Sound localization in noise with hearing protectors: The effect of aging

Abstract

Sound localization ability was assessed in two groups of 24 normal-hearing subjects, aged 20–35 and 40–60 years. The test was conducted in a semi-reverberant chamber, using an array of six speakers, surrounding the subject at azimuth angles 60° apart, at a distance of 1 m. Three variables were investigated: the wearing of hearing protectors (unoccluded, conventional E-A-R plug and E-A-R muff, and Bilsom 2392 stereophonic muff with limited amplification), background (quiet vs 65 dB SPL white noise), and stimulus frequency (500 vs 4000 Hz). For each of the 16 listening conditions, one block of 120 trials was presented. Within a block, the test sound, an 80-dB SPL 300-ms one-third octave noise band, was randomly presented from each speaker on 20 trials. The subject judged the direction using a hand-held response box with an array of microswitches configured like the speaker array. Analysis of the overall and conditional proportions of correct response and the correct and incorrect response times is currently underway. Focii of interest are the effects of (1) stereophonic amplification on accuracy and (2) aging on decision reaction time.

The effects of hearing protection devices on spatial awareness in complex listening environments

“…Localization performance was negatively affected by HPDs, with significant effects observed in the OTE and OTE-LPF listening conditions when compared to the NH condition. Previous studies have demonstrated increased localization errors with loss of spectral cues either through the use of a low-pass filter [ 60 – 62 ], or through the use of HPDs [ 6 , 11 , 13 , 14 , 37 , 39 ]. NIHL was simulated by removal of spectral information from the speech signals using a high order low-pass filter set at 2.5 KHz.…”

Effect of Hearing and Head Protection on the Localization of Tonal and Broadband Reverse Alarms

“…Conventional passive HPDs, the most commonly used type of hearing protection, have been shown to reduce sound localization performance relative to unprotected ear (Berger, 2003;Berger & Casali, 1997;Bolia et al, 2001;Borg et al, 2008;Brungart et al, 2007;McKinley, 2000;Nixon & Berger, 1998;Noble et al, 1990;Simpson et al, 2005;Takimoto et al, 2007), and increase the number of front/back confusion errors (Abel & Armstrong, 1993;Abel & Hay, 1996;Alali & Casali, 2011;Brown et al, 2015;Gallagher et al, 2014, Gallagher et al, 2015a, Gallagher et al, 2015bZimpfer & Sarafian, 2014). In addition, earmuff-type devices are generally more detrimental to sound localization than earplugs (Abel & Hay, 1996;Russell, 1976;Suter, 1989;Talcott et al, 2012;Vaillancourt et al, 2013).…”