A Self-Controlled Trial to Evaluate the Use of Active Hearing Defenders in the Engine Rooms of Operational Naval Vessels

INTRODUCTION: Active Hearing Defenders are established hearing protectors with in-built electro-acoustics that shut-off ambient noise while allowing effective communication between users. METHODS: A blinded, self-controlled trial was conducted among naval servicemen to compare the effectiveness of two types of active hearing defenders (Howard-Leight Thunder TM and COM-55) in relation to passive hearing defenders in an operational environment. RESULTS: Subjects felt that the active hearing defenders were more comfortable, durable, and that the active hearing defenders helped them work better. When subjects were tested with a speech discrimination battery (Central Institute of the Deaf, Spondee Word lists), there was a significant difference (p value of 0.04, using the Kruskall-Wallis ANOVA test) between the two active and the passive defenders. However, no significant difference was found between the two types of active hearing defenders. CONCLUSION: Active hearing defenders are an acceptable and efficacious means of hearing protection in noisy environments. Language: en