Condition · Outer / middle ear

Conductive Hearing Loss

Middle-ear pathology — reflex blocked on the probe side

Two ways a conductive lesion blocks the reflex

A conductive lesion in the probe ear blocks measurement of the admittance change. A conductive lesion in the stimulus ear attenuates the eliciting sound, raising the effective level needed. Even modest air–bone gaps frequently abolish the recordable reflex.

The reflex signature

Stim. Right
Stim. Left
Probe Right
Absent
Absent
Probe Left
Elevated
110 dB HL
Present
90 dB HL
The characteristic four-cell grid for this condition.

Absent responses on the affected probe side, plus possible elevation when the affected ear is the stimulus ear because the sound is attenuated.

Reflex decay

0s2s4s6s8s10s0%50%100%50% criterion
Negative (normal) decay — amplitude is well maintained across the 10-second hold. Not assessable on the affected side because no reflex can be recorded.

Pure-tone audiogram

0204060801002505001k2k4k8kFrequency (Hz)Hearing level (dB HL)
○ Right ear✕ Left ear
Right ear: flat conductive loss with an air–bone gap; bone conduction normal.

Frequencies plotted: 250, 500, 1k, 2k, 4k, 8k Hz.

References for this page

  1. Wilson RH, Margolis RH (1984). Acoustic-reflex measurements. In: Hearing Assessment (Rintelmann WF, Ed.), University Park Press.
  2. Hall JW (2014). Introduction to Audiology Today. Pearson, Boston.
  3. Katz J (Ed.) (2015). Handbook of Clinical Audiology (7th ed.). Wolters Kluwer, Philadelphia.
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