This aim of this study was to examine the mechanisms underlying the neuropsychiatric symptoms in dementia with Lewy bodies by investigating regional cerebral blood flow.
Participants were 27 patients who fulfilled the diagnostic criteria for probable dementia with Lewy bodies. All subjects underwent single-photon emission computed tomography scans using technetium-99 m hexamethylpropyleneamine oxime. Neuropsychiatric symptoms were evaluated by neuropsychiatric inventory. Multiple regression analyses using neuropsychiatric inventory and voxel-based analyses of covariance of the regional cerebral blood flow images between subjects with or without each neuropsychiatric symptom were performed. Additionally, similar voxel-based analyses of covariance between subjects with each neuropsychiatric symptom and normal subjects were performed.
There were no significant correlations in any psychiatric symptoms in multiple regression analyses. All subjects had hallucination but none had euphoria. We analyzed eight neuropsychiatric symptom scores with the exception of hallucination and euphoria using voxel-based analyses of covariance. Significant differences of regional cerebral blood flow were shown in groups with agitation, disinhibition, and irritability. Subjects with agitation showed hypoperfusion in the parietal lobule, the precuneus, and the angular gyrus, and hyperperfusion in the fusiform gyrus, the lingual gyrus, and the thalamus. Subjects with disinhibition showed hypoperfusion in the left frontal gyrus. Subjects with irritability showed hyperperfusion in the right frontal gyrus. There were no significant differences in regional cerebral blood flow between subjects with any neuropsychiatric symptoms and normal subjects.
This study reveals that dysfunction of specific brain regions is associated with various neuropsychiatric symptoms in dementia with Lewy bodies.