title: Hippocampal volume and white matter disease in the prediction of dementia in Parkinson's disease.
abstract: BACKGROUND
  Longitudinal neuroimaging studies could provide insights into pathophysiology of cognitive impairment in PD. We examined the role of hippocampal atrophy and cerebral white matter disease as risk factors for mild cognitive impairment and dementia in PD.
  
  
  METHODS
  Prospective longitudinal study of patients with mild PD in a tertiary neurology center. All subjects underwent baseline MRI brain and had baseline and 6 monthly cognitive evaluations. Cognitive impairment was diagnosed based on the Movement Disorder Society Criteria. The predictive role of hippocampal volume and white matter hyperintensity at baseline on progression of cognitive impairment was studied.
  
  
  RESULTS
  97 subjects with mean age 65.3 years, mean education of 10.3 years and mean Hoehn & Yahr of 1.9 were studied. Over 2 years, 16 subjects developed mild cognitive impairment and 8 subjects with mild cognitive impairment progressed to dementia. After adjusting for age and vascular risk factors, hippocampal volume was a significant predictor for mild cognitive impairment (OR 7.05, CI 1.5-34.1; p = 0.015) and dementia (OR 7.03, CI 2.39-25.2; p = 0.001). With Cox regression, hippocampal volume was a significant predictor for "time to cognitive impairment" (HR 7.67; CI 3.47-16.95, p < 0.001). Difference between survival curves based on volume of white matter hyperintensity in predicting "time to mild cognitive impairment" was significant (p = 0.0295).
  
  
  CONCLUSIONS
  Hippocampal volume is a major factor predicting the development of mild cognitive impairment and dementia in PD. White matter hyperintensity also contributes to the longitudinal cognitive status in PD.
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore; Duke-NUS, Graduate Medical School, 8 College Road, Singapore 169857, Singapore. Electronic address: Nagaendran_Kandiah@nni.com.sg.
authors.forename: Nagaendran
authors.initials: N
authors.lastname: Kandiah
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore.
authors.forename: Nur Hani
authors.initials: NH
authors.lastname: Zainal
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore.
authors.forename: Kaavya
authors.initials: K
authors.lastname: Narasimhalu
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore.
authors.forename: Russell Jude
authors.initials: RJ
authors.lastname: Chander
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore.
authors.forename: Aloysius
authors.initials: A
authors.lastname: Ng
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore.
authors.forename: Elijah
authors.initials: E
authors.lastname: Mak
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore; Duke-NUS, Graduate Medical School, 8 College Road, Singapore 169857, Singapore.
authors.forename: Wing Lok
authors.initials: WL
authors.lastname: Au
authors.affiliation: Duke-NUS, Graduate Medical School, 8 College Road, Singapore 169857, Singapore; Department of Neuroradiology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore.
authors.forename: Yih Yian
authors.initials: YY
authors.lastname: Sitoh
authors.affiliation: Centre for Quantitative Medicine, Duke-NUS, 8 College Road, Singapore 169857, Singapore.
authors.forename: Nivedita
authors.initials: N
authors.lastname: Nadkarni
authors.affiliation: Department of Neurology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore; Duke-NUS, Graduate Medical School, 8 College Road, Singapore 169857, Singapore.
authors.forename: Louis C S
authors.initials: LC
authors.lastname: Tan
mesh_terms: D000328:Adult; D000368:Aged; D003704:Dementia / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D056784:Leukoencephalopathies / Q000209:etiology*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012720:Severity of Illness Index
keywords: Cerebrovascular disease; Cognition; Hippocampus; MRI; Parkinson's disease