The sucking reflex appears between 0 and 3 months of age, and the infant will suck when something is placed in the infant’s mouth. If it is still present after 1 year of age, a positive sucking reflex indicates cortical dysfunction. The presence of the sucking reflex in non-childhood is most often seen in frontal lobe lesions and pseudobulbar palsy. So, what diseases should be differentially diagnosed with a positive sucking reflex? 1.Frontal lobe lesion: The growth rate and the direction of development of tumor are different, and the clinical symptoms are also different. If the tumor invades the anterior cingulate gyrus bilaterally, mutism, vegetative disorder, paralysis of one or both lower extremities and loss of left hand, and impairment of consciousness when used. A positive strong grip reflex is seen contralateral to the invasion of the premotor area. If the sucking reflex is positive, or the Hoffmam and Babinski signs are positive, the possibility of frontal ataxia or psychiatric symptoms should be highly suspected. 2, pseudobulbar palsy (pseudobulbaupalsy): the main clinical manifestations of dysarthria, fulminant speech. Lip and laryngeal sounds are ambiguous, and the pronunciation is monotonous, muffled and coarse and blunt. Difficulty in eating Inability to push food toward the pharynx. Paralysis of the soft palate and pharyngeal muscles. The soft palate regurgitation disappears and the pharyngeal reflex is present, which is an important sign of pseudobulbar palsy and is more diagnostic at an early stage. Pseudobulbar palsy is an upper motor neuron palsy, so in addition to the physiological brainstem reflexes that are active or hyperactive, there are also some pathological reflexes, called pathological brainstem reflexes such as sucking reflex, palmar chin reflex, head tilt reflex, and jaw reflex, which can be elicited in the absence of obvious pyramidal fasciculus or cerebral signs, thus making early diagnosis valuable.