Functional oropharyngeal sensory disruption interferes with the cortical control of swallowing.
BACKGROUND
Sensory input is crucial to the initiation and modulation of swallowing. From a clinical point of view, oropharyngeal sensory deficits have been shown to be an important cause of dysphagia and aspiration in stroke patients. In the present study we therefore investigated effects of functional oropharyngeal disruption on the cortical control of swallowing. We employed whole-head MEG to study cortical activity during self-paced volitional swallowing with and without topical oropharyngeal anesthesia in ten healthy subjects. A simple swallowing screening-test confirmed that anesthesia caused swallowing difficulties with decreased swallowing speed and reduced volume per swallow in all subjects investigated. Data were analyzed by means of synthetic aperture magnetometry (SAM) and the group analysis of the individual SAM data was performed using a permutation test.


RESULTS
The analysis of normal swallowing revealed bilateral activation of the mid-lateral primary sensorimotor cortex. Oropharyngeal anesthesia led to a pronounced decrease of both sensory and motor activation.


CONCLUSIONS
Our results suggest that a short-term decrease in oropharyngeal sensory input impedes the cortical control of swallowing. Apart from diminished sensory activity, a reduced activation of the primary motor cortex was found. These findings facilitate our understanding of the pathophysiology of dysphagia.
Teismann
Inga K
IK
Institute for Biomagnetism and Biosignalanalysis, University of Muenster, Muenster, Germany. i.teismann@uni-muenster.de
Steinstraeter
Olaf
O
Stoeckigt
Kati
K
Suntrup
Sonja
S
Wollbrink
Andreas
A
Pantev
Christo
C
Dziewas
Rainer
R
D000328:Adult; D000344:Afferent Pathways / Q000187:drug effects / Q000503:physiopathology; D000779:Anesthetics, Local / Q000009:adverse effects; D003679:Deglutition / Q000187:drug effects / Q000502:physiology; D003680:Deglutition Disorders / Q000209:etiology* / Q000503:physiopathology; D004525:Efferent Pathways / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009055:Mouth / Q000294:innervation / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D010614:Pharynx / Q000294:innervation / Q000503:physiopathology*; D012678:Sensation Disorders / Q000139:chemically induced / Q000150:complications* / Q000503:physiopathology; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000503:physiopathology; D013003:Somatosensory Cortex / Q000503:physiopathology*
D000779:Anesthetics, Local