Key Words
listening levels - risk factors - young adults
INTRODUCTION
A high percentage (i.e., 90–95%) of college-aged young adults report owning a personal
audio system (PAS) with earphones ([Torre, 2008]; [Danhauer et al, 2009]). However, within the last 5–10 yr, the PAS devices have transitioned from ones
such as an iPod, Walkman, or a compact disc player to the iPhone or Android device,
which allow for more music storage and longer listening opportunities. PAS use with
earphones is a recreational noise exposure that is an intermittent exposure, different
from occupational noise exposure that can be impulse in nature or more likely, a constant,
higher level exposure. Occupational noise exposure, and the evaluation of risk for
noise-induced hearing loss is federally monitored by the Occupational Safety and Health
Administration ([OSHA, 2007]) and the National Institute for Occupational Safety and Health ([NIOSH, 1998]). These standards, however, were based on an 8-hour workday and a permissible time-weighted
average level (i.e., 90-dBA time-weighted average for Occupational Safety and Health
Administration). Industrial types of noise will vary from setting to setting, can
have either a narrower frequency response or a more broad frequency, but the sound
source can be at a distance from the worker. Music, on the other hand, will also have
a broader frequency response, and, when the user is wearing earphones, will be delivered
in close proximity to the tympanic membrane. Because exposure to music through earphones
varies both by number of hours within the day and number of days within the week,
calculations of risk can be made but by using an 8-hour equivalent of a recreational
noise exposure day.
Because of the ubiquitous aspect of PASs with earphones, especially on college/university
campuses ([Torre, 2008]; [Danhauer et al, 2009]; [Hoover and Krishnamurti, 2010]), there are more researchers objectively evaluating the preferred listening levels
of young adults using probe microphone measures ([Hodgetts et al, 2007]; [Torre, 2008]; [Worthington et al, 2009]; [Torre and Grace, 2014]; [Park et al, 2017]). Preferred listening levels can range, on average, as low as 58 dBA ([Torre and Grace, 2014]) but more likely at levels of ∼70–80 dBA ([Hodgetts et al, 2007]; [Torre, 2008]; [Worthington et al, 2009]; [Park et al, 2017]), with young adult men having higher preferred listening levels compared with women.
However, the sex difference for volume/preferred listening level is not consistent
in the literature because some researchers have not reported a difference in women
and men ([Epstein et al, 2010]; [Hoover and Krishnamurti, 2010]).
In one of the few studies to evaluate reported PAS use and preferred listening level,
[Worthington et al (2009)] developed an equation, L
pmse = L
Aeq + 10 log(T/8), where L
pmse is the level of daily personal music exposure, L
Aeq is the A-weighted equivalent continuous noise level, and T is the reported use time per day, in hours. This equation combined the reported number
of hours of PAS use with the level measured from the ear canal using a probe microphone.
In this study, 30 normal-hearing young adults (18 women and 12 men; mean age = 22
yr, standard deviation [SD] = 3.4 yr) participated and none of the 30 young adults
listened at a hazardous level, in quiet. In fact, even when listening in the presence
of a background noise and accounting for diffuse-field equivalency, only one participant
was determined to be listening at a level >85 dBA.
Because of the cost of probe microphones and the procedure involved in measuring the
preferred listening level, researchers have also used questionnaires to assess preferred
listening volume ([Torre, 2008]; [Danhauer et al, 2009]; [Torre et al, 2013]). [Danhauer et al (2009)] used both an online questionnaire as well as a paper-and-pencil questionnaire in
more than 600 college students whereas [Torre (2008)] completed interviewer-administered questionnaires in just more than 1,000 university
students. Just more than 50% of respondents in both studies reported a typical listening
volume of medium, but [Torre (2008)] found that more than 40% reported either loud or very loud listening volumes compared
with 34% reported by [Danhauer et al (2009)]. [Torre (2008)] also found that men were significantly more like likely to report very loud as their
preferred listening volume compared with women. What is not presently known is how
subjective assessments of preferred listening volume (i.e., medium, loud, or very
loud) compare with objective measures of chosen listening level using a probe microphone
system.
