Utility of auditory steady-state and brainstem responses in age-related hearing loss in rats.
CONCLUSIONS
The results support the idea that auditory steady-state response (ASSR) is a more accurate test for studying age-related hearing loss (ARHL) in Sprague-Dawley rats. Differences in the rat middle ear may explain the variations of the click properties, with a displacement of the energy toward the 8 and 10 kHz frequencies compared with humans.


OBJECTIVE
The purpose of this study was to evaluate ARHL in older and younger Sprague-Dawley rats using auditory clicks and tone burst with auditory brainstem response (ABR), in addition to ASSR.


METHODS
This was a prospective cohort study with 50 animals divided into 5 groups based on their age in months. A total of 100 registers were elicited from each one of the 3 auditory measurements systems in an electrically shielded, double-walled, sound-treated cabin. Nine frequencies, from 0.5 to 16 kHz were analyzed with the auditory steady-state response and compared with the results elicited by the clicks and tone-burst ABR.


RESULTS
Comparisons between the different frequencies showed lower thresholds in those frequencies below 2 kHz, independently of their age in months. The ARHL was detected by each one of the three auditory measurement systems, but with lower thresholds with the ASSR test. Finally, auditory clicks showed better correlations with 8 and 10 kHz elicited by ASSR, which was different to what was expected, based on human studies.
Department of Otolaryngology, University Hospital of Getafe, Madrid,Spain.
Ricardo
R
Sanz-Fernández
Carolina
C
Sánchez-Rodriguez
José Juan
JJ
Granizo
Enrique
E
Durio-Calero
Eduardo
E
Martín-Sanz
D000367:Age Factors; D000818:Animals; D001300:Audiometry, Evoked Response; D001301:Audiometry, Pure-Tone; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D034381:Hearing Loss / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results
ABR; ASSR; Sprague-Dawley rats; auditory clicks