title: Contact endoscopic comparison of morphology of human fungiform papillae of healthy subjects and patients with transected chorda tympani nerve.
abstract: BACKGROUND
  The chorda tympani nerve (CTN) carries gustatory fibers from taste buds of fungiform papillae (fPap) of the anterior portion of the tongue. Accordingly, middle ear surgery with transection of the CTN may result in gustatory impairment. With use of contact endoscopy, the present study aimed to compare number and shape of fPap and subepithelial vessel formation in patients after CTN transection with that of healthy controls.
  
  
  METHODS
  The number of fPap per square centimeter was obtained in addition to measures of gustatory sensitivity using electrogustometry and intensity ratings of natural taste stimuli. Data from 32 healthy subjects (mean age 40 yr; 16 female, 16 male) were compared with those from 14 patients whose CTN had been cut and partly resected during middle ear surgery because of cholesteatoma (mean age 38 yr; 7 female, 7 male). Middle ear surgery was performed by two of the authors.
  
  
  RESULTS
  In healthy subjects, a higher fPap density was found on the tongue's tip compared with its edge; younger subjects had higher densities than older subjects. No sex-related differences were observed. Patients with transected CTN exhibited a significant decrease of taste function as measured with both natural and electric stimuli. In patients, we found significantly fewer and flatter fPap on the side of the tongue where surgery had been performed in comparison with the contralateral side. In addition, fPap density at the ipsilateral side was significantly lower compared with fPap density on the respective side in healthy controls.
  
  
  CONCLUSIONS
  As established through contact endoscopy, the number of fPap decreases in relation to deafferentation and also in relation to the subjects' age, both of which are accompanied by a decreased gustatory sensitivity.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University of Rostock, Germany. tino.just@med.uni-rostock.de
authors.forename: Tino
authors.initials: T
authors.lastname: Just
authors.forename: Hans Wilhelm
authors.initials: HW
authors.lastname: Pau
authors.forename: Martin
authors.initials: M
authors.lastname: Witt
authors.forename: Thomas
authors.initials: T
authors.lastname: Hummel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002814:Chorda Tympani Nerve / Q000502:physiology / Q000601:surgery*; D004408:Dysgeusia / Q000473:pathology* / Q000503:physiopathology; D019723:Endoscopes; D004724:Endoscopy / Q000379:methods*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013650:Taste Buds / Q000166:cytology* / Q000502:physiology; D013652:Taste Threshold / Q000502:physiology