Researchers have evaluated whether certain questions (i.e., Do you feel you have a
hearing loss?) can be a strong predictor of audiometrically defined hearing loss ([Clark et al, 1991]; [Voeks et al, 1993]; [Nondahl et al, 1998]). [Voeks et al (1993)] used the question, “Do you have trouble hearing?” with nursing home residents and
reported 69% sensitivity (defined as residents who correctly identified themselves
as having a hearing loss). In 60- to 85-yr-old women, [Clark et al (1991)] used a similar question, “Would you say that you have any difficulty hearing?” and
found 51% sensitivity and 88% specificity (women who correctly identified themselves
as having normal hearing). Last, [Nondahl et al (1998)] used the question, “Do you feel you have a hearing loss?” to evaluate how 48 to
92 yr olds identify themselves as having a hearing loss. That screening question had
71% for both sensitivity and specificity. From an epidemiologic perspective, the goal
of any screening measure, or survey question, is to maximize both sensitivity and
specificity, but if researchers have to make a choice, then that depends on what is
being identified. If, for example, the goal is to identify the presence of a disease
or risk behavior, then maximizing sensitivity would be best. If the choice is to identify
those without the disease or risk behavior, then maximizing specificity would be optimal.
As mentioned previously, no screening question has been evaluated to predict whether
young adults are engaging in risky listening behavior with PASs. As a result, the
purpose of the present study was to evaluate how two questions predicted chosen listening
level in young adults with normal hearing. The main objective was to calculate sensitivity
and specificity and determine if one or two questions could be used in young adults
to examine whether they listen to a PAS with earphones at potentially high levels.
The implication of this is that the question(s) could be then used in a clinical case
history form to assist in counseling for noise-induced hearing loss.
METHODS
Participants
From [Table 1], 160 San Diego State University (SDSU) undergraduate students were recruited from
Exercise and Nutritional Sciences, Public Health, and Social Work course (i.e., non-Speech,
Language, and Hearing Sciences courses). There were 111 women (mean age = 20.9 yr,
SD = 2.6 yr) and 49 men (mean age = 20.9 yr, SD = 3.3 yr) who volunteered for the
study and received extra credit in their course for their participation. More than
one-quarter (28.1%) of participants reported their ethnicity as Hispanic or Latino
and 113 (70.6%) participants reported their ethnicity as Not Hispanic or Latino, 2
(1.3%) declined to state ethnicity. Participants also had the opportunity to provide
racial background data, and the data for the specific racial categories are shown
in [Table 1].
Table 1
Sex, Ethnicity, and Race Characteristics of the Study Participants
|
Participants (n = 160)
|
|
n
|
Percent
|
|
Women
|
111
|
69.4
|
|
Men
|
49
|
30.6
|
|
Ethnicity (n = 160)
|
|
|
|
Hispanic or Latino
|
45
|
28.1
|
|
Not Hispanic or Latino
|
113
|
70.6
|
|
Decline to state
|
2
|
1.3
|
|
Race (n = 160)
|
|
|
|
American Indian/Alaska Native
|
1
|
0.6
|
|
Asian
|
23
|
14.4
|
|
Native Hawaiian/Pacific Islander
|
5
|
3.1
|
|
Black/African American
|
12
|
7.5
|
|
White
|
98
|
61.3
|
|
Decline to state
|
21
|
13.1
|
Procedures
These data are a portion of the data that were included in the Risk Factors for Hearing
Loss in Young Adults Study approved by the SDSU Institutional Review Board. Other
data from this study (i.e., pure-tone thresholds and distortion product otoacoustic
emissions) will be reported elsewhere. Once informed consent was obtained, research
assistants administered the Risk Factors Survey. A section of this survey included
demographic questions of sex, age, ethnicity, race, and questions specific to PAS
use. If the participant answered No to the question, “Do you listen to a personal
music system using earphones?” then that part of the survey was completed. If Yes,
then additional questions regarding type of earphone used, typical duration of listening,
longest single use during the day, most common volume used, and if they noticed any
problems (e.g., ringing and hearing loss) after using a personal music system were
completed. Two of the closed-set survey questions of interest in this study were “For
a typical day, what is the most common volume used during this day?” “Low” (coded
as 1 for statistical analyses), “Medium/Comfortable” (2), “Loud” (3), or “Very Loud”
(4); and “Do you listen to your personal music system at a volume where you…” “Easily
hear people” (coded as 1 for statistical analyses), “Have a little trouble hearing
people” (2), “Have a lot of trouble hearing people” (3), or “Cannot hear people” (4).
