Essay: Are hearing conservation programs effective?

INTRODUCTION
With the increased access to personal listening devices, and increased popularity of those devices such as mp3 players and smartphones, it has become a normality to see people wearing ear buds or headphones walking down the street listening to music. This increased popularity is very evident in the sales numbers. Since the Ipods launch over 260 million units have been sold. (Danhauer JL, 2012) According to research, using these personal listening devices in public has become a status symbol. These devices, now popular with adolescents are slowly getting more popular with children of a younger age, and this trend is a concerning one. (Levey S, 2011)
With the increased usage of these personal listening devices (MA, 2008), activities that would normally be conducted in relative silence such as commuting or taking the dog for a walk, can nowadays be done whilst listening to music at a dangerously loud volume (Serra MR, 2005). The high levels of decibels emitted by such devices are capable of causing irreversible noise induced hearing loss (SCENIHR., 2008).
Noise induced hearing loss is loss of hearing caused by loud sounds. Loud sounds can over stimulate the hair cells of the inner ear, this overstimulation can in turn lead to a production of reactive oxygen species which will cause the hair cells to die, and the cells don’t have the ability to regenerate. This means that noise induced hearing loss is permanent and irreversible. (Jahn AF, 2001)
Noise induced hearing loss is now affecting people of young age and has the capability to cause extensive long term consequences(RV., 2008). Hearing loss caused by exposure to loud music is becoming a growing public health concern. One research concluded that half of their sample group of middle school children listened to music on their IPod’s at unsafe levels, and that they also underestimated the levels at which they were listening to music. Also in a large national study it was estimated that 12,5% of approximately 5,2 million US children, ages 6 to 19, had noise-induced threshold shifts. (Niskar AS, 2001)
As a result of this growing public health problem, several preventive educative programs have been developed to help prevent noise induced hearing loss in children and adolescents. Prevention and education at such an early stage is more effective, since it’s a lot easier to prevent a child from learning bad habits, than it is to make an adult change the bad habits which he has already developed for many years. At this moment education about hearing loss has not yet become a standard part of the school program. (Hoover A, 2010)
A few examples of such hearing conservation programs are: Dangerous Decibels, Sound sense, It’s How You Listen That Counts, Cheers for ears. Some of which will be discussed in this article.
The goal of this article is to find out if these hearing conservation programs are effective. Do they prevent noise induced hearing loss? To what degree do they manage to accomplish this goal, and what is it that makes these programs effective? Besides preventing noise-induced hearing threshold shifts, it is also important to find out if these programs managed to increase knowledge in children and adolescents about hearing loss, and if these programs managed to effect the childrens attitudes towards loud music on a long term basis.
METHODS
I performed a PubMed search from the 1st until the 24th of June 2015.
My search strategy was the following:
((“noise induced hearing loss”) AND “prevention”) AND child Filters: published in the last 5 years; Child: birth-18 years
This search strategy found 22 items.
Inclusion criteria:
Studies were included into the review if they examined the effect of noise-induced hearing loss preventive programs at school.
Exclusion criteria:
Studies were excluded if they examined other methods of preventing noise-induced hearing loss other than the school programs.
Data extraction:
After having collected suitable studies for this review, I read through them all and extracted data from it and summarized it all in a table, which can be found in the results.
RESULTS
Sample characteristics
The sample groups that were studied included children from the age of nine up until the age of 18. Intervention sample group sizes varied between 53 students and 1120. Five of the eight studies examined for this review used control groups.
Methods of noise-induced hearing loss prevention
The goal of a hearing conservation program is to educate the children about the effect loud noise can have on your hearing and to provide them with ways in which they can prevent that from happening. The hearing programs studied in this review attempted to educate their sample groups in different ways. The most used method out of the reviewed studies were classroom presentations. These presentations were designed with the input of audiologists, teachers and students. Some studies also provided the children with brochures containing additional info and a set of earplugs. One of the randomized control trials also had the sample group visit a museum exhibition.
Measuring hearing conservation
Different methods of measuring the effectiveness of the hearing conservation programs were used. Most of the studies merely used questionnaires at baseline and at a period of time after the intervention to assess the sample group’s knowledge on the subject and to see if they had changed their attitudes towards noise, if they were using hearing protective strategies and if they decreased their exposure to loud sounds. This follow-up period varied between 3 months and 16 years. Most studies used questionnaires such as YANS (Youth Attitude to Noise Scale) and BAHPHL (Beliefs About Hearing Protection and Hearing Loss) and used the scores that came from those scales as outcome measures. Some studies chose to make small adaptations to those questionnaires or to create their own.
Only one study used audiometric testing as a method to quantify the amount of noise-induced hearing loss over time.
Outcomes
Overall all the studies reported a significant improvement in the attitudes towards noise and knowledge about the consequences. Some studies also found a significant increase in the use of hearing protection and a decrease in the exposure to loud music. Some studies that performed a follow up questionnaire found that this effect slowly decreased over time. The study that also executed the audiometric testing came to the conclusion that no difference was found between the intervention group and the control group with respect to noise-induced hearing loss.
DISCUSSION
The goal of this review was to find out if hearing conservation programs at school were effective at preventing noise-induced hearing loss in children, if it changed their attitudes and knowledge, and what made them effective. From the results gathered in this review we can conclude that these hearing conservation programs are effective in short term. Unfortunately there wasn’t enough research done in the long term to make any conclusions about the long term effect of these hearing conservation programs. With one study concluding that the effect had decreased after three months, and another study concluding there was no difference between the sample and control group regarding reduced levels of noise-induced hearing loss, the long term effect of these hearing conservation programs does not look to promising yet. Fortunately marlenga did find that after 16 years their sample group used more hearing protection.
