title: Selective preservation of the beat in apperceptive music agnosia: a case study.
abstract: BACKGROUND
  Music perception involves processing of melodic, temporal and emotional dimensions that have been found to dissociate in healthy individuals and after brain injury. Two components of the temporal dimension have been distinguished, namely rhythm and metre. We describe an 18 year old male musician 'JM' who showed apperceptive music agnosia with selectively preserved metre perception, and impaired recognition of sad and peaceful music relative to age and music experience matched controls after resection of a right temporoparietal tumour.
  
  
  METHODS
  Two months post-surgery JM underwent a comprehensive neuropsychological evaluation including assessment of his music perception abilities using the Montreal Battery for Evaluation of Amusia (MBEA, Peretz, Champod, & Hyde, 2003). He also completed several experimental tasks to explore his ability to recognise famous songs and melodies, emotions portrayed by music and a broader range of environmental sounds. Five age-, gender-, education- and musical experienced-matched controls were administered the same experimental tasks.
  
  
  RESULTS
  JM showed selective preservation of metre perception, with impaired performances compared to controls and scoring below the 5% cut-off on all MBEA subtests, except for the metric condition. He could identify his favourite songs and environmental sounds. He showed impaired recognition of sad and peaceful emotions portrayed in music relative to controls but intact ability to identify happy and scary music.
  
  
  CONCLUSIONS
  This case study contributes to the scarce literature documenting a dissociation between rhythmic and metric processing, and the rare observation of selectively preserved metric interpretation in the context of apperceptive music agnosia. It supports the notion that the anterior portion of the superior temporal gyrus (STG) plays a role in metric processing and provides the novel observation that selectively preserved metre is sufficient to identify happy and scary, but not sad or peaceful emotions portrayed in music.
authors.affiliation: School of Psychology, The University of Queensland Neuropsychology Research Unit, Brisbane, Australia; ARC Centre of Excellence in Cognition and its Disorders, Australia.
authors.forename: Amee D
authors.initials: AD
authors.lastname: Baird
authors.affiliation: BrizBrain & Spine, The Wesley Hospital, Brisbane, Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Walker
authors.affiliation: BrizBrain & Spine, The Wesley Hospital, Brisbane, Australia.
authors.forename: Vivien
authors.initials: V
authors.lastname: Biggs
authors.affiliation: School of Psychology, The University of Queensland Neuropsychology Research Unit, Brisbane, Australia. Electronic address: g.robinson@psy.uq.edu.au.
authors.forename: Gail A
authors.initials: GA
authors.lastname: Robinson
mesh_terms: D000293:Adolescent; D000377:Agnosia / Q000523:psychology*; D001307:Auditory Perception / Q000502:physiology; D001932:Brain Neoplasms / Q000150:complications / Q000523:psychology / Q000601:surgery; D003071:Cognition / Q000502:physiology; D003399:Craniotomy / Q000009:adverse effects; D006801:Humans; D008297:Male; D009146:Music / Q000523:psychology*; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D009837:Oligodendroglioma / Q000150:complications / Q000523:psychology / Q000601:surgery; D011183:Postoperative Complications / Q000523:psychology; D021641:Recognition, Psychology / Q000502:physiology
keywords: Apperceptive amusia; Metre; Music; Neuropsychology; Temporal processing