Use of a motion sickness history questionnaire for prediction of simulator sickness.

This research assessed the usefulness of the Motion History Questionnaire (MHQ) for the prediction of simulator sickness, a form of motion sickness experienced by pilots training in ground-based flight simulators. Four MHQ scoring keys were compared: (1) the original MHQ key which had been validated on a sample of U.S. Navy student pilots exposed to Coriolis forces, (2 and 3) two keys which had been validated on a sample of civilian college students exposed to simulated ship motions, and (4) a simulator sickness key empirically derived in the present research and cross-validated. Navy and Marine Corps aviators (N = 456) filled out the MHQ prior to their regularly scheduled flight simulator training and were divided into validation and cross-validation samples. All scoring keys were predictive of reported symptoms of sickness, but highest correlations were obtained with the empirically-derived simulator sickness (SS) key. It is suggested that the SS key be used for self-testing so that pilots may be made aware of their risk for developing simulator sickness.     

Simulator sickness in the U.S. Army UH-60A Blackhawk flight simulator.

Realistic training in aviation now includes the use of sophisticated flight simulators which can provide near total perception of aircraft flight. Reports of simulator sickness seem to be increasing in simulators with multi-directional motion, computer-generated imagery, and infinity optics. A voluntary, subjective, symptom-oriented questionnaire was completed by 141 pilots after training in the UH-60A 2B38 Blackhawk flight simulator. Thirty-six percent reported positive symptoms of motion sickness. Pilots may be at risk if they fly too soon after simulator training and a mandatory grounding time is advised.     

Simulator sickness in U.S. Navy flight simulators

Flight simulators have become a major factor in pilot training. A general finding from Navy research on simulator design is that equipment features that offer faithful representation improve pilot performance and promote pilot acceptance. To the extent that an aircraft produces motion sickness, its simulator should induce the same result. However, reports of simulator sickness appear to be increasing and a shortcoming in simulation is implied when these effects occur in simulators during maneuvers that do not occasion them in the aircraft. This article presents incidence data from surveys of the 10 simulators at 6 different Naval/Marine Corps Air Stations. Approximately 1,200 simulator flights were recorded. Some severe motion sickness symptoms were recorded and some simulators induced unsteadiness afterwards. Individuals experiencing effects may be at risk if they drive themselves home or return to demanding activities at work. The simulators which exhibited the highest incidences of sickness were helicopter simulators with cathode ray tube (CRT) infinity optics and six-degrees-of-freedom moving base systems. Of those studied, fixed-wing, fixed-base, dome displays had relatively low incidence of simulator sickness.     

Simulator induced syndrome: evidence for long-term aftereffects

Pilots have experienced various adverse symptoms hours and even days following flight simulator training. This study surveyed pilots undergoing simulator training in an attempt to provide an initial gauge of the extent, severity, and possible risk factors of long-term (greater than 1 day) simulator aftereffects. A three-part voluntary and anonymous questionnaire was used to gather data. We studied pilots of varying experience undergoing advanced flight training which included the use of flight simulators. Some 238 pilots participated in the study, and 196 completed the follow-up survey concerning long-term effects. Nine (4.6%) pilots experienced adverse symptoms 24 h or more after completion of their last simulator training, which they attributed to their recent simulator experience. Symptoms reported included: recurrent visual flashbacks, continued balance disturbance, and hand-eye discoordination. Three pilots (1.5%) reported difficulties flying aircraft. Pilot flight experience level, total simulator time, length of simulator session, and sex were not predictive of risk. This study suggests that long-term (greater than 1 day) adverse aftereffects may occur following simulator training.     