My hypothesis was that these hearing conservation programs would prove to be effective in changing the attitudes of children. However it was surprising to see that in marlenga even though the attitudes had persisted, there was no difference between the sample group and control group in respect to the amount of noise-induced hearing loss.
I think the positive results from the studies have to be taken with a grain of salt. The children were tested shortly after having gotten the intervention, so there isn’t much evidence that these hearing conservation programs will work for longer than a few months. Also the way the effectiveness was tested leaves much to be desired. A lot of the positive results was based solely on the questionnaires, which I don’t think gives an accurate representation of the way children behave towards loud noise. I would have liked to have seen a lot more studies use audiometric testing, so not just the attitudes and knowledge are tested, but the outcome that actually matters: the hearing loss. I believe it’s important that some of these hearing conservation programs get a follow up years after the intervention, like marlenga did, to research if the hearing conservation programs actually prevented noise-induced hearing loss, and not solely improved hearing protective behavior.
One of the limitations of this review was the fact that it was carried out by only one person. Normally there are at least two people working on it, gathering articles, analyzing them, and checking each other’s work. Since it was carried out by only one person, there is a good chance some valuable articles were missed, or analyzed incompletely. Also limited research has been done in this field, only recently has this become an important topic and research is slowly increasing. So as of right now, with mostly short term results, it’s hard to tell what effect this prevention method will have in the years to come. Based on the results it is however clear that there is at least a strong positive short term effect, and it should therefore be recommended that at least some form of a hearing conservation program should be implemented in the standard curriculum of primary and/or high schools.
CONCLUSION
Author (year) Study Design Sample group Method Results
Knobel KA1, Lima MC.
2014 Prospective longitudinal controlled study Third to fifth graders, n=220
Control group=51 60 minutes classroom presentation, follow up questionaire, activity booklet, 3 months follow up questionaire improvements in knowledge, attitudes, intended behavior, decreased exposures, use of hearing protective strategies.
Gilles A1, Paul Vde H2.
2014 Cohort 14-18 year old flemish high school students, n=547 Questionnaire, campaign attitudes toward noise and hearing protection assessed YANS and BAHPHL. YANS, BAHPHL decreased significantly (p < 0.001) more negative attitude toward noise and a more positive attitude toward hearing protection. Use hearing protection increased significantly from 3.6% to 14.3% (p = 0.001) Taljaard DS1, Leishman NF, Eikelboom RH. 2013 Survey study Median age 11, n=318 2 interactive sessions Effective in increasing knowledge on the harmful effects of noise, may prevent future noise-induced hearing loss. Martin WH1, Griest SE, Sobel JL, Howarth LC. 2013 Randomized trial Fifty-three fourth grade classrooms (1120 students) (1) A classroom presentation (2) classroom presentation (3). Exploration of museum exhibition (4). internet-based virtual museum. Comparison group received no intervention. Produced significant improvements, the number of improvements decreased over time. The classroom programs more effective than the internet-based virtual exhibit, which was more effective than the visit to the museum exhibition. Dell SM1, Holmes AE. 2012 Cohort 12-14 year olds, n=64 24 questions assess adolescents' attitudes towards noise; a post-test measure included the identical 24 questions in addition to three subjective questions. A statistically significant reduction (P< 0.003) in pro-noise attitudes after the intervention. HCP facilitated a change in pro-noise attitudes Neufeld A1, Westerberg BD, Nabi S, Bryce G, Bureau Y. 2011 Prospective, randomized, mixed design controlled study. Participants were grade-six students from 16 Vancouver School Board schools behavioral questionnaire measured at baseline, then at 2 weeks and 6 months after administration of Sound Sense program. Significant interactions for improved earplug use at 2 weeks post intervention relative to baseline. Improvements in children's earplug use at 6 months post intervention relative to baseline. Behavior in the intervention group compared to control group improved in earplug relative to baseline. Tendency in intervention group to reduce the duration of use of personal music after the hearing conservation program, which was nonsignificant. Author (year) Study design Sample group Method Results Marlenga B1, Linneman JG, Pickett W, Wood DJ, Kirkhorn SR, Broste SK, Knobloch MJ, Berg RL. 2011 Randomized Control trial 200 intervention group, 192 control group, 16 years after hearing conservation program exposure history questionnaire, clinical audiometric examination. Rates of NIHL and use of hearing protection compared. Intervention group reported significantly greater use of hearing protection compared with the control group (25.9% vs 19.6%; P .015). Intervention group reported significantly greater use of hearing protection for shooting guns (56.2% vs 41.6%; P .029), but the groups reported similar uses of protection in other contexts. There was no significant difference between groups with respect to objective measures of NIHL Marlenga B1, Linneman JG, Pickett W, Wood DJ, Kirkhorn SR, Broste SK, Knobloch MJ, Berg RL. 2009 Pragmatic cluster-randomized controlled trial 753 high school students involved in farm work 34 Rural schools recruited, randomized to intervention or control. Classroom instruction, distribution of hearing protection devices, direct mailings, noise level assessments, yearly audiometric testing. The control group received the audiometric testing. More frequent use OF hearing protection devices, no evidence of reduced levels of noise-induced hearing loss (NIHL).