Regional cerebral blood flow in Parkinson disease with nonpsychotic visual hallucinations.
BACKGROUND
Patients with Parkinson disease (PD) often experience visual hallucinations (VH) with retained insight (nonpsychotic) but the precise mechanism remains unclear.


OBJECTIVE
To clarify which neural substrates participate in nonpsychotic VH in PD, the authors evaluated regional cerebral blood flow (rCBF) changes in patients with PD and VH.


METHODS
The authors compared 24 patients with PD who had nonpsychotic VH (hallucinators) and 41 patients with PD who had never experienced VH (non-hallucinators) using SPECT images with N-isopropyl-p-[(123)I]iodoamphetamine. There were no significant differences in age, sex, duration of disease, doses of PD medications, Hoehn and Yahr scale, or Mini-Mental State Examination (MMSE) scores between the two groups. The rCBF data were analyzed using statistical parametric mapping (SPM).


RESULTS
The rCBF in the right fusiform gyrus was lower in the hallucinators than in the non-hallucinators (corrected p < 0.05 at cluster levels). The hallucinators revealed higher rCBF in the right superior and middle temporal gyri than the non-hallucinators (uncorrected p < 0.001). These significant differences were demonstrated after MMSE scores and duration of disease, which are the relevant factors associated with VH, were covariated out.


CONCLUSIONS
Nonpsychotic visual hallucinations in Parkinson disease (PD) may be associated with hypoperfusion in the right fusiform gyrus and hyperperfusion in the right superior and middle temporal gyri. These temporal regions are important for visual object recognition and these regional cerebral blood flow changes are associated with inappropriate visual processing and are responsible for nonpsychotic visual hallucinations in PD.
Oishi
N
N
Human Brain Research Center, Kyoto University Graduate School of Medicine, Japan. noishi@kuhp.kyoto-u.ac.jp
Udaka
F
F
Kameyama
M
M
Sawamoto
N
N
Hashikawa
K
K
Fukuyama
H
H
D000368:Aged; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006212:Hallucinations / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011237:Predictive Value of Tests; D013702:Temporal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon; D014793:Visual Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D014795:Visual Pathways / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D014796:Visual Perception / Q000502:physiology