All participants had normal hearing (≤25 dB) from 250 through 8000 Hz, including 3000
and 6000 Hz and normal middle ear function measured with tympanometry (i.e., type
A tympanogram).
With the participant seated in a double-walled sound-treated room (Industrial Acoustics
Company, Inc., North Aurora, IL), chosen listening level data for this quiet setting
were collected using an ER 7C Probe Microphone Series B (Etymotic Research, Inc.,
Elk Grove Village, IL) system set to a 0-dB gain connected to Electroacoustics Toolbox
software (Version 3.8.3; Faber Acoustical, LLC) on an iMac (Apple, Inc., Cupertino,
CA) computer. A probe microphone was placed in the ear canal at an insertion depth
of approximately 28 mm from the end of the probe to the intertragal notch. This depth
is common for probe microphone measures in adults because the proximity to the tympanic
membrane will most likely reduce the effect of standing waves within the ear canal
([Dirks and Kincaid, 1987]).
Within the Electroacoustics Toolbox, the Sound Level Meter and Octave Band Analyzer
functions were used. The Sound Level Meter function was used to measure the L
Aeq whereas the Octave Band Analyzer was used to collect 1/3 octave data of the music
participants listened to. Before chosen listening level data were obtained, the probe
microphone system was calibrated; the ER 7C system has a built-in 1 kHz, 94.0-dB SPL
calibration tone along with a probe microphone calibration cavity. To ensure the microphone
was calibrated with the Electroacoustics Toolbox software, the probe microphone was
placed in the cavity, the tone was presented, and the software, specifically the Sound
Level Meter function, was required to display 94.0-dB SPL. Once calibration was completed,
the probe microphone was secured in the test ear canal in two ways: a small piece
of medical tape on the ear lobe, and the participant’s preferred earphones. The participant
then listened to 1 hour of continuous music, and they were allowed to change music
and the level as they desired. When 1 hour was finished, the average L
Aeq and 1/3 octave band data were exported from the Electroacoustic Toolbox software
for off-line analyses.
Statistical Analyses
All questionnaire data were analyzed using a χ2 approach (SAS, Version 9.4; SAS Institute, Cary, NC) to evaluate these categorical
data for any differences between women and men across the questions. Probe microphone
1/3 octave band data between 200 and 8000 Hz for each participant were put into an
Excel spreadsheet to calculate diffuse-field equivalent level (L
DFeq) for a closed canal and converted to free-field equivalent (FFE). This same Excel
spreadsheet was used by [Worthington et al (2009)] so L
DFeq could be interpreted using the National Institute for Occupational Safety and Health
standard (i.e., 85 dBA). This spreadsheet, however, only allows for a conversion for
earbud earphones. Furthermore, daily PAS use exposure (L
PASe) was calculated as L
PASe = L
DFeq + 10log(T/8), where T is the reported use time per day, in hours, by the participant during the survey.
This formula is adapted from [Worthington et al (2009)], where the current approach substitutes L
DFeq for L
Aeq. Analyses involving L
DFeq and L
PASe data were completed using PROC GLM (generalized linear model) in SAS (Version 9.4;
SAS Institute). Independent variables for these analyses included sex, age, ethnicity,
and earphone type.
Two separate approaches were used to evaluate how well survey questions could determine
if an individual would objectively listen to music using earphones at a hazardous
level. First, 2 × 2 contingency tables were generated to calculate sensitivity and
specificity of the two survey questions, separately, as they relate to exposure risk.
Participant responses to the question asking about typical volume of PAS were categorized
into two groups: Non-Loud (comprised of low and medium/comfortable responses) and
Loud (comprised of loud and very loud). Participants were also categorized into two
groups based upon their responses to the question asking about whether they can hear
others when listening to their PAS. Specifically, the category Can Hear was comprised
of participants who reported they could easily hear people or have a little trouble
hearing people. The category Cannot Hear included combined responses of having a lot
of trouble hearing people and cannot hear people. Chosen listening level (i.e., L
DFeq) was stratified as ≤85 dBA or >85 dBA. Sensitivity was defined as those individuals
who either reported Loud as a common daily volume or Cannot Hear people while listening
to music and listened at >85 dBA and specificity was defined as those individuals
who either reported Non-Loud as a common daily volume or Can Hear people while listening
to music and listened at ≤85 dBA. Linear regression analysis (SAS, Version 9.4; SAS
Institute) was used to determine the amount of variance explained by the two survey
questions as predictors of measured L
DFeq.
