Gustatory Stimulation Research Articles

Effects of Gustatory and Olfactory Stimulation on Feeding Outcomes in Preterm Infants: A Systematic Review and Meta-Analysis.

Few primary studies have examined the impact of olfactory and gustatory stimulation on premature infants, and variability exists in reported outcomes. To explore the effects of olfactory and gustatory stimulation on feeding outcomes in preterm infants. A literature search was conducted in 4 databases (CENTRAL, PubMed, Embase, CINAHL) from the inception of the databases to May 2024. Randomized controlled trials (RCTs) or quasi-RCTs to explore the effects of olfactory and gustatory stimulation on feeding outcomes in preterm infants were included. Two reviewers independently extracted data from the included studies and completed the form designed for data extraction. Eleven RCTs and quasi-RCTs comprising 1009 preterm infants were included. Meta-analysis found that olfactory and gustatory stimulation significantly shortened the time to reach full oral feeds ( days ) (mean difference [MD]:-2.52, 95% confidence interval [CI]:-3.88 to -1.16, P =.0003), while they had no significant differences in time to achieve full enteral feeds ( days ), postmenstrual age (PMA) at the removal of the nasogastric tube ( weeks ), weight at discharge ( grams ), weight gain ( grams ), head circumference at discharge ( cm ), length at discharge ( cm ), total duration of parenteral nutrition ( days ), necrotizing enterocolitis, hospitalization duration ( days ), PMA at discharge ( weeks ). Large sample, multicenter studies are needed to demonstrate the effectiveness of olfactory and gustatory stimulation on feeding outcomes in preterm infants.

Effects of olfactory and/or gustatory stimuli on feeding of preterm infants: A systematic review and meta-analysis.

To evaluate the effect of olfactory and/or gustatory stimulation interventions on feeding outcomes in preterm infants. We conducted systematic searches across various academic databases, including PubMed, Embase, Web of Science, the Cochrane Library, the Chinese Biomedical Literature Service System, China National Knowledge Infrastructure, the Wanfang Database, and the Wipu Database. These searches aimed to identify randomized controlled trials investigating the impact of olfactory and/or gustatory stimulation on preterm infants. The search period spanned from the inception of the databases until December 2022. Two independent evaluators autonomously reviewed the literature, extracted pertinent data, assessed the quality of the included studies, and conducted a meta-analysis using RevMan 5.3 software. A total of 7 randomized controlled trials or quasi-experimental studies were included, with a total of 871 participants. Olfactory and gustatory stimulation demonstrated a reduction in the time to full enteral feeds in preterm infants when compared to usual care (MD = -1.60 days; 95% CI = -2.31, -0.89; p<0.0001). No substantial evidence was identified regarding the influence of olfactory and gustatory stimulation on the duration of gastric tube placement, length of hospitalization, incidence of necrotizing enterocolitis, or occurrence of spontaneous bowel perforation in preterm infants. Olfactory and gustatory stimulation show potential benefits for preterm infants. However, due to the low to very low level of certainty associated with the available data, our ability to assess the effects is limited. Further trials and studies are essential to enhance our understanding of the mechanisms and effectiveness of olfactory and gustatory stimulation therapies.

Regulation of brain cognitive states through auditory, gustatory, and olfactory stimulation with wearable monitoring

Inspired by advances in wearable technologies, we design and perform human-subject experiments. We aim to investigate the effects of applying safe actuation (i.e., auditory, gustatory, and olfactory) for the purpose of regulating cognitive arousal and enhancing the performance states. In two proposed experiments, subjects are asked to perform a working memory experiment called n-back tasks. Next, we incorporate listening to different types of music, drinking coffee, and smelling perfume as safe actuators. We employ signal processing methods to seamlessly infer participants’ brain cognitive states. The results demonstrate the effectiveness of the proposed safe actuation in regulating the arousal state and enhancing performance levels. Employing only wearable devices for human monitoring and using safe actuation intervention are the key components of the proposed experiments. Our dataset fills the existing gap of the lack of publicly available datasets for the self-management of internal brain states using wearable devices and safe everyday actuators. This dataset enables further machine learning and system identification investigations to facilitate future smart work environments. This would lead us to the ultimate idea of developing practical automated personalized closed-loop architectures for managing internal brain states and enhancing the quality of life.

