SUMMARY OF SAFETY & EFFECTIVENESS THE DISPOSABLE EARPHONE COVER
Infection Control - Acoustically Transparent
Recent concerns for patient/ client health prompted the ASHA Committee of Quality Assurance to
encourage all clinicians who provide services in any work setting to incorporate the Centers for
Disease Control's modified "Universal Precautions" (ASHA, 1989).
Time constraints, inconvenience, and risk of earphone transducer damage by liquids such as alcohol
and bleach/water solutions have resulted in an unacceptable lack of earphone cleanliness by today's
recommended standards. Although the risk of patient/client cross-contamination by viral, bacterial,
fungal and rickettsial micro organisms is very small, the patient/client deserves and will increasingly
demand that shared instrument surfaces be clean and free of contamination.
The disposable infection control and acoustically transparent earphone cover protects the patient from cross-contamination without necessitating the need to re-calibrate the audiometer.
Five Studies Evaluated the Infection Control and Acoustical Properties of the Cover:
A viral penetration study examined the qualities of the earphone cover material (Nelson Lab., 1992).
"The study consisted of placing a viral suspension with a concentration of greater than 1 x 6^6 PIaque
Forming Units/mL (PFU/mL) on the surface of the test sample in an assay plate. The test incorporated
the viral challenge into sterile simulated serum to simulate the surface tension effects of serum.
Test samples were exposed to the challenge for up to 1 hour." "The triplicate results of the (sample)
showed no viral penetration occurring on the assay plates, indicating that the samples were effective
barriers to the virus challenge throughout the 60 minute exposure time."
In an acoustical transparency study, sponsored by the Veteran's Administration, National Institute of
Standards and Technology evaluated the effects of the cover with KEMAR (Burnett, 1993). Measurements
of frequency and dB were taken without and with the cover on; differences were 3.3dB or less at all
audiological test frequencies. The effects caused by the tensioning of the cover (limp verses taut)
are audiologically insignificant.
In a separate KEMAR study of the earphone cover, Revit (1992) found no practical differences (cover
on versus cover off).
Five randomly chosen prototype covers were evaluated for Percent Total Harmonic Distortion (Overturf,
1992). No distortion was noted for any of the covers.
The final acoustical transparency study evaluated the effect of the earphone cover on the pure tone
thresholds of twenty-seven adult subjects (fifty ears) (Ullrich, 1992). A paired sample t-test
statistical analysis of the threshold differences was run for all frequencies. At all frequencies,
little, if any, cover effect was found. The greatest cover on versus cover off difference was only
2.2dB. The standard deviations were all less than 5dB and reflect the 5 dB audiometer steps more
than an actual cover effect.
- AIDS/HIV: "Implications for Speech-Language Pathologists and Audiologists", ASHA June-July 1989), pp 33-38.
- E.D. Burnett, "The Acoustical Performance of Earphone Covers with KEMAR", National Institute of Standards and Technology (United States Department of Commerce 1993), Communication to E. Wintercorn, Department of Veterans Affairs.
- Nelson Laboratories. Inc. (Salt Lake Citv. UT), "Final Report, Viral Penetration Study", Protocol No. 922721-1. (Laboratory No. 45904, 1992),
- J. Overturf(Starkey Labs), "Determining the Percent Total Harmonic Distortion of the Earphone Cover" (Unpublished Study 1992).
- L.J. Revit, Frye Electronics, Inc., Tigard, OR 97223 (Unpublished Data 1992).
- K.A. Ullrich, "The Effects of the Earphone Cover on Pure Tone Hearing Thresholds" (Unpublished Study 1992).Back to Top