Background: Mild cognitive impairment (MCI) may be accompanied by extra pyramidal signs (EPS), which are related to the severity and type of cognitive impairment. We aimed to elucidate further the relationship between MCI and EPS, analyzing the correlation between the severity of EPS and cognitive functions, and the presence of EPS and neuro-psychiatric features.
Methods: Data were obtained from a longitudinal study of 150 MCI outpatients. Participants underwent a clinical assessment including the Unified Parkinson Disease Rating Scale, the Neuropsychiatric Inventory, the Tinetti Scale, and a standardized neuropsychological battery. Mild EPS could be defined as being present (MCI with mild EPS) using a subscale of UPDRS, based on three specific symptoms: bradykinesia, rigidity and tremor.
Results: The two groups, one with mild EPS (24%) and one without EPS (76%), differed in gait abnormalities and presence of extrapyramidal symptoms. Groups did not differ in terms of general cognitive functions evaluated using the Mini-mental State Examination, while subjects with MCI with mild EPS performed significantly worse than those with MCI without EPS in total global score and in non-memory items of the Alzheimer's Disease Assessment Scale. Moreover, severity of EPS was significantly correlated with low performance on executive functions and with high performance on episodic memory. The group with MCI with mild EPS were observed to have a greater prevalence of patients with anxiety, depression, apathy and sleep disturbances than in MCI without EPS.
Conclusion: MCI may be associated with mild parkinsonian signs, the severity of which are related to the severity of cognitive impairment, in particular of non-memory functions, and to a differential pattern of psycho-behavioral symptoms.