Effect of Facilitated Tucking and Gustatory Stimulation on Preterm Neonates’ Physical Growth and Behavioral Regulation

Effect of Facilitated Tucking and Gustatory Stimulation on Preterm Neonates’ Physical Growth and Behavioral Regulation

Amplitude of low-frequency fluctuation after taste exposure revealed by resting-state fMRI

Taste perception has been deeply explored from the behavioural level to delineating neural mechanisms. However, most previous studies about the neural underpinnings of taste perception have focused on task-related brain activation. Notably, evidence indicates that task-induced brain activation often involves interference from irrelevant task materials and only accounts for a small fraction of the brain's energy consumption. Investigation of the resting-state spontaneous brain activity would bring us a comprehensive understanding of the neural mechanism of taste perception. Here we acquired resting-state functional magnetic resonance imaging (rs-fMRI) data from twenty-two participants immediately after they received sweet, sour and tasteless gustatory stimulation. Our results showed that, in contrast to the tasteless condition, the sour exposure induced decreased amplitude of low-frequency fluctuation (ALFF) in the somatosensory cortex in the left post-central gyrus, and the sweet exposure led to increased ALFF in the bilateral putamen involved in reward processing. Moreover, in contrast to the sweet stimulation condition, the sour stimulation condition showed increased ALFF in the right superior frontal gyrus, which has been linked to functioning in high-order cognitive control. Altogether, our data indicate that taste exposure may affect the spontaneous functional activity in brain regions, including the somatosensory areas, reward processing areas and high-order cognitive functioning areas. Our findings may contribute to a further understanding the neural network and mechanisms after taste exposure.

Effect of continuous sweet gustatory stimulation on salivary flow rate over time

ObjectiveThis study aimed to determine changes in saliva secretion and subjective taste intensity during a sustained period with continuous gustatory stimulation. DesignTwenty-two healthy adults participated in this study. The selected taste solutions were aspartame, sucralose, and acesulfame potassium, which are nonnutritive sweeteners. The concentrations of sucralose1 and acesulfame potassium were set to show the same sweetness intensity as aspartame. Sucralose2 was twice the concentration of sucralose1. The solution was continuously fed into the oral cavity at a flow rate of 0.04 mL / min through a neck-worn precise infusion system. The salivary flow rate (g/min) after 10 min of intraoral water supply from the device was used as the baseline. Salivary flow rate, subjective taste intensity evaluated by the visual analog scale (VAS), and salivary flow rate relative to the baseline were recorded at 10, 30, 60, and 120 min after the start of the test. ResultsIn the aspartame, sucralose1, and sucralose2 groups, the salivary flow rate increased significantly from 10 min to 120 min after the start of the test when compared to the rate at baseline (p < 0.05). The relative salivary flow rate increased and the VAS value decreased significantly over time and were affected by the time factor (p < 0.001, p = 0.013, respectively) but not by the sweetener-group factor and the interaction effects. ConclusionsContinuous gustatory stimulation may maintain increased salivary production for a sustained period.