RESULTS
Five participants (four women and one man) reported not using a PAS with earphones;
these participants were only included in L
DFeq analyses. Most of the participants who reported listening to music with earphones
(n = 155) listened between 1 and 7 hours/week, at a medium/comfortable volume, and
had a little trouble hearing other people while using earphones ([Table 2]). Also in [Table 2], 17.4% (n = 27) noticed ringing in their ears after listening to music through earphones
whereas 6.5% (n = 10) felt that they had a hearing loss. Those who reported ringing
in their ears did not report a significantly higher amount of loud or very loud volume
(χ2(1) = 1.09, p > 0.05) or higher rates of >85 dBA (χ2(1) = 0.68, p > 0.05). However, with such a low percentage of participants reporting ringing in
their ears, these results should be interpreted cautiously. Men reported a significantly
higher rate of loud or very loud as the common volume used compared with women (χ2(3) = 8.64, p < 0.05). More than 75% of participants (n = 118) reported total daily listening time
between <1 and 3 hours ([Figure 1]), and this figure shows the distribution of responses by women and men, in percentages.
This difference between women and men was not statistically significant (χ2(9) = 14.10, p > 0.05). [Figure 2] shows the reported longest single daily use for men and women and once again, more
than 75% of participants (n = 119) reported between <1 and 1 hour, but the difference
in reported use between women and men was not statistically significant (χ2(4) = 4.19, p > 0.05).
Table 2
Participant Responses (n = 155) to the Hearing-Related Questions of the Risk Factors
for Hearing Loss in Young Adults Study Survey
|
Question
|
Response n (%)
|
|
How would you describe your weekly personal music system listening use?
|
|
|
Low (<1 hour/week)
|
23 (14.8)
|
|
Medium (1–7 hours/week)
|
92 (59.4)
|
|
Heavy (>7 hours/week)
|
40 (25.8)
|
|
For a typical day, what is the longest single use during this day (in hours)?
|
|
|
<1
|
74 (47.7)
|
|
1
|
45 (29.0)
|
|
2
|
25 (16.1)
|
|
3
|
10 (6.5)
|
|
4
|
1 (0.7)
|
|
For a typical day, what is the most common volume used during this day?[*]
|
|
|
Low
|
1 (0.6)
|
|
Medium/comfortable
|
97 (63.0)
|
|
Loud
|
48 (31.2)
|
|
Very Loud
|
8 (5.2)
|
|
Do you listen to your personal music system at a volume where you
|
|
|
easily hear people
|
16 (10.3)
|
|
have a little trouble hearing people
|
100 (64.5)
|
|
have a lot of trouble hearing people
|
22 (14.2)
|
|
cannot hear people
|
17 (11.0)
|
|
Have you noticed any problem with your hearing after using a personal music system?
|
|
|
No
|
135 (87.1)
|
|
Yes
|
6 (3.9)
|
|
Not sure
|
14 (9.0)
|
|
Have you noticed any ringing in your ears after using a personal music system?
|
|
|
No
|
122 (78.7)
|
|
Yes
|
27 (17.4)
|
|
Not sure
|
6 (3.9)
|
|
Did you know that prolonged use of a personal music system at high volume can lead
to hearing loss?
|
|
|
No
|
15 (9.7)
|
|
Yes
|
137 (88.4)
|
|
Not sure
|
3 (1.9)
|
|
Do you feel that you have a hearing loss?
|
|
|
No
|
127 (81.9)
|
|
Yes
|
10 (6.5)
|
|
Not sure
|
18 (11.6)
|
Note: Five participants reported not being a personal music system user and were not asked
any listening use questions.
* One participant reported Not Sure to this question.
Figure 1 Bar graphs for the reported total daily listening time, in hours, by the 155 participants.
Percentage of women is displayed using black bars whereas percentage of men is displayed
in gray bars.
