It is rare that it is caused by the cortex; the intracranial segment of the vagus nerve can cause laryngeal paralysis due to tumors, hemorrhage, trauma, inflammation, etc.

More common, especially the left recurrent laryngeal nerve

 Unilateral: ① Symptoms are not obvious, there was a short-term hoarseness, and then recovered; ② Laryngoscopy: During inhalation, the vocal cord of the affected side is in the middle position and cannot abduct, but the vocal cord of the contralateral side abducts normally, and the glottis remains still during pronunciation. Can be closed

 Bilateral: ① Laryngeal obstruction and dyspnea; ② Laryngoscope: During breathing, the vocal cords on both sides are in the middle position, with only a small crack left in between; the glottis can still be closed during pronunciation

 Unilateral: ① Hoarseness, easy fatigue, and a sense of air leakage when speaking and coughing (but it can improve due to compensation in the later stage); no dyspnea; ② Laryngoscope: the affected side's vocal cord is fixed in the paramedian position; during initial pronunciation , the vocal cords on the unaffected side close to the center position, and there is a gap between the two vocal cords; when compensation occurs in the later stage, the vocal cords on the unaffected side retract past the midline and move closer to the affected side, and the pronunciation improves.

Both sides: ① Hoarseness, difficulty speaking (such as whispering), shortness of breath (but no dyspnea), the glottis cannot be closed, resulting in aspiration and choking; ② Laryngoscope: Both sides of the vocal cords are located in the middle, and cannot Closure and abduction; in acute onset cases, the vocal cords on both sides are in the middle position, causing difficulty in breathing.

Dysphonia occurs suddenly after being stimulated. It mainly occurs when speaking. The pronunciation is normal when coughing, crying and laughing, and breathing is completely normal; it can then suddenly return to normal.

Laryngoscope: There is no abnormality in the vocal cords; the vocal cords can be abducted and the glottis can be opened during inhalation, but the vocal cords cannot move closer to the midline when making the "yi" sound; the patient is asked to cough and laugh, and at this time the vocal cords can be seen moving closer to the midline (VS true adductor paralysis)

Inspiratory dyspnea: main symptom; especially when it causes congestion and swelling of the laryngeal mucosa

Inspiratory stridor

Hoarseness: However, if the lesion is located in the ventricular belt/subglottic cavity, it appears later/is not obvious.

Symptoms of hypoxia: Not obvious at first; then they may become more severe, with deep and rapid breathing, accelerated heart rate, rising blood pressure, and even hypoxia, irritability, and cyanosis, until profuse sweating, thin pulse, shallow and fast breathing, convulsions, coma, and heart failure. sudden stop

Soft tissue depression during inhalation: caused by increased negative pressure in the chest; manifested as three depressions (suprasternal fossa, supraclavicular fossa, intercostal space), four depressions (three depressions, subxiphoid/upper abdominal depression), more obvious in children (muscles) Tension is weak)