The time course of postflight simulator sickness symptoms

Reports of posteffects following training sessions in Navy and Army flight simulators were obtained from pilots to determine the time course of recovery from simulator sickness. Results imply that posteffects may be a more serious problem than previously considered; 45% of all those queried (N greater than 700) reported having experienced symptoms of simulator sickness; 25% of the symptoms lasted more than 1 h after leaving the simulator; and 8% lasted more than 6 h. Postexposure symptoms were classified into three categories: visuomotor (based on disturbances in oculomotor control; e.g., eyestrain), disorientation (based on disturbance in postural control; e.g., dizziness), and nausea (vagal/autonomic symptoms). A safety risk may be posed particularly by the moderately high frequency of symptoms involving postural disequilibrium. Guidelines for coping with risks are discussed.     

Simulator induced syndrome in Coast Guard aviators

The incidence of adverse symptoms in Coast Guard aviators undergoing flight simulator training was determined. A voluntary, multi-part questionnaire was completed by 238 pilots. During the first simulator flight 64.3% of pilots reported at least one adverse symptom, 39.4% during the last flight. Simulator induced syndrome (SIS) was present in 47.1% of subjects during the first simulator flight, 23.5% during their last flight. Most subjects reported their symptoms as mild, with some symptoms rated as moderate or severe in nature. There was no statistically significant association (p greater than 0.05) between the development of SIS and flight experience, simulator experience, length of simulator session, or self-determined motion sickness susceptibility. There was a significant association (p less than 0.05) between SIS development and the use of simulators with computer-generated imagery (CGI). Nine pilots experienced adverse symptoms at least 2 d after their last simulator flight. In conclusion, this study revealed that SIS occurs frequently, is more common when CGI is present, may recur, suggests an adaptative process, and may not be associated with some factors previously claimed.     

Epidemiology of musculoskeletal and soft tissue injuries aboard a U.S. Navy ship

OBJECTIVE: The objective of this study was to characterize injuries occurring to crew members aboard a U.S. Navy ship. METHODS: A retrospective review of crew member medical records was conducted covering a 90-day period during which the ship was intermittently at sea. Data on new injuries were collected and sorted. Injuries were classified as soft tissue or musculoskeletal, acute or overuse, and occurring with the ship at sea or in port. RESULTS: There was a total incidence of 16.5 injuries per 100 man-months. Acute musculoskeletal injuries contributed 2.6 injuries per 100 man-months and resulted in 79 lost and 192.5 modified work days. Overuse musculoskeletal injuries were responsible for 9.3 injuries per 100 man-months and caused 1 lost and 255.5 modified work days. Soft tissue injuries had an incidence of 4.6 injuries per 100 man-months and resulted in no lost and only 106 modified work days. The relative risk of sustaining a soft tissue injury in port compared with at sea was 1.1, but this was not statistically significant. The relative risk of sustaining an acute musculoskeletal injury in port compared with at sea was 3.5 (p = 0.01). CONCLUSIONS: Overuse musculoskeletal injuries occurred with the greatest incidence, but acute musculoskeletal injuries were responsible for the greatest morbidity. Soft tissue injuries occurred with an intermediate incidence but had the lowest overall morbidity. The safest place for crew members assigned to this Navy ship was aboard that ship at sea. Further studies of this nature could help guide medical efforts at injury treatment and prevention for shipboard personnel.     

Flight simulator platform motion and air transport pilot training

The influence of flight simulator platform motion on pilot training and performance was examined in two studies utilizing a B-727-200 aircraft simulator. The simulator, located at Ames Research Center, is certified by the FAA for upgrade and transition training in air carrier operations. Subjective ratings and objective performance of experienced B-727 pilots did not reveal any reliable effects of wide variations in platform motion design. Motion platform variations did, however, affect the acquisition of control skill by pilots with no prior heavy aircraft flying experience. The effect was limited to pitch attitude control inputs during the early phase of landing training. Implications for the definition of platform motion requirements in air transport pilot training are discussed.     

Simulator sickness provoked by a human centrifuge.

