Establishing a reliable protocol to measure tongue sensation

The "Ghost shaped" antero-lateral thigh flap for total tongue reconstruction: A case report

Squamous cell carcinoma is the most common cancer of the oral cavity, particularly of the tongue. Surgery is the treatment of choice, but it can have a dramatic impact on patients' quality of life. Although the primary goal of tongue reconstruction is the restoration of vital functions such as swallowing and speech, a good cosmetic result should also be achieved. Herein we present the case of a 54-year-old woman who underwent total glossectomy, describing and highlighting the advantages of our modified technique: the "Ghost-shaped" anterolateral thigh perforator flap.

A review of assessment methods for measuring individual differences in oral somatosensory perception

While taste and smell perception have been thoroughly investigated, our understanding of oral somatosensory perception remains limited. Further, assessing and measuring individual differences in oral somatosensory perception pose notable challenges. This review aimed to evaluate the existing methods to assess oral somatosensory perception by examining and comparing the strengths and limitations of each method. The review highlighted the lack of standardized assessment methods and the various procedures within each method. Tactile sensitivity can be assessed using several methods, but each method measures different tactile dimensions. Further investigations are needed to confirm its correlation with texture sensitivity. In addition, measuring a single textural attribute may not provide an overall representation of texture sensitivity. Thermal sensitivity can be evaluated using thermal-change detection or temperature discrimination tests. The chemesthetic sensitivity tests involve either localized or whole-mouth stimulation tests. The choice of an appropriate method for assessing oral somatosensory sensitivity depends on several factors, including the specific research objectives and the target population. Each method has its unique intended purpose, strengths, and limitations, so no universally superior approach exists. To overcome some of the limitations associated with certain methods, the review offers alternative or complementary approaches that could be considered. Researchers can enhance the comprehensive assessment of oral somatosensory sensitivity by carefully selecting and potentially combining methods. In addition, a standardized protocol remains necessary for each method.

The Feel of Speech: Multisystem and Polymodal Somatosensation in Speech Production

PURPOSE

The oral structures such as the tongue and lips have remarkable somatosensory capacities, but understanding the roles of somatosensation in speech production requires a more comprehensive knowledge of somatosensation in the speech production system in its entirety, including the respiratory, laryngeal, and supralaryngeal subsystems. This review was conducted to summarize the system-wide somatosensory information available for speech production.

METHOD

The search was conducted with PubMed/Medline and Google Scholar for articles published until November 2023. Numerous search terms were used in conducting the review, which covered the topics of psychophysics, basic and clinical behavioral research, neuroanatomy, and neuroscience.

RESULTS AND CONCLUSIONS

The current understanding of speech somatosensation rests primarily on the two pillars of psychophysics and neuroscience. The confluence of polymodal afferent streams supports the development, maintenance, and refinement of speech production. Receptors are both canonical and noncanonical, with the latter occurring especially in the muscles innervated by the facial nerve. Somatosensory representation in the cortex is disproportionately large and provides for sensory interactions. Speech somatosensory function is robust over the lifespan, with possible declines in advanced aging. The understanding of somatosensation in speech disorders is largely disconnected from research and theory on speech production. A speech somatoscape is proposed as the generalized, system-wide sensation of speech production, with implications for speech development, speech motor control, and speech disorders.

Depth of resection predicts loss of tongue tip sensation after partial glossectomy in oral tongue cancer: A pilot study

OBJECTIVE(S)

To characterize the change in sensory function following partial glossectomy for oral tongue cancer (OTC) and to identify predictors of loss of tongue-tip sensation (LoTTS).

MATERIALS AND METHODS

Patients with at least three months follow-up after partial glossectomy for primary OTC were included. All patients underwent a qualitative tongue sensation assessment and an objective tongue sensory exam of the native tongue tip. Additional details regarding the oncologic resection, surgical reconstruction, and pathological stage were collected. Multiple linear and logistic regressions were used for statistical analysis.

RESULTS

Sixty-four patients were enrolled, including 34 (53%) men with a median age of 65 at enrollment. Ten (15%) patients reported LoTTS. Increased depth of resection (DOR) was an independent predictor of LoTTS on multivariate analysis, with an increased risk at a threshold of 1.3 cm. LoTTS was also associated with worse subjective quality of life and perceptive speech performance in our qualitative tongue assessment.

CONCLUSIONS

In this pilot study, we found that DOR is a critical prognostic factor in predicting post treatment function. Patients with an increased DOR, particularly above 1.3 cm, are at greatest risk of LoTTS and associated morbidity. These findings may be used to predict post-operative sensory deficits, manage patients' expectations, and optimize the reconstructive approach. Future studies are needed to validate and replicate our results.

Effects of tongue lesions and palatal coverage on oral sensory functions

STATEMENT OF PROBLEM

Oral stereognosis (OS) plays a significant role in the oral rehabilitation of patients with edentulism, as it influences their adaptation to new prostheses. Because of the essentially tactile characteristic of oral sensory perception, the tongue and palate appear to have a crucial function in OS. However, little is known about the influence of tongue lesions on OS and sensorial function. In addition, controversies remain regarding the role of the palate.

PURPOSE

The purpose of this clinical study was to evaluate whether tongue lesions and palatal coverage are disruptive to OS and gustatory function.

MATERIAL AND METHODS

Seventy participants (mean age=30.7 ±6.7 years) were divided into a tongue lesion group (experimental; n=35) and a control group (n=35). The tongue lesion group included participants with geographic, fissured, or hairy tongue. OS was evaluated with the oral stereognosis ability (OSA) test. Gustatory function was assessed with exposure to flavored solutions. After completing the above tests, the participants received a palate covering device, and then OS and gustatory function were immediately reevaluated. Data were analyzed