TONGUE JAW LINKAGES IN FEEDING

目前基于液体命令吞咽的吞咽范式并不适用于吃固体食物的受试者。在正常成年人中，固体食物是在口腔中加工的，而丸剂是在口咽部形成的。累积的药丸在舌头的循环表面上向前和向后携带。没有经典描述的口腔后封。提出了以固体食物为食的过程模型（Hiiemae和Palmer， 1999）。我们计划进行三个实验来验证该模型，通过测试以下四个假设：a)硬食物和软食物之间存在不同的体积/稠度阈值，超过该阈值时，丸剂的形成通常发生在口咽部；B)“按指令吞咽”的指令会破坏正常的丸剂形成，表明大脑皮层覆盖了后脑模式产生器；C)进食时呼吸变慢、不规律，咀嚼时打开水龙头，鼻气压出现高频振荡；D)软腭会表现出一些内在的节律性，但除了早期的咀嚼周期外，不会与舌头有规律的接触。将使用以下技术：(a)横向荧光影像（VFG），对不透射线的食物进行分级初始咬入大小和稠度（2-12克香蕉，1-8克饼干），并对10-25毫升的液体吞咽进行评估，以评估咬入大小和稠度对喂养的影响。其中一半受试者将有软腭标记或嗅钡以突出腭面和咽后壁；射线不透明的标记也将粘在舌头的一个子集；(b) VFG（横向和纵向），被试作为自己的对照，测试“命令吞咽”对序列行为的影响。8 VFG同时记录呼吸频率（用胸应变计和鼻压力传感器测量）、咬肌肌电和舌骨上肌电，在进食香蕉（12 g）和饼干（6 g）时，描绘呼吸、咀嚼和吞咽在完整进食序列中的相互作用。数据将通过可视化、数字化和适当的协调操作进行分析。事件之间的联系将受到考验。该结果将进一步描述口咽丸形成的情况，并与吞咽困难患者的评估直接相关，这些患者有食物加工问题，并增强我们对咀嚼和吞咽的中枢神经系统控制的认识。

The current paradigm for swallowing based on liquid command swallows does not apply to subjects eating solid foods. In normal adults, solid foods are processed in the oral cavity but the bolus is formed in the oropharynx. The accumulating bolus is carried forwards and backwards on the cycling surface of the tongue. There is no posterior oral seal as classically described. A Process Model for feeding on solid foods is proposed (Hiiemae and Palmer, 1999). We plan three experiments to validate the model by testing the following four hypotheses: a) there is a volume/consistency threshold which differs between hard and soft foods, and above which bolus formation normatively occurs in the oropharynx; b) the 'swallow on command' instruction will disrupt normal bolus formation, suggesting a cortical override of the hindbrain pattern generators; c) respiration will become slower and less regular during feeding, and high frequency oscillations in nasal air pressure will occur in chewing when the fauces are open; d) the soft palate will exhibit some intrinsic rhythmicity, but not make regular contact with the tongue except in early chewing cycles. The following techniques will be used: (a) lateral videofluorography (VFG) with radiopaque food in graduated initial bite sizes and consistencies (2-12 g banana, 1-8 g cookie), and with liquid swallows from 10-25 cc to assess the effect of bite size and consistency on feeding. Half of these subjects will have a soft palate marker or sniff barium to highlight the palatal surface and the posterior pharyngeal wall; radiopaque markers will also be glued to the tongue in a subset; (b) VFG (lateral and P-A) with subjects serving as their own controls to test the effect of the "command swallow" on sequence behavior. 8 VFG with simultaneous recording of respiratory rate (measured with a thoracic strain gauge and nasal pressure transducer), and masseter and suprahyoid EMG during feeding on natural bite sizes of banana (12 g) and cookie (6 g) to delineate the interactions between respiration, mastication, and swallowing in complete feeding sequences. Data will be analyzed visually, and by digitization and coordinate manipulation as appropriate. The linkages between events will be tested. The results will further delineate the circumstances in which oropharyngeal bolus formation occurs and have direct relevance to the evaluation of dysphagic patients, those with food processing problems and enhance our knowledge of CNS control of mastication and swallowing.