Figure 2 Bar graphs for the reported longest single daily use, in hours, for the 155 participants.
Percentage of women is displayed using black bars whereas percentage of men is displayed
in gray bars.
The distribution for L
DFeq stratified for percentages of women and men is shown in [Figure 3]. The distribution for men is shifted slightly higher than the distribution for women.
Mean L
DFeq for all participants was 72.5 dBA (SD = 11.0 dB; minimum = 49.4 dBA; maximum = 94.9
dBA); after adjusting for age, earphone type used, and ethnicity, women had a significantly
lower mean L
DFeq (mean = 70.8 dBA; SD = 10.6 dBA) than men (mean = 76.5 dBA; SD = 10.8 dBA) [F
(1,153) = 9.32, p < 0.05]. But 18 participants (11.3%) did listen at a level >85 dBA; 9 women (8.1%)
and 9 men (18.4%) listened at this level. The main effect for earphone type was not
statistically significant [F
(2,153) = 0.42, p > 0.05]; the adjusted means for earphones were similar (Apple earbuds [n = 92], mean
= 71.6 dBA [SD = 11.1 dBA]; insert-type earphones [n = 47], mean = 73.9 dBA [SD =
9.6 dBA]; and over-the-ear earphones [n = 21], mean = 73.7 dBA [SD = 13.1 dBA]). The
association between earphone type and reported trouble hearing other people was analyzed,
and there was no significant effect for earphone type (χ2(2) = 1.26, p > 0.05). L
PASe was also calculated for those 155 participants who reported using a PAS with earphones.
The distribution for L
PASe stratified for percentages of women and men is shown in [Figure 4]. Similar to [Figure 3], the distribution for men is shifted slightly higher than the distribution for women,
where there are substantially more women in the <60 dBA category. Overall mean L
PASe was 66.3 dBA (SD = 11.9 dBA). After adjusting for age, earphone type, and ethnicity,
women had a significantly lower mean L
PASe of 64.0 dBA (SD = 11.7 dBA) than men who had a mean L
PASe of 71.3 dBA (SD = 10.9 dBA) [F
(1,148) = 13.38, p < 0.05]. This result is based on men having a significantly higher mean chosen listening
level and having a higher percentage of longer reported daily listening times. In
fact, of the nine participants with an L
PASe > 85 dBA, six were men.
Figure 3 Bar graphs for the measured L
DFeq, in dBA, for the 155 participants. Percentage of women is displayed using black bars
whereas percentage of men is displayed in gray bars.
Figure 4 Bar graphs for the calculated L
PASe, in dBA, for the 155 participants. Percentage of women is displayed using black bars
whereas percentage of men is displayed in gray bars.
Sensitivity for the question asking about the most common volume used during this
day was 88.9% (16 of 18) whereas specificity for this question was 70.6% (96 of 136).
In other words, this means that 29.4% reported loud or very loud volume, yet did not
listen at a high listening level (defined as false alarms), whereas only 11.1% (2
of 18) reported Non-Loud responses to this question, but listened at a high level
(defined as misses). For the question asking participants to report whether listening
to their PAS affects hearing others, sensitivity was 83.3% (15 of 18) and specificity
was 82.5% (113 of 137). This means that 17.5% reported that they had a lot of trouble
hearing others or could not hear others, yet did not listen at a high listening level
(defined as false alarms), whereas 16,7% reported that they could hear people while
using their PAS, but did listen at a high listening level (defined as misses). Both
of these survey items had high sensitivity and specificity values although the second
question had stronger combined sensitivity and specificity values.
Result of the linear regression analysis showed that self-reported typical listening
volume accounted for 25.9% of the variability associated with preferred listening
level, L
DFeq (Y = 50.2 + 9.3[Loud]; see “Methods” section for coding of the responses to this question).
Given the significant differences in chosen listening level as a function of Sex (coded
as 0 for women and 1 for men), Sex was added to the regression model. Self-reported
typical listening volume and Sex accounted for 28.4% of the variability associated
with chosen listening level (Y = 50.6 + 8.6[Loud] + 3.9[Sex]).
The linear regression model for second survey item asking about being able to hear
others when using a PM accounted for only 19.3% of the variability associated with
chosen listening level (Y = 58.5 + 6.2[Hear]; see “Methods” section for coding of responses to this question).
