Sensorial differences according to sex and ages

Encoding contact size using static and dynamic electrotactile finger stimulation: natural decoding vs. trained cues

Electrotactile stimulation through matrix electrodes is a promising technology to restore high-resolution tactile feedback in extended reality applications. One of the fundamental tactile effects that should be simulated is the change in the size of the contact between the finger and a virtual object. The present study investigated how participants perceive the increase of stimulation area when stimulating the index finger using static or dynamic (moving) stimuli produced by activating 1 to 6 electrode pads. To assess the ability to interpret the stimulation from the natural cues (natural decoding), without any prior training, the participants were instructed to draw the size of the stimulated area and identify the size difference when comparing two consecutive stimulations. To investigate if other "non-natural" cues can improve the size estimation, the participants were asked to enumerate the number of active pads following a training protocol. The results demonstrated that participants could perceive the change in size without prior training (e.g., the estimated area correlated with the stimulated area, p < 0.001; ≥ two-pad difference recognized with > 80% success rate). However, natural decoding was also challenging, as the response area changed gradually and sometimes in complex patterns when increasing the number of active pads (e.g., four extra pads needed for the statistically significant difference). Nevertheless, by training the participants to utilize additional cues the limitations of natural perception could be compensated. After the training, the mismatch in the activated and estimated number of pads was less than one pad regardless of the stimulus size. Finally, introducing the movement of the stimulus substantially improved discrimination (e.g., 100% median success rate to recognize ≥ one-pad difference). The present study, therefore, provides insights into stimulation size perception, and practical guidelines on how to modulate pad activation to change the perceived size in static and dynamic scenarios.

Consumer acceptability of no added sugar pound cakes under blind and informed testing conditions

Stevia is an emerging natural high-intensity sweetener. There are negative perceptions of zero-calorie sweeteners, but studies that provide knowledge of these sweeteners improve their perception. This study evaluated consumer acceptability of a zero-sugar bakery product under blind and informed conditions (n = 96) along with physicochemical analysis of the products. Rebaudioside A (Reb A) and the new types of stevia (Rebs D and M) with sugar as a control were used to formulate pound cakes. Panelists evaluated the overall hedonic impressions (aroma, texture, flavor, and aftertaste) and intensity (sweetness and bitterness) of the cakes under blind and informed conditions with an enforced 2-week break between evaluations. During the informed session, a document was provided prior to evaluating samples that included stevia's health benefits and the nutritional facts panels for the cakes. The cakes underwent volatile profile (electronic nose [e-nose]) and water activity (aw ) analysis. Overall, stevia cakes showed an increase in flavor and texture liking during the informed session when compared to the blind session, but only Reb A showed a significant difference (p < 0.05). The increase in liking scores indicated that information positively affected the consumer's perception of the stevia-sweetened cakes attributes. The e-nose confirmed differences in aroma. There was a significant difference in aw of the samples Rebs A, D, M versus sucrose (p < 0.05). No significant differences were observed among the Rebs (p > 0.05). This study illustrates that stevia, despite non-browning or fermenting, can be used in a practical baking application, and product-related information impacts consumer acceptability. PRACTICAL APPLICATION: This study demonstrates that product-related information may have an impact on the consumer acceptability of the product. Through potential labeling improvements, overall consumer perception and acceptability of zero-sugar added or low-sugar products could be improved. This study also illustrates that stevia, despite being a non-browning or fermenting sugar alternative, can be used in a practical baking application.

Late Blindness and Deafness are Associated with Decreased Tactile Sensitivity, But Early Blindness is Not

Perceptual experience is shaped by a complex interaction between our sensory systems in which each sense conveys information on specific properties of our surroundings. This multisensory processing of complementary information improves the accuracy of our perceptual judgments and leads to more precise and faster reactions. Sensory impairment or loss in one modality leads to information deficiency that can impact other senses in various ways. For early auditory or visual loss, impairment and/or compensatory increase of the sensitivity of other senses are equally well described. Investigating individuals with deafness (N = 73), early (N = 51), late blindness (N = 49) and corresponding controls, we compared tactile sensitivity using the standard monofilament test on two locations, the finger and handback. Results indicate lower tactile sensitivity in people with deafness and late blindness but not in people with early blindness compared to respective controls, irrespective of stimulation location, gender, and age. Results indicate that neither sensory compensation nor simple use-dependency or a hindered development of the tactile sensory system is sufficient to explain changes in somatosensation after the sensory loss but that a complex interaction of effects is present.

Endocrinology of Taste with Aging

Taste is one of our five primary senses, and taste impairment has been shown to increase with aging. The ability to taste allows us to enjoy the food we eat and to avoid foods that are potentially spoiled or poisonous. Recent advances in our understanding of the molecular mechanisms of taste receptor cells located within taste buds help us decipher how taste works. The discoveries of "classic" endocrine hormones in taste receptor cells point toward taste buds being actual endocrine organs. A better understanding of how taste works may help in reversing taste impairment associated with aging.

Evaluation of the intensity of cigarette odors based on the perception of consumers

INTRODUCTION

We evaluated the tobacco odor intensity of cigarettes based on a large consumer panel and explored the differences of odor intensity perception based on sex, age and smoking habits.

METHODS

The perceived intensity of tobacco odor of cigarettes was evaluated using a consumer group method. A consumer panel of 240 volunteers (80 smokers, 80 ex-smokers and 80 non-smokers) was asked to smell eleven unlit cigarettes and then report their tobacco odor intensity in a specific questionnaire.

RESULTS

All volunteers clearly determined the presence of tobacco odor in all cigarettes. There is a general decrease of the perceived odor intensity with age, for both males and females. Moreover, tobacco odor perceived intensity, among all volunteer groups (smokers, non-smokers, ex-smokers), was higher for females than for males. Non-smokers declared the highest perceived tobacco odor intensities, followed by ex-smokers and smokers, who recorded the lowest perceived odor intensity. Perceived odor intensity decreased with age, with a higher rate for females compared to males, but independently of the smoking habits.

CONCLUSIONS

Regular and untrained consumers confirmed that a tobacco odor of different intensity can be perceived during the smelling of unlit cigarettes. This perceived intensity depends on sex, age and smoking habits.

Somatosensory and Gustatory Profiling in the Orofacial Region

Quantitative sensory testing (QST) is a standard procedure in medicine to describe sensory patterns in various pathologies. The aim of this prospective clinical study was to define reference values of the trigeminal nerve (V3), including taste qualities, to create a compatibility for sensory loss or gain in pathologies. Fifty-one patients were included, and a standardized testing battery with 11 QST parameters according to the German Research Network on Neuropathic Pain (DFNS) was applied complemented by quantitative gustatory assessments. Significant somatosensory differences were found between the test sites (MDT at the chin, WDT at the lower lip) but no effect was detected for gender, age, and between body types. Taste sensitivity was dependent on concentration, gender (females being more sensitive) and increasing age (for bitter and sour taste). We provide reference values for somatosensory and gustatory testing of the facial area. Our data facilitate the detection of neurosensory abnormalities in the orofacial region. This might also serve as a control setting for COVID-19.

