title: Change in the cortical complexity of spinocerebellar ataxia type 3 appears earlier than clinical symptoms.
abstract: Patients with spinocerebellar ataxia type 3 (SCA3) have exhibited cerebral cortical involvement and various mental deficits in previous studies. Clinically, conventional measurements, such as the Mini-Mental State Examination (MMSE) and electroencephalography (EEG), are insensitive to cerebral cortical involvement and mental deficits associated with SCA3, particularly at the early stage of the disease. We applied a three-dimensional fractal dimension (3D-FD) method, which can be used to quantify the shape complexity of cortical folding, in assessing cortical degeneration. We evaluated 48 genetically confirmed SCA3 patients by employing clinical scales and magnetic resonance imaging and using 50 healthy participants as a control group. According to the Scale for the Assessment and Rating of Ataxia (SARA), the SCA3 patients were diagnosed with cortical dysfunction in the cerebellar cortex; however, no significant difference in the cerebral cortex was observed according to the patients' MMSE ratings. Using the 3D-FD method, we determined that cortical involvement was more extensive than involvement of traditional olivopontocerebellar regions and the corticocerebellar system. Moreover, the significant correlation between decreased 3D-FD values and disease duration may indicate atrophy of the cerebellar cortex and cerebral cortex in SCA3 patients. The change of the cerebral complexity in the SCA3 patients can be detected throughout the disease duration, especially it becomes substantial at the late stage of the disease. Furthermore, we determined that atrophy of the cerebral cortex may occur earlier than changes in MMSE scores and EEG signals.
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Tzu-Yun
authors.initials: TY
authors.lastname: Wang
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC; Department of Recreation Sports and Health Promotion, Asia-Pacific Institute of Creativity, Tao-Fen, Taiwan, ROC.
authors.forename: Chii-Wen
authors.initials: CW
authors.lastname: Jao
authors.affiliation: The Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
authors.forename: Bing-Wen
authors.initials: BW
authors.lastname: Soong
authors.affiliation: Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.
authors.forename: Hsiu-Mei
authors.initials: HM
authors.lastname: Wu
authors.affiliation: Department of Electrical Engineering, National Central University, Chung-Li, Taiwan, ROC.
authors.forename: Kuo-Kai
authors.initials: KK
authors.lastname: Shyu
authors.affiliation: The Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC; The Neurological Institute, Taipei Municipal Gan-Dau Hospital, Taipei, Taiwan, ROC; Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Po-Shan
authors.initials: PS
authors.lastname: Wang
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC; Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Yu-Te
authors.initials: YT
authors.lastname: Wu
mesh_terms: D016022:Case-Control Studies; D002524:Cerebellar Ataxia / Q000473:pathology*; D002540:Cerebral Cortex / Q000473:pathology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D017827:Machado-Joseph Disease / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged