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Objective: The significance of the human sense of taste is typically underestimated until it is altered or even lost. Hypogeusia, a diminished capacity to taste, has an adverse influence on a patient's quality of life. Similar to interactions between the oral senses and between olfaction and intranasal trigeminal sensitivity, taste disturbance may also affect the mechanosensitivity of the tongue. In this study, we investigated the lingual tactile sensitivity of patients with subjective taste disturbance and people with normogeusia., Study Design: Prospective case-control study., Methods: Forty-six patients with subjective taste disturbance (mean age 60 years) and 43 participants with normogeusia (mean age 55 years) were enrolled and underwent a stereognostic test of edge and point sensitivity based on 3D-printed letters sized from 2 to 8 mm. Gustatory function and salivary production were also tested., Results: Patients with dysgeusia needed significantly bigger letters to recognize them compared with controls (P = .01). Apart from this, patients with dysgeusia had no significant association between gustatory function and salivary production. Duration of dysgeusia and age were not associated with the presently obtained measures of gustatory or oral mechanosensory function., Conclusions: The results of this study indicate that taste dysfunction has a negative impact on oral mechanosensitivity and hence possibly on oral texture perception., Level of Evidence: 3 Laryngoscope, 131:2572-2577, 2021., (© 2021 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: Distortion of taste sensations is a common chemotherapy-induced side effect; however, treatment evidence is limited. Pilot data indicated that acupuncture might be able to improve symptoms of dysgeusia. Thus, the aim of this study is to investigate the effects and side effects of hypoglossal acupuncture in the treatment of dysgeusia in patients with breast cancer undergoing chemotherapy., Methods/design: The study is a randomized controlled trial comparing a single verum acupuncture treatment with two active comparators: sham acupuncture and dietary recommendations. Sample size calculation revealed a total of 75 patients pending an alpha of 0.05, a power of 0.8, and an estimated effect size of 0.80. Patients with breast cancer undergoing platinum- or taxane-based chemotherapy will be included if they present with phantogeusia (abnormal taste sensations without an external oral stimulus) with an intensity of 4 points or above on an 11-point numeric rating scale (NRS). The primary outcome is phantogeusia; secondary outcomes include parageusia (abnormal taste of food), hypogeusia (reduced taste sensations), hypergeusia (increased taste sensations), xerostomia (dry mouth), stomatitis, appetite, and functional impairment. All outcomes will be assessed at baseline and prior to the next chemotherapy administration using an 11-point NRS for each. All adverse events will be recorded., Discussion: The results of this study will demonstrate the extent to which hypoglossal acupuncture may influence the intensity of and functional impairment due to chemotherapy-induced dysgeusia., Trial Registration: Clinical Trials.gov, NCT02304913 . Registered on 19 November 2014.

Objectives: Patients after middle ear surgery often complain of taste disturbance and a lingual numbness. The purpose of this study was to objectively assess changes in the somatosensation of the tongue and taste function in patients undergoing stapes surgery., Study Design: Prospective study., Methods: Symptoms of taste disturbance and tongue numbness after surgery were investigated before and after surgery in 41 patients (13 males, 28 females; mean age 41.8 years) who underwent stapes surgery. Twenty-eight patients (9 males, 19 females; mean age 43.1 years) underwent sensory and taste function tests before and after surgery. Sensory function of the tongue was measured at the operated side and the nonoperated side using the 2-point discrimination test and an electrostimulator test. Taste function was assessed with electrogustometry (EGM)., Results: The chorda tympani nerve (CTN) was gently touched or stretched in all patients. Postoperative thresholds on the operated side were significantly higher than preoperative thresholds in all tests in the patients who underwent all three kinds of tests. Tongue somatosensory symptoms improved significantly earlier than the taste disturbance postoperatively, and the sensory thresholds returned to the baseline along with recovery of symptoms., Conclusion: These findings suggest that dysfunction of the CTN occurred following surgery even when the CTN was preserved, and that the sensory nerve threshold of the tongue correlated with the symptom of lingual numbness. The CTN may play a role not only in taste function but also in the somatosensory function of the tongue., Level of Evidence: 4. Laryngoscope, 128:701-706, 2018., (© 2017 The American Laryngological, Rhinological and Otological Society, Inc.)

Striking taste disturbances are reported in cancer patients treated with Hedgehog (HH)-pathway inhibitor drugs, including sonidegib (LDE225), which block the HH pathway effector Smoothened (SMO). We tested the potential for molecular, cellular, and functional recovery in mice from the severe disruption of taste-organ biology and taste sensation that follows HH/SMO signaling inhibition. Sonidegib treatment led to rapid loss of taste buds (TB) in both fungiform and circumvallate papillae, including disruption of TB progenitor-cell proliferation and differentiation. Effects were selective, sparing nontaste papillae. To confirm that taste-organ effects of sonidegib treatment result from HH/SMO signaling inhibition, we studied mice with conditional global or epithelium-specific Smo deletions and observed similar effects. During sonidegib treatment, chorda tympani nerve responses to lingual chemical stimulation were maintained at 10 d but were eliminated after 16 d, associated with nearly complete TB loss. Notably, responses to tactile or cold stimulus modalities were retained. Further, innervation, which was maintained in the papilla core throughout treatment, was not sufficient to sustain TB during HH/SMO inhibition. Importantly, treatment cessation led to rapid and complete restoration of taste responses within 14 d associated with morphologic recovery in about 55% of TB. However, although taste nerve responses were sustained, TB were not restored in all fungiform papillae even with prolonged recovery for several months. This study establishes a physiologic, selective requirement for HH/SMO signaling in taste homeostasis that includes potential for sensory restoration and can explain the temporal recovery after taste dysgeusia in patients treated with HH/SMO inhibitors., Competing Interests: The authors declare no conflict of interest.

Dysgeusia causes a decrease in appetite, and it is one of the major factors in undernutrition. Dysgeusia is elicited by numerous causes, and in many cases it is still difficult to treat the various symptoms complained of by patients. We herein report a case in which dysgeusia was improved by transient cooling of the mouth.

The anatomical basis of taste are discussed both in their peripheral and in central aspects. The perception is based upon four principal flavors; this happens by complex chemical interactions between peripheral receptors of papillae and the taste producing substances. The nervous stimulus flows through fibres of VII-IX-X cranial nerves up to the tractus solitarius nucleus; successive elaboration leads to the taste sensation, whose principal cortical site is the zone between Silvius and Rolando's sulcus. The distribution of the sensible zones for the fundamental flavors is presented.