Forward masking in gerbils: the effect of age.
We investigated forward masking in 21 gerbils as a function of age (5-47 months) using 400ms maskers at 40dB SPL and a 20ms, 2.85kHz probe presented 2.5ms after the masker. Elevated thresholds for the unmasked probe were only observed in animals older than 3 years. Unmasked thresholds showed no significant age-dependent hearing loss in animals below 3 years of age. In these animals without peripheral hearing loss, we found a significant age-dependent increase of masker-induced threshold shift. A regression analysis revealed that threshold shift increased from 23dB in 1 year old gerbils to 37dB in 3 year old animals. Increased forward masking in these animals with no sign of peripheral hearing loss points to a central processing deficit.
Gleich
Otto
O
ENT-Department, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany. otto.gleich@klinik.uni-regensburg.de
Hamann
Ingo
I
Kittel
Malte C
MC
Klump
Georg M
GM
Strutz
Jürgen
J
D000161:Acoustic Stimulation; D000375:Aging / Q000502:physiology / Q000523:psychology*; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D005849:Gerbillinae / Q000502:physiology / Q000523:psychology*; D006313:Hearing Loss, Central / Q000503:physiopathology / Q000523:psychology; D010470:Perceptual Masking / Q000502:physiology*