Oral and Mucosal Complaints among Institutionalized Care Seniors in Malopolska Voivodeship-The Utility of the Mirror Sliding Test in an Assessment of Dry Mouth

The purpose of this article was to evaluate reported oral and mucosal complaints among seniors residing in institutionalized 24-h care of the Municipal Center for Older and Dependent People (MHCOD) and the 3-month rehabilitation program of the Daily Medical Care House (DMCH). We evaluated the feasibility of using the dental mirror slidding test to assess dry mouth of seniors. Patients underwent a questionnaire, and clinical examination. The Visual Analogue Scale (VAS) was used to assess pain, Fox's questionnaire and Challacombe's scale with Clinical Oral Dryness Score to assess dryness of the mouth, dental mirror slidding test to assess buccal mucosal resistance. Dryness, mucosal burning, impaired taste, food intake are symptoms associated with seniors, and their frequency does not depend on the type of care. The incidence of mucosal burning (Mdn = 4.0, IQR = 4.75, p = 0.032) and difficulty in using dental prosthetics (Mdn = 3.0, IQR = 4.00, p = 0.010) increase with the length of stay at MHCOD. Seniors are at risk of side effects of polypharmacy, which cause dryness (p = 0.036), complaints of lack of saliva (p = 0.009) and taste disorders (p = 0.041. Seniors with higher levels of dry mouth are more likely to exhibit mucosal burning (p = 0.026) and difficulty in taking food (p = 0.037). The implementation of the dental mirror slidding test in the scope of the primary care of geriatric examination should be discussed.

The risk factors of neuropathic pain in neuromyelitis optica spectrum disorder: a retrospective case-cohort study

Background

Neuropathic pain is a common complication in neuromyelitis optica spectrum disorder (NMOSD), which seriously affects the quality of life of NMOSD patients, with no satisfactory treatment. And risk factors of neuropathic pain are still uncertain.

Objective

To investigate the risk factors of neuropathic pain in a NMOSD cohort.

Materials and methods

Our study was a retrospective case-cohort study, the patients diagnosed with NMOSD in the Department of Neurology from the Second Affiliated Hospital of Guangzhou University of Chinese Medicine from January 2011 to October 2021 were screened. Inclusion criteria were: (1) patients diagnosed as NMOSD according to the International Panel for NMO Diagnosis (IPND) criteria, (2) the aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) test was performed. Patients without AQP4-IgG antibody were excluded. Clinical data, including sex, age of the first onset, symptoms of the first episode including neuropathic pain and attack types, localization of lesions of the first episode on Magnetic Resonance Imaging (MRI), Extended disability status Scale (EDSS) of the first onset, treatment of immunosuppression in the first acute phase, disease modifying therapy (DMT), treatment of neuropathic pain and APQ4-IgG status were collected from the hospital system database. Neuropathic pain was defined according to the International Association for the Study of Pain criteria and was described as “pain arising as a direct consequence of a lesion or disease affecting the somatosensory system”.

Results

One hundred nineteen patients were screened and finally 86 patients fulfilling the inclusion and exclusion criteria were enrolled in our study. The prevalence of neuropathic pain in patients with NMOSD was 43.0%. Univariate analysis showed that the factors associated with neuropathic pain were the age at the onset, the attack type of optic neuritis, the attack type of myelitis, length of spinal cord involvement, localization of thoracic lesion, optic lesion, upper thoracic lesions, lower thoracic lesions, extended spinal cord lesions (≥ 3 spinal lesions), extended thoracic lesions (≥ 4 thoracic lesions), intravenous immunoglobulin and mycophenolate mofetil. Multivariate regression analysis showed that extended thoracic lesions (OR 20.21 [1.18–346.05], P = 0.038) and age (OR 1.35 (1–1.81) P = 0.050) were independently associated with neuropathic pain among NMOSD patients and that gender (OR 12.11 (0.97–151.64) P = 0.053) might be associated with neuropathic pain among NMOSD patients.

Conclusion

Extended thoracic lesions (≥ 4 thoracic lesions), age and gender might be independent risk factors of neuropathic pain among patients with NMOSD. However, with a small sample size and predominantly female, caution must be applied and these results need validating in further cohorts.

Personal influencing factors for pressure pain threshold in healthy people: A systematic review and meta-analysis

All studies that investigated personal factors influencing pressure pain threshold (PPT) in healthy people were synthesized. Data was summarized, and risk of bias (RoB) and level of evidence were determined. Results were pooled per influencing factor, grouped by body region and included in meta-analyses. Fifty-four studies were eligible. Five had low, nine moderate, and 40 high RoB. Following meta-analyses, a strong conclusion was found for the influence of scapular position, a moderate for the influence of gender, and a weak for the influence of age (shoulder/arm region) and blood pressure on PPT. In addition, body mass index, gender (leg region), alcohol consumption and pain vigilance may not influence PPT. Based on qualitative summary, depression and menopause may not influence PPT. For other variables there was only preliminary or conflicting evidence. However, caution is advised, since the majority of included studies showed a high RoB and several were not eligible to include in meta-analyses. Heterogeneity was high in the performed meta-analyses, and most conclusions were weak. More standardized research is necessary.

Impact of the Filling Medium on the Colour and Sensory Characteristics of Canned European Eels (Anguilla anguilla L.)

The different vegetable oils used in canned fish as a filling medium have a preserving effect and contribute to the palatability of the product. In this study, the colour of European eels and the filling medium (sunflower oil, olive oil or spicy olive oil) was measured at different steps of the canning process. The sensorial characteristics of canned eels packed in the different oils were also evaluated. Colour scores (CieLab values) were higher in canned eels packed in sunflower and spicy olive oil than in canned eels packed in olive oil. The changes in colour parameters depended on the type of oil, the stage of the process and the storage time. Colour changes in canned eels packed in olive oil were highest during the sterilization process. Spicy olive oil was the filling medium in which the colour change was greatest, probably due to the migration of some of the spice components into the oil. Organoleptic properties were directly related to the type of oil used as the filling medium. The canned eels packed in sunflower oil were those awarded the highest scores in consumer tests, although the preferences varied depending on the age and gender of the consumers.

Sensory characteristics and chronic facial pain conditions: Cross-sectional study

OBJECTIVES

This study investigated patients with neuropathic, myofascial and other orofacial pain conditions according to the differences and similarities of the sensory profile, and the association between sensory findings and neuropathic or non-neuropathic conditions.

DESIGN

132 healthy controls were compared with 174 orofacial pain patients that were classified into three groups (neuropathic, masticatory myofascial and other orofacial pain condition) and evaluated with a systematized protocol of sensory testing. Data were analyzed with chi-quare and Bonferroni correction (categorical data), Student´s t test, oneway ANOVA, Tukey (quantitative features), Pearson´s coefficient for correlations and logistic regression.

