Association of Hemispheric Asymmetry of Dopamine-Transporter Binding with Risk of Parkinsonian Depression

Depression is the most common psychiatric disorder diagnosed in patients with Parkinson's disease (PD). A direct role in PD depression for loss of dopaminergic terminals and dopamine-transporter (DAT) expression in the striatum is revealed by many studies.

The objective was to discern the relationship between DAT neuroimaging and risk of depression in PD.

One hundred and ninety-eight PD patients (101 with depression, 97 without depression) were evaluated using an extensive protocol from 2015 to 2023. DAT availability at striatal terminals was assessed with single-photon emission computed tomography with ¹²³I-Ioflupane. Specific binding ratio (SBR) of ¹²³I-Ioflupane and the whole striatum asymmetry index (SASI) were calculated. Data were analyzed with univariate/multivariate models as well as receiver operating characteristic (ROC) curves.

A logistic regression model adjusting for confounding risk factors of depression indicates that SASI and PD duration are associated with the odds of having parkinsonian depression. SASI is the strongest predictor of risk of parkinsonian depression. Following ROC analysis, SASI is found to be an accurate factor for detecting parkinsonian depression because a cutoff value of 3.4895 of SASI shows good accuracy (0.813), sensitivity (81.1%), and specificity (80%). Higher SASI is also linked to more disease-related limitations in activities of daily living.

The whole SASI is the strongest predictor of risk of parkinsonian depression. The findings could be valuable in evaluating depression in PD patients.