Background

The aim of this study was to investigate the feasibility of assessing cognitive impairment in patients with PD, presenting to a specialist neurology clinic, using an automated abbreviated version of the CANTAB battery. 

Figure 1: Three cognitive tests were used.  A: The spatial working memory task, which assesses working memory and executive function.  B: The paired associates learning task which assesses episodic memory.  C: The match to sample task, which assesses attention and processing speed.  D: Once testing was completed a report was instantly generated for the clinician to view, which summarised the patients performance on each cognitive domain, compared to the expected level for someone of their age, level of education and gender. 

Depressive symptoms were measured using the Geriatric Depression Scale, and self-reported cognitive function was also reported. 

Data were analysed after adjustment for age, education and gender variables. 

Results

One third (32%) of the group showed an impairment in a single cognitive domain (i.e. z-score <-1.5), and 18% had multi-domain cognitive deficits.  28% were unimpaired on any test. 

The most commonly impaired cognitive domain was executive function, followed by working memory. 

Our measure of processing speed, which examines relative slowing with additional, rather than absolute reaction time, was found to be relatively preserved in this sample. 

Conclusions

Clinically significant depression scores were seen in nearly 40% of patients with PD tested in clinic.  Impaired cognitive scores were seen in more than half of patients.  Executive function and working memory were most often affected. 

These data are consistent with other studies in multiple sclerosis and head injury supporting the use of computerised cognitive testing in routine clinical visits for cognitive profiling cognitive function in patients with neurological disorders.