Cerebral-Cerebellar Cortical Activity and Connectivity Underlying Sensory Trick in Cervical Dystonia

The objective of this study was to investigate the activity and connectivity of cerebral and cerebellar cortices underlying the sensory trick (ST) effects in patients with cervical dystonia (CD), using electroencephalography (EEG).

We recruited 15 CD patients who exhibited clinically effective ST and 15 healthy controls (HCs) who mimicked the ST maneuver. EEG signals and multiple-channel electromyography (EMG) were recorded simultaneously during resting and acting stages. EEG source analysis and functional connectivity were performed. To account for the effects of sensory processing, we calculated relative power changes as the difference in power spectral density between resting and the maneuver execution.

ST induced a decrease in low gamma (30-50 Hz) spectral power in the primary sensory and cerebellar cortices, which remained lower than in HCs during the maintenance period. Compared with HCs, patients exhibited consistently strengthened connectivity within the sensorimotor network during the maintenance period, particularly in the primary sensory-sensorimotor cerebellum connection.

The application of ST resulted in altered cortical excitability and functional connectivity regulated by gamma oscillation in CD patients, suggesting that this effect cannot be solely attributed to motor components. The cerebellum may play important roles in mediating the ST effects.