Brain Activation Site of Laryngeal Elevation during Swallowing: An fMRI Study of Post-stroke Patients with Reduced Laryngeal Elevation

Research Objectives: To investigate the central mechanism of laryngeal elevation during swallowing was explored by comparing the brain activation areas before and after treatment with that of healthy subjects.

Design: Patients poststroke with reduced laryngeal elevation were treated with electrical stimulation. Control group is age matched normal adults. Functional magnetic resonance imaging (fMRI) was used to observe brain activation of the normal healthy control group and treatment group during voluntary swallowing. Statistics were used to analyze the differences in brain activation between and within the groups.

Setting: Comprehensive hospital in Shanghai China

Participants: Experimental group: 12 post stroke patients with reduced laryngeal elevation screened by videofluoroscopy
Control group: 21 healthy subjects who are age matched.

Interventions: Patient in the experimental group were treated with electrical stimulation at the motor points of the muscles related to laryngeal elevation. The
frequency was 2 Hz, 20 min each time, once a day, 5 times a week, and 10 times in total.

Main Outcome Measures: Brain activation areas before and after the electrical stimulation

Results: Compared with the control group, the experimental group had a wider range of brain activation including the left supplementary motor area, the cingulate gyrus, the inferior frontal gyrus, the right thalamus, and the right putamen. After the electrical stimulation, the brain stem subregion, the left cerebellar lobule IV and V, and parts of the cerebral cortex were more active, while the left supplementary motor area, paracentral lobule, and occipital lobule were less active post-treatment.

Conclusions: (1) The brainstem and putamen are the specific brain regions that control laryngeal movement. (2) The enhanced activation of the cortical–basal ganglia–thalamic circuit after stroke is a compensatory mechanism. (3) The improvement of hyoid bone elevation was related to the enhanced activation of the IV and V lobes of the cerebellar hemisphere. The over-activation of the supplementary motor area poststroke would subside
once the motor function improved.

Author(s) Disclosures: There is no conflict of interests for all authors involved.