Selective hypometabolism in the inferior frontal lobe in depressed patients with Parkinson's disease

TLDR

Depression frequently occurs in patients with Parkinson’s disease. The study used 18F‑fluoro‑2‑deoxy‑D‑glucose PET to quantify regional cerebral glucose metabolism in depressed and nondepressed PD patients and age‑matched controls. Depressed PD patients showed significantly reduced metabolism in the caudate and orbital‑inferior frontal lobe, with an inverse correlation to depression scores, indicating that dysfunction of basal ganglia‑frontal circuits underlies mood disturbance in PD.

Abstract

Abstract Depression is a frequent finding in patients with Parkinson's disease (PD). Regional cerebral glucose metabolism was measured in depressed and nondepressed patients with PD and in age‐comparable normal control subjects using 2‐[ 18 F]‐fluoro‐2‐deoxy‐D‐glucose and positron emission tomography (PET). Relative metabolic activity in the caudate and orbital‐inferior region of the frontal lobe was significantly lower in the depressed patients with PD as compared to both nondepressed patients and control subjects. There was a significant inverse correlation between relative glucose metabolism in the orbital‐inferior area of the frontal lobe and depression scores. This study suggests that depression in PD is associated with dysfunction in the caudate and orbital‐inferior area of the frontal lobe. This metabolic pattern is unlike that seen in patients with PD who have other behavioral deficits such as dementia, and suggests that disruption of basal ganglia circuits involving the inferior region of the frontal lobe may affect the regulation of mood.