Simulator sickness is now a well-recognized entity. It is recognized as a form of motion sickness, having a higher incidence in the more sophisticated simulators. Human centrifuges (dynamic simulators) are the newest innovation in aircrew training devices. Simulator sickness has never been reported in human centrifuges. We are reporting on a case of delayed simulator sickness in a pilot-subject after a centrifuge experience. A review of the "psycho-physiological" problems routinely experienced by subjects on human centrifuges indicates such problems are due to simulator sickness, although they are not reported as such. In this paper, we give a brief overview of simulator sickness and briefly discuss simulator sickness, as related to the human centrifuge experience.     

模拟不同海况舰船环境下行去骨瓣减压术的可行性研究

目的 探讨不同海况舰船环境下实验犬去骨瓣减压术的操作时间及可行性.方法 采用摇摆舱液压模拟器,分别模拟舰船航行时4种(A、B、C、D)不同船体摇摆度条件,行专家咨询论证的海战时常用的去骨瓣减压术,选取20条杂种犬随机分组并分别进行操作时间测定与可行性研究.结果 去骨瓣减压术在不同海况下船上操作均顺利完成,实验犬术后观察48 h无死亡发生,操作时间差异无统计学意义(P>0.05).结论 虽然舰船上操作的精准程度受一定影响,但去骨瓣减压术在上述4种海况中实施是安全可行的.     

Tuberculosis outbreak investigation of a U.S. Navy amphibious ship crew and the Marine expeditionary unit aboard, 1998

A Marine deployed aboard a U.S. Navy amphibious ship had smear-positive, cavitary pulmonary tuberculosis (TB). Contact investigation ultimately found 21 active cases of TB among sailors and Marines who were aboard the affected ship. Approximately 3 months lapsed between onset of the source patient's illness and appropriate diagnosis and treatment. During the contact investigation, 3,338 persons received tuberculin skin tests and 712 were identified as new latent tuberculosis infection cases. Four persons diagnosed with latent tuberculosis infection developed active TB because of poor compliance with treatment. After personnel disembarked from the ship, persistent efforts to identify persons with active disease and latent infections were successful in controlling further spread of tuberculosis in military units and local communities. The Mycobacterium tuberculosis bacteria isolated from the source patient and 16 of the other active cases were susceptible to all drugs commonly used to treat TB.     

Heart rate and performance during combat missions in a flight simulator

INTRODUCTION: The psychological workload of flying has been shown to increase heart rate (HR) during flight simulator operation. The association between HR changes and flight performance remains unclear. METHODS: There were 15 pilots who performed a combat flight mission in a Weapons Tactics Trainer simulator of an F-18 Hornet. An electrocardiogram (ECG) was recorded, and individual incremental heart rates (deltaHR) from the HR during rest were calculated for each flight phase and used in statistical analyses. The combat flight period was divided into 13 phases, which were evaluated on a scale of 1 to 5 by the flight instructor. RESULTS: HR increased during interceptions (from a mean resting level of 79.0 to mean value of 96.7 bpm in one of the interception flight phases) and decreased during the return to base and slightly increased during the ILS approach and landing. DeltaHR appeared to be similar among experienced and less experienced pilots. DeltaHR responses during the flight phases did not correlate with simulator flight performance scores. Overall simulator flight performance correlated statistically significantly (r = 0.50) with the F-18 Hornet flight experience. CONCLUSIONS: HR reflected the amount of cognitive load during the simulated flight. Hence, HR analysis can be used in the evaluation of the psychological workload of military simulator flight phases. However, more detailed flight performance evaluation methods are needed for this kind of complex flight simulation to replace the traditional but rough interval scales. Use of a visual analog scale by the flight instructors is suggested for simulator flight performance evaluation.     

