Contralateral Acoustic-Reflex Growth Function in a Patient with a Cerebellar Tumor

A Case Study

¹ New York Medical College, New York, NY
² Brooklyn College, City University of New York, Brooklyn, NY and Veterans Administration Medical Center, East Orange, NJ
³ Hunter College, City University of New York, New York, NY

The contralateral acoustic-reflex growth functions (ARGFs) for 500-Hz and 1000-Hz tonal activators were obtained pre- and postsurgery in a patient with a right cerebellar tumor. The acoustic-reflex magnitude was quantified as the change in equivalent air volume at the tympanic membrane during acoustic-reflex contraction. The presurgical ARGFs were shallow in the right ear and steep in the left ear at both activator frequencies. The postsurgical ARGFs were steep, bilaterally, reflecting a return to normal in the right ear. The implications with respect to the use of the ARGF measure in differential diagnosis are discussed.

Key Words: acoustic reflex • acoustic-reflex growth function • cerebellar tumor • acoustic-reflex magnitude

Submitted on March 3, 1988
Accepted on October 13, 1988