Potential Imaging Biomarker for Neuropsychiatric Symptoms in Early PD

In patients with Parkinson disease, decreased monoamine availability in the thalamus may be an imaging biomarker of neuropsychiatric symptoms, according to a study published online in Neurological Sciences. 

“Neuropsychiatric symptoms are relatively common in Parkinson disease,” researchers wrote. “Many studies have revealed that striatal monoamine availability is associated with specific neuropsychiatric symptoms. This study was aimed to investigate the association between comprehensive neuropsychiatric symptoms and striatal monoamine availability in patients with early Parkinson disease without dementia.” 

The study included 156 newly diagnosed patients with Parkinson disease but without dementia. Researchers used the 12-item Neuropsychiatric Inventory to assess participants’ mental and behavioral symptoms. Patients also underwent positron emission tomography (PET) with 18F-N-(3-fluoropropyl)-2beta-carbon ethoxy-3beta-(4-iodophenyl) nortropane and brain magnetic resonance imaging (MRI). 

“After normalizing the PET images to spatially normalized MRI,” researchers explained, “regional standardized uptake value ratios (SUVRs) with a volume of interest template were analyzed for the two groups.” 

More than half of participants had more than one neuropsychiatric symptom, according to the study. In those with neuropsychiatric symptoms, SUVRs in the thalamus were significantly lower independent of age, sex, disease duration, and motor symptom severity compared with those with no neuropsychiatric symptoms. 

“Patients with early Parkinson disease who have neuropsychiatric symptoms had a lower monoamine availability in the thalamus than those with no neuropsychiatric symptoms,” researchers concluded. “This finding suggests that decreased monoamine transporter availability in the thalamus may be an imaging biomarker of neuropsychiatric symptoms in patients with Parkinson’s disease.” 

—Jolynn Tumolo

Reference 

Oh YS, Kim JH, Yoo SW, et al. Neuropsychiatric symptoms and striatal monoamine availability in early Parkinson's disease without dementia [published online ahead of print, 2020 Oct 31]. Neurol Sci. 2020;10.1007/s10072-020-04859-8. doi:10.1007/s10072-020-04859-8