Sex was again added to this model and the item response and Sex accounted for 22.8%
of the variability associated with chosen listening level (Y = 57.9 + 5.8[Hear] + 4.6[Sex]).
DISCUSSION
To date, this is the first study in young adults with normal hearing to evaluate the
use of survey questions regarding preferred listening volume compared with objectively
measured chosen listening level in quiet. Overall mean L
DFeq was 72.5 dBA, but young adult men had a significantly higher mean L
DFeq than women; however, 18 of 155 participants did listen at a level >85 dBA. Recall,
that the FFE conversion used in the present study only accounted for earbud earphones,
so if participants used other types of earphones, the chosen listening level will
likely be overestimated. Of these 18 participants, 16 (88.9%) did report that they
listened either loud or very loud to the question regarding the most common volume
used during a typical day. Furthermore, 15 of the 18 participants (83.3%) also reported
that they have a lot of trouble or cannot hear people when they are listening to a
PAS with earphones. The results of the present study demonstrate at least two points.
First, approximately 11% of the participants listen to a PAS with earphones where
>85 dBA, but in a quiet background. Second, those who do listen at this level are
fairly accurate at reporting this potentially risky behavior.
For the question asking about being able to hear others while using a PAS, specificity
was similar to sensitivity, but for the question asking about typical volume used,
specificity was just more than 70%. Given this result, slightly less than 30% of participants
in the present study reported loud or very loud volume to the typical listening level
question, but did not listen at a level >85 dBA. Although 70% specificity is not a
poor result, it is possible that the participants interpreted the question in their
everyday environment; in other words, in a background with noise, such as at the gym
or walking around campus, rather than in quiet background, like that of a sound-treated
room.
Mean L
DFeq of the present study is very similar to what [Park et al (2017)] reported for the library setting (mean = 70.4-dBA FFE). [Park et al (2017)] also reported a significant sex difference such that men had a higher chosen listening
level, in dBA FFE, in the library environment than women. The sex difference in that
environment was approximately 3 dB, but in the present study, men had a chosen listening
level that was approximately 6 dB higher than women. In both studies, participants
were young adults enrolled at a university; there are, however, minor differences
between the studies. In the present study, 160 (111 women and 49 men) completed the
study whereas in [Park et al (2017)], only 52 university students (15 women and 37 men) had chosen listening levels measured
after they were recruited when exiting the library. Although both studies estimated
listening risk by compensating for ear canal characteristics and by converting the
frequency response of the music to either free-field or diffuse-field, in the present
study a probe microphone in the ear canal was used to record the acoustic energy averaged
over 1 hour. In contrast, [Park et al (2017)] measured the level from the PAS using a Jolene mannequin then converted to FFE to
estimate risk. The participants in the present study were allowed to change tracks
of music and adjust the volume accordingly over the 1 hour in an effort to represent
a real-world listening situation. Young adults recruited by [Park et al (2017)] were instructed to leave the volume and music track set at the point in which they
agreed to participate. Some of the participants reported that they had changed the
volume when they were approached by researchers to talk with them; it is unclear,
however, how many of these participants were from the library condition.
There are substantial similarities between [Worthington et al (2009)] and the present study. Young adults in both studies were university students and
were confirmed to have normal middle ear function and normal hearing sensitivity using
tympanometry and pure-tone thresholds, respectively. Both studies used a diffuse-field
conversion approach using probe microphone measures in the ear canal of participants.
Mean L
DFeq in quiet for both studies was approximately 70 dBA, although [Worthington et al (2009)] calculated L
DFeq from a 3-min music sample from 23 participants. Mean L
PASe was slightly higher (66.3 dBA) in the present study than that described by [Worthington et al (2009)] who reported approximately 60 dBA. Based on these daily music exposure calculations
for both studies, none of the participants in [Worthington et al (2009)] listened >85 dBA, but nine participants in the present study had an L
PASe > 85 dBA.
This is the first study where performance of two survey questions was examined in
an effort to predict listening levels while using a PAS with earphones. As a result,
specific test performance (i.e., sensitivity and specificity) of the present study
cannot be compared with a previous literature. These results can, however, be compared
with other studies on hearing-related test performance of case history questions.
