Noise exposure and temporary hearing loss of indoor hockey officials: a pilot study.
Exposure to hazardous levels of noise might cause hearing damage and affect one's health, communication, and quality of life. Prolonged exposures to sounds of less than 75 decibels (dB) are not likely to cause hearing loss, yet repetitive exposures to sounds at or above 85 dB are hazardous, increase risk of hearing loss, and may cause permanent hearing loss (American Speech-Language-Hearing Association, 2016; National Institute on Deafness and Other Communication Disorders, 2014). Researchers have found that repeated exposure to hazardous noise levels might eventually result in a temporary threshold shift (TTS) in hearing such as tinnitus and "fullness in head" (Ward, 1970), and repeated TTSs may cause permanent shifts (Kirchner et al., 2012).
Damage-risk criteria provide the basis for recommending occupational noise exposure limits based on noise level and exposure duration, assuming nonoccupational noise levels are low enough to allow the ear to recover. The Occupational Safety and Health Administration (OSHA) permits an 8-hour time-weighted average (TWA) sound level of 90 A-weighted decibels (dBA) with a 5 dB exchange rate (U.S. Department of Labor, 2016), whereas the American Conference of Governmental Industrial Hygienists (ACGIH) recommends an 8-hour TWA sound level of 85 dBA with a 3 dB exchange rate (ACGIH, 2014).
Various noise exposure studies have been conducted on spectators and employees at sporting events (Cranston, Brazile, Sandfort, & Gotshall, 2013; Engard, Sandfort, Gotshall, & Brazile, 2010). Researchers studying noise exposures of fans and ushers at two indoor hockey arenas found that fans and ushers at collegiate and semiprofessional hockey games exceeded ACGIH noise exposure criteria (Cranston et al., 2013). Investigators who assessed the noise exposures of fans and workers at various-sized football stadiums found that 96% of workers and 96% of fans were considered overexposed according to ACGIH recommendations (Engard et al., 2010).
There have been a limited number of TTS studies for sports venues. Researchers performed a pure-tone audiometry study during the 2006 Stanley Cup and found the average noise exposure levels for each game were above 101 dB and hearing thresholds of two subjects deteriorated by 5 to 10 dB for most frequencies (Hodgetts & Liu, 2006). Recently, researchers studied the intensity of noise exposure and hearing thresholds of attendees during basketball games at Utah State University and found that the hearing thresholds of the attendees deteriorated by 4.43 dB (England & Larsen, 2014).
Although spectators of various sports have been evaluated for noise exposure and TTSs, sports officials have not been assessed, possibly to the detriment of their hearing. A literature review revealed that indoor hockey officials' noise exposure levels and temporary hearing losses have not been studied previously. This population of over 23,000 registered hockey officials, not including nonregistered officials, is unique for various reasons: officiating can begin as early as 10 years of age (USA Hockey, 2014), noise exposures include sources on and off the ice (e.g., whistles, crowd noise), and the hockey game noise exposure is supplemental to any noise exposure experienced during the official's normal workday. The purpose of this pilot study was to determine if indoor hockey officials are exposed to hazardous levels of noise and whether or not they experienced a temporary hearing loss.
The pilot study was conducted at two small indoor hockey arenas in northern Colorado with fewer than 200 spectators in attendance. Investigators monitored the noise exposures of indoor hockey officials of the American Collegiate Hockey Association (ACHA) and the Western States Hockey League (WSHL) who officiated collegiate and junior league hockey games. Pre and postgame audiometric tests were administered in areas adjacent to the ice arena. The results of this study might identify a population that might be at an increased risk of noise-induced hearing loss (NIHL) at an early age and might reduce future cases of NIHL in hockey officials and officials of other sporting events.
Study participants included indoor hockey officials of WSHL and ACHA who officiated junior and collegiate hockey games in two northern Colorado ice arenas during the 2013-2014 hockey season. All study participants were male and 21 years of age or older. All aspects of this study were conducted in compliance with a human subjects study protocol approved by Colorado State University's Institutional Review Board.
Audiometric tests were conducted on 18 offiicials from November 2013 through January 2014. All officials completed a hearing history questionnaire and received an ear examination with an otoscope prior to each pregame hearing test. The questionnaire was used to determine the length of time since the last excessive noise exposure and nonoccupational noise exposures (e.g., music, firearms). The otoscopic examination was conducted to identify conditions that could exclude the official from participation in the study (e.g., excessive ear wax, ruptured tympanic membrane).
