Objective: To assess locus coeruleus volumes in Parkinson’s disease patients with depressive symptoms.

Background: Depression associated with Parkinson disease (PD) has a different symptom profile to endogenous depression, with high frequency and severity of anxiety. The aetiology of depression in PD remains uncertain though abnormal noradrenergic neurotransmission could play a role. We aimed to assess the integrity of locus coeruleus function via in vivoneuromelanin-sensitive MRI in antidepressant-naive patients with PD.

Method: Thirty-four patients with PD were enrolled and underwent a full clinical battery including the patient-reported Beck Depression Inventory-II (BDI-II), the clinician-reported Hamilton Rating Scale for Depression (HRSD), and the structured clinical interview for DSM-IV Axis I Disorders (SCID-I). All subjects underwent a 3T neuromelanin-sensitive MRI.

Results: Ten of 34 patients with PD (29.4%) had BDI-II and HRSD scores above the discriminative cut-off for PD depression though only half of these patients could be classed on SCID-I criteria as having an anxiety/mood disorder. Patients with PD with the highest scores for depression symptoms showed significantly lower volume of locus coeruleus (P<0.05) on neuromelanin-sensitive MRI compared to low score cases, and lower volume of locus coeruleus was correlated with higher BDI-II (r=0.671, P<0.001) and HRSD scores (r=0.751, P<0.001).

Conclusion: Depressive symptoms in antidepressant-naive patients with PD correlate with lower volume in the locus coeruleus possibly reflecting lower extracellular noradrenaline levels. Our data are compatible with a key role of abnormal noradrenergic neurotransmission contributing to the pathophysiology of PD depression. This abstract was also submitted for presentation at the 2019 European Academy of Neurology Conference.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/depressive-symptoms-are-associated-with-lower-locus-coeruleus-volumes-in-parkinsons-disease/