RESULTS

Cold, olfactory and superficial pain thresholds were higher in the group of neuropathic facial pain compared with the other groups, and the highest vibratory thresholds were observed in the group of other orofacial pain conditions. Deep pain thresholds were statistically lower in the group with masticatory myofascial pain.

CONCLUSIONS

Positive sensory findings (eg. hyperalgesia) were more common in the group of patients with masticatory myofascial pain, supporting inflammatory systemic mechanisms, and negative sensory findings not restricted to the trigeminal nerve (eg. hypoesthesia, hyposmia) were more frequent in patients with neuropathic conditions. Non-classical neuropathic orofacial pains also showed sensory impairment from pain chronification and from the overlap with functional disorders.

Sex differences in the taste-evoked functional connectivity network

The central gustatory pathway encompasses multiple subcortical and cortical regions whose neural functional connectivity can be modulated by taste stimulation. While gustatory perception has been previously linked to sex, whether and how the gustatory network differently responds to basic tastes between men and women is unclear. Here, we defined the regions of the central gustatory network by a meta-analysis of 35 fMRI taste activation studies and then analyzed the taste-evoked functional connectivity between these regions in 44 subjects (19 women) in a separate 3 Tesla activation study where sweet and bitter solutions, at five concentrations each, were administered during scanning. From the meta-analysis, a network model was set up, including bilateral anterior, middle and inferior insula, thalamus, precentral gyrus, left amygdala, caudate and dorsolateral prefrontal cortex. Higher functional connectivity than in women was observed in men between the right middle insula and bilateral thalami for bitter taste. Men exhibited higher connectivity than women at low bitter concentrations and middle-high sweet concentrations between bilateral thalamus and insula. A graph-based analysis expressed similar results in terms of nodal characteristics of strength and centrality. Our findings add new insights into the mechanisms of taste processing by highlighting sex differences in the functional connectivity of the gustatory network as modulated by the perception of sweet and bitter tastes. These results shed more light on the neural origin of sex-related differences in gustatory perception and may guide future research on the pathophysiology of taste perception in humans.

Investigation of taste function and eating behavior in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age that is associated with eating disorders and disordered eating. No data is available regarding taste function in women with PCOS. The aim of this study was to assess taste function and eating behavior in patients with PCOS compared to healthy women and investigate potential impact of oral contraceptive (OC) use on those. Forty-four patients with PCOS and 36 age and body-mass-index matched healthy controls were enrolled. Gustatory function was assessed by taste strips (sweet, sour, salty, bitter) and Food Cravings Questionnaire-Trait (FCQ-T), Night Eating Questionnaire (NEQ) and Three Factor Eating Questionnaire-R18 (TFEQ-R18) were applied. All measurements were repeated in patients after receiving an OC along with general lifestyle advice for 3 months. At baseline, PCOS group had lower total taste strip test (TST) scores compared to controls (11.7 ± 2.2 vs. 13.1 ± 1.4; p = 0.001). Subgroup analysis showed lower sour and salty taste scores in PCOS group (2.4 ± 0.9 vs. 2.9 ± 0.7; p = 0.004; and 2.6 ± 1 vs. 3.1 ± 0.7; p = 0.01 respectively). Sweet and bitter taste scores were similar. No difference was determined in eating behavior. Linear regression analysis revealed that hyperandrogenism was significant predictor for total TST score (R² = 0.22, p < 0.001). Higher free androgen index (FAI) was associated with lower total TST score (p = 0.01). Total TST score, TFEQ-R18 and NEQ scores remained unaltered after treatment in the PCOS group whereas FCQ-T scores showed significant reduction (p = 0.02), mainly due to a decrease in lack of control subscale (p = 0.01). Our results suggest that taste perception is reduced in PCOS, and short-term OC use does not alter taste functions in the syndrome.

Gustatory Function and Salivary Flow Rate in Healthy Adults

OBJECTIVES/HYPOTHESIS

In this study, we assessed gustatory function and whole-mouth saliva in healthy adults and investigated the association between gustatory function, salivary flow rate (SFR), and dry mouth.

STUDY DESIGN

Descriptive clinical study.

METHODS

We recruited 413 participants who reported a normal sense of smell-taste, comprising 206 females and 207 males with an age range of 19 to 80 years. Taste scores were obtained using whole-mouth tests to evaluate the gustatory function, SFR was assessed using the spitting method, and dry mouth was measured with the visual analog scale.

RESULTS

The total taste score (TTS) and SFR were significantly negatively correlated with age (r_taste  = -0.522, P < .001; r_SFR  = -0.200, P < .001): TTS was significantly lower after the age of 50 and SFR decreased significantly after age 65. Women exhibited a significantly higher TTS than men (P < .001). However, there was no effect of sex on SFR. Dry mouth was negatively correlated with TTS (r = -0.223, P < .01) and SFR (r = -0.218, P < .01). Multiple regression analysis showed the independent variables of age, sex, and dry mouth predicted 34% of the variation in taste, while the independent variables of age and dry mouth predicted 6.1% of the variation in whole-mouth saliva. TTS was not significantly correlated with the SFR in healthy adults (r = 0.094, P = .056).

CONCLUSIONS

Age and dry mouth are important factors affecting gustatory function and whole-mouth saliva, with women exhibiting better taste sensitivity than men. Furthermore, there is no direct correlation between SFR and gustatory function in healthy adults.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Normative data on the subjective gustatory function of Chinese adults

PURPOSE

the study aims to assess the gustatory function of healthy Chinese adults with the whole-mouth test based on five basic tastants, including umami taste.

METHODS

the study recruited 464 participants reporting a normal sense of smell/taste (227 females and 237 males with an age range of 19-65 years). A drop (approximately 0.1 mL) of liquid tastant was applied on the anterior third of the extended tongue of each subject. The taste solutions involved 5 tastants (sour, sweet, salty, umami, and bitter) and 7 concentrations. Taste perception scores and recognition scores of the five basic tastants were obtained with this whole-mouth taste method.

RESULTS

total taste score of recognition showed a significant negative correlation with age. The elder group (51-65 years) had the lowest scores. The 10th percentile of total taste score of recognition in the group of 36 to 50 years was used to distinguish normogeusic subjects from hypogeusic subjects. The perception scores and recognition scores of females were higher than those of males. The perception and recognition thresholds of salty, umami, and bitter for females were lower than those for males. Total taste score of recognition for non-smokers was significantly higher than that of smokers. The whole-mouth method showed a high test-retest reliability with an intra-class correlation coefficient (ICC) from 0.774 to 0.833.

CONCLUSION

this whole-mouth method is simple and time-saving and can be easily adjusted to obtain reliable data. The gustatory function was significantly negatively correlated with age. Females were more sensitive to the sour, salty, umami and bitter tastes than males. The gustatory function of non-smokers was more sensitive.