Areas used for audiometric testing were selected to best achieve acceptable background noise levels, as per Table D-1 of OSHA 1910.95 Appendix D (U.S. Department of Labor, 2016). An exercise room adjacent to the ice in arena I and the stairwell closest to the officials' locker room in arena II were used for administering hearing tests. The background octave band sound pressure levels (SPLs) were measured at 500, 1,000, 2,000, 4,000, and 8,000 Hz before and after the pre and postgame hearing tests. Background ambient noise levels were measured using a CEL 383 sound level meter/ octave band analyzer, which was pre and post-calibrated with the CEL 282 calibrator at 114 dB to assure calibration was maintained.
Audiometric tests were performed by a certified researcher from the Council of Accreditation in Occupational Hearing Conservation using an Earscan 3 ES3S pure-tone audiometer. A functional, "look and listen" calibration of the audiometer was performed prior to the first hearing test of each sampling day. The modified Hughson-Westlake technique was used to manually test the threshold for each ear at 500, 1,000, 2,000, 3,000, 4,000, 6,000, and 8,000 Hz. The descending (10 dB) and ascending (5 dB) process was repeated until the official responded at a specific intensity at least 50% of the time at each of the frequencies. Postgame audiometry was conducted after the official's departure from the ice.
Personal noise dosimetry was conducted on 23 officials in January and February 2014. Each official was fitted with a Larson Davis Model 706 RC noise dosimeter. The dosimeters were calibrated before and after sampling using a Larson Davis CAL 150 at 94 dB and 114 dB, and collected data were downloaded with the Larson Davis Blaze software package. Noise sampling was performed in accordance with the OSHA Technical Manual, Section III, Chapter 5. The dosimeter was secured to each official before the start of the game. The microphone (including windscreen) was attached to the official's shoulder or lapel on the dominant side (opposite the whistle hand). The microphone and cable were secured with adhesive tape in order to keep the microphone upright and the cable from snagging on players' hockey sticks. Each official was instructed to not remove, tap, or yell into the microphone and operating conditions of the dosimeter and microphone were confirmed and adjusted, if necessary, at each of the intermissions. The dosimeter was stopped and removed after the official exited the ice at the end of the game.
SAS version 6.1 was used to perform statistical analysis. Descriptive statistics were used to express the proportion of officials exceeding the 85 dB equivalent sound pressure level ([L.sub.eq]) and the noise regulations/recommendations, and the proportion of officials who experienced a 10 dB or greater decrease in hearing sensitivity.
A total of 18 questionnaires were completed by the officials about their hearing history prior to the pregame hearing test. The study participants were male and ranged from 21 to 65 years of age, with an average officiating experience of 12.9 years (range 4-37 years). When asked to report the source of their most recent noise exposure, 27.8% (5/18) reported hockey, 11.1% (2/18) reported music, and 61.1% (11/18) reported no recent noise exposure.
Audiometric tests were conducted in the most feasible space adjacent to the ice rink in each arena. The background SPLs for each testing area were under the maximum allowable SPLs for audiometric test rooms for 2,000, 4,000, and 8,000 Hz, but exceeded the allowable limit at 500 and 1,000 Hz.
We conducted 18 pre and postgame hearing tests on 15 different officials. One official was sampled three times and another was sampled twice. An increase in hearing threshold of 10 dB or greater was exhibited in more than half (55.6%) of the sampled officials.
Of those officials with the [greater than or equal to] 10 dB decrease in hearing sensitivity, 70.0% experienced a threshold shift in more than one ear and/or at more than one frequency and 20% experienced a 15 dB threshold shift. The proportions of those officials with [greater than or equal to] 10 dB deterioration of hearing thresholds in each ear at each of the tested frequencies are shown in Figure 1.
The Wilcoxon signed-rank test was performed on the paired audiometry data because it was not normally distributed. Based on the results of the Wilcoxon signed-rank test, there were significant differences between the pre and postgame hearing thresholds at 2,000 Hz for the left ear (p = .012) and at 4,000 Hz for the right and left ears (p = .037, p = .017, respectively). The differences at the other frequencies for both ears were not significant (p > .05).
Noise dosimetry was conducted during four hockey games at arena I and two hockey games at arena II. A total of 23 personal noise dosimetry samples were collected over an average hockey game time of 2 hours and 42 minutes (Table 1). The mean peak sound pressure level ([L.sub.peak],) and the mean [L.sub.eq] were 133 dB and 90 dBA, respectively. None of the officials was overexposed to noise based on OSHA noise criteria, yet 65% of hockey officials were overexposed to noise based on ACGIH recommendations.
