title: Aetiology of auditory dysfunction in amusia: a systematic review.
abstract: BACKGROUND
  Amusia, a music-specific agnosia, is a disorder of pitch interval analysis and pitch direction change recognition which results in a deficit in musical ability. The full range of aetiological factors which cause this condition is unknown, as is each cause's frequency. The objective of this study was to identify all causes of amusia, and to measure each of their frequencies.
  
  
  METHODS
  
  
  
  METHODS
  systematic review was conducted by search of multiple databases for articles related to the aetiology of amusic auditory dysfunction. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting of systematic reviews were followed, utilizing the PRISMA checklist and PRISMA flowchart methodology.
  
  
  METHODS
  Retrospective medical database review.
  
  
  METHODS
  evidence yielded from the systematic review process.
  
  
  RESULTS
  The initial search protocol identified 5723 articles. Application of a classification review filter and exclusion of irrelevant or duplicates led to the initial identification of 56 relevant studies which detailed 301 patients. However, these studies were of poor quality. Because of this, synthesis and statistical analysis were not appropriate.
  
  
  CONCLUSIONS
  Although initially a large number of relevant studies were identified, and might point in future to potential diagnostic categories, it was not appropriate to synthesise and analyse them due to poor quality, considerable heterogeneity and small numbers. This suggests that large, high quality studies focussed directly on understanding the aetiology of amusia are required.
authors.affiliation: Merton College, University of Oxford, Oxford OX1 4JD, UK. daniel.casey@merton.ox.ac.uk.
authors.forename: Daniel Aj
authors.initials: DA
authors.lastname: Casey