title: Cognitive status correlates with white matter alteration in Parkinson's disease.
abstract: Patients with Parkinson's disease (PD) can develop mild cognitive impairment (PD-MCI), frequently progressing to dementia (PDD). Here, we aimed to elucidate the relationship between white matter alteration and cognitive status in PD and dementia with Lewy bodies (DLB) by using diffusion tensor imaging. We also compared the progression patterns of white and gray matter and the cerebral perfusion. We enrolled patients with PD cognitively normal (PD-CogNL, n = 32), PD-MCI (n = 28), PDD (n = 25), DLB (n = 29), and age- and sex-matched healthy control subjects (n = 40). Fractional anisotropy (FA) map of a patient group was compared with that of control subjects by using tract-based spatial statistics. For the patient cohort, intersubject voxel-wise correlation was performed between FA values and Mini-Mental Status Examination (MMSE) scores. We also evaluated the gray matter and the cerebral perfusion by conducting a voxel-based analysis. There were significantly decreased FA values in many major tracts in patients with PD-MCI, PDD, and DLB, but not in PD-CogNL, compared with control subjects. FA values in the certain white matter areas, particularly the bilateral parietal white matter, were significantly correlated with MMSE scores in patients with PD. Patients with PDD and DLB had diffuse gray matter atrophy. All patient groups had occipital and posterior parietal hypoperfusion when compared with control subjects. Our results suggest that white matter damage underlies cognitive impairment in PD, and cognitive impairment in PD progresses with functional alteration (hypoperfusion) followed by structural alterations in which white matter alteration precedes gray matter atrophy.
authors.affiliation: Department of Neurology and Neurological Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hattori
authors.forename: Satoshi
authors.initials: S
authors.lastname: Orimo
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
authors.forename: Kenji
authors.initials: K
authors.lastname: Ito
authors.forename: Osamu
authors.initials: O
authors.lastname: Abe
authors.forename: Atsushi
authors.initials: A
authors.lastname: Amano
authors.forename: Ryo
authors.initials: R
authors.lastname: Sato
authors.forename: Kasumi
authors.initials: K
authors.lastname: Sakai
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Mizusawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D010300:Parkinson Disease / Q000150:complications / Q000473:pathology*