Cognitive Deficits in Early Parkinson’s Disease: New Areas of Research

Cognitive deficits in Parkinson’s disease (PD) are heterogeneous, including in the early stages of the disease. The prognostic value of early cognitive deficits is still under debate, but there is particular interest in identifying deficits that are capable of predicting patients at risk of developing dementia. To date, research has focused on four neuropsychological domains (executive/attention, visuo-spatial, memory, and language), but there is recent evidence that impairment may extend beyond this, in particular into the field of social neuroscience. This review will briefly discuss the cognitive impairments in early PD, including the recent evidence for deficits in theory of mind, before evaluating the diagnostic criteria for, and utility of, the term “mild cognitive impairment” in PD.