地面模拟长航时飞行时飞行学员心率和心率变异性的变化

目的探讨飞行人员长航时飞行中生理变化特点,观察心理疲劳对抗措施对长航时飞行心理疲劳的缓解作用。方法20名健康男性教-8飞行学员随机分为对照组和试验组,在教-8飞行模拟器上进行8h的长航时模拟飞行。试验组在飞行中的休息阶段采取放松措施,对照组休息阶段不采取任何措施。记录飞行学员模拟飞行过程中的心电信号,分析心率、心率变异性（heart rate variability,HRV）以及体动强度。结果模拟长航时飞行中,试验组的平均心率显著低于对照组（F-184．241,P-0．000）,试验组休息时平均心率低于飞行时（F-17．564,P-0．000）;而对照组在飞行和休息时心率变化规律不明显（F-2．014,P-0．156）。对照组休息时较飞行时校正低频功率（low frequency normalized unit,LFnu）、低频高频比值（LF／HF）显著增加,校正高频功率（highfre-quency normalized unit,HFnu）显著降低。而试验组在休息时LFnu、HFnu、LF／HF指标与飞行时比较,仅第1次第有明显变化（P〈O．05）。对照组的体动强度在休息时显著高于飞行阶段,而试验组没有明显改变。结论地面模拟长航时飞行试验中,受试者的自主神经兴奋性因试验因素的变化存在明显的变化规律。从心率变化分析,地面模拟长航时飞行属于单位时问内低负荷持续作业的试验模型。在飞行中的休息阶段实施放松措施能有效缓解受试者的焦虑、烦躁情绪。HRV频域指标中,LFnu、HFnu、LF／HF可作为评价情绪负荷较为敏感的指标。     

The effects of acoustic orientation cues on instrument flight performance in a flight simulator

An initial version of an acoustic orientation instrument (AOI), in which airspeed was displayed as sound frequency, vertical velocity as amplitude modulation rate, and bank angle as right-left lateralization, was evaluated in a T-40 (Link GAT-3) motion-based simulator. In this study, 15 pilots and 3 non-pilots were taught to use the AOI and flew simulated flight profiles under conditions of neither visual nor auditory instrumentation (NO INPUT), AOI signals only (AOI), T-40 simulator instrumentation only (VISUAL), and T-40 simulator instrumentation with AOI signals (BOTH). Bank control under AOI conditions was significantly better than under the NO INPUT condition for all flying tasks. Bank control under VISUAL conditions was significantly better than under the AOI condition only during turning and when performing certain complex secondary tasks. The pilots' ability to use the AOI to control vertical velocity and airspeed was less apparent. However, during straight-and-level flight, turns, and descents the AOI provided the pilots with sufficient information to maintain controlled flight. Factors of potential importance in using sound to convey aircraft attitude and motion information are discussed.     

运用六自由度舰船模拟装置建立人体晕船模型可行性分析

目的 分析运用六自由度舰船模拟装置建立人体晕船模型的可行性,为防治晕船和抗晕船药物研究提供实验模型.方法 运用舰船模拟装置对60名受试对象进行加速度暴露,判断晕船发生情况.根据Graybiel运动病评分法判定晕船严重程度,结合既往运动病史,分析运用舰船模拟装置建立人体晕船模型的可行性.结果 共42人出现了晕船症状,晕船发生率70%,晕船严重程度分布与既往运动病严重程度分布大致相同,晕船发生情况与既往运动病史存在相关(C=0.41,P＜0.01).结论 经过舰船模拟装置对受试对象进行加速度暴露后,大部分人出现了晕船症状,成功地建立了人体晕船模型.     

Ship size as a factor in illness incidence among U.S. Navy vessels

Illness incidence was examined aboard U.S. Navy vessels to ascertain whether sick call rates vary with ship size. Outpatient data from ships of three different sizes (destroyers/frigates, cruisers, aircraft carriers) were surveyed, controlling for geographical region of deployment. Overall rates of illness were lower for the largest ships when contrasted with the smallest vessels for all three operational theaters; these rate differences were significant for the East Asia and Indian Ocean regions. Among major categories of disease, significantly higher rates aboard the small vessels were seen in at least two of the geographic regions for respiratory disorders, digestive diseases, and musculoskeletal problems. Infective and parasitic diseases, skin and subcutaneous disorders, as well as symptoms and ill-defined disorders were significantly higher for small ships in one theater. It was concluded that ship size is a factor in illness incidence and should be considered in medical resource planning.     

