title: A Dextral Primary Progressive Aphasia Patient with Right Dominant Hypometabolism and Tau Accumulation and Left Dominant Amyloid Accumulation.
abstract: BACKGROUND
  Primary progressive aphasia (PPA) is a degenerative disease that presents as progressive decline of language ability with preservation of other cognitive functions in the early stages. Three subtypes of PPA are known: progressive nonfluent aphasia, semantic dementia, and logopenic aphasia (LPA).
  
  
  METHODS
  We report the case of a 77-year-old patient with PPA whose clinical findings did not correspond to the three subtypes but mainly fit LPA. Unlike other LPA patients, however, this patient showed a right hemisphere predominant glucose hypometabolism and tau accumulation and a left hemisphere predominant amyloid deposition. The right-handed patient presented with comprehension difficulty followed by problems naming familiar objects. This isolated language problem had deteriorated rapidly for 2 years, followed by memory difficulties and impairment of daily activities. Using a Korean version of the Western Aphasia Battery, aphasia was consistent with a severe form of Wernicke's aphasia. According to the brain magnetic resonance imaging and (18)F-fludeoxyglucose positron emission tomography results, right hemisphere atrophy and hypometabolism, more predominant on the right hemisphere than the left, were apparent despite the fact that Edinburgh Handedness Questionnaire scores indicated strong right-handedness. On Pittsburgh compound B-PET, amyloid accumulation was asymmetrical with the left hemisphere being more predominant than the right, whereas (18)F-T807-PET showed a right dominant tau accumulation.
  
  
  CONCLUSIONS
  This is the first report of atypical PPA, in which the patient exhibited crossed aphasia and asymmetrical amyloid accumulation.
authors.affiliation: Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea; Neuroscience Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Young Kyoung
authors.initials: YK
authors.lastname: Jang
authors.affiliation: Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea; Neuroscience Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Seongbeom
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea; Neuroscience Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, and Departments of, Clinical Research Design and Evaluation, Seoul, Korea.
authors.forename: Hanna
authors.initials: H
authors.lastname: Cho
authors.affiliation: Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, and Departments of, Clinical Research Design and Evaluation, Seoul, Korea.
authors.forename: Chul Hyoung
authors.initials: CH
authors.lastname: Lyoo
authors.affiliation: Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea; Neuroscience Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Clinical Research Design and Evaluation, Sungkyunkwan University, Seoul, Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Seo
authors.affiliation: Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea; Neuroscience Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea.
authors.forename: Duk L
authors.initials: DL
authors.lastname: Na
keywords: Asymmetric amyloid accumulation; Asymmetric tau accumulation; Crossed aphasia; Primary progressive aphasia