Impaired Desynchronization of Beta Activity Underlies Memory Deficits in People with Parkinson’s Disease

Abstract

There is a pressing need to better understand the mechanisms underpinning the increasingly recognised non-motor deficits in Parkinsons disease. Brain activity during Parkinsons disease is excessively synchronized within the beta range (12-30Hz). However, relatively little is known about how the abnormal beta rhythms impact on non-motor symptoms. In healthy adults, beta desynchronization is necessary for successful episodic memory formation. We investigated whether there was a direct relationship between decreased beta modulation and memory formation in Parkinsons disease. Electroencephalography recordings were made during an established memory-encoding paradigm. Parkinsons participants showed impaired memory strength (P = 0.023) and reduced beta desynchronization (P = 0.014) relative to controls. Longer disease duration was correlated with a larger reduction in beta desynchronization, and a concomitant reduction in memory performance. These novel results extend the notion that pathological beta activity is causally implicated in the motor and (lesser appreciated) non-motor deficits inherent to Parkinsons disease.