Parkinsonism and Related Disorders xxx (2015) 1e9
Contents lists available at ScienceDirect
Parkinsonism and Related Disorders journal homepage: www.elsevier.com/locate/parkreldis
Review
Structural and functional neuroimaging in patients with Parkinson's disease and visual hallucinations: A critical review Abhishek Lenka a, b, Ketan Ramakant Jhunjhunwala a, b, Jitender Saini c, Pramod Kumar Pal b, * a
Department of Clinical Neurosciences, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India Department of Neurology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India
b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 26 November 2014 Received in revised form 5 April 2015 Accepted 8 April 2015
Patients with Parkinson's disease (PD) may develop various non-motor symptoms (NMS) during the course of the illness and psychosis is one of the common NMS of PD. Visual hallucinations (VH) are the most common manifestation of psychosis in PD. The exact pathogenesis of VH in patients with PD is not clearly understood. Presence of VH has been described to be associated with rapid cognitive decline and increased nursing home placements in PD patients. A large number of structural and functional neuroimaging studies have been conducted to understand the cerebral basis of VH in PD. Structural imaging studies (Voxel Based Morphometry) have reported grey matter atrophy in multiple regions of the brain such as primary visual cortex, visual association cortex, limbic regions, cholinergic structures such as pedunculopontine nucleus and substantia innominata, which conclude possible alterations of brain regions associated with functions such as visuospatial-perception, attention control and memory. Most functional neuroimaging studies (functional MRI, positron emission tomography and single photon emission computerized tomography) have reported altered activation, blood flow, or reduced metabolism in both dorsal and ventral visual pathways, which probably indicates an alteration in the normal bottom-top visual processing and the presence of an aberrant top-down visual processing. This review critically analyzes the published studies on the structural and functional neuroimaging in PD patients with VH. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Parkinson's disease Visual hallucinations VBM fMRI PET SPECT
1. Introduction Parkinson's disease (PD) is a progressive neurodegenerative disease with a prevalence of 0.3% among people aged
Contents lists available at ScienceDirect
Parkinsonism and Related Disorders journal homepage: www.elsevier.com/locate/parkreldis
Review
Structural and functional neuroimaging in patients with Parkinson's disease and visual hallucinations: A critical review Abhishek Lenka a, b, Ketan Ramakant Jhunjhunwala a, b, Jitender Saini c, Pramod Kumar Pal b, * a
Department of Clinical Neurosciences, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India Department of Neurology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India
b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 26 November 2014 Received in revised form 5 April 2015 Accepted 8 April 2015
Patients with Parkinson's disease (PD) may develop various non-motor symptoms (NMS) during the course of the illness and psychosis is one of the common NMS of PD. Visual hallucinations (VH) are the most common manifestation of psychosis in PD. The exact pathogenesis of VH in patients with PD is not clearly understood. Presence of VH has been described to be associated with rapid cognitive decline and increased nursing home placements in PD patients. A large number of structural and functional neuroimaging studies have been conducted to understand the cerebral basis of VH in PD. Structural imaging studies (Voxel Based Morphometry) have reported grey matter atrophy in multiple regions of the brain such as primary visual cortex, visual association cortex, limbic regions, cholinergic structures such as pedunculopontine nucleus and substantia innominata, which conclude possible alterations of brain regions associated with functions such as visuospatial-perception, attention control and memory. Most functional neuroimaging studies (functional MRI, positron emission tomography and single photon emission computerized tomography) have reported altered activation, blood flow, or reduced metabolism in both dorsal and ventral visual pathways, which probably indicates an alteration in the normal bottom-top visual processing and the presence of an aberrant top-down visual processing. This review critically analyzes the published studies on the structural and functional neuroimaging in PD patients with VH. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Parkinson's disease Visual hallucinations VBM fMRI PET SPECT
1. Introduction Parkinson's disease (PD) is a progressive neurodegenerative disease with a prevalence of 0.3% among people aged