Cognitive categorization of new hybrid products and implicit attitude formation: Empirical study of sensory stimulation

According to social psychology researchers, categorizing a new product may involve the formation of automatic judgments at the subconscious level. This study aimed to ascertain if attitudes might be formed unintentionally when categorizing a new hybrid product under the effect of associated sensory inputs. Data were collected using an explicit and implicit approach: an explicit categorization measure, an explicit attitude scale, and the “Single Category Implicit Association Test’’ (SC-IAT), from 280 Moroccan university students having a normal sense of smell and taste, under the effects of two types of sensory stimuli (smell and taste) and according to two learning conditions linked to two categories of existing products. The data were then computed and processed using the “Statistical Package for Social Sciences” and the “Inquisit Lab’’. The study’s findings revealed that the respondents were able to categorize the new product into one of the targeted categories (depending on the learning condition of each category) after exposure to sensory stimuli (olfactory and gustatory stimuli) related to this product and were also able to form an implicit and explicit attitude towards it. The occurrence of the categorization process and the formation of these two distinct types of attitudes can be explained by the olfactory and gustatory sensory stimulation during the experiment, which helped the participants recognize the basic domain of the new product and then transfer knowledge and affects to it.

Olfaction and gustatory senses promote feeding through different pathways in yellowtail, Seriola quinqueradiata

For sustainable aquaculture, the replacement of dietary fishmeal with plant protein is becoming more common because fishmeal resources are limited. However, in the case of carnivorous fish such as yellowtail (Seriola quinqueradiata), reducing the dietary fishmeal level often causes low feed intake. Improving feed intake is important in the use of a non- and low-fishmeal diet. However, little is known about the mechanisms that regulate feeding in yellowtail. The relationship between appetite, feeding behaviour, and food intake needs to be examined to elucidate the mechanisms of feeding regulation. The senses of smell (olfaction) and taste (gustation) are important for feeding in fish. However, it is unclear how each of these senses stimulates feeding behaviour, appetite, and feed intake. In this study, the effects of olfactory and gustatory stimuli on feeding behaviour, brain expression of neuropeptide Y (NPY), and feed intake in yellowtail were investigated using a strong olfactory stimulant (alanine, Ala) and a strong gustatory stimulant (proline, Pro). By using observation tanks, feeding behaviour was divided into ‘search’ and ‘bite’. Ala promoted ‘search’ feeding behaviour and significantly decreased npy mRNA expression in the olfactory bulb and telencephalon as the olfactory centre and hypothalamus as the appetite centre. No increment in feed intake was found in the Ala-supplemented diets compared to the control diet. Meanwhile, Pro increased npy mRNA expression in the gustatory centre (cerebellum), promoted ‘bite’ feeding behaviour, and increased feed intake. Odour stimulation promoted ‘search’ through npy mRNA expression but was not reflected in feed intake. Taste stimulation promoted ‘bite’ through npy mRNA expression, which increased feed intake. Thus, olfactory and gustatory senses may promote feeding through different pathways in the yellowtail. These results will contribute to increasing the feeding amount of non- and low-fishmeal diet in the feed of yellowtail towards sustainable aquaculture.

Functional Evaluation of Major Salivary Glands Using Viscosity PLUS and 2D Shear-Wave PLUS Elastography Techniques in Healthy Subjects-A Pilot Study.

Biological soft tissues are characterized by viscoelastic properties. The propagation of shear waves within tissues is influenced by both elasticity, which is linked to the shear wave speed, and viscosity, which is linked to the shear wave dispersion. This study aimed to functionally assess the parotid glands (PG) and submandibular glands (SMG) in a group of 40 healthy subjects using the novel Viscosity PLUS (Vi.PLUS) and 2D Shear-Wave Elastography PLUS (2D-SWE.PLUS) techniques. The viscosity and stiffness of PG and SMG were measured before and after gustatory stimulation with a sialagogue agent (commercially available lemon juice) using the new SuperSonic MACH 30 ultrasound system equipped with a curvilinear C6-1X transducer. PG presented a mean basal viscosity and elasticity of 2.10 ± 0.19 Pa.s and 11.32 ± 1.91 kPa, respectively, which significantly increased poststimulation to 2.39 ± 0.17 Pa.s (p < 0.001) and 12.58 ± 1.92 kPa (p < 0.001), respectively. SMG did not present statistically increased values of viscosity and elasticity following stimulation (2.31 ± 015 Pa.s vs. 2.37 ± 0.18 Pa.s, p = 0.086, and 10.40 ± 1.64 kPa vs. 10.90 ± 1.98 kPa, p = 0.074, respectively). Vi.PLUS measurements presented a good positive correlation with 2D-SWE.PLUS values for PG and SMG, before and after stimulation. Gender and BMI were not confounding factors for these two parameters. Vi.PLUS represents an innovative non-invasive imaging technique that, together with 2D-SWE.PLUS proves to be useful in functionally assessing the major salivary glands in healthy subjects.

Effect of Olfactory and Gustatory Stimulations on Preterm Neonates’ Feeding Progression and Sniffing Away Feeding Tube

Effect of Olfactory and Gustatory Stimulations on Preterm Neonates’ Feeding Progression and Sniffing Away Feeding Tube

A Sexually Dimorphic Olfactory Neuron Mediates Fixed Action Transition during Courtship Ritual in Drosophila melanogaster.

Animals perform a series of actions in a fixed order during ritualistic innate behaviors. Although command neurons and sensory pathways responding to external stimuli that trigger these behaviors have been identified, how each action is induced in a fixed order in response to multimodal sensory stimuli remains unclear. Here, the sexually dimorphic lateral antennal lobe tract projection neuron 4 (lPN4) in male Drosophila melanogaster mediates the expression of a fixed behavioral action pattern at the beginning of the courtship ritual, in which a male taps a female body and then extends a wing unilaterally to produce a courtship song. We found that blocking the synaptic output of lPN4 caused an increase in the ratio of male flies that extended a wing unilaterally without tapping the female body, whereas excitation of lPN4 suppressed the transition from the tapping phase to the unilateral wing extension phase. Real-time calcium imaging showed that lPN4 is activated by a volatile pheromone, palmitoleic acid, whose responses were inhibited by simultaneous gustatory stimulation with female cuticular hydrocarbons, showing the existence of an "AND-gate" for multimodal sensory inputs during male courtship behaviors. These results suggest that the function of lPN4 is to suppress unilateral wing extension while responding to a female smell, which is released by appropriate contact chemosensory inputs received when tapping a female. As the female smell also promotes male courtship behaviors, the olfactory system is ready to simultaneously promote and suppress the progress of courtship actions while responding to a female smell.SIGNIFICANCE STATEMENT Although it has been 80 years since Konrad Lorenz and Niko Tinbergen introduced how multiple acts comprising separate innate behaviors are released in a fixed order according to external stimuli, the neural circuits responsible for such fixed action patterns remain largely unknown. The male courtship behavior of Drosophila melanogaster is a good model to investigate how such a fixed behavioral sequence is determined in the brain. Here, we show that lateral antennal lobe tract projection neuron 4 (lPN4) in D. melanogaster functions as an "AND-gate" for volatile and contact chemosensory inputs, mediating the expression of tapping behaviors before unilateral wing extension during male courtship rituals.

The effect of eating on the uptake of PSMA ligands in the salivary glands

RationalePSMA-directed therapy for metastatic prostate cancer is gaining adoption as a treatment option. However, accumulation of 177Lu/225Ac-PSMA in the salivary glands remains a problem, with risk of dose-limiting xerostomia and potentially severe effect on the quality of life. Gustatory stimulation is an approach that has commonly been used in radioactive iodine therapy to reduce accumulation in the salivary glands. However, based on theoretical differences in biodistribution, it was hypothesized that this could potentially lead to adverse increased toxicity for PSMA-ligand therapy. The primary objective of this work was to determine if gustatory stimulation by eating an assortment of sweet/fatty/acidic foods during the biodistribution phase of [18F]DCFPyl could result in a clinically relevant (> 30%) change in the uptake of the tracer in the salivary glands.Methods10 patients who already received a whole-body [18F]DCFPyl PET/CT scan for evaluation of prostate cancer, underwent a repeat (intervention) PET/CT scan within a month of the first (control) scan. During the intervention scan, patients chose from an assortment of sweet/fatty/acidic foods, which they then chewed and swallowed for a period of time starting 1 min before tracer administration to 10 min thereafter. Data from both scans were analyzed by placing VOIs on the major salivary glands and segmenting them using relative thresholds.ResultsA slight increase in PSMA uptake in the parotid glands was observed on the intervention scan when compared to the baseline scan (+ 7.1% SULmean and + 9.2% SULmax, p < 0.05). No significant difference in PSMA uptake in the submandibular glands was seen.ConclusionsEating only slightly increases uptake of [18F]DCFPyl in the parotid glands. We nonetheless recommend refraining from gustatory stimulation during the administration and early biodistribution phase of radionuclide therapy with PSMA-ligands to reduce the risk of avoidable additional toxicity.

