Is Palmomental Reflex Actually A Part of Feeding Behavior?

Purpose and hypothesis: Palmomental reflex is considered to be a primitive reflex and related to pathologic processes. The reflex can be obtained from every individual by electrophysiologic measures. There have been no reports concerning submental, orbicularis oris and masseter muscle reflex responses provoked by median nerve stimulation in healthy elderly individuals and patients with dementia up to now. Method: In the present study the median nerve was stimulated below the pain threshold and activities obtained from mental, submental, orbicularis oris and masseter muscles were recorded simultaneously in patients with dementia (n = 18) and in healthy elderly individuals (n = 18). Result: Latencies obtained from mental, submental, orbicularis oris and masseter muscles were approximately recorded within 80 - 100 milliseconds and the differences between the latencies were not statistically significant. Conclusion: The palmomental reflex seems to be an activity co-occurring with functions like mouth opening and swallowing, and reflecting hand - mouth reaction, rather than being only a primitive reflex involving mental muscle. We believe close temporal relationship among the activities of mental, submental, orbicularis oris and masetter muscles after hand stimulation requires these reflexes to be investigated in the physiology of hand and mouth coordination in further studies.