title: [The study of acoustically evoked short latency negative responses in normal guinea pigs].
abstract: OBJECTIVE
  To compare acoustically evoked short latency negative responses (ASNR) elicited from normal and profound hearing loss guinea pig ears and to confirm their vestibular nuclei origination.
  
  
  METHODS
  Forty healthy guinea pigs were employed in the experiment, which were randomly divided into the control group (8 subjects, 16 ears), the masking group (16 subjects, 32 ears) and the deafened group (16 subjects, 32 ears). Air conductive white noise was chosen for masking. Masking dilemma was avoidable by an appropriate 15 dB gap between stimulus and masking sound. Both the masking group and the deafened group were further divided into ASNR group and non-ASNR group based on the presence of ASNR. Electrolytic lesion was conducted to the vestibular nuclei, followed by ABR/ASNR recording. The lesioned brainstem slices were microscopically verified.
  
  
  RESULTS
  In the masking group, ASNR were present in 24 ears (75.0%, 24/32) and 12 ears (46.2%, 12/26) in deafened group, showing statistically higher presence rate for masking group (χ(2)=5.07, P=0.024). There were no significant differences for the ASNR threshold and latency between the masking ASNR group and the deafened ASNR group. For the two ASNR groups, electrolytic destruction to the vestibular nuclei subsequently eliminated the ASNR. Brainstem slice proved the accurate sites of electrolytic lesion.
  
  
  CONCLUSIONS
  Moderate white noise masking prevents hearing system potential overlap without affecting vestibular system, therefore, ASNR is successfully elicited in normal guinea pigs. Both ASNRs from normal and deafened guinea pigs are of similar natures and origination from, the vestibular nuclei.
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China.
authors.forename: Chenxi
authors.initials: C
authors.lastname: Lin
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China; Email: nongdx@gxmu.edu.cn.
authors.forename: Dongxiao
authors.initials: D
authors.lastname: Nong
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China.
authors.forename: Anzhou
authors.initials: A
authors.lastname: Tang
mesh_terms: D000818:Animals; D003638:Deafness / Q000503:physiopathology*; D016057:Evoked Potentials, Auditory, Brain Stem; D006168:Guinea Pigs; D006309:Hearing / Q000502:physiology*; D006320:Hearing Tests; D009622:Noise; D010470:Perceptual Masking; D011930:Reaction Time; D013016:Sound; D014726:Vestibular Nuclei / Q000502:physiology