment, and functional impact, are considered. A policy for medical certification following a diagnosis of myasthenia gravis is proposed.Jagathesan T, O’Brien MD. Myasthenia gravis and its aeromedical implications. Aerosp Med Hum Perform. 2017; 88(1):30–33.

INTRODUCTION: This study explores the U.S. experience with waivers for insulin treatment for third-class medical certificates. From 1997 through 2014, the Federal Aviation Administration (FAA) approved an estimated 1500 waivers for insulin-treated diabetes with a total of 450 active waivers as of December 31, 2014. These pilots were involved in 25 accidents, but none were attributed to medical issues.METHODS: Data for the insulin waiver group and control group were obtained from the FAA’s aeromedical certification system and matching accident data from the NTSB database. A logistic regression model comparing accidents in this group to the overall population of third-class certificate holders adjusted for gender, age, and flight times was performed. A novel technique for calculating accident rates was also employed.RESULTS: No statistically significant association between waivers for insulin treatment and accident risk was found by logistic regression. The overall accident rate for pilots possessing an insulin waiver was 7.0 per 100,000 flight hours and an estimate for all third-class pilots was also 7.0 per 100,000 flight hours. Only 8% of waivers for insulin treatment were later terminated for adverse changes related to the applicant’s diabetes. Of these pilots, 8% also had coronary artery disease severe enough to require its own waiver.CONCLUSION: Taken together, these findings suggest that pilots holding special issuance waivers for insulin-treated diabetes are not detectably less safe than other airmen with third-class medical certificates and most are able to successfully comply with the FAA’s stringent medical certification protocol for insulin treated diabetes.Mills WD, DeJohn CA, Alaziz M. The U.S. experience with waivers for insulin-treated pilots. Aerosp Med Hum Perform. 2017; 88(1):34–41.

BACKGROUND: One of the most difficult challenges in aviation medicine is to diagnose, as early as possible, pilots with psychiatric disorders that may impair pilot performance and increase the risk of incidents and accidents. This diagnosis applies particularly to bipolar disorder (BD), where return to flying duty is not an option in the majority of cases. BD is a long-term mental disorder presenting remittent depressive, hypomanic, manic, or mixed episodes between low symptomatic or asymptomatic intermediate periods. Onset in most cases is in late teen or early adult years. Suicidal intentions and suicide risk are significantly elevated in individuals with BD compared to the general population.METHODS: A systematic literature search was performed of BD and aviation accidents and the National Transportation Safety Board database of fatal general aviation accidents was searched. One case report and two database reports of interest from 1994 to 2014 were identified.RESULTS: The findings set a minimum frequency of BD in general aviation fatalities to be approximately 2 out of 8648 (0.023%) in the United States.DISCUSSION: The reported incidence may underestimate the real number of BD cases for several reasons, including the fact that the medical history of pilots is not always available or is sometimes not the primary interest of a safety investigation. This study suggests that the demarcation of psychiatric disorder related to fitness to fly is an important step in safety.Vuorio A, Laukkala T, Navathe P, Budowle B, Bor R, Sajantila A. Bipolar disorder in aviation medicine. Aerosp Med Hum Perform. 2017; 88(1):42–47.

INTRODUCTION: One of the mechanisms leading to spatial disorientation (SD) is overstimulation of the vestibular system by various aircraft maneuvers. The objective of this study was to observe respiratory rate and pulse changes during vestibular system stimulations with the help of two selected SD training profiles.METHODS: The respiration and pulse rates of 15 subjects were recorded in response to 2 sequential SD training profiles on a motion-based simulator. The session started with a motionless instruction period (IP), continued with a Coriolis profile (CP) which stimulated the semicircular canals, and ended with a Dark Takeoff profile (DP) which stimulated the otolith organs. Recorded parameter means during profiles were statistically compared with IP mean values.RESULTS: The average age of all subjects was 23.67 ± 1.11. Mean CP respiratory rate (23.43 ± 3.21) was higher than mean IP respiratory rate (21.39 ± 4.27) and mean DP pulse rate (79.88 ± 10.39) was lower than mean IP pulse rate (84.76 ± 14.26) of the subjects. These differences were statistically significant.DISCUSSION: Data indicate that stimulation of the semicircular canals increased respiration rate while stimulation of the otoliths caused a reduction in pulse rate. This was considered to be a result of vestibulorespiratory reflex. Inputs from the vestibular otolith organs contribute to the control of blood pressure during movement and changes in posture. Predicting pulse and respiratory changes due to aerial maneuvers may be important for pilot safety during flight.Ilbasmis S, Yildiz S. Respiratory and pulse changes due to vestibular stimulations in a motion-based simulator. Aerosp Med Hum Perform. 2017; 88(1):48–51.

