Age as a Factor of Growth in Mastoid Thickness and Skull Width.

Objectives: To understand the growth rate of mastoid thickness and skull width associated with the age for both normal and malformed inner-ear anatomy groups. Also, to determine if there is any mathematical relation between cochlear size as measured by the "A" value against the age, mastoid thickness, and skull width.

Methods: Ninety-two computed tomography image datasets of human temporal bone were made available that contained normal (n = 44) and malformed inner-ear (n = 48) anatomies.

Behavioral evaluation of auditory function abnormalities in adult rats with normal hearing thresholds that were exposed to noise during early development.

Noise-exposed rat pups provide a model of early deprivation of sensory input to the central auditory system, allowing the study of developmental neuroplasticity. Our previous results have demonstrated that a brief exposure of rats to broadband noise (125 dB SPL 8 min, 14th postnatal day) at the onset of hearing resulted in an altered intensity perception and frequency discrimination in adulthood despite normal hearing thresholds. In this study, we assessed the gap-detection ability and possible presence of tinnitus- and hyperacusis-like behavior in adult rats after the same neonatal acoustic trauma, using measurements of the acoustic startle response (ASR) in quiet and noisy environments and its prepulse inhibition by gaps in noise (gap-PPI).