John G. Casali
Dr. John G. Casali is the Grado Chaired Professor of Industrial & Systems Engineering at Virginia Tech and Director of the Auditory Systems Lab. He also is Founder of Hearing, Ergonomics and Acoustics Resources (HEAR) LLC, a product design, testing, and litigation support company. A Fellow of the Human Factors & Ergonomics Society and the Institute of Industrial Engineers, he received the NIOSH-NHCA Safe-in-Sound Award for Innovation (auditory situation awareness-ASA) in 2016, and the NHCA Outstanding Hearing Conservationist Award in 2009. He has directed over 110 research projects sponsored by U.S. government/military agencies as well as many corporations, totaling over $14M. Many of the 200+ publications emanating from his research concern hearing protection, ASA, military hearing scenarios, and auditory displays/warnings. Dr. Casali also holds 6 Patents, 4 of which relate to hearing protection. During the past decade, he led the development of the "DRILCOM" indoor ASA test facility and the “PASAT” ASA training system. These facilities are applied to testing of advanced hearing protection and headset effects on human auditory situation awareness, as well as training users to improve their auditory perceptual capabilities. He will speak on this body of auditory situation awareness research at the symposium.
Auditory Situation Awareness: The Conundrum of Protecting Hearing While Preserving Auditory Cues
The human hearing sense is critical for maintaining vigilance to events in our realm and a keen awareness of our surroundings. In part, this is due to the auditory sense’s omnidirectionality, “always on” functionality, and signal detection/recognition capabilities. When the auditory system is damaged by noise or other etiologies of hearing loss, auditory situation awareness (ASA) will suffer. Prevention of noise-induced hearing loss via hearing protection devices (HPDs), together with concomitant preservation of one's ASA and vigilance to the surrounding acoustic environment, is critical. Examples include construction workers who wear electronic earmuffs but must hear backup alarms, and soldiers who wear gunfire-noise-protective headsets but must hear enemy threats. Over the past decade, 10 in-field and in-lab experiments at Virginia Tech’s Auditory Systems Laboratory have demonstrated that certain advanced HPDs and military Tactical-Communications-and-Protective-Systems (TCAPS), all designed to pass-through signals/communications, in fact do not provide truly natural hearing or "transparency," and have deleterious effects on ASA. Experimental stimuli have included warning signals such as vehicle backup alarms, as well as military-relevant sounds, such as weapons preparation (e.g., cocking), sniper shots, foreign language, footfalls, and vehicular/aircraft signatures. Measures of ASA performance have included: hearing threshold (dB) at detection, accuracy and response time in recognizing/identifying signatures and for localization, and intelligibility of communications. Based on these experiments, an objective, repeatable test battery was developed for evaluating HPD and TCAPS effects on the ASA tasks of: Detection, Recognition/Identification, Localization (azimuth and frontal elevation), and COMmunication, known as "DRILCOM." Also, a new, highly portable system was developed for training individuals to adapt their hearing to new products, the Portable Auditory Situation Awareness Training (PASAT) system. Example results from DRILCOM testing include: For detection of a rifle being cocked, a common military earplug, the passive, rocker-style Combat Arms™ in its "hear-through" setting, resulted in 111% worse detection than with the open ear, while an electronic TCAPS (Quiet Pro+™) resulted in 52% worse detection. A common military electronic earmuff, the ComTac-III™, yielded 37% worse azimuthal localization than open ear for a broadband sound using DRILCOM, while the earlier version ComTac-II™ added 0.9-second to making gunshot localization decisions outdoors. This presentation will cover additional ASA data, and demonstrate that prior to deployment, devices must be evaluated for their impact on hearing perception. This work received the "Safe in Sound Award for Innovation in Hearing Conservation," awarded by the National Institute for Occupational Safety and Health (NIOSH). See Safe in Sound winners.