The relationships between mild cognitive impairment and phenotype in Parkinson’s disease

A subset of patients with Parkinson’s disease (PD) shows a higher frequency of mild cognitive impairment (MCI). Disease pathways underlying cognitive symptoms of PD are not well understood, making it difficult to determine which patients are at highest risk. Researchers in Australia led by Simon Lewis at the University of Sydney analyzed cognitive and other variables in 209 patients with early stage PD, using new diagnostic criteria proposed by the International Parkinson and Movement Disorder Society. The team confirmed that patients could be divided into four groups: younger onset, tremor dominant, non-tremor dominant (NTD), and rapid disease progression. The NTD subgroup showed the highest frequency of MCI (54%), combined with a higher prevalence of other symptoms. Improving understanding of MCI in PD may therefore help to identify patients who would benefit from dementia intervention strategies.