title: Non-invasive detection and monitoring of experimental hydrocephalus with distortion product otoacoustic emissions.
abstract: OBJECTIVE
  We aimed to find out the effects of short term and long term hydrocephalus and intracranial ventricular volume changes on cochlear functions by using distortion product otoacoustic emission (DPOAE) in experimental hydrocephalus rat models for the first time in literature.
  
  
  METHODS
  This study was performed with 48 healthy, adult (8 weeks old), Sprague-Dawley rats which weighed between 200 and 240g. Six groups were formed in this study: short term control, short term sham, short term hydrocephalus, long term control, long term sham and long term hydrocephalus groups. Each group contained eight rats. Short term period was 4 weeks and long term period was 8 weeks after the study started. At the end of these periods, DPOAE measurements were performed and then rats were sacrificed to determine ventricular volumes.
  
  
  RESULTS
  DPOAE values at all frequencies were significantly decreased in the short term hydrocephalus group when compared to the short term control and short term sham groups. DPOAE values at all frequencies were significantly decreased in the long term hydrocephalus group when compared to the long term control and long term sham groups. Besides, long term sham group which had higher ventricular volumes than long term control group also had lower DPOAE measurements. Significant associations were present between DPOAE measurements and ventricular volumes in hydrocephalus models.
  
  
  CONCLUSIONS
  The functional disturbances in cochlear functions due to hydrocephalus have been demonstrated with DPOAE measurements in this study. DPOAE measurements may be thought as an easily applicable non-invasive method in detection and follow-up of patients with hydrocephalus. Our findings should be supported with clinical studies in humans.
authors.affiliation: Ufuk University Medical School, Department of Otorhinolaryngology, Turkey. Electronic address: handearslan5@yahoo.com.
authors.forename: Hande
authors.initials: H
authors.lastname: Ezerarslan
authors.affiliation: Ufuk University Medical School, Department of Otorhinolaryngology, Turkey.
authors.forename: Güçlü Kaan
authors.initials: GK
authors.lastname: Beriat
authors.affiliation: Ufuk University Medical School, Department of Neurosurgery, Turkey.
authors.forename: Raziye Handan
authors.initials: RH
authors.lastname: Nurhat
authors.affiliation: Ufuk University Medical School, Department of Neurosurgery, Turkey.
authors.forename: Burak
authors.initials: B
authors.lastname: Kazancı
authors.affiliation: Ankara University Medical School, Department of Histology and Embriology, Turkey.
authors.forename: Ferda Topal
authors.initials: FT
authors.lastname: Çelikkan
authors.affiliation: Ankara University Medical School, Department of Histology and Embriology, Turkey.
authors.forename: Bizden
authors.initials: B
authors.lastname: Sabuncuoğlu
authors.affiliation: Ufuk University Medical School, Department of Neurosurgery, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Sabuncuoğlu
mesh_terms: D000818:Animals; D003051:Cochlea / Q000503:physiopathology*; D004195:Disease Models, Animal; D006849:Hydrocephalus / Q000503:physiopathology*; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: Hydrocephalus; Inner ear; Obstructive hydrocephalus; Otoacoustic emissions