Sensitivity values for both questions in the present study were higher than those
in the earlier research in older adults and test performance of questions used to
predict hearing loss ([Clark et al, 1991]; [Voeks et al, 1993]; [Nondahl et al, 1998]). Compared with other research, specificity values varied depending on the question
being evaluated. Specificity in the present study was similar to [Nondahl et al (1998)] for one question (i.e., typical volume used) but higher than [Nondahl et al (1998)] for the second question (i.e., hear people). Specificity values for both questions
were lower than the specificity reported by [Clark et al (1991)]. These studies, however, were primarily in older adults. There are no data in young
adults on whether a question can correctly identify hearing loss; this is not surprising
given the lower prevalence of hearing loss in younger adults compared with older adults.
Because the purpose of this study was to evaluate questions in an effort to identify
a potential risk behavior, in this case higher listening levels of music with earphones,
higher sensitivity with the potential consequence of lower specificity, is preferred.
In a recent, well-designed study by [Johnson et al (2017)], a subset of participants completed an 11-item questionnaire to estimate their annual
noise exposure (ANE) in both occupational and nonoccupational settings. One aim of
this study was to develop a 1-min noise-screening questionnaire to accurately predict
ANE. In fact, these researchers used three questions, firearm usage, noisy job, and
any other loud noise as the screening tool. Responses to these questions were never
= 0; every few months = 1; monthly = 2; weekly = 3; and daily = 4, and a cumulative
score (0–12) was calculated. This score was then evaluated for its accuracy in identifying
high-risk ANE. A screening score of ≥5 yielded a sensitivity value of 91.7% and a
specificity value of 83.0%; a score that achieved the most balanced values for sensitivity
and specificity. The combination of results from [Johnson et al (2017)] and the present study is important in that there are questions that can be used
to identify potentially higher listening levels in young adults from a more transient
perspective and questions that be used to identify more cumulative risk exposure.
There are some limitations of the present study. First, as mentioned previously, the
conversion used to determine FFE only accounted for earbuds, so it is likely that
some measured chosen listening level were overestimated. Second, although the participants
were asked to set the volume of their PAS to their chosen listening level, the setting
was in a quiet background. This quiet background was a sound-treated room within an
auditory research laboratory space, probably the most unlikely place to listen to
music for an hour. During the 1 hour, participants were allowed to change musical
tracks or adjust the volume accordingly; this was done in an effort to replicate a
real-world listening condition. In most cases of daily listening, however, there is
some type of background noise present, especially on a university campus. Young adults
will turn the level up in the presence of background noise ([Worthington et al, 2009]; [Park et al, 2017]) and, depending of the type of earphone used, that noise might also leak into the
ear canal creating an additional acoustic source. Second, daily PAS use exposure (L
PASe) was calculated by combining preferred listening level and the response to a question
about typical daily listening time. This exposure will vary considerably, especially
for university students. As mentioned previously, background environments will change
affecting volume used and daily listening times will vary from day-to-day based on
how much free time a university student has. Academic, work, and social schedules
are variable, and as a result, PAS use will vary along with them. Last, every effort
was made to recruit a somewhat even distribution between women and men, but for this
study, there were twice as many women as men. This is not an ideal sex distribution;
however, it was representative of the sex distribution in courses offered within the
College of Health and Human Services at SDSU from which participants were sampled.
CONCLUSIONS
The data from the present study suggest that two very straightforward closed-set questions
can be used, either in isolation or included in a clinic’s case history form, to accurately
identify young adults who might be listening to a PAS with earphones at a high level.
In fact, the participants in this study were young adults with normal hearing, and
although there is research on the effects of preferred listening levels on short-term
changes in auditory function (i.e., distortion product otoacoustic emissions) ([Torre and Grace, 2014]), the long-term effects of these listening levels is not known. However, if a young
adult is identified as indicating this risk behavior, then it is hoped that the behavior
can subsequently be modified so as to maintain normal hearing sensitivity as long
as possible.
Abbreviations
FFE:
free-field equivalent
L
Aeq
:
A-weighted equivalent continuous noise level
L
DFeq
:
diffuse-field correction, free-field equivalent level
L
PASe
:
daily personal audio system use exposure
L
pmse
:
daily personal music system exposure
PAS:
personal audio system
SD:
standard deviation