BACKGROUND: Little is known about the possible electromagnetic interferences (EMI) in the single-engine fixed-wing aircraft environment with implantable cardio-defibrillators (ICDs). Our hypothesis is that EMI in the cockpit of a single-engine fixed-wing aircraft does not result in erroneous detection of arrhythmias and the subsequent delivery of an inappropriate device therapy.METHODS: ICD devices of four different manufacturers, incorporated in a thorax phantom, were transported in a Piper Dakota Aircraft with ICAO type designator P28B during several flights. The devices under test were programmed to the most sensitive settings for detection of electromagnetic signals from their environment. After the final flight the devices under test were interrogated with the dedicated programmers in order to analyze the number of tachycardias detected.RESULTS: Cumulative registration time of the devices under test was 11,392 min, with a mean of 2848 min per device. The registration from each one of the devices did not show any detectable “tachycardia” or subsequent inappropriate device therapy. This indicates that no external signals, which could be originating from electromagnetic fields from the aircraft's avionics, were detected by the devices under test.CONCLUSION: During transport in the cockpit of a single-engine fixed-wing aircraft, the tested ICDs did not show any signs of being affected by electromagnetic fields originating from the avionics of the aircraft. This current study indicates that EMI is not a potential safety issue for transportation of passengers with an ICD implanted in a single-engine fixed-wing aircraft.de Rotte AAJ, van der Kemp P, Mundy PA, Rienks R, de Rotte AA. Electromagnetic interference in implantable defibrillators in single-engine fixed-wing aircraft. Aerosp Med Hum Perform. 2017; 88(1):52–55.

INTRODUCTION: Wolff-Parkinson-White (WPW) pattern is occasionally found in asymptomatic aviators during routine ECGs. Aeromedical concerns regarding WPW pattern include risk of dysrhythmia or sudden cardiac death (SCD), thus affecting the safety of flight. The purpose of this study was to determine the prevalence and outcomes of aviators with asymptomatic WPW pattern and assess for risk factors that contribute to progression to dysrhythmia or symptoms.METHODS: The U.S. Air Force (USAF) ECG library database containing over 1.2 million ECGs collected over the past 68 yr was used to identify 638 individual aviators with WPW pattern. Demographic, medical history, and outcome data were obtained by medical record review. Aviators who developed high risk features defined as symptoms, arrhythmia, or ablation of a high risk pathway, were compared to those who remained asymptomatic.RESULTS: Prevalence of WPW pattern was 0.30% among all USAF aviators. Of the 638 individuals, 64 (10%) progressed to the combined endpoint of SCD, arrhythmia, and/or ablation of a high risk pathway over 6868 patient years, with average follow-up of 10.5 yr. There were two sudden cardiac deaths (0.3%). Annual risk of possible sudden incapacitation was 0.95% and of SCD 0.03%. Those that progressed to high risk were significantly younger, had lower diastolic blood pressure, lower total cholesterol, and better physical fitness testing scores.DISCUSSION: WPW pattern on ECG found in asymptomatic aviators confers < 1% annual risk of arrhythmia or incapacitating events with the highest risk in the younger, healthier, and most fit populations.Davenport ED, Rupp KAN, Palileo E, Haynes J. Asymptomatic Wolff-Parkinson-White pattern ECG in USAF aviators. Aerosp Med Hum Perform. 2017; 88(1):56–60.

INTRODUCTION: Despite technological advances, hypoxia remains a concern in aviation. Hypoxia can present with a vast array of symptoms that are unique to each aviator. Military aviators undergo hypoxia awareness trainings to learn their unique constellation of hypoxia symptoms.CASE REPORT: This case report describes a military aviator who was flying in a B1 when the cabin depressurized. While performing the emergency checklist, the aviator was moving about the cabin and began to experience hypoxia symptoms. His symptoms occurred at an altitude below 3048 m (10,000 ft), and his fellow crewmembers remained asymptomatic. Previous hypoxia awareness trainings enabled the aviator to recognize his symptoms as hypoxic. His symptoms resolved within seconds of applying supplemental oxygen via his facemask, and he did not have any recurrence of his symptoms.DISCUSSION: Aviators reliably remember their hypoxic symptoms from previous hypoxia awareness trainings up to 4.5 yr later. This enables the aviator to quickly take action to correct his or her symptoms. While hypoxia is commonly thought to only occur at altitudes greater than 4267 m (14,000 ft), it can occur at lower altitudes, especially if it is compounded with the physiological changes from exercise.Tristan LR. Hypoxia occurrence in a military aviator below 3048 m. Aerosp Med Hum Perform. 2017; 88(1):61–64.

BACKGROUND: Baro-otalgia is a common complaint among passengers in an aircraft, in particular those who had a recent upper respiratory tract infection. The underlying pathophysiology is secondary to unequal aeration of the middle ear cleft with the surrounding atmosphere and it can be explained using Boyle’s Law. We describe an unusual presentation of baro-otalgia in a pilot secondary to cholesteatoma obstructing the aditus despite normal middle ear pressure equalization provided by a grommet in the ear.CASE REPORT: A 26-yr-old pilot with a presenting complaint of conductive hearing loss was diagnosed and treated for congenital cholesteatoma. His hearing improved, but 4 yr later he developed ear pain during the cruising phase of flight at an altitude of 9144 m (30,000 ft) above sea level. This pain persisted until descent to 4876 m (16,000 ft). Despite insertion of a middle ear ventilating tube, he remained symptomatic, requiring further investigation. This led to the diagnosis of recurrent cholesteatoma obstructing the aditus to the mastoid cavity. Upon surgical removal of the cholesteatoma, symptoms resolved.DISCUSSION: We hypothesize that the recurrent cholesteatoma caused obstruction to normal aeration of the mastoid air cells during the changing atmospheric air pressure, thus producing pain. This is akin to sinus barotrauma instead of the usual pathophysiology underlying barotitis.Govindaraju R, Adaikappan M, Rajagopalan R. Baro-otolagia secondary to cholesteatoma. Aerosp Med Hum Perform. 2017; 88(1):65–67.

Timboe AM. You’re the flight surgeon: seborrheic dermatitis. Aerosp Med Hum Perform. 2017; 88(1):68–70.