Parkinson’s disease includes the classic motor signs but also many non-motor signs, some of which belong to the cognitive and neuro-behavioral register (apathy, dysexecutive syndrome, anxio-depressive syndrome, decreased libido …)
If we take Braak’s diagram concerning the progression of the disease (digestive tract, locus coeruléus, cortical areas), we better understand the onset of cognitive disorders in Parkinson’s disease related to Lewy bodies and alpha-synuclein aggregates.
The risk of developing severe cognitive impairment (dementia) is multiplied by a factor of 2 to 6 compared to the general population with known risk factors (age, duration of disease, male sex, axial signs of the disease, smoking, occurrence of hallucinations under treatment).
Imaging means (MRI, FDG Petscanner) can be used to better visualize the cortical areas affected and assess the evolving risk.
At an advanced stage of the disease, we can find attentional disorders, dysexecutive disorders (alteration initiation, planning, conceptualization), visuospatial disorders (alteration orientation and perception), then memory and language disorders that occur later.
An early assessment of cognitive disorders and the realization of a neuro-psychological assessment can therefore be useful to better specify the degree of the impairment and guide the management especially non-drug (speech therapy, occupational therapist …) and limit the risk of side effects likely to occur under drug treatment (L.Dopa or dopaminergic agonist).