Sensory characteristics according to chronic diseases and chronic pain in adults: cross-sectional study

Aim: To investigate somatosensory, gustative and olfactory characteristics of subjects according to their chronic diseases and the presence of chronic pain complaints. Materials & methods: A total of 254 chronic pain patients and 52 healthy subjects were evaluated with a clinical and sensory systematized evaluation. Statistical analysis consisted of Fisher's exact, Student's t-tests, Pearson's co-efficient and multivariate nonlinear/logistic regressions. Results: Patients had more chronic diseases (p < 0.001) than healthy subjects. Chronic pain was associated with vibratory hypoesthesia (p = 0.047) and sour hypergeusia (p = 0.001) and several chronic diseases correlated with sensory features. Hyposmia was strongly associated with chronic pain symptoms, chronic diseases and cardiovascular disease. Conclusion: The sensory findings observed suggest the need for further investigation about the overlap between the olfactory function, pain chronification, chronic diseases and cognitive impairment in these patients.

Relationship between polypharmacy, xerostomia, gustatory sensitivity, and swallowing complaints in the elderly: A multidisciplinary approach

Oral dysfunctions are common in the elderly but the literature lacks a multidisciplinary approach on the relationship between polypharmacy, saliva flow, xerostomia, taste, and swallowing complaints. This cross-sectional study included 204 non-institutionalized elderly (>60 years; 123 women/81 men), free of severe disabilities and non-alcohol/tobacco consumers, from whom specific pharmacological therapies were evaluated, as well xerostomia (Xerostomia Inventory-XI) and swallowing complaints (EAT-10 questionnaire), salivary flow rate and gustatory sensitivity. Statistical analysis included Chi-square, Mann-Whitney, Two-way ANCOVA, and linear multiple regression. Polypharmacy (≥5 drugs daily), hyposalivation, and severe taste dysfunction were found in 18, 46, and 10% of the participants, respectively. Polypharmacy was related with xerostomia (p = .041) and swallowing complaints (p < .001; power = 94%), but not with taste dysfunction. Dry mouth complaint and higher risk of swallowing disorders were found in 50 and 12% of the elderly, respectively, and angiotensin-converting enzyme (ACE) inhibitors users (n = 36) showed higher EAT-10 scores (p = .038). Regression models showed that stimulated salivary flow rate was dependent on gender and diuretic use, while xerostomia scores were dependent on the number of medications and unstimulated saliva flow (p < .001). In conclusion, the results draw attention to the high frequency of oral and maxillofacial dysfunctions found in non-institutionalized elderly, especially polypharmacy, xerostomia and swallowing complaints, and the side effects of drugs that can disturb the oral functions, the acceptance of food, and the adherence to oral therapies.

Thermal Psychophysics and Associated Brain Activation Patterns Along a Continuum of Healthy Aging

OBJECTIVE

To examine psychophysical and brain activation patterns to innocuous and painful thermal stimulation along a continuum of healthy older adults.

DESIGN

Single center, cross-sectional, within-subjects design.

METHODS

Thermal perceptual psychophysics (warmth, mild, and moderate pain) were tested in 37 healthy older adults (65-97 years, median = 73 years). Percept thresholds (oC) and unpleasantness ratings (0-20 scale) were obtained and then applied during functional magnetic resonance imaging scanning. General linear modeling assessed effects of age on psychophysical results. Multiple linear regressions were used to test the main and interaction effects of brain activation against age and psychophysical reports. Specifically, differential age effects were examined by comparing percent-signal change slopes between those above/below age 73 (a median split).

RESULTS

Advancing age was associated with greater thresholds for thermal perception (z = 2.09, P = 0.037), which was driven by age and warmth detection correlation (r = 0.33, P = 0.048). Greater warmth detection thresholds were associated with reduced hippocampal activation in "older" vs "younger" individuals (>/<73 years; beta < 0.40, P < 0.01). Advancing age, in general, was correlated with greater activation of the middle cingulate gyrus (beta > 0.44, P < 0.01) during mild pain. Differential age effects were found for prefrontal activation during moderate pain. In "older" individuals, higher moderate pain thresholds and greater degrees of moderate pain unpleasantness correlated with lesser prefrontal activation (anterolateral prefrontal cortex and middle-frontal operculum; beta < -0.39, P < 0.009); the opposite pattern was found in "younger" individuals.

CONCLUSIONS

Advancing age may lead to altered thermal sensation and (in some circumstances) altered pain perception secondary to age-related changes in attention/novelty detection and cognitive functions.

Analysis of Epigenetic Age Predictors in Pain-Related Conditions

Chronic pain prevalence is high worldwide and increases at older ages. Signs of premature aging have been associated with chronic pain, but few studies have investigated aging biomarkers in pain-related conditions. A set of DNA methylation (DNAm)-based estimates of age, called “epigenetic clocks,” has been proposed as biological measures of age-related adverse processes, morbidity, and mortality. The aim of this study is to assess if different pain-related phenotypes show alterations in DNAm age. In our analysis, we considered three cohorts for which whole-blood DNAm data were available: heat pain sensitivity (HPS), including 20 monozygotic twin pairs discordant for heat pain temperature threshold; fibromyalgia (FM), including 24 cases and 20 controls; and headache, including 22 chronic migraine and medication overuse headache patients (MOH), 18 episodic migraineurs (EM), and 13 healthy subjects. We used the Horvath's epigenetic age calculator to obtain DNAm-based estimates of epigenetic age, telomere length, levels of 7 proteins in plasma, number of smoked packs of cigarettes per year, and blood cell counts. We did not find differences in epigenetic age acceleration, calculated using five different epigenetic clocks, between subjects discordant for pain-related phenotypes. Twins with high HPS had increased CD8+ T cell counts (nominal p = 0.028). HPS thresholds were negatively associated with estimated levels of GDF15 (nominal p = 0.008). FM patients showed decreased naive CD4+ T cell counts compared with controls (nominal p = 0.015). The severity of FM manifestations expressed through various evaluation tests was associated with decreased levels of leptin, shorter length of telomeres, and reduced CD8+ T and natural killer cell counts (nominal p < 0.05), while the duration of painful symptoms was positively associated with telomere length (nominal p = 0.034). No differences in DNAm-based estimates were detected for MOH or EM compared with controls. In summary, our study suggests that HPS, FM, and MOH/EM do not show signs of epigenetic age acceleration in whole blood, while HPS and FM are associated with DNAm-based estimates of immunological parameters, plasma proteins, and telomere length. Future studies should extend these observations in larger cohorts.

Psychophysical characterisation of burning mouth syndrome-A systematic review and meta-analysis

BACKGROUND

Primary burning mouth syndrome (BMS) is an oro-facial disease with neuropathic characteristics. Psychophysics, such as quantitative sensory testing (QST), is used to sub-classify neuropathic pain syndromes, but their usefulness in characterising BMS is not yet clear.