Apparent diffusion coefficient measurement of the parotid gland parenchyma.

The measurements of apparent diffusion coefficient (ADC) with diffusion weighted magnetic resonance imaging (DW-MRI) is becoming a popular diagnostic and research tool for examination of parotid glands. However, there is little agreement between the reported ADC values of the parotid gland in published literature. In this review 43 studies on ADC measurement of the parotid glands were included. The analyses indicated several possible culprits of the observed ADC discrepancies. For example, DW-MRI examinations under gustatory stimulation gives higher ADC values compared to the unstimulated parotid gland (P=0.003). The diffusion weighting factors (b-values) can either increase (b-value <200 s/mm2) or decrease ADC values (b-values >1,000 s/mm2). The timing of follow-up DW-MRI after radiotherapy (RT) indicates correlation to the found ADC values (R2 =0.39). Interestingly, the choice of regions of interest (ROI) appears not to affect the measurements of ADC (P=0.75). It can be concluded that there is a critical need for standardization of ADC measurement of the parotid glands to allow valid inter-study comparisons and eventually to reach consensus on the use of ADC as biomarker.

Salivary Gland Organ Regeneration for Oral Health

Salivary glands play essential roles in normal upper gastrointestinal tract function and oral health via saliva production. There are three types of salivary glands; the submandibular gland and parotid gland, which secrete serous saliva, and the sublingual gland secretes mucous saliva in mice [1]. Therefore, salivary gland dysfunction due to atrophy of acinar cells caused by Sjogren’s syndrome, radiation therapy for head and neck cancer, and aging and saliva reduction, and results in xerostomia (dry mouth syndrome), causes various clinical problems in oral health and influences overall bodily health [2]. Xerostomia induces various clinical problems in oral health, such as dental decay, bacterial infection, and disorders of mastication and swallowing, which result in a general reduction in the quality of life [3]. Current standard to cure xerostomia are symptomatic treatments, such as the administration of artificial saliva substitutes and sialogogues, and the administration of parasympathetic stimulation drugs, including pilocarpine and cevimeline [4]. In salivary gland regenerative therapy, stem cell transplantation, which expressed c-kit and Sca-1 as stem cell markers and exhibit high proliferative capacities [5,6], and gene modification for water channel aquaporin-1 (AQP1) and Interleukin-17 (IL-17) receptor antibody is performed to restore the damaged acinar tissue and recover the flow of saliva [7,8]. Salivary glands arise from the organ germ, which is induced by reciprocal epithelial and mesenchymal stem cell interactions during embryonic development [9]. In this two decades, advances in developmental biology have led to break-through in regeneration of functional bioengineered organ in vitro by using embryonic organ-inductive potential stem cells. Recently, regeneration of fully functional salivary gland as a next-generation organ regeneration has been reported after the transplantation of bioengineered salivary gland germ developed by using embryonic organ-inductive potential stem cells as well as iPS cells [10,11]. In 2013, we demonstrated the fully functional salivary gland regeneration by recapitulating the embryonic morphogenesis. The bioengineered salivary gland organ germ, which was reconstituted by our Organ Germ Method using organ-inductive potential stem cells derived from submandibular gland germs of ED 13.5 mice [12], showed reciprocal epithelial and mesenchymal interactions in in vitro organ culture. Following the orthotopic transplantation, the bioengineered germ develops into a mature salivary gland via acinar formations with a myoepithelium and innervation. The bioengineered salivary gland produces saliva in response to the pilocarpine administration and gustatory stimulation by citrate, protected against bacterial infection and restores normal swallowing function in a mouse model. This study provides a proofof- concept for bioengineered salivary gland regeneration. The next breakthrough first reported in 2008 was the emergence of an organoid as a mini-organ that was generated by inducing body patterning and a subsequent organ-forming field formation in pluripotent stem cells [13]. Organoids are useful to recapitulate the process of organogenesis, which are strictly regulated by morphogen signalling and transcriptional networks. To date, multiple types of