Clinically assessing cognitive function in Parkinson's disease

Abstract Although Parkinson's disease (PD) is typically framed as a motor disorder, people with the disease may experience a plethora of other nonmotor symptoms that may be equally debilitating. The management of cognitive impairment is an area of growing clinical interest given its heterogeneous manifestations and the increased relative risk of dementia; hence there is an urgent need to be able to effectively assess cognitive function and identify patients in the early stages of cognitive deterioration. Cognitive impairment is frequently reported at the time of PD diagnosis, with executive, attentional, and visuospatial abilities being primarily affected. Formal cognitive assessments are the most efficient, comprehensive, and reliable way to confirm the presence of early cognitive symptoms in PD. However, there are an array of varying evaluative tools with diverse strengths and weaknesses, and the reliability of cognitive evaluations can be clouded by associated symptoms, level of education, and reproducibility of the procedures over time. As such, the selection of the most relevant, reliable, and sensitive protocols for cognitive assessment is imperative. Research endeavors continue to identify more reliable and discriminating protocols as well as biomarkers that will allow earlier diagnosis of cognitive and behavioral deficits and the accurate assessment of new therapeutic approaches to delay or stop their progression.