Cognitive Impairment in Parkinson’s Disease: An Updated Overview Focusing on Emerging Pharmaceutical Treatment Approaches

Cognitive impairment in patients with Parkinson’s disease (PD), which may occur in various severities, represents one of the commonest and most disabling non-motor manifestations during the course of the disease, causing a negative impact on patients’ quality of life. Eventually, it becomes a burden for the family members and/or the caregivers of patients, as it progresses to PD dementia. Current pharmacological treatments for cognitive impairment in PD exhibit partial efficacy, while novel effective therapeutic strategies are required. Accumulating preclinical and clinical evidence shows that several agents may provide beneficial effects on patients with PD and cognitive impairment, including ceftriaxone, ambroxol, intranasal insulin, nilotinib, atomoxetine, mevidalen, blarcamesine, prasinezumab, SYN120, ENT-01, NYX-458, GRF6021, fosgonimeton, INT-777, Neuropeptide S, silibinin, osmotin, cordycepin, huperzine A, fibroblast growth factor 21, Poloxamer 188, ginsenoside Rb1, thioredoxin-1, tangeretin, istradefylline, and Eugenia uniflora. Potential underlying mechanisms include the inhibition of a-synuclein aggregation, improvement of mitochondrial function, regulation of synaptic plasticity, impact on gut-brain axis, modulation of neuroinflammation, upregulation of neurotrophic factors, as well as cholinergic, dopaminergic, serotoninergic and norepinephrine neurotransmission. In this overview, we aim to cover the clinical aspects of PD associated cognitive impairment, highlighting recent evidence on emerging treatment approaches that are currently under investigation at a preclinical and clinical level.