Characterization Of Cognitive Decline Over 5 Years in an Incident Parkinson’s Disease Cohort

Posted on 13 March 2015 in Clinical Trials / Research

Author: Pradeep Nathan, Senior Scientific Director

Although Parkinson’s disease (PD) is largely defined in terms of its motor symptoms, it is increasingly recognised that non-motor symptoms including cognitive deficits form an important part of the illness. Dementia is a common feature of the disease, with an estimated prevalence of between 24 and 31% and it has been shown that dementia has a major impact on quality of life, prognosis and risk factor for nursing home placement, with serious health economics implications.

Currently there are a number of Pharmaceutical companies developing drugs targeting non-motor symptoms including cognitive dysfunction. However, the nature of the cognitive changes in PD is complex due to regional differences in brain changes, medication dose and stage of illness. This makes it challenging to develop drugs for cognition in PD, particularly early in the illness (for example in PD-MCI).

From a large dataset gathered from the CamPaIGN study at the University of Cambridge, we examined how cognitive performance in multiple domains changed over the first 5 years from diagnosis in a cognitively able subgroup of a population-representative, incident PD cohort and assessed the effects of medication and relationship with day to day function.

Our findings suggest that there is a progressive impairment in executive and memory processes associated with frontostriatal and dopamine function as assessed using the CANTAB Stockings of Cambridge (SOC) and Spatial Recognition Memory (SRM) tasks in a group of patients that are non-dementing. Interestingly this impairment was not dependent on medication use and associated with a reduction in functional independence and therefore of functional relevance to patients. These findings further highlight that these specific cognitive processes with functional relevance to patients could be an additional target for future drug development programs in PD.

Overall, the findings highlight the sensitivity of CANTAB tasks such as SOC and SRM in probing disease progression and cognitive impairment in PD and add to the already strong literature on the sensitivity of the CANTAB in detecting cognitive impairment and pro-cognitive effects of pharmacological treatments including L-DOPA in patients with Parkinson’s disease. 

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