The hearing history questionnaire was used to determine the length of time since the officials' last excessive noise exposure. Of the 18 officials queried, 11 (61%) reported no recent noise exposure, whereas 5 (28%) reported a previous hockey game as a noise exposure. In retrospect, it might have been more appropriate to ask the source and duration of the noise exposure within the last 48 hours, including sports officiating. Officiating more hockey games than documented or the increased background noise levels in the audiometric testing rooms might explain a higher pregame hearing threshold (>25 dB) found in 10 (56%) of the officials. The questionnaire should have included a question regarding the presence of TTS symptoms before and after the hockey game, similar to that done by researchers investigating hearing loss associated with loud music exposure (Sadhra, Jackson, Ryder, & Brown, 2002). Although the noise exposures from the officials' nonoccupational and leisure noise exposures were not measured in this study, they likely are contributing to the officials' overall noise exposure and associated symptoms, as supported by Clark's literature review (1991) of noise exposures from leisure activities.
Pure-tone threshold shifts of 10 dB or greater were identified at all of the tested frequencies in one or both ears, with the largest percentage of shifts occurring at 4,000 Hz. These results are similar to those found by Hodgetts and Liu (2006) during a Stanley Cup game. The researchers found a pure-tone shift of 5-10 dB for most of the tested frequencies, with one subject experiencing a 20 dB shift in one ear. The audiometric testing, however, occurred on only two spectators in the Hodgetts and Liu study (2006), and therefore the results might not be representative. The current study results are consistent with those of several researchers who have used pure-tone audiometry to identify the presence of a TTS after exposure to loud music (Le Prell et al., 2012; Sadhra et al., 2002). In particular, the results and design of the study by Sadhra and co-authors (2002) are similar to the current study in that it measured the noise exposure and hearing thresholds of employees in a noisy environment, not just the spectators/attendees. Furthermore, they found that the correlation between TTS and personal exposure was higher at 4,000 Hz. Le Prell and co-authors (2012) found the 4,000 Hz "notch" that is typical of NIHL after noise exposure from digital music players.
The differences between pre and postgame hearing thresholds were significantly different at 4,000 Hz in both ears and at 2,000 Hz in the left ear. The Wilcoxon signed-rank test results were less powerful due to the small sample size and sampling officials multiple times occurred because only a small pool of 28 to 32 officials work the hockey games in northern Colorado. England and Larsen (2014) used i-tests with Bonferroni adjustments and found significant differences between pre and postgame pure-tone audiometry at basketball games at all tested frequencies in both ears, except for the left ear at 1,000 Hz and right ear at 6,000 Hz. The inconsistency in results with the current study might be explained by the unfavorable audiometric testing conditions in the current study.
Background noise levels of audiometric testing areas did not meet the acceptable levels for 500 and 1,000 Hz and the results at those frequencies might not be indicative of actual hearing thresholds, as 61% of officials had pregame hearing thresholds >25 dB at those frequencies. Limited funding, time, and instrumentation did not allow for optional testing environments or continual background noise measurements. The inconsistencies might also be because several of the postgame hearing tests were conducted more than 30 minutes after the game's end, therefore possibly underestimating the number of hearing threshold shifts. Ideally, the audiometric testing would occur in an audiometric testing booth that meets or exceeds the requirements outlined in OSHA's Appendix D and testing would be done quickly after the game, as the ear begins to heal from a TTS in as little as a few minutes after removal of the noise source (Melnick, 1991; Ward, 1980).
Previous researchers (England & Larsen, 2014; Le Prell et al., 2012; Sadhra et al., 2002) included a follow-up hearing test within 48 hours of the noise exposure and found that the TTS recovery was essentially complete within the first 4 hours after exposure. Unlike previous studies, the researchers were unable to coordinate a follow-up hearing test and assumed that the threshold shifts were only temporary. The study participants were notified to contact a physician if symptoms persisted for more than 48 hours.
All of the hockey officials who participated in this study were exposed to an [L.sub.eq] >85 dBA, with a mean [L.sub.eq] of 90 dBA. The mean [L.sub.eq] of 90 dBA in this study was similar to the mean [L.sub.eq] of 85 dBA found by England and Larsen (2014) in basketball arenas, and within the [L.sub.eq] range found by area monitoring at two indoor hockey venues by Cranston and co-authors (2013). During National Hockey League playoff games, researchers found L values in a range from 101-104 dBA (Hodgetts and Liu, 2006), which was greater than the [L.sub.eq] found in the current study. The previous study had more attendees, as would be expected for a Stanley Cup playoff, and crowd noise was most likely a contributing factor.
