Cognitive bedside assessment in atypical parkinsonian syndromes

Background: Despite the growing recognition of the importance of cognitive symptoms for the diagnosis and management of atypical parkinsonian syndromes, the cognitive assessment of the patients in clinical practice often remains very limited. Objectives: To examine the ability of a brief and simple cognitive screening test to detect cognitive deficits in atypical parkinsonian syndromes. Methods: Addenbrooke's cognitive examination (ACE), the mini-mental state examination (MMSE), and the dementia rating scale (DRS) were applied to 26 patients with multiple system atrophy (MSA), 39 with progressive supranuclear palsy (PSP), and 25 with corticobasal degeneration (CBD). The results were then compared with those obtained in 30 healthy age matched volunteers and 30 patients with Alzheimer's disease. Results: In all four diseases the rate of detection of cognitive impairment on ACE was higher than on MMSE and comparable with DRS. The severity of cognitive impairment was most pronounced in the CBD group, which showed a similar degree of impairment to the Alzheimer group. In contrast, MSA patients were the least cognitively impaired. The PSP group took an intermediate position. Conclusions: Cognitive impairment in atypical parkinsonian syndromes can be detected using a brief and clinically applicable bedside test such as ACE.