Depression is one of the most frequent and burdensome non-motor symptoms in
Parkinson's disease (PD), across all stages. Even when its severity is mild, PD depression …

Normal maintenance of human motivation depends on the integrity of subcortical structures
that link the prefrontal cortex with the limbic system. Structural and functional disruption of …

Abstract Objective The Parkinson's Progression Markers Initiative (PPMI) is an
observational, international study designed to establish biomarker‐defined cohorts and …

As a multi-factorial degenerative disease, Parkinson's disease (PD) leads to tremor, gait
rigidity, and hypokinesia, thus hampering normal living. As this disease is usually detected …

Executive dysfunction can be present from the early stages of P arkinson's disease (PD). It is
characterized by deficits in internal control of attention, set shifting, planning, inhibitory …

Objective: Nonmotor symptoms (NMS) are common in patients with established Parkinson
disease (PD) but their frequency in early PD has not been extensively studied. Our aim was …

Importance Sleep disturbances are recognized as a common nonmotor complaint in
Parkinson disease but their etiology is poorly understood. Objective To define the sleep and …

Depression occurs in around 35% of patients with Parkinson disease (PD) and is often
persistent. Symptoms of depression can be evident in individuals at the time of diagnosis …

A dopaminergic deficiency in patients with Parkinson's disease (PD) causes abnormalities of
movement, behaviour, learning, and emotions. The main motor features (ie, tremor, rigidity …

This study was undertaken to determine the prevalence and correlates of cognitive
impairment (CI) and neuropsychiatric symptoms (NPS) in early, untreated patients with …