Time-frequency analysis of the EEG mu rhythm as a measure of sensorimotor integration in the later stages of swallowing

Abstract

Objective: Electroencephalography (EEG) was used to map the temporal dynamics of sensorimotor integration relative to the strength and timing of muscular activity during swallowing. Methods: 64-channel EEG data and surface electromyographic (sEMG) data were recorded from 25 neurologically-healthy adults during swallowing and tongue-tapping. Events were demarcated so that sensorimotor activity primarily from the pharyngeal and esophageal phases of swallowing could be compared to activity resulting from tongue tapping. Results: Independent component analysis identified bilateral clusters of sensorimotor mu components localized to the premotor and primary motor cortices as well as an infrahyoid myogenic cluster. Subsequent event-related spectral perturbations (ERSP) analyses showed event-related desynchronization (ERD) in the spectral power in the alpha (8-13 Hz) and beta (15-25 Hz) frequency bands of the mu clusters in both tasks. Mu ERD was stronger during swallowing when compared to tongue tapping (pFDR .05) and the differences in sensorimotor processing between conditions was greater in the right hemisphere than the left, suggesting stronger right hemisphere lateralization for swallowing than tongue-tapping. Conclusion: Mu activity was interpreted as representing a normal feed forward and feedback driven sensorimotor loop during the later stages of swallowing. Significance: Results support further use of this novel neuroimaging technique to concurrently map neural and muscle activity during swallowing in clinical populations using EEG.