Transcript Hearing Disorders In Drivers

Hearing Disorders In
Drivers
Dr Majid Golabadi
Noise induced hearing loss in drivers

gradual decrease in hearing acuity resulting from
continuous exposure to high sound pressure levels, causing
injury to the inner and outer hair cells of the organ of
Corti.

It is characterized by sensorineural hearing loss,
irreversible, almost always bilateral and symmetrical,

not exceeding 40 dB (NA) at low frequencies and 75 dB
(NA) at high frequencies,

Manifesting itself first in 6000 Hz, 4000 Hz and / or
3000Hz,).

Occupational noise may also contribute to accidents in
the workplace;

it increases communication difficulties, maintenance of
attention, concentration and memory, in addition to
stress and excessive fatigue

Road surface, traffic congestion, wind noise, and driving
speed were stated to be the contributing factors.
In
heavy
motor
vehicles,
as
noise
is
usually
experienced simultaneously with vibration there is a
combined assault from both sources.
Some studies
Prevalence of noise-induced hearing
loss in drivers
Lopes AC, Otowiz VG, et al
Int. Arch. Otorhinolaryngol. 2012;16(4):509-514.
Results

The prevalence of abnormal tests was 22.36% with the lowest
thresholds for tritonal average of 3,000, 4,000 and 6,000Hz.

The higher the age, the higher thresholds.
ARE YOUNG BUS DRIVERS AT A RISK OF
DEVELOPING NIHL??A PRELIMINARY
STUDY
RASHMI PAI
Proceedings of The IRES International Conference, Seoul,
South Korea, 23rd May 2015

Patwardhan, Kolate and More (1996) carried out a study
assessing the loudness levels and the effects of noise among
the bus drivers in their cabin and compared it to the controls
who were exposed to the noise level of 50-62dB.

It was found that, the intensity of noise in the drivers cabins
ranged from 89 to 106 dB and 89% of the drivers showed
abnormal audiograms whereas the percentage of affected
audiograms among the controls was only 19%.

A study by Seshagiri B. (1998) revealed the drivers are
exposed to noise ranging from 78 to 89 dB(A), with a
mean of 82.7 dB(A).

Operating the radio increased the mean by 2.8 dB,

driving with the side window open increased the mean
exposure by 1.3 dB,

and driving with the window open and operating the
radio resulted in an increase of 3.9 dB

Kumar et. al (2005) in their study compared the hearing
status of tractor driving farmers and nontractor driving
farmers matched for age, gender and related factors.

The noise levels observed on tractors in different
operations were in the range of 90–110dBA.

The study revealed a higher prevalence of abnormalities
in tractor drivers compared to nontractor drivers.
According to research presented at the AAO-HNSF Annual
Meeting (2009)

Drivers are consistently exposed noise levels between
88 to 99dBA.
EFFECT OF NOISE POLLUTION ON HEARING
OF PUBLIC TRANSPORT DRIVERS IN LAHORE
CITY
Pak J Med Sci January - March 2008 Vol. 24 No. 1 142-146
Results:

65% of the subjects had noise induced hearing loss.
(NIHL) 25% had normal hearing threshold and 10% had
disabling hearing loss.
Conclusions:

Public transport drivers are exposed to excess noise on
roads in Lahore and most of them are suffering from
noise induced hearing loss.
The Prevalence and Correlates of Hearing
Loss in Drivers in Isfahan, Iran
Mohsen Janghorbani PhD•*, Ali Sheikhi MSc*, Siamak
Pourabdian MD
Archives of Iranian Medicine, Volume 12, Number 2, 2009:
128 – 134.
Methods

A cross-sectional study was conducted on a random
sample of 4300 long-distance drivers age ≥20 years in
the city of Isfahan,

The drivers were interviewed and underwent clinical
and laboratory examinations and pure-tone audiometry
in a sound-treated booths.

The mean (SD) age of the participants was 40.8 (11.0)
years with a mean (SD) duration of professional driving
of 14.7 (9.6) years.
Results:

The prevalence of bilateral hearing loss was 18.1%

The prevalence rates were higher in the left ear only 6.5% than
the right ear only 3.0%

When bilateral HL was entered in the model, fasting blood
glucose (FBS) was a significant predictor of NIHL .

Blood pressure, cholesterol, triglyceride, body mass index, and
marital status had no significant independent association with
HL
Conclusion

These findings indicate that noise-induced hearing loss
among the long-distance drivers appears to be similar to
the world's population endures noise-induced hearing
loss caused by occupational exposure to noise, with
higher prevalence in the left ear only.
‫بررسي كاهش آستانه شنوايي و عوامل مرتبط با‬
‫آن در رانندگان كاميون كرمان‬
‫منيژه دادبخش‪ ،‬زهره فروزانفر ‪ ،‬محسن نقي زاده‪ ،‬نرگس خانجاني‬
‫مجله دانشكده علوم پزشكي نيشابور‪/‬سال دوم‪ /‬شماره ‪3‬‬
‫‪ /‬تابستان ‪1393‬‬
‫‪ ‬اين مطالعه توصيفي‪ -‬تحليلي بصورت مقطعي در سال ‪ 1390‬بر روي‬
‫‪ 150‬نفر از رانندگان حرفه اي كه در مركز غربالگري بيماريهاي شغلي‬
‫در كرمان پرونده داشتند‪ ،‬انجام گرفت‪.‬‬
‫‪ ‬كاهش شنوايي در گوش چپ در فركانسهاي باالتر از ‪ 2000‬به طور‬
‫معني داري بيشتر از گوش راست بود‪.‬‬
Assessment of hearing state in heavy and
semi-heavy vehicle drivers
Marziyeh Moallemi. Fahimeh Hajiabolhassan.
J Rehab Med. 2014; 2(4): 31-36.
Materials and Methods:

