Processing of Local and Global Auditory Deviants in Parkinson Disease: Electrophysiological Evidence for Enhanced...

To investigate automatic auditory-change detection in patients with Parkinson disease (pwPD).

Previous results regarding changes in preattentive processing in pwPD have been inconclusive.

We employed a paradigm assessing the preattentive processing of sequences of auditory tones containing deviants at either the local or global level, or at both levels. Twenty pwPD and 20 age-matched healthy controls were exposed to the tone series while they performed a visual task and had their event-related potentials recorded by electroencephalogram.

Event-related potentials showed a mismatch negativity, which was largest for the double-deviant stimuli, of intermediate amplitude for the local deviant stimuli, and smallest for the global deviant stimuli. The mismatch negativity was of similar size in the patients and controls, with the exception of the double-deviant condition (larger in controls). By contrast, the subsequent positive component was more pronounced for the Parkinson disease group than controls, particularly for the double-deviant condition.

The larger positivity suggests that pwPD are more prone to distraction than healthy controls, probably because dopaminergic medication shifts the stability-flexibility balance toward cognitive flexibility with increased distractibility.