Morphology variations of click-evoked auditory brainstem response with low and high rate stimuli in rat

  • Sadegh Jafarzadeh Department of Audiology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
  • Akram Pourbakht Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
Keywords: Auditory brainstem response; rat; latency; morphology; rate


Background and Aim: The auditory brainstem response (ABR) is one of the most common objective hearing tests conducting in animal and human. The purpose of this study was evaluating the morphology variations of ABR waveforms in rats with low and high rate click stimuli.Methods: First, rats with ABR thresholds higher than 55 dB SPL were excluded and total 81 ears remained in study. Absolute and interpeak latencies of wave I, II, IV were evaluated at low (17.7 Hz) and high rate (88.7 Hz) for click stimuli at 120 dB SPL.Results: At low rate stimuli, ABR waveforms showed different morphologies. The most com­mon complex for waves II to IV was wave III placed on downward slope of wave II (71% of cases). Almost the same morphologies were seen at higher rate; but in some waves, it rounded and decreased amplitude. For waves IV-V, the most common morphology was equal amplitude of wave IV and V in low and high rates (35% vs 56%, respectively). Generally, the high rate stimuli didn’t severely change morphology patterns except for later waves.Conclusion: Normal click-evoked ABR could result in different waveforms. Using click stimuli at low and high rate result in different morphology patterns. Recognizing morphology variations of ABR waveforms are essential for detecting any pathological conditions. The high rate stimuli increased latencies, especially for later waves.


1. Reichmuth C, Mulsow J, Finneran JJ, Houser DS, Supin YA. Measurement and response characteristics of auditory brainstem responses in pinnipeds. Aquat Mamm. 2007;33(1):132-38,140-50.
2. Yamada K, Kaga K, Sakata H, Uno A, Tsuzuku T. Auditory evoked responses under total spinal anesthesia in rats. Ann Otol Rhinol Laryngol. 1997;106(12):1087-92. doi: 10.1177/000348949710601214
3. Land R, Burghard A, Kral A. The contribution of inferior colliculus activity to the auditory brainstem response (ABR) in mice. Hear Res. 2016;341:109-18. doi: 10.1016/j.heares.2016.08.008
4. Wilson WJ, Bailey KL, Balke CL, D'Arbe CL, Hoddinott BR, Bradley AP, et al. On the dual structure of the auditory brainstem response in dogs. Clin Neurophysiol. 2006;117(10):2211-20. doi: 10.1016/j.clinph.2006.06.711
5. Alvarado JC, Fuentes-Santamaría V, Jareño-Flores T, Blanco JL, Juiz JM. Normal variations in the morphology of auditory brainstem response (ABR) waveforms: a study in Wistar rats. Neurosci Res. 2012;73(4):302-11. doi: 10.1016/j.neures.2012.05.001
6. Spankovich C, Hood LJ, Wesley Grantham D, Polley DB. Application of frequency modulated chirp stimuli for rapid and sensitive ABR measurements in the rat. Hear Res. 2008;245(1-2):92-7. doi: 10.1016/j.heares.2008.09.001
7. Liu XP, Chen L. Auditory brainstem response as a possible objective indicator for salicylate-induced tinnitus in rats. Brain Res. 2012;1485:88-94. doi: 10.1016/j.brainres.2012.04.048
8. Popelar J, Groh D, Pelánová J, Canlon B, related changes in cochlear and brainstem auditory functions in Fischer 344 rats. Neurobiol Aging. 2006;27(3):490-500. doi: 10.1016/j.neurobiolaging.2005.03.001
9. Alvarado JC, Fuentes-Santamaría V, Gabaldón-Ull MC, Blanco JL, Juiz JM. Wistar rats: a forgotten model of age-related hearing loss. Front Aging Neurosci. 2014;6:29. doi: 10.3389/fnagi.2014.00029
10. Aydın E, Aydoğan F, Taştan E, Iriz A, Karaca G, Haberal Can I. Are systemic voriconazole and caspofungin ototoxic? An experimental study with rats. Clin Exp Otorhinolaryngol. 2012;5(3):145-9. doi: 10.3342/ceo.2012.5.3.145
11. Church MW, Hotra JW, Holmes PA, Anumba JI, Jackson DA, Adams BR. Auditory brainstem response (ABR) abnormalities across the life span of rats prenatally exposed to alcohol. Alcohol Clin Exp Res. 2012;36(1):83-96. doi: 10.1111/j.1530-0277.2011.01594.x
12. Church MW, Jen KL, Anumba JI, Jackson DA, Adams BR, Hotra JW. Excess omega-3 fatty acid consumption by mothers during pregnancy and lactation caused shorter life span and abnormal ABRs in old adult offspring. Neurotoxicol Teratol. 2010;32(2):171-81. doi: 10.1016/
13. Chen TJ, Chen SS. Generator study of brainstem auditory evoked potentials by a radiofrequency lesion method in rats. Exp Brain Res. 1991;85(3):537-42.
14. Ping LL, Jiang ZD. Comparison of brainstem auditory evoked response at different click rates between preterm babies after neonatal necrotizing enterocolitis and healthy preterm babies. Neonatology. 2014;106(4):317-22. doi: 10.1159/000363491
15. Newton EH, Cooper WA Jr, Coleman JR. Rate and frequency interactions in the auditory brainstem response of the adult rat. Hear Res. 1992;60(1):73-9.
16. Lu TM, Wu FW, Chang H, Lin HC. Using click-evoked auditory brainstem response thresholds in infants to estimate the corresponding pure-tone audiometry thresholds in children referred from UNHS. Int J Pediatr Otorhinolaryngol. 2017;95:57-62. doi: 10.1016/j.ijporl.2017.02.004
17. Sanz-Fernandez R, Sanchez-Rodriguez C, Granizo JJ, Durio-Calero E, Martin-Sanz E. Utility of auditory steady-state and brainstem responses in age-related hearing loss in rats. Acta Otolaryngol. 2015;135(1):35-41. doi: 10.3109/00016489.2014.953203
How to Cite
Jafarzadeh S, Pourbakht A. Morphology variations of click-evoked auditory brainstem response with low and high rate stimuli in rat. Aud Vestib Res.
Research Article(s)