Aeromedical waiver status in U.S. Naval aviators involved in Class A mishaps

PURPOSE: U.S. Naval aviators are subject to stringent aeromedical standards. Aeromedic waivers are considered when a naval aviator develops a medical condition that is deemed safe for flight, allowing that aviator to continue in a flying status. No Class A (serious) mishap to date has been directly attributable to an aviator's waivered condition. However, to date no study has been conducted to review the overall mishap rate among aviators who are flying with a waiver. This study evaluated the aeromedical waiver status of naval aviators involved in Class A mishaps from 1992-1999. METHOD: Aviation mishaps in the U.S. Navy are investigated by trained personnel, who report their detailed findings to the U.S. Naval Safety Center (NSC). The Navy Operational Medicine Institute (NOMI) maintains a database of all aviation physicals, including the waiver status of individual aviators. A collaborative NSC/NOMI study was done to investigate the prevalence of waivers in mishap and non-mishap aviators. Records were retrieved on 234 naval aviators who were the "pilot at the controls" of Class A mishaps occurring from 1992-1999. This mishap waiver rate was compared with the baseline waiver rate for all pilots in 1994 (midpoint). Odds Ratios were calculated of having a Class A mishap if the aviator had a waiver. RESULTS AND CONCLUSIONS: Analysis failed to find a statistical difference in waiver rates between mishap aviators and the general naval aviator population indicating that the U.S. Naval Aeromedical Service is providing aeromedically safe naval aviators to the fleet.     

Different flying histories in flying phobics: association with psychopathology and treatment outcome

INTRODUCTION: Passengers experiencing fear of flying can threaten the safety of a flight, its passengers, and crew. In the present study we investigated the effect of different flying histories on the nature and treatment of fear of flying and attempted to determine the following: 1) the prevalence of different flying histories in a sample of self-referred flying phobics; 2) the demographic and psychopathologic characteristics of flying phobics differing with respect to flying history; and 3) the predictive value of different flying histories for treatment outcome. METHODS: Of 2001 self-referred adults who applied for a flying treatment program, 85.6% reported that they had flown before and that their flights had been uneventful; 8.7% had no previous experience with flying; 5.7% had flown before and had experienced an eventful (5.4%) or even a traumatic flight (0.3%). RESULTS: Participants who had never flown before reported higher levels of fear of flying (FAS, FAM, VAFAS), agoraphobia (FSS-III), and general anxiety (SCL-90). Moreover, these subjects showed significantly more anxiety reduction following a 1- or 2-d group treatment than the other participants (statistically corrected for any pretreatment differences). CONCLUSIONS: For participants who had never flown before, anxiety probably primarily reflects more generalized avoidance tendencies and a proneness to over-predict the magnitude and intensity of their fear.     

Retrospective analysis of Naval Special Boards of Flight Surgeons, 1974-83

The Naval Special Board of Flight Surgeons was established in 1956 for the evaluation of Navy, Marine Corps, and Coast Guard problem aeromedical cases. This paper examines a sample 248 of these cases for the period of 1974-83 with respect to the characteristics of those referred, their referral diagnostic category, and the recommendation of the Special Board regarding return to a flying status. Those cases with a referral diagnostic category of ENT and Ophthalmology were less likely to be returned to flight status. Older, more senior pilots, and pilots with more total flight time were less likely to be returned to unrestricted flying than were their younger, more junior, and less experienced counterparts. Otherwise, no significant difference in outcome based on age, rank, marital status, branch of service, specialty, or flight hours was detected. Overall, 61% of those evaluated by the SBFS were returned to flight status.