OBJECTIVE

The aim of this study was to summarise and to quantitatively and qualitatively analyse the available information about QST findings in BMS, and to reflect on possible mechanisms of disease.

METHODS

In this systematic review and meta-analysis, different search strategies were used to screen for articles in PubMed, Embase, EBSCOhost, Cochrane Library, Web of Science, Google Scholar and two sources of conference abstracts. Primary clinical studies focused on QST assessment in patients with BMS were included. Data were synthesised qualitatively and quantitatively. Risk of bias was assessed following the AHRQ guidelines.

RESULTS

Thirteen articles with low to moderate risk of bias and one conference abstract were selected from 45 unique articles that were identified. Individually, the studies reported combinations of thermal and mechanical sensory impairments measured by QST. The meta-analysis showed significant sensory differences between patients and controls in warmth (effect size = 0.683; P < .05) and cold detection thresholds (effect size = -0.580; P < .001).

CONCLUSION

The results indicate that thermal sensitivity seems to be altered in patients with BMS compared to controls, suggesting a small-fibre neuropathy. However, study protocols were highly variable and heterogeneous. Therefore, studies with better designs and complete reporting of results should be performed to bring value to the use of psychophysics in the assessment of BMS.

Influence of Menstrual Cycle Phases on Neural Excitability in the Primary Somatosensory Cortex and Ankle Joint Position Sense

Introduction: Ankle sprain (AS) is one of the most common injuries among women engaged in competitive sports and recreational activities. Many studies have shown that several factors contributing to AS are influenced by the menstrual cycle. Despite the finding that abnormal joint position sense (JPS) is one of the major risk factors of AS, the alteration of the JPS throughout the menstrual cycle and its associated neural mechanisms remain unclear.

Objective: This study aimed to examine whether the menstrual cycle phases affect neural excitability in the primary somatosensory cortex (S1) and JPS.

Methods: Fourteen right-footed women participated in this study. Somatosensory-evoked potential and paired-pulse inhibition (PPI) were measured to assess S1 excitatory and inhibitory functions. Ankle JPS was measured using an active joint position matching method. Menstrual syndrome was evaluated using the menstrual distress questionnaire. All assessments were conducted in the follicular, ovulatory, and luteal phases.

Results: The two main findings of this study were as follows: First, PPI decreased in the ovulatory phase than in the follicular phase. This may have been the reason for estrogen altering the neural inhibition and facilitation balance throughout the menstrual cycle. Second, JPS was not changed during the menstrual cycle.

Conclusion: In conclusion, phases of the menstrual cycle affect the neural excitability in S1 as shown by the decreased PPI in the ovulatory phase, and the ankle JPS was unchanged throughout the menstrual cycle.

Characterization of pain syndromes in patients with neuromyelitis optica

BACKGROUND

Pain is common and refractory in spinal cord injury (SCI). Currently, most studies evaluated pain in male-predominant traumatic-SCI. Also, concomitant secondary pain syndromes and its temporal evolution were seldom reported.

METHODS

We aimed to prospectively describe the main and secondary pain and its associated factors in inflammatory-SCI evaluating neuromyelitis optica (NMO) patients. In-remission NMO patients underwent neurological, imaging and autoantibody evaluations. Questionnaires detailing main and secondary pains, functional state, mood, catastrophizing, quality of life (QoL) and "non-motor symptoms" were used at two time points.

RESULTS

Pain was present in 53 (73.6%) of the 72 patients included. At-level neuropathic pain was the most common main pain syndrome, affecting 32 subjects (60.4% of those with pain). Over 70% (n = 38) of this cohort reported two pain syndromes. Those without pain were significantly younger (26.1 ± 12.7 y.o. in those without pain and 40.1 ± 12.5, 37.2 ± 11.4 y.o. in those whose main pain was neuropathic and non-neuropathic, respectively, p = .001), and no differences in the inflammatory status were observed between groups. On follow-up, one-fifth (n = 11) had a different main pain syndrome from the first visit. Pain impacted QoL as much as disability and motor strength.

CONCLUSION

Pain is a prevalent and disabling non-motor symptom in NMO-SCI. Most patients experience more than one pain syndrome which can change in time even in the absence of clinical relapse. Age of the inflammatory-SCI was a major determinant of pain. Acknowledging temporal changes and multiplicity of pain syndromes in NMO-SCI may give insights into more precise designs of clinical trials and general management of pain in SCI.

SIGNIFICANCE

In this longitudinal study with NMO-related SCI, pain affected almost three-quarters of patients with NMO. Over 70% have more than one pain syndrome and at-level neuropathic pain is the most common type of pain syndrome. Patients without pain were significantly younger but had the same burden of inflammatory lesions than those with pain. During follow-up, up to one fifth of patients presented with changes in the main pain syndromes, which can occur even in the absence of clinical activity of the inflammatory disease. In this cohort, Pain affected quality of life as much as disability or motor strength.

Influences of Age, Sex and Smoking Habit on Flavor Recognition in Healthy Population

(1) Background: Flavor is one of the main factors influencing food preferences and dietary choices, and a reduction in flavor recognition has been associated with several diseases. A novel quantitative test to assess flavor has been recently developed and validated. The aim of the present work was to define the standard of flavor recognition in the general healthy population. (2) Methods: Three hundred and forty-eight healthy volunteers (18–80 years) performed the flavor test (FT). The test consisted of the oral administration of aqueous aromatic solutions, identifying 21 different compounds. Flavor score (FS) was calculated as the sum of the properly recognized flavors (range 0–21). (3) Results: Normal ranges for FT were produced. Flavor recognition was found to decrease with age. Females obtained slightly higher scores than males, mostly at older ages. Cigarette smoking seemed not to influence flavor recognition. (4) Conclusion: The normal values found for the flavor test in the healthy population will allow its usage as a diagnostic tool in several diseases.

Sex, blinking, and dry eye

Blinking sustains the corneal tear film generated by sexually dimorphic lacrimal and meibomian glands. Our study examines whether trigeminal control of blinking is also sexually dimorphic by investigating trigeminal reflex blinking, associative blink modification, and spontaneous blinking in male and female rats before and after unilateral dry eye caused by exorbital gland removal. Before gland removal, female rats exhibited a lower threshold for evoking trigeminal reflex blinks, a weaker effect of associative blink modification, and longer-duration spontaneous blinks than males. Spontaneous blink rate, reflex blink excitability, and occurrence of blink oscillations did not differ between the sexes. Reanalysis of previous data showed that humans showed the same blink sexual dimorphisms as rats. During the first 2 wk of dry eye, trigeminal blink circuit excitability and blink oscillations steadily rose in male rats, whereas excitability and blink oscillations did not change in females. Following dry eye, spontaneous blink duration increased for both males and females, whereas spontaneous blink rate remained constant for males but decreased for females. The associative modification treatment to depress trigeminal blink amplitude initially produced blink depression in males that converted to blink potentiation as trigeminal excitability rose, whereas females exhibited progressively more blink depression. These data indicated that dry eye increased excitability in male trigeminal reflex blink circuits at the expense of circuit modifiability, whereas trigeminal modifiability increased in females. This increased modifiability of female trigeminal blink circuits with dry eye may contribute to the preponderance of females developing the focal dystonia, benign essential blepharospasm.NEW & NOTEWORTHY All the elements controlling the corneal tear film are sexually dimorphic. Blinking, which smooths and maintains the tear film, also exhibits sex differences. Dry eye increases the sexual dimorphisms of blinking, including increased exaggeration of excitability in males and enhanced modifiability of the female trigeminal complex. This increased modifiability may explain female predominance in the development of the focal dystonia, benign essential blepharospasm.