organoids, including the retina, pituitary gland, liver, and lung have been successfully generated in vitro. Our colleagues identified a specific combination of two transcription factors, Sox9 and Foxc1, are responsible for the differentiation of mouse ES cells-derived oral ectodermal region into the salivary gland rudiment in a threedimensional organoid culture system [11]. The induced salivary gland rudiment showed a similar morphologies and gene expression profiles to those of the embryonic salivary gland rudiment of normal mice. Following orthotopic transplantation into salivary glands-defected mice, the induced salivary gland germ exhibited characteristics of mature salivary glands including histological morphologies, nerve innervation and saliva secretion. This study is the first report of the fully functional organ regeneration by using organoid, demonstrating the potential of salivary gland organ regeneration from pluripotent stem cells for an additional organ replacement regenerative therapy. As part of regenerative medicine, the autogenous transplantation of stem cells, including bone marrow, and tissue sheets such as skin, cornea, and cardiac muscle, has already been applied clinically through cell and tissue transplantation therapies. The progress made in the past two decades has been remarkable, paving the way for possible future organ replacement regenerative therapies. There remains a critical issue as to whether next-generation organ regenerative therapy can be adopted as a novel clinical therapy for patients of the loss of organ function. The bioengineered salivary gland organ germ by using both embryonic organ-inductive potential stem cells and pluripotent stem cells can grow where salivary grand should be in oral cavity and produce the saliva in response to various taste stimulations. These works indicate the potentials for clinical application of salivary gland organ regeneration. Applying knowledge of these basic research will enable the regeneration of salivary gland organ in the next decades.

Effect of a newly developed pastille on the salivary flow rate in subjects with dry mouth symptoms: a randomized, controlled, monocentric clinical study

BackgroundXerostomia is associated with several diseases and is a side effect of certain drugs, resulting from reduced saliva secretion. Often, aged and sometimes younger people suffer from (idiopathic) xerostomia. Chewing gum and sucking pastilles may relieve symptoms of xerostomia by increasing the salivary flow rate due to the mechanical effect of sucking and gustatory stimulation. Swallowing problems and the urge to cough or experiencing a tickling sensation in the throat might be alleviated through a reduction in dry mouth symptoms. We investigated whether a pastille containing four polysaccharides increased the salivary flow rate and relieved the symptoms of dry mouth.MethodsParticipating subjects with xerostomia were randomized into two equally balanced treatment groups. Subjects received the pastille on Day 1 and a control product (Parafilm®) on Day 3, or vice versa. Unstimulated saliva was collected every 2.5 min for 0–10 min. Stimulated saliva was collected after subjects sucked the pastille or the control product. The salivary flow rate was determined gravimetrically, and, in parallel, the feeling of dry mouth was assessed using a visual analog scale. Saliva surface tension was measured in pooled saliva samples (0–5 min of sampling). Additionally, in stimulated saliva from six subjects who sucked the pastille, the presence of the main ingredient—gum arabic—was examined by Raman spectroscopy.ResultsChewing the pastille significantly increased the mean salivary flow rate by 8.03 g/10 min compared to the mean changes after chewing the control product (+ 3.71 g/10 min; p < 0.0001). The mean score of dry mouth was significantly alleviated by the pastille (− 19.9 ± 17.9 mm) compared to the control product (− 3.3 ± 18.1 mm). No difference between the two products was seen regarding the saliva surface tension. Gum arabic was present in the saliva of all investigated subjects for up to 10 min after sucking the pastille.ConclusionsThe pastille was well tolerated and effective in increasing the salivary flow rate and reducing mouth dryness after sucking. These results were in line with the detection of the main ingredient, gum arabic, in saliva for up to 10 min after sucking the pastille.Trial registration German Register Clinical Trials (Deutsches Register Klinische Studien, DRKS) DRKS-ID: DRKS00017393, Registered 29 May 2019, https://www.drks.de/drks_web/navigate.do?navigationId=trial. HTML&TRIAL_ID = DRKS00017393.

