title: Effect of contralateral stimulation on acoustic reflectance measurements.
abstract: BACKGROUND
  Acoustic reflectance is an important tool in the assessment of middle ear afflictions, and the method is considered advantageous in relation to tympanometry. There has been a growing interest in the study of contralateral acoustic stimulation and its effect on the activation of the efferent auditory pathway. Studies have shown that the introduction of simultaneous stimulation in the contralateral ear generates alterations in auditory response patterns.
  
  
  OBJECTIVE
  To investigate the influence of contralateral stimulation on acoustic reflectance measurements.
  
  
  METHODS
  Case study of 30 subjects with normal hearing, of both genders, aged 18-30 years. The test and retest acoustic reflectance was conducted in the frequency range 200-6000Hz. The procedure was repeated with the simultaneous presence of contralateral white noise at 30dBNS.
  
  
  RESULTS
  The analysis of the conditions of test, retest, and test with contralateral noise showed statistical difference at the frequency of 2kHz (p=0.011 and p=0.002 in test and retest, respectively) in the right ear.
  
  
  CONCLUSIONS
  The activation of the auditory efferent pathways through contralateral acoustic stimulation produces alterations in response patterns of acoustic reflectance, increasing sound reflection and modifying middle ear acoustical energy transfer.
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo (FM-USP), São Paulo, SP, Brazil. Electronic address: tpichelli@gmail.com.
authors.forename: Tathiany Silva
authors.initials: TS
authors.lastname: Pichelli
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo (FM-USP), São Paulo, SP, Brazil.
authors.forename: Jordana Costa
authors.initials: JC
authors.lastname: Soares
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo (FM-USP), São Paulo, SP, Brazil.
authors.forename: Bruna Carla
authors.initials: BC
authors.lastname: Cibin
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo (FM-USP), São Paulo, SP, Brazil.
authors.forename: Renata Mota Mamede
authors.initials: RM
authors.lastname: Carvallo
mesh_terms: D000158:Acoustic Impedance Tests; D000161:Acoustic Stimulation / Q000379:methods*; D000293:Adolescent; D000328:Adult; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D012022:Reflex, Acoustic / Q000502:physiology; D055815:Young Adult
keywords: Acoustic reflex; Audição; Hearing; Hearing tests; Middle ear; Orelha média; Reflexo acústico; Testes auditivos