Characteristics of patients who perceive dental treatment as a cause of oral mucosal lesions

This retrospective study aims to investigate the proportion and characteristics of patients who perceive dental treatment (DT) as a cause of oral mucosal lesions (OMLs). A total of 2,302 patients with OMLs visited the Oral Medicine Department of Pusan National University Dental Hospital. The patients were divided into a study group (280 patients who perceived DT as a cause of OMLs) and a control group (300 randomly selected patients). Percentages of DT types, clinical characteristics, and the frequencies of diagnoses and chief complaint (CC) sites were analyzed in both groups. Among the patients with OMLs, 12.2% attributed OMLs to DT. Among the diagnoses, allergic reaction (AR) and traumatic ulcer/irritation (TU) were significantly more frequent in the study group. The DT types most frequently perceived as the cause of OMLs were implants. According to patients, TU and candida occurred most frequently following denture placement (68-79%), whereas oral lichen planus and AR occurred most commonly following implant treatment (52-53%). The gingiva was significantly more frequent as the CC site in the study group than in the control group (P < 0.05 for all outcomes). It is important to inform patients of the potential complications of DT and the importance of regular check-ups.

Long Term Cosmetic Application Improves Tactile Discrimination in the Elderly; a New Psychophysical Approach

Introduction: Tactile sensitivity is impaired in older adults, which contributes to the loss of manual dexterity and mobility function. The reliability of classical psychophysical tests, such as two-point gap discrimination, has been questioned. Here we tested a new method to determine tactile acuity during dynamic touch, which is more functional than static touch. The aim was to validate a method providing a high level of discrimination of tactile acuity in the elderly.

Methods: We tested the ability of subjects to evaluate the distance between bands printed on poly-methyl-methacrylate (PMMA) sheets. Pairs of sheets were compared in two groups of participants aged from 60 to 74 years; the test group was required to apply a cosmetic foam with an active ingredient on both their hands twice a day for 1 month, the control group had an identical task but used the same cosmetic foam without any active ingredient. The tests were run in a double-blind, placebo-controlled study.

Results: The tactile discrimination threshold decreased by 83 μm after 1 month of cosmetic application in the group using the active ingredient, while it was unchanged in the control group.

Discussion: The test presented here provided highly accurate results and should be useful to determine tactile performance. It allows the monitoring of tactile rehabilitation and/or skin treatments used to restore tactile acuity in the elderly.

Quantitative sensory testing in elderly: longitudinal study

ABSTRACT Objective: To evaluate elderly patients in a geriatric service, along with their sensory characteristics and their association with clinical aspects. Methods: This was a descriptive longitudinal study. We enrolled 36 healthy participants of both sexes in this study. The following instruments were used and evaluations performed: clinical evaluation, Mini-Mental State Exam, and quantitative sensory testing. Results: During the follow-up, there was reduction of mean corpuscular volume at each evaluation (p < 0.001) and significant increase in mean corpuscular hemoglobin concentration (p < 0.001). There was an increase of the olfactory (p < 0.001), salty (p = 0.024), sour (p = 0.020), bitter (p = 0.001), facial cold (p = 0.019), hand cold (p = 0.004), facial tactile (p < 0.001), hand tactile (p = 0.012) and facial vibration (p = 0.018) thresholds. Previous existing morbidities were associated with sensitivity changes in the individuals in this sample. Conclusion: This longitudinal study suggests that the loss of sensitivity with aging may be associated with the presence of morbidities in elders.

The Use of the Anchor System Reduces Postural Sway During Upright Standing Irrespective of Plantar Flexors Muscle Fatigue in Young and Older Adults

Our purpose was to verify the effects of the use of the anchors on postural control after the fatigue of the plantar flexor muscles in young and older adults. They stood barefoot, with their eyes closed in four conditions combining the use of the anchors and the fatigue. When using the anchors, participants held one cable in each hand and kept the cable taut without removing the loads (125 g) from the ground. The fatigue protocol consisted of performing a single series of bilateral plantar flexion movements. The fatigue protocol increased postural sway in both groups. Both groups reduced postural sway with the anchors, but this effect was independent of fatigue. We conclude that the anchors contributed to the reduction of postural sway in young and older adults, but they were unable to compensate for the disturbing effect in postural control created by fatigue of the plantar flexor muscles.

Influence of Sexual Hormones on Neural Orofacial Perception

Objective

To investigate the trigeminal somatosensory (thermal, pain, tactile, vibratory, and electric), gustative (salty, bitter, sweet, sour), and olfactory thresholds in healthy women during the menstrual cycle and investigate any association with estradiol and progesterone levels in saliva.

Methods

We examined/tested 39 women between age 19 and 47 years and with regular menstrual cycles and no comorbidities. All women were informed about the purposes of the study, and only those who signed the informed consent were included. The tests were performed at three stages within the cycle: menstrual phase, follicular phase, and luteal phase. The procedure consisted of saliva collection at the beginning of each session to measure hormone levels, salivary flow, somatosensory evaluation with quantitative sensory testing applied to the right trigeminal maxillary branch and right forearm, gustative (sweet [glucose], salt [sodium chloride], sour [citric acid], and bitter [urea]) and olfactory (isopropanol at different concentrations) thresholds.

Results

During the menstrual cycle, thresholds for sweet, salty, sour, cold, vibration, and deep pain decreased, but warmth, electrical, and superficial pain thresholds increased. The bitter threshold was high, and the olfactory threshold was low in the follicular phase. Low estrogen levels were correlated to high deep pain thresholds in the forearm ( P  = 0.008) and face ( P  = 0.041), high tactile thresholds ( P  = 0.001), and high superficial pain ( P  = 0.006) thresholds in the face. High levels of progesterone were associated with a high deep pain threshold in the face and a high salty threshold ( P  < 0.001).

Conclusion

Estrogen and progesterone seem to be involved in sensory neuromodulation in women during the menstrual cycle.

