TONGUE-JAW LINKAGES IN HUMAN FEEDING - A PRELIMINARY VIDEOFLUOROGRAPHIC STUDY

Motions of the tongue and jaw art closely coupled during feeding in ma mmals, but this relation has not been studied in humans. A videofluoro graphic method for measuring tongue movement relative to jaw motion us ing small radiopaque markers affixed to the tongue with dental adhesiv e was developed and tested in five individuals. Sagittal movements of the anterior tongue marker (ATM) and the lower jaw were measured for c omplete feeding sequences with a computerized image-analysis system. T he ATM and jaw moved in loosely linked, semirhythmic cycles. Vertical and horizontal maxima of ATM motion were determined for each motion cy cle in relation to maximum and minimum gape (greatest jaw opening and closeing, respectively). The amplitude of tongue movements and their t iming differed between hard and soft foods (p < 0.001). For both food types, motions varied as the feeding sequence progressed from ingestio n to terminal swallow (P < 0.001). A basic temporal sequence was found in 70% of the 224 cycles analysed. On average, the ATM reached its mo st inferior position just after maximum gape, its most posterior durin g jaw closing, its most superior just after minimum gape, and its most anterior during jaw opening (p < 0.001). This study confirms that ton gue and jaw movements are linked during human feeding, as they are in other mammals. (C) 1997 Elsevier Science Ltd.