Casali John G, Ahroon William A, Lancaster Jeff A
Auditory Systems Laboratory, Virginia Tech, Blacksburg, VA, USA.
Noise Health. 2009 Jan-Mar;11(42):69-90. doi: 10.4103/1463-1741.48564.
Operational hearing protection and maintenance of audibility of signals and speech are considered force multipliers in military operations, increasing Soldier survivability and lethality. The in-field research described in this paper was conducted to examine operational performance effects of three different hearing enhancement protection systems (HEPS) that are intended to provide both protection and audibility. The experiment utilized operationally-defined measures in full-scale, simulated combat scenarios with Army ROTC Cadet Soldiers as subjects. The Soldiers' operational performance was evaluated in two missions: reconnaissance and raid (attack on enemy camp). Both missions had substantial hearing requirements, including communications, signal detection/recognition, and distance judgments. Operational performance was measured by objective metrics of Squad performance, including the distances required to detect an enemy insurgent camp under each HEPS, and by subjective metrics, such as the Army's dimensions of combat-related mission success as evaluated by Army Officers who served as training leaders/observers. Other subjective ratings were obtained after each training exercise from both the Officers and the Soldiers, including detailed impressions about each HEPS after extended use. Two of the three HEPS were electronic sound transmission devices (comprising an ambient sound pass-through filtering and amplification circuit): a Peltor Comtac II circumaural headset (NRR=21; 16 dB maximum gain); and a Communications Enhancement Protection System (CEPS) (NRR=29; 36 dB maximum gain). One passive, level-dependent HEPS was used, the yellow end of the Combat Arms Earplug, which provides amplitude-sensitive attenuation that sharply increases when the ambient sound is above about 110 dB (e.g., due to a gunshot), but which provides an NRR of 0 and very little attenuation below 1000 Hz in lower ambient noise levels. In the military mission entailing location of and attack on an enemy camp, the CEPS device resulted in the longest (earliest) average auditory detection distance of the camp (400 feet), followed by the Peltor (233 feet) and then the Combat Arms Earplug (150 feet), in comparison to detection by the unprotected, normal ear at about 220 feet. Commanding officers' ratings of mission performance and overall success slightly favored the electronic HEPS, but these ratings were dependent upon the particular mission undertaken. Ergonomics and usability issues abounded with the electronic HEPS, and the Soldiers' subjective ratings showed variability across all three devices, with device preference depending upon the particular dimension being rated (e.g., comfort vs. hearing ability). Clearly, the results of this in-field experiment demonstrate that more development is needed to achieve the levels of hearing performance and user acceptance from the HEPS that is desirable and needed for combat conditions. In this vein, it is important to note that HEPS designs are continually evolving, and certain upgrades to the three devices evaluated in the late 2006 timeframe of this study have occurred and further evaluations are thus warranted.
作战听力保护以及信号和语音可听度的维持被视为军事行动中的力量倍增器，可提高士兵的生存能力和杀伤力。本文所述的实地研究旨在检验三种不同的听力增强保护系统（HEPS）的作战性能影响，这些系统旨在同时提供保护和可听度。该实验在全面、模拟战斗场景中采用了作战定义的测量方法，以陆军后备军官训练队学员士兵为受试者。在两项任务中评估了士兵的作战性能：侦察和突袭（对敌方营地的攻击）。两项任务都有大量听力要求，包括通信、信号检测/识别和距离判断。作战性能通过班组性能的客观指标来衡量，包括在每种HEPS下检测敌方叛乱分子营地所需的距离，以及通过主观指标来衡量，例如由担任训练领导/观察员的陆军军官评估的与战斗相关任务成功的陆军维度。在每次训练演习后，从军官和士兵那里都获得了其他主观评分，包括在长时间使用后对每种HEPS的详细印象。三种HEPS中的两种是电子声音传输设备（包括环境声音直通滤波和放大电路）：一个Peltor Comtac II耳周式头戴式耳机（降噪率=21；最大增益16分贝）；以及一个通信增强保护系统（CEPS）（降噪率=29；最大增益36分贝）。使用了一种被动的、与水平相关的HEPS，即战斗武器耳塞的黄色端，它提供幅度敏感衰减，当环境声音高于约110分贝（例如由于枪声）时急剧增加，但在较低环境噪声水平下，其降噪率为0，在1000赫兹以下几乎没有衰减。在需要定位和攻击敌方营地的军事任务中，与未受保护的正常耳朵在约220英尺处的检测相比，CEPS设备导致营地的平均听觉检测距离最长（最早）（400英尺），其次是Peltor（233英尺），然后是战斗武器耳塞（150英尺）。指挥官对任务性能和总体成功的评分略微倾向于电子HEPS，但这些评分取决于所执行的特定任务。电子HEPS存在大量人体工程学和可用性问题，士兵的主观评分显示在所有三种设备中存在差异，设备偏好取决于所评级的特定维度（例如舒适度与听力能力）。显然，这项实地实验的结果表明，需要更多的研发来实现战斗条件下所需的HEPS听力性能和用户接受度水平。在这方面，重要的是要注意到HEPS设计在不断发展，在本研究2006年末期评估的三种设备已经进行了某些升级，因此有必要进行进一步评估。