This study was conducted on 320 heavy and semi-heavy
vehicle drivers in Isfahan city .
Results:

Among participants 174 subjects indicated some degrees
of hearing loss (mild to profound).

Comparison of threshold means between two ears
showed significant differences at 3 to 8 kHz frequencies
(P< 0.05). The thresholds were worse in the left ear.
Prevalence of noise induced hearing loss among
vehicle drivers at Bandar Abbas freight terminal,
south of Iran
Leila Rezaei, Vali Alipour
Environmental Health Engineering and Management
Journal 2015, 2(3), 135–139
Methods:
1000 long distance occupational drivers in Bandar Abbas freight
terminal not certified by underlying medical conditions were
selected for this study.
Results: Approximately 52% of drivers studied had a degree of
hearing loss. The most common type of hearing loss was
sensorineural with mild loss of 69% and 70.9% for the left and
right ears, respectively.
Noise-induced hearing loss in bus and truck
drivers in Mazandaran province, 2011.
Alizadeh A, Etemadinezhad S, Charati JY, Mohamadiyan M.
Int J Occup Saf Ergon. 2016;22(2):193-8.

METHODS: In a cross-sectional descriptive study, 2283 drivers
were examined clinically and para-clinically. All participants
were evaluated for the air and bone thresholds of both ears.

RESULTS: Of the drivers, 37.5% had hearing loss in the right
ear and 41.8% of the drivers had hearing loss in the left ear in
one or more frequencies of sound. Hearing loss was
significantly more frequent in the left ear and in 6000 Hz
followed by 4000 Hz.
Reducing Noise in the Driving Environment

A number of interventions can reduce the potential
harmful effects of noise in the tractor cab. The most
common are the use of hearing protection devices
(HPDs) and soundproofing of the truck cab.

HPDS (individually tit earplugs, earmuffs, etc.) reduce
all sounds in the driving environment, including noise
and signals that may be of interest to the driver.
THE ROLE OF HEARING IN DRIVING

The first area we examine is the degree to which
hearing is needed in the driving task Opinions range
widely on this issue.

Some believe driving is a purely visual task; some
believe hearing is essential.
Four senses are likely to influence the driver’s ability

vision,

hearing,

touch,

smell
Henderson and Burg (1974) concluded that:

vision makes up most of the driving task.

hearing plays a small role in the driving task.
The Federal Highway Administration concluded that:

hearing is important when a driver must act on
emergency sounds or improper mechanical sounds and
when a driver needs to communicate

Due to lack of research data in this area, the effect of
impaired hearing on the ability to drive safely is still
untested.

The best available information suggests that totally
deaf drivers may have a slightly increased risk of an
accident.

Most deaf drivers have rejected this theory and say that
because of their hearing loss their other senses,
especially eyesight and vibration sensory are heightened
to such a degree that they make up for any loss of
hearing.

Results from studies indicate that, for the majority
(70%) of study measures, no significant relationship was
found between hearing loss and adverse driving
outcomes
Hearing Standards for
Driving

Compliance with the standard should be clinically
assessed initially. If there is doubt about the person’s
hearing, audiometry should be arranged.

The person should not undergo audiometry if their
hearing is satisfactory.
Clinical Assessment
Three Meters Test:

This test requires that a person can hear each word
spoken in a normal conversational voice at a distance of
three metres.
Audiometry

Failure of three meters test requires formal audiometric
hearing tests to be carried out with pure tone air conduction
audiometry.

If on audiometry: the person has unaided hearing loss greater
than or equal to 40 dB in the better ear (averaged over the
frequencies 0.5, 1, 2 and 3 KHz)

If the standard is able to be met with a hearing aid, the
driver licensing authority may consider a conditional
licence, subject to periodic assessment of hearing and
of the hearing aids at a frequency advised by the health
professional.

Stable conditions may not require periodic review.
If the standard is not able to be met with a hearing aid,
this in itself does not disqualify the person from driving

They should be offered individualised assessment :
medical assessment

• the person’s medical history, for example, childhood deafness
may have led to good adaptation

• the person’s driving record prior to and since the occurrence of
hearing loss

• the nature of the driving task, for example, type of vehicle
(truck, bus, etc.), roads and distances to be travelled

• the ergonomics of the driving cab, for example, assistive
devices such as mirrors and a GPS

• concomitant medical conditions such as vision impairment or
cognitive impairment
practical driver assessment
Multiple medical conditions and agerelated change

Where a vehicle driver has multiple conditions or a
condition that affects multiple body systems, there may
be an additive or a compounding detrimental effect on
driving abilities