Physiological approaches to establishing the evaluation of eating and swallowing disorders

来自口、咽和喉结构的传入信号可能在吞咽的起始过程中起着重要作用。在这项研究中，我们探索了味道和温度对人类吞咽反射的影响，记录了吞咽行为，并评估了吞咽难度。采用物理性质稳定的增稠剂作为试验食品。在正常受试者中，味觉和温度参数都影响吞咽困难，但不影响吞咽行为，如肌肉活动和喉部运动。结果表明，在高于口腔温度和口感的条件下制备的增稠剂更容易引起吞咽反射，当食物团从口腔转移到咽部时可能会引起吞咽反射。虽然刺激喉上神经(SLN)确实会在麻醉动物中引起吞咽，但在健康人中，咽部周围的机械刺激可能不会引起吞咽。更确切地说，呕吐反射占主导地位。对于吞咽困难的CP患者，咽部冷刺激被认为可以使吞咽变得更容易。此后，我们推测皮质可能在吞咽的起始过程中起着重要作用。因此，我们比较了麻醉期间和慢性准备中清醒时刺激SLN吞咽的阈值。实验结果表明，麻醉深度越轻，阈值越低，清醒和静息期阈值越高。

Afferent signals arising from the oral, pharyngeal and laryngeal structures may have important roles on the initiation of swallow. In this study, we sought the effects of taste and temperature on swallowing reflex in humans, in which swallowing behavior was recorded and swallow difficulty was evaluated. A thickening agent, that is stable in the physical properties, was employed as the test food. In case of the normal subject, both the parameters of taste and temperature were found to affect swallow difficulty, however, they did not affect the swallowing behavior, such as muscle activities and laryngeal movements. The result suggests that thickening agents prepared at higher temperature than oral temperature and with taste may make easier the initiation of swallowing reflex.Swallowing reflex may be initiated when food bolus is transferred from the oral cavity to pharynx. Although superior laryngeal nerve (SLN) stimulation does elicit swallowing in the anesthetized animal, mechanical stimulation around the pharynx may not elicit swallowing in healthy humans. Rather gag reflex is pedominant. In case of CP patients with difficulty in swallowing, cold stimulus to the pharynx is believed to make the swallow easier. Thereafter, we hypothesized that cortex may have an important role on the initiation of swallowing. We thus compared the threshold of SLN stimulation for swallowing during anesthesia and awake in the chronic preparation. A positive result was obtained in that the threshold decreased with lightening the depth of anesthesia, however it increased when the animal was in the awake and rest stage.