Hypoperfusion of the visual pathway in parkinsonian patients with visual hallucinations

Abstract

Little is known about the developing mechanisms of visual hallucinations in Parkinson's disease. This study aimed to investigate perfusion changes in parkinsonian patients with visual hallucinations using n-isopropyl-p-[123I]iodoamphetamine ([123I]IMP) single photon emission computed tomography imaging. A total of 70 consecutive patients, including 31 patients with visual hallucinations, and 39 patients without hallucinations, participated in this study. Patients with severe cognitive impairment (Mini-Mental State Examination score < 20), nonvisual hallucinations, or confusion were excluded. We compared brain perfusion changes between the two groups. We found that hallucinatory patients had significant perfusion reductions in the bilateral inferior parietal lobule, inferior temporal gyrus, precuneus gyrus, and occipital cortex compared to nonhallucinatory patients. These results suggested that hypoperfusion of the visual pathway was closely related to visual hallucinations in Parkinson's disease.

Cerebral Metabolic Dysfunction in Patients with Dementia with Lewy Bodies and Visual Hallucinations

“…In addition to our own previous 18 F-FDG PET study on VH in PD [1] , in which we reported a significant hypometabolism of brain regions of the 2 visual streams. Matsui et al [26] also described significant functional damage to these visual pathways in hallucinating patients with PD. This finding is also mirrored in a study by Nagano-Saito et al [27] , who also reported a relative metabolic deficit in posterior cortical areas in a hallucinating PD group.…”

Visual Hallucinations and Cognitive Impairment in Parkinson's Disease

“…One study reported hyperperfusion of the right superior and middle temporal gyri in PD patients with VH 6 , whereas the other study found that hallucinating PD patients exhibited hypoperfusion in the bilateral inferior parietal lobules and inferior temporal gyrus 24 .…”

“…Visual hallucination in PD patients is an important risk factor in terms of nursing home placement, poor quality of life, and mortality 4 . Neuroimaging studies suggested that brain regions involved in higher-order visual processing, ventral or dorsal pathways, were associated with VH in PD patients [5][6][7][8][9] . Pathologic study in Lewy body (LB) disease reported a striking association between the distribution of temporal lobe LB and VH 10 .…”

Combinations of Markers Provide Clues to the Underlying Neurodegenerative Disorder in REM Sleep Behavior Disorder

“…In terms of early intervention, it is important to determine which patterns on the [ 18 F]-FDG PET scans of iRBD patients are suggestive of underlying prodromal DLB or PD. A single photon emission computed tomography imaging study showed that PD patients with visual hallucinations had perfusion reductions in the bilateral inferior parietal lobule, inferior temporal gyrus, precuneus gyrus and occipital cortex (Matsui et al, 2006). In a cerebral SPECT study (Shirakawa et al, 2002) that compared iRBD patients with a control group, a statistically significant decrease in blood flow was observed in the upper portion of the frontal lobe on the left and right sides and the pons in the iRBD group.…”