Effects of Earplugs and Protective Headgear on Auditory Localization Ability in the Horizontal Plane

By Vause, Nancy L.; Grantham, D. Wesley | Human Factors, June 1999 | Go to article overview

Effects of Earplugs and Protective Headgear on Auditory Localization Ability in the Horizontal Plane


Vause, Nancy L., Grantham, D. Wesley, Human Factors


INTRODUCTION

Localization represents a fundamental auditory skill that contributes to survival by indicating the presence and position of mates, prey, and enemies. Moreover, identification of sound source positions is an intimate part of modern-day orientation and surveillance of the environment. The ability to accurately localize and quickly identify the position of potential hazards is critical in combat and in many of today's work environments.

Military helmets are designed to protect soldiers from possible head injury during training and combat operations. Unfortunately, this protective headgear may also hinder the ability of a soldier to localize sounds. Although Randall and Holland (1972) reported that earlier helmet designs (the Hayes-Stewart and M-1 helmets) did not disrupt localization performance, Howse and Elfner (1982) reported that tanker helmets, when worn with various hearing-protective devices (HPDs), did result in an increase in localization errors compared with unprotected conditions. The differences in these results may have been attributable to the different shapes of the helmets studied. Specifically, the tanker helmet occluded the pinnae more than the earlier two helmet designs. The effects on localization of the newer Kevlar[R] helmet (Gentex Corp., Carbondale, PA; [ILLUSTRATION FOR FIGURE 1 OMITTED]), which is currently in use in the army, have not been investigated.

Additionally, it is well documented that HPDs (e.g., earmuffs and earplugs) designed to protect soldiers or employees from noise hazards and the possibility of noise-induced hearing loss result in significant localization difficulties (Abel & Hay, 1996; Atherly & Noble, 1970; Noble, Murray, & Waugh, 1990; Noble & Russell, 1972). However, it is not yet clear if the primary factor underlying decreased localization ability with HPDs is simply the overall attenuation provided by HPDs, or if the altered shape of the spectrum produced by HPDs also contributes to poorer performance. The former notion, called the attenuation hypothesis, received some support from studies indicating that as the attenuation of an HPD increased, so did the detrimental effect on localization performance (Mershon & Lin, 1987; Noble et al., 1990; Noble & Russell, 1972). However, given that these studies did not measure the frequency-specific attenuation characteristics of the various HPDs, it is not possible to know how disruption of spectral shape may have also contributed to the decreased localization performance.

Etymotic Research (Elk Grove Village, IL) has recently developed the ER25 "musician's" earplug, which is designed to attenuate evenly across the frequency spectrum (Killion, DeVilbiss, & Stewart, 1988; [ILLUSTRATION FOR FIGURE 2B OMITTED]). (Since this study was initially conceived, other manufacturers have developed "flat-response" HPDs, such as the 9000 earmuff and the "high-fi" earplug manufactured by Aearo Company, Indianapolis, IN.) By comparing performance with this earplug to performance obtained in a control condition in which no earplugs are worn but the source signal is attenuated by 25dB (the nominal specified attenuation for the ER25 earplug), it should be possible to determine whether such "flat" earplugs offer a significant advantage over conventional plugs in a localization task.

The purpose of the present study was to examine the effect of wearing the Kevlar helmet, one of two types of earplugs, or both the helmet and earplugs, on localization ability. Two sets of questions were addressed:

1. What are the effects, individually, of the Kevlar helmet, the E-A-R earplug (Aearo Co.), and the Etymotic ER25 musician's earplug on localization performance in the horizontal plane? If performance is degraded with the musician's earplug (compared with a bareheaded listening condition), can the degradation be accounted for simply by the attenuation provided?

2. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Effects of Earplugs and Protective Headgear on Auditory Localization Ability in the Horizontal Plane
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.