The researchers measured a mean [L.sub.peak] of 133 dB in the current study that is consistent with the [L.sub.peak] range (130-146 dB) found by Engard and co-authors (2010), yet higher than the area monitoring [L.sub.peak] range of 105-124 dB at venue 1 and the 110-117 dB at venue 2 found by Cranston and co-authors (2013). The variations between personal and area monitoring might explain the difference in results. Area sampling in the current study might have been beneficial in assessing the frequency spectra of the noise in various locations in the hockey arenas.
Our findings that 65% of officials exceeded ACGIH noise exposure criteria are consistent with the findings of Cranston and co-authors (2013). The researchers of the current and previous study concur that none of the study participants exceeded OSHA noise criteria. The Engard and co-authors' study results (2010) support the current study's findings based on ACGIH criteria, yet those researchers found that 20% of fans exceeded OSHA permissible exposure limit of 90 dBA. The differences might be the result of different arena/stadium acoustics, location of personal sampling, and number of people in attendance.
For example, the current study included fewer than 200 spectators, while the Engard and co-authors' study (2010) included a range of 19,721-75,703 spectators. The larger crowd likely produced more noise, which might account for increased noise exposure levels in the Engard study. It is also possible that the results from the smaller venue with fewer spectators underestimated the noise exposures of officials in larger arenas.
The hockey officials in this study often use officiating as supplementary income to their primary employment. Personal noise dosimetry data were only collected for the duration of the hockey game, but the occupational noise criteria are based on an 8-hour workday.
The researchers chose not to report results that compared to OSHA or ACGHI 8-hour TWA because the calculations would have assumed that the official's remaining noise exposure for the day was less than the threshold dB value, which is unlikely. For instance, other common noise sources integrated in a daily noise exposure may include noise from another job or occupation, music, hunting, power tools, and other sporting events, as is supported by Clark's literature review (1991) of noise exposures from leisure activities.
This pilot study was the first step in evaluating the noise exposure and hearing loss of indoor hockey officials. Preliminary surveys indicate engineering controls are not feasible and officials do not wear hearing protection. Exposure to hazardous levels of noise increases the risk of repetitive TTSs, which may increase the risk of permanent hearing loss. Based on the results of this study, indoor hockey officials are exposed to levels of noise that may result in repetitive TTSs; further research is warranted.
Future research should include noise monitoring at a larger venue, audiometric testing in a room with allowable background noise levels, and postgame audiometry within minutes of the game's end. Further research has the potential to identify officials of other sporting events, regionally and nationally, who might be at an increased risk of NIHL. In an effort to reduce noise exposure, hockey officials should consider wearing hearing protection while officiating games.
Karin L. Adams, PhD
Ammon Langley, MS
William Brazile, PhD, CIH
Department of Environmental & Radiological Health Sciences Colorado State University
Acknowledgements: The authors thank Dan Van Arsdall for his cooperation and supervision of the ACHA and WSHL officials who volunteered for the project. This research was partially funded by the Mountain & Plains Education and Research Center.
Corresponding Author: Karin L. Adams, School of Allied Sciences, Department of Community and Environmental Health, Boise State University, 1910 University Drive, Boise, ID 83725-1835. E-mail: firstname.lastname@example.org.
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TABLE 1 Noise Dosimetry Results of Hockey Officials in Arenas I and II * Criteria Criteria OSHA Action ACGIH Threshold Limit (a) Limit Values (b) Parameter Mean SD Mean SD Dose (%) 19.2 5.63 119.9 96.3 [L.sub.eq] CD 90 2.13 90 2.13 TWA (dBA) (c) 86 1.78 90 2.16 [L.sub.max] (dBA) 115 4.50 115 4.50 [L.sub.peak] CD 133 5.49 133 5.49 * N = 23 officials. (a) Dosimeter settings for Occupational Safety and Health Administration (OSHA) action limit criteria include: A-weighting, slow averaging, 85 criterion level, 8-hour criterion time, 80 threshold level, 5 dB exchange rate. (b) Dosimeter settings for American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values include: A-weighting, slow averaging, 85 criterion level, 8-hour criterion time, 80 threshold level, 3 dB exchange rate. (c) Time-weighted average (TWA) for time sampled: Average of 2 hours, 42 minutes.
Please note: Some tables or figures were omitted from this article.
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|Title Annotation:||ADVANCEMENT OF THE SCIENCE|
|Author:||Adams, Karin L.; Langley, Ammon; Brazile, William|
|Publication:||Journal of Environmental Health|
|Date:||Nov 1, 2016|
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