From the foot-mouth reflex to the hand-mouth reflex. A continuum of responses to appendicular compression.

We studied the mouth opening response to appendicular compression in two groups of children. This study was performed with the intention of testing the semiologic role of the act of mouth opening following stimulation of various regions, based on the hand mouth reflex of Babkin. Group I was formed by 33 normal children who underwent monthly follow up assessments since birth; and group II consisted of 50 children older than 6 months of age, known to have a neurologic deficit and a neuro-psychomotor development equivalent to that of a child in the first trimester of life. We observed that the normal mouth opening response in group I was more pronounced following compression of the hand and forearm when compared to compression of the arm (p < 0.001). This response could persist for as long as the first 6 months of life. We were not able to elicit a mouth opening response following compression of the lower limb in this group. Among children from group II, we observed mouth opening responses to stimulation of all limb segments. Within the upper limb, the response was more pronounced following compression of the hand in comparison to the forearm (p < 0.01), and forearm in comparison to the proximal arm (p < 0.01). Stimulation of the foot was more effective in eliciting a mouth opening response when compared to equivalent stimulation of the lower leg (p < 0.05). However, there was no statistical difference when responses to stimulation of the lower leg and thigh were compared. The presence of the previously unreported foot-mouth response may serve as an indicator of central nervous system compromise and could be associated with a poorer prognosis. We believe that our observations of the specific foot-mouth response patterns may serve as a marker of early neuro-psychomotor development dysfunction during childhood.