Parkinson’s disease: a review of non-motor symptoms

Abstract

Parkinson's disease (PD) is a neurodegenerative disorder resulting from degeneration of the substantia nigra and the dopaminergic nigrostriatal pathway. Most treatments are geared toward the management and relief of motor symptoms in Parkinson's patients; however, as the disease progresses, various complications can be observed. Non-motor symptoms (NMS) may arise simply from the disease itself and are highly destructive to quality of life. These symptoms include mood disorders, cognitive dysfunction, pain, sensory dysfunction, and dysautonomia. Though it is undisputed that many NMS may appear years or even decades prior to the clinical diagnosis of PD, the focus of this review will be the overt motor phase of the condition. As such, the focus of this paper is to review the major NMS found in PD patients status post-diagnosis, their etiology, as well as treatment options available for the individual NMS.

Impaired long contact white matter fibers integrity is related to depression in Parkinson's disease

“…Depression is one of the most common mood disturbances in PD, but its pathogenesis is unclear . Studies using advanced neuroimaging generally suggest increased neural activity in the prefrontal regions and decreased functional connectivity between the prefrontal‐limbic networks in depressed PD patients .…”

“…Parkinson's disease (PD) is one of the most common neurodegenerative disorders, which have typical motor symptoms including resting tremor, rigidity, bradykinesia, and postural reflex abnormalities . Increasing studies have shown that most PD patients will experience a series of nonmotor symptoms such as paresthesia, sleep disorders, autonomic dysfunction, neuropsychiatric symptoms, and behavioral disorders . Depression is the most common neuropsychiatric symptom, and up to 50% PD patients have suffered from this psychiatric disorder .…”

“…Early recognition, diagnosis, and treatment of depression in PD patients will help to improve the quality of life and delay the progress of PD. But till now, the pathophysiological mechanism of depression in PD is still unclear …”

Abnormalities of regional brain function in Parkinson’s disease: a meta-analysis of resting state functional magnetic resonance imaging studies

“…PD is traditionally defined as a movement disorder resulting from a prominent loss of dopaminergic neurons of the nigrostriatal pathway, but more recently it has been demonstrated that widespread non-motor symptoms, such as cognitive impairment and mood disorders, are also prevalent, which involve extensive brain regions3456. PD is clinically and etiologically heterogeneous and its complex neurobiological underpinnings remain to be fully elucidated3.…”

Previous Injury and Chronic Pain are Associated with Side of Onset in Parkinson’s Disease

“…On the other hand, it is well known that PD can affect many non-motor systems. Chronic pain has been known to be part of PD, as many PD patients have reported differential pain [9], and levodopa has been shown to be associated with increased pain threshold in PD [10]. Thus, it is conceivable that higher chronic pain from limb injuries may represent the lower pain threshold in the pre-PD state.…”