Hyposalivation Affecting Womens' Voice

Balanced hydration is crucial for optimal physiological function, whereas hypohydration may cause adverse effects. Like many other organs, the larynx is negatively affected by hypohydration, potentially affecting voice production. Therefore, the purpose of this study was to examine voice properties in women diagnosed with dry-mouth. Twenty-four women diagnosed with hyposalivation and 24 age-matched controls were recruited. All participants underwent three sialometry tests for quantifying oral-dryness. These tests were conducted in three conditions: after 2-hour fasting, after gustatory salivary stimulation and after drinking water. After each sialometry, participants were recorded while producing the vowels /a/ and /i/, and during a standardized reading task. A basic set of acoustic measures was extracted from these recordings. Self-evaluation of voice was performed using the VHI-10 questionnaire; and listeners' perception of the voice was performed by five professional judges who rated the recordings perceptually, using the GRBAS scale. Significant group differences were found in fundamental frequency and jitter, but not in shimmer and noise-to-harmonic ratio (corrected P < 0.05). The participants in the hyposalivation group exhibited higher scores on the VHI-10 questionnaire compared to the control group (P=0.002), and the judges perceptually rated their voices higher on the Grade and Roughness scales (0.03 ≤ P ≤ 0.04). In contrast with the significant group differences, no significant differences were found between the three study conditions. Women suffering from oral-dryness were shown to exhibit degradation in voice quality, evident in both acoustic, perceptual and self-evaluation measures. However, in this paradigm, short-term superficial hydration was not shown to elicit a significant improvement in voice properties. These findings highlight the importance of consistent oral-hydration for voice, especially among people suffering from hyposalivation.

Effect of Gustatory versus Auditory Stimulations on Physiological and Behavioral Indicators of Neonates undergoing Endotracheal Suctioning

Background: Neonatal stress is often poorly managed and many stressful procedures such as suctioning are carried out without paying attention to relieve stress. So, gustatory and auditory sensory stimulations help nurses provide developmental care for neonates during stressful procedures. Aim: This study aimed to determine the effect of gustatory versus auditory stimulation on physiological and behavioral indicators of neonates during endotracheal suctioning. Hypothesis: Neonates who receive gustatory stimulation exhibit stable physiological and behavioral indicators than those who do not. Neonates who receive auditory stimulation exhibit stable physiological and behavioral indicators those who do not. Design: A quasi experimental design was used to accomplish this study. Setting: This research was carried out in Neonatal Intensive Care Unit at specialized Smouha hospital in Alexandria. Sample: This study comprised of 75 neonates. Data collection: Two tools were used namely; Bio-demographic characteristics and medical history of neonates' assessment sheet which includes characteristics of neonates and their medical data and Neonatal Infant Pain Scale. Results: The main result showed that, after suctioning, all neonates in the gustatory stimulation group and the majority in the auditory stimulation group exhibited stability in physiological and behavior indicators compared to none of the neonates in the control group. Moreover, three quarters of the neonates among the control group had severe level of stress compared to none of neonates among the gustatory and auditory stimulations groups. The difference was statistically significant between the three groups(p=0.000). Conclusion: gustatory and auditory stimulations were effective in improving neonates' physiological and behavioral indicators of stress during and after endotracheal tube suctioning. Recommendation: Gustatory and auditory stimulations should be incorporated in NICUs policies to relive neonate stress during stressful procedures.