Visual-Somatosensory Integration in Older Adults: Links to Sensory Functioning

Research investigating multisensory integration (MSI) processes in aging is scarce, but converging evidence for larger behavioral MSI effects in older compared to younger adults exists. The current study employed a three-prong approach to determine whether inherent age-related sensory processing declines were associated with larger (i.e., worse) visual-somatosensory (VS) reaction time (RT) facilitation effects. Non-demented older adults ( n = 156 ; mean age = 77 years; 55% female) without any medical or psychiatric conditions were included. Participants were instructed to make speeded foot-pedal responses as soon as they detected visual, somatosensory, or VS stimulation. Visual acuity was assessed using the Snellen test while somatosensory sensitivity was determined using vibration thresholds. The aims of the current study were to: (1) replicate a reliable MSI effect; (2) investigate the effect of unisensory functioning on VS RT facilitation; and (3) determine whether sensory functioning combination groups manifested differential MSI effects. Results revealed a significant VS RT facilitation effect that was influenced by somatosensory sensitivity but not visual acuity. That is, older adults with poor somatosensory sensitivity demonstrated significantly larger MSI effects than those with intact somatosensory sensitivity. Additionally, a significant interaction between stimulus condition and sensory functioning group suggested that the group with poor visual acuity and poor somatosensory functioning demonstrated the largest MSI effect compared to the other groups. In summary, the current study reveals that worse somatosensory functioning is associated with larger MSI effects in older adults. To our knowledge, this is first study to identify potential mechanisms behind increased RT facilitation in aging.

Family history of alcoholism and the human brain response to oral sucrose

A heightened hedonic response to sweet tastes has been associated with increased alcohol preference and alcohol consumption in both humans and animals. The principal goal of this study was to examine blood oxygenation level dependent (BOLD) activation to high- and low-concentration sweet solutions in subjects who are either positive (FHP) or negative (FHN) for a family history of alcoholism. Seventy-four non-treatment seeking, community-recruited, healthy volunteers (22.8 ± 1.6 SD years; 43% men) rated a range of sucrose concentrations in a taste test and underwent functional magnetic resonance imaging (fMRI) during oral delivery of water, 0.83 M, and 0.10 M sucrose. Sucrose compared to water produced robust activation in primary gustatory cortex, ventral insula, amygdala, and ventral striatum. FHP subjects displayed greater bilateral amygdala activation than FHN subjects in the low sucrose concentration (0.10 M). In secondary analyses, the right amygdala response to the 0.10 M sucrose was greatest in FHP women. When accounting for group differences in drinks per week, the family history groups remained significantly different in their right amygdala response to 0.10 M sucrose. Our findings suggest that the brain response to oral sucrose differs with a family history of alcoholism, and that this response to a mildly reinforcing primary reward might be an endophenotypic marker of alcoholism risk.

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Studies in humans and animals have suggested sweet tastes as a trait correlate of alcohol risk.

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Oral sucrose resulted in robust BOLD activation of gustatory and limbic areas.

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Amygdala responses to 0.10 M sucrose were greatest in drinkers with family histories of alcoholism.

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This study is first to suggest endophenotypic brain responses to sucrose in familial alcoholism.

Influence of Japanese consumer gender and age on sensory attributes and preference (a case study on deep-fried peanuts)

BACKGROUND

Detailed exploration of sensory perception as well as preference across gender and age for a certain food is very useful for developing a vendible food commodity related to physiological and psychological motivation for food preference. Sensory tests including color, sweetness, bitterness, fried peanut aroma, textural preference and overall liking of deep-fried peanuts with varying frying time (2, 4, 6, 9, 12 and 15 min) at 150 °C were carried out using 417 healthy Japanese consumers. To determine the influence of gender and age on sensory evaluation, systematic statistical analysis including one-way analysis of variance, polynomial regression analysis and multiple regression analysis was conducted using the collected data.

RESULTS

The results indicated that females were more sensitive to bitterness than males. This may affect sensory preference; female subjects favored peanuts prepared with a shorter frying time more than male subjects did. With advancing age, textural preference played a more important role in overall preference. Older subjects liked deeper-fried peanuts, which are more brittle, more than younger subjects did.

CONCLUSION

In the present study, systematic statistical analysis based on collected sensory evaluation data using deep-fried peanuts was conducted and the tendency of sensory perception and preference across gender and age was clarified. These results may be useful for engineering optimal strategies to target specific segments to gain greater acceptance in the market. © 2017 Society of Chemical Industry.

Occlusal, chewing, and tasting characteristics associated with orofacial dysfunctions in children with unilateral cleft lip and palate: a case-control study

OBJECTIVE

The objective of this study is to assess the associations between orofacial dysfunctions with malocclusion, masticatory performance, and taste in children with and without unilateral cleft lip and palate (UCLP).

MATERIAL AND METHODS

A patient-based, matched, case-control study was conducted involving 108 8- to 10-year-old children divided in UCLP and control groups. Orofacial dysfunctions were evaluated using the Nordic Orofacial Test-Screening (NOT-S). Orthodontic treatment need was evaluated using the Goslon Yardstick Index (GYI) and the Index of Orthodontic Treatment Need (IOTN) of patients and controls, respectively. Masticatory performance was assessed using a chewable test material to determine median particle size (X ₅₀) and distribution of particles in different sieves (b value). Taste perception was evaluated using four solutions (sweet, salty, bitter, or acid) in three different concentrations.

RESULTS

More than half of the patients needed orthodontic surgery. UCLP group presented higher median particle size and needed more chewing cycles to comminute the artificial test into particles smaller than the median than those of controls. UCLP group had less perception of salty flavor than controls. There was a positive correlation between b value and NOT-S examination score for patients. In regression analysis, a significant interrelationship was observed between NOT-S examination score and b value.

CONCLUSIONS

In the UCLP patients, masticatory performance was compromised probably as a result of facial asymmetry and speech disturbance; whereas, taste was less perceived only for salty flavor.

CLINICAL RELEVANCE

These findings provide preliminary evidence that mastication and taste are altered in children with UCLP, so these factors must be followed up to ensure oral and general health in growing individuals.

Oral infections, comorbidities and sensory evidences in elderly: Cross-sectional study

BACKGROUND

Oral infections affect the general health and overlap with chronic diseases due to infectious-immune mechanisms. On the other side, sensory abnormalities may be symptoms of this association.

OBJECTIVE

To evaluate the prevalence of oral infections, comorbidities, health parameters and sensory abnormalities in elderly patients.

METHODS

Thirty (30) elderly with mean age 70.4 yo, distributed according to ages were evaluated with a protocol that included demographics, comorbidities, medications, laboratory tests, blood pressure, heart rate, mini-mental state examination, clinical oral evaluation and systematized sensory testing (gustative, olfactory, thermal, mechanical and pain thresholds). Data were tabled and statistically analyzed.

RESULTS

Twenty-three (76.6%) subjects had chronic diseases that increased according to the age. Seventeen (56.7%) elderly were having medication. Mean probing pocket depth was 1.90mm±0.39mm, mean clinical attachment level was 0.76mm±0.54mm and mean gingival bleeding index was 29.10%±29.05%. All periodontal indexes increased with age (p <0.05) and were associated with comorbidities and use of medication. Patients with chronic diseases had more numbness and pricking sensations (p=0.031; p=0.000). Main sensory findings were: abnormal gustative and vibratory thresholds, which were associated with hematological parameters (blood count, cholesterol levels and glycaemia). Periodontal parameters were associated with facial cold threshold (p=0.000).

