The excessive, indiscriminate use of masking during measurements of pure-tone bone-conduction thresholds can reduce or eliminate air-bone gaps. This may result in an abnormal, audiometrically induced bone-conduction threshold shift and suggest to the otologist the need for auditory brainstem response testing and/or magnetic resonance imaging. A case is presented in which the inappropriate use of the masking plateau method resulted in a reduction of the air-bone gap in an ear with a mild conductive hearing loss. The audiometric Weber test should be used in these cases, and nonmasked bone thresholds should be used to determine the actual level of the cochlear reserve.
References
1.
ShinnJ.B., BaranJ.A., MoncrieffD.W., MusiekF.E.Differential attention effects on dichotic listening. J Am Acad Audiol2005; 16(4): 205–18.
2.
MillerM.H.Clinical Applications of Paired Masking Enclosures in Pure Tone Air and Bone Conduction Testing of Subjects Having a Differential in the Hearing Acuity of the Two Ears of 30 Decibels or More [dissertation].New York: Columbia University; 1956.
3.
JergerJ., WertzM.The indiscriminate use of masking in bone-conduction audiometry. Arch Otolaryngol1959; 70: 419–20.
4.
GelfandS.A.Essentials of Audiology. 2nd ed. New York: Thieme Medical Publishers; 2001: 293.
5.
HoodJ.D.The principles and practice of bone conduction audiometry: A review of the present position. Laryngoscope1960; 70: 1211–28.
6.
KatzJ., LezynskiJ.Clinical masking. In: KatzJ., ed. Handbook of Clinical Audiology. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2002: 136.
7.
WilberL.A., FeldmanA.S.The middle ear measurement battery. In: WilberL.A., FeldmanA.S., eds. Acoustic Impedance and Admittance: The Measurement of Middle Ear Function.Baltimore: Williams & Wilkins; 1976: 345–77.
8.
JergerJ., TillmanT.A new method for the clinical determination of sensorineural acuity level (SAL). Arch Otolaryngol1960; 71: 948–55.
9.
RainvilleM.J.New methods of masking for the determination of bone conduction curves. Translations of the Beltone Institute for Hearing Research1959; 11: 1–10.
10.
TillmanT.W.Clinical applicability of the SAL test. Arch Otolaryngol1963; 78: 20–32.
11.
GelfandS.A.Essentials of Audiology. 2nd ed. New York: Thieme Medical Publishers; 2001: 165.
12.
MarkleD.M., FowlerEPJr., MoulonguetH.The audiometer Weber test as a means of determining the need for, and the type of, masking. Ann Otol Rhinol Laryngol1952; 61(3): 888–900.
GelfandS.A.Essentials of Audiology. 2nd ed. New York: Thieme Medical Publishers; 2001: 298.
16.
StudebakerG.A.Clinical masking of the nontest ear. J Speech Hear Disord1967; 32(4): 360–71.
17.
LidenG., NilssonG., AndersonH.Masking in clinical audiometry. Acta Otolaryngol1959; 50(2): 125–36.
18.
NauntonR.F.Clinical bone-conduction audiometry. The use of a frontally applied bone-conduction receiver and the importance of the occlusion effect in clinical bone-conduction audiometry. AMA Arch Otolaryngol1957; 66(3): 281–98.