Interoceptive accuracy and its impact on neuronal responses to olfactory stimulation in the insular cortex.

The insular cortex plays a key role in the integration of multimodal information and in interoceptive and exteroceptive processing. For instance, neurons in the central dorsal insula that are active during interoceptive tasks, also show an adaptation to gustatory stimulation. We tested the link between interoception and exteroception for the olfactory system (i.e., the second domain of chemosensation). In a sample of 31 participants, olfactory function was assessed in a two dimensional approach while the Heartbeat Perception Task served as a measurement for cardiac interoceptive accuracy. Subsequent fMRI sessions were performed on a 3‐Tesla MR scanner containing 12–15 olfactory stimulation trials with a mildly pleasant food‐related odor (coffee). Persons scoring high in the cardiac interoceptive accuracy task presented stronger smelling abilities as well as enhanced BOLD responses following olfactory stimulation. The olfactory stimulation triggered enhanced insular activation patterns in the central dorsal insular cortex. Consistent with prior findings on the coherence of gustatory and interoceptive processing in the central dorsal insula, these results base the insula as a common region for the integration of interoception and exteroception. We propose an explanatory model of how exteroception triggers the integration of intero‐ and exteroceptive sensations in the central dorsal insular cortex.

Type a botulinum toxin in the management of spontaneous salivary otorrhea: a case report

BackgroundSpontaneous salivary otorrhea is a rare presentation only previously documented twice in literature where parotid salivary secretions are found in the external auditory canal. Conventional treatment of spontaneous parotid salivary fistulas includes surgical management with interposed grafts, fistula tract ablation, and possible superficial parotidectomy. Associated risks include facial nerve injury, Frey syndrome and facial scarring. Here we report the first case of spontaneous salivary otorrhea conservatively managed with a type A botulinum toxin (BTA) injection.Case presentationA 17-year-old female presented with a 5-month history of left sided otorrhea and transient left facial swelling associated with gustatory stimulation. The otorrhea fluid tested positive for salivary amylase and negative for beta 2 transferrin. Fifty units of BTA were injected into the left parotid gland under ultrasound guidance. Cessation of symptoms was achieved 3 weeks after intervention. The patient remains symptom-free at the 2 year follow up.ConclusionBTA injection was well tolerated under ultrasound guidance and has led to long-term resolution of the patient’s symptoms. BTA injection appears to be a safe and effective way to conservatively manage this rare presentation of spontaneous salivary otorrhea.

Patient-related outcomes in Sjögren syndrome treated with stimulants of salivary secretion: Randomized clinical trial.

To investigate the impact of gustatory stimulants of salivary secretion (GSSS) on Sjögren's syndrome patients' self-perception of xerostomia, oral health-related quality of life (OHRQoL) and salivary secretion. A total of 110 Sjögren's syndrome patients were randomly allocated to be treated with either a malic acid lozenge or a citric acid mouthwash and then crossed over. Before and after the interventions, the Xerostomia Inventory 5 (SXI-5-PL) and the Oral Health Impact Profile (OHIP-14-PT) questionnaires (both in the Portuguese language) were administered to patients. Unstimulated, mechanical and gustatory-stimulated salivary flows were determined. Repeated measures and between-subject analyses were performed. Statistical significance was set at 5%. After the intervention and within each group, both GSSS elicited a reduction in the SXI-5-PL and OHIP-14-PT scores and an increase in salivary output, significant in the malic acid lozenge group. The malic acid treatment resulted in a greater effect size and percentage improvement than citric acid mouthwash. The malic acid lozenge also produced a significant greater salivary output than the citric acid rising solution. In Sjögren's syndrome patients, lozenges containing malic acid increased saliva production and xerostomia relief, resulting in improved quality of life.