title: Auditory spatial deficits in brainstem disorders.
abstract: OBJECTIVE
  Brainstem disorders seem to negatively influence the central auditory system, causing spatial hearing deficits.
  
  
  METHODS
  We tested 11 patients with brainstem lesions due to ischemic stroke (IS), multiple sclerosis (MS), or cerebellopontine angle tumor (CPAT) together with 50 age- and sex-matched healthy volunteers. We used pure tone audiometry (PTAud), brainstem auditory evoked potentials (BAEPs) and the horizontal minimum audible angle test (HMAAT) for 8 azimuths with binaural stimulation.
  
  
  RESULTS
  The chosen patients and the controls had normal or near normal hearing in PTAud. BAEPs interaural wave I-V latency difference was over 7 times longer in the patients group compared to the controls. Additionally, 9 of the 11 patients (81.1%) had abnormal HMAAT results. The biggest quantitative disturbances in HMAAT were present in the CPAT and the MS patients. The sound localization ability in HMAAT was significantly worse in the patients in 0° azimuth in comparison with the controls, and in 45° and 90° azimuth in patients with auditory pathway involvement compared with the ones without the involvement.
  
  
  CONCLUSIONS
  Our study confirms the strong relationship between various brainstem pathologies and sound localization disability and sheds some light on the complexity of the relationship.
authors.affiliation: Department of Otolaryngology, Medical University of Gdańsk, Gdańsk, Poland. Electronic address: tprzew@gumed.edu.pl.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Przewoźny
authors.affiliation: Department of Neurology of Adults, Medical University of Gdańsk, Gdańsk, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Gójska-Grymajło
authors.affiliation: Department of Neurosurgery, Medical University of Gdańsk, Gdańsk, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Szmuda
authors.affiliation: II Department of Radiology, Medical University of Gdańsk, Gdańsk, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Markiet
mesh_terms: D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D001308:Auditory Perceptual Disorders / Q000503:physiopathology*; D001927:Brain Diseases / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000473:pathology; D001933:Brain Stem / Q000473:pathology / Q000503:physiopathology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology; D009464:Neuroma, Acoustic / Q000473:pathology; D013017:Sound Localization / Q000502:physiology*; D020521:Stroke / Q000473:pathology; D055815:Young Adult
keywords: Brainstem; Central auditory processing disorders; Central hearing loss; Sound localization impairment; Stroke