CONCLUSION

This study showed an association between systemic diseases, periodontal indexes and sensory thresholds. Sensory findings were associated with blood parameters and are potential tools for periodical health evaluation. Inflammatory or neural mechanisms need further investigation.

Somatosensory function in old age

Sensory decline is viewed as an inevitable consequence of the ageing process. However, reports of declines have not been a consistent finding across the sensory systems. Reports from psychophysical studies indicate that the most common declines with ageing are in vision and audition and, to a lesser degree, olfaction and gustation. Findings for the somatosensory system (mechanoreception, warming and cooling thermoreception and pain) are less conclusive. Factors that contribute to individual differences in sensory ratings beyond chronological ageing include stimulus factors including stimulus type and body location, response measures and instructions, systemic disease that may affect the peripheral or central nervous system and environmental factors that may affect the skin integrity.

Age changes in pain perception: A systematic-review and meta-analysis of age effects on pain and tolerance thresholds

Demographic changes, with substantial increase in life expectancy, ask for solid knowledge about how pain perception might be altered by aging. Although psychophysical studies on age-related changes in pain perception have been conducted over more than 70 years, meta-analyses are still missing. The present meta-analysis aimed to quantify evidence on age-related changes in pain perception, indexed by pain thresholds and pain tolerance thresholds in young and older healthy adults. After searching PubMed, Google Scholar and PsycINFO using state-of-art screening (PRISMA-criteria), 31 studies on pain threshold and 9 studies assessing pain tolerance threshold were identified. Pain threshold increases with age, which is indicated by a large effect size. This age-related change increases the wider the age-gap between groups; and is especially prominent when heat is used and when stimuli are applied to the head. In contrast, pain tolerance thresholds did not show substantial age-related changes. Thus, after many years of investigating age-related changes in pain perception, we only have firm evidence that aging reduces pain sensitivity for lower pain intensities.

Co-occurrence of Pain Symptoms and Somatosensory Sensitivity in Burning Mouth Syndrome: A Systematic Review

Background

Burning mouth syndrome (BMS) is a chronic and spontaneous oral pain with burning quality in the tongue or other oral mucosa without any identifiable oral lesion or laboratory finding. Pathogenesis and etiology of BMS are still unknown. However, BMS has been associated with other chronic pain syndromes including other idiopathic orofacial pain, the dynias group and the family of central sensitivity syndromes. This would imply that BMS shares common mechanisms with other cephalic and/or extracephalic chronic pains. The primary aim of this systematic review was to determine whether BMS is actually associated with other pain syndromes, and to analyze cephalic and extracephalic somatosensory sensitivity in these patients.

Methods

This report followed the PRISMA Statement. An electronic search was performed until January 2015 in PubMed, Cochrane library, Wiley and ScienceDirect. Searched terms included “burning mouth syndrome OR stomatodynia OR glossodynia OR burning tongue OR oral burning”. Studies were selected according to predefined inclusion criteria (report of an association between BMS and other pain(s) symptoms or of cutaneous cephalic and/or extracephalic quantitative sensory testing in BMS patients), and a descriptive analysis conducted.

Results

The search retrieved 1512 reports. Out of these, twelve articles met criteria for co-occurring pain symptoms and nine studies for quantitative sensory testing (QST) in BMS patients. The analysis reveals that in BMS patients co-occurring pain symptoms are rare, assessed by only 0.8% (12 of 1512) of the retrieved studies. BMS was associated with headaches, TMD, atypical facial pain, trigeminal neuralgia, post-herpetic facial pain, back pain, fibromyalgia, joint pain, abdominal pain, rectal pain or vulvodynia. However, the prevalence of pain symptoms in BMS patients is not different from that in the age-matched general population. QST studies reveal no or inconsistent evidence of abnormal cutaneous cephalic and extracephalic somatosensory sensitivity.

Conclusions

There is no evidence for a high rate of other pain symptoms or somatosensory impairments co-occurring with BMS. These results thus suggest that BMS rather depends on specific mechanisms, likely at the trigeminal level. Nevertheless, more thoroughly conducted research is required to draw definitive conclusion.

Descriptive analysis of the masticatory and salivary functions and gustatory sensitivity in healthy children

OBJECTIVE

The objective of this study is to better understand salivary and masticatory characteristics, this study evaluated the relationship among salivary parameters, bite force (BF), masticatory performance (MP) and gustatory sensitivity in healthy children. The secondary outcome was to evaluate possible gender differences.

MATERIALS AND METHODS

One hundred and sixteen eutrophic subjects aged 7-11 years old were evaluated, caries-free and with no definite need of orthodontic treatment. Salivary flow rate and pH, total protein (TP), alpha-amylase (AMY), calcium (CA) and phosphate (PHO) concentrations were determined in stimulated (SS) and unstimulated saliva (US). BF and MP were evaluated using digital gnathodynamometer and fractional sieving method, respectively. Gustatory sensitivity was determined by detecting the four primary tastes (sweet, salty, sour and bitter) in three different concentrations. Data were evaluated using descriptive statistics, Mann-Whitney/t-test, Spearman correlation and multiple regression analysis, considering α = 0.05.

RESULTS

Significant positive correlation between taste and age was observed. CA and PHO concentrations correlated negatively with salivary flow and pH; sweet taste scores correlated with AMY concentrations and bitter taste sensitivity correlated with US flow rate (p < 0.05). No significant difference between genders in salivary, masticatory characteristics and gustatory sensitivity was observed. The regression analysis showed a weak relationship between the distribution of chewed particles among the different sieves and BF.

CONCLUSIONS

The concentration of some analytes was influenced by salivary flow and pH. Age, saliva flow and AMY concentrations influenced gustatory sensitivity. In addition, salivary, masticatory and taste characteristics did not differ between genders, and only a weak relation between MP and BF was observed.

Controversies in fat perception

Nutritional fat is one of the most controversial topics in nutritional research, particularly against the background of obesity. Studies investigating fat taste perception have revealed several associations with sensory, genetic, and personal factors (e.g. BMI). However, neuronal activation patterns, which are known to be highly sensitive to different tastes as well as to BMI differences, have not yet been included in the scheme of fat taste perception. We will therefore provide a comprehensive survey of the sensory, genetic, and personal factors associated with fat taste perception and highlight the benefits of applying neuroimaging research. We will also give a critical overview of studies investigating sensory fat perception and the challenges resulting from multifaceted methodological approaches. In conclusion, we will discuss a multifactorial approach to fat perception to gain a better understanding of the underlying mechanisms that cause varying fat sensitivity which could be responsible for overeating. Such knowledge might be beneficial in new treatment strategies for obesity and overweight.