The Initiation of Swallowing Can Indicate the Prognosis of DOC

Studies suggest that the initiation and patterning of swallowing of the pharyngeal phase is also under active cortical control for both spontaneous as well as volitional swallowing in awake humans and non-human primates. A recent study found that most patients of disorders of consciousness (DOC) would recover their swallowing ability quickly. And there is no study about detecting the initiation of swallowing act in DOC patients. This study is aimed to detect the initiation of swallowing act in DOC patients, to find if it is a good item as a stimulus and to detect the relationship between the initiation of swallowing act and the prognosis of DOC patients. DOC patients were recruited (standard diagnosis procedure is 4 times CRS-R testing within 2 weeks). The different four stimuli were as follows: 1) One command (as recommended in CRS-R) which was "open your mouth". 2) Put a spoon in front of the patient's mouth without a command. 3) One command with a spoon in front of the mouth, the command is "there is a spoon and open your mouth". 4) One command with a spoon full of water in front of the mouth, the command is "there is a spoon with water and open your mouth". We presented these stimuli orderly in front of the patient's mouth and presented any one of them over 4 trials at 15 second intervals.

Inclusion criteria

• age ≥ 18 years
• no administration of central nervous system stimulant, neuro-muscular blocking agents, or sedative within the prior 24 hours
• a diagnosis of VS or MCS-, based on the behavioral assessment of standardized CRS-R
• periods of eye opening (indicating preserved sleep-wake cycles).

Exclusion criteria

• documented history of prior brain injury
• premorbid illness resulting in documented functional disabilities up to time of the injury
• acute illness (e.g., pyrexia, pneumonia, diarrhea)
• receiving hyperbaric oxygen treatments within 2 hours
• fracture of the mandible.