The cognitive ability of an incident cohort of Parkinson’s patients in the UK. The CamPaIGN study

TLDR

The CamPaIGN study recruited a population‑representative cohort of newly diagnosed Parkinson’s patients in the UK over two years and performed detailed home or clinic assessments to refine diagnoses and characterize phenotypic variability at diagnosis. Incidence of Parkinson’s disease was 13.6 per 10,000 person‑years (10.8 age‑standardised) and parkinsonism 20.9 per 10,000 (16.6 age‑standardised), with 36 % of Parkinson’s patients showing cognitive impairment, suggesting early‑stage cognitive sub‑groups linked to regional neuropathology.

Abstract

We have used multiple sources to identify a population-representative cohort of newly diagnosed patients with parkinsonism and Parkinson's disease in the UK over a 2-year period. All patients have been invited to participate in a detailed clinical assessment either at home or in an outpatient clinic. These assessments have been used to refine clinical diagnoses of parkinsonism using established criteria, and describe some of the phenotypic variability of Parkinson's disease at the time of diagnosis. The crude incidence of Parkinson's disease was 13.6/10(5yr-1) [confidence interval (CI) 11.8-15.6 and of parkinsonism was 20.9/10(5yr-1) (CI 18.7-23.3). Age-standardized to the 1991 European population, the incidence figures become 10.8/10(5yr-1) (CI 9.4-12.4) for Parkinson's disease and 16.6/10(5yr-1) (CI 14.8-18.6) for parkinsonism. Thirty-six per cent of the Parkinson's disease patients had evidence of cognitive impairment based on their performance in the Mini-Mental State Examination, a pattern recognition task, and the Tower of London task. The pattern of cognitive deficits seen among these patients using these and further cognitive tasks suggests that sub-groups of patients based on cognitive ability might be identifiable even in the early stages of disease, which may reflect regional differences in the underlying neuropathological processes.