Frequently Asked Questions
No. Hard, non-porous objects and surfaces are the best candidates for
disinfection. Unfortunately, insert eartips are neither. They are porous and
soft and do not disinfect well. More importantly, if they are soaked in a
solution, the solution is almost certain to stay within the tips thus posing a
health hazard to the person who uses it. This is particularly true if someone
soaks such a tip in glutaraldehyde (Cidex, Wavicide). The residual glutaldehyde
is toxic to the person who receives this tip in the ear.
Bob Kemp, Oaktree Products, Inc.
No. Insert eartips were designed to be a single-use item, thrown away
after each use. Items like insert eartips can become contaminated by the ear or
the hands, and can present a health hazard to the next patient, particularly
those with diminished immune systems. Audiology patients often have weakened
immune systems due to age, underlying disease state (diabetes, HIV) or drug
treatment (chemotherapy). Ubiquitous organisms passed from person to person via
insert eartips can cause opportunistic infections. Insert eartips should always
be thrown away after a single use. Supporting research is as follows:
a. Breathnach, Jenkins and Pedler (1992) found that 26 of 29 stethoscopes were
contaminated with staphylococci, and concluded that stethoscopes were a vector
for staph infections.
Breathnach, A.S., Jenkins, D.R. & Pedler, S.J. (1992)
Stethoscopes as possible vectors of infection by staphylococci. British Medical
b. Brook (1985) evaluated airline headsets worn by 20 male passengers and found them
to be contaminated with staph aureus, staph epidermis, streptococci and
corynebacterium. This study led to airlines using disposable headphones and
better disinfection of headphones.
Brook, I. (1985) Bacterial flora of airline headset devices.
American Journal of Otolaryngology 6:111-114.
c. Bankaitis (2000) examined in-the-ear hearing aids and found that ten of ten were
contaminated with bacteria and fungus. While most of the bacteria found on the
hearing aids were of the varieties normally found in the ear, some were not
normally found in the ear, like fecal-born bacteria. This demonstrated that
items that come in contact with the ears can become contaminated by the ear or
by the hands.
Bankaitis, A.U. (2000) Hearing aid infection control (IRB
#10679) submitted for publication. St. Louis University, St. Louis, MO.
Insert earphones should always be
calibrated prior to use. Insert earphones were originally designed to "mimic"
the response of TDH headphones. Over time, TDH headphones get banged around, and
due to normal wear and tear, it is highly likely that they've "drifted" from
their original performance over the years. When equipment is regularly
calibrated, this isn't a big problem, since any "off-spec" responses can be
compensated for by adjustments to the internal board of the audiometer. However,
over the years, these changes can add up, and the ER-3A's assume "original
integrity" of the TDH phones--so if they're just plugged in and not calibrated,
you might get results that differ from the TDH headphones.
For ER-3A insert earphones, there will typically be a 0-5 dB correction at
frequencies at and below 4000 Hz, and slightly larger corrections at 6000 and
8000 Hz. If you use TDH headphones as the default, remember to have the insert
earphones calibrated at your annual calibration. Many clinicians have their
audiometers calibrated for insert earphones as the default and use correction
factors for their TDH headphones. A nice feature on some newer audiometers is
having both types of earphones selectable, so that either TDH headphones or
insert earphones can be used on a patient-by-patient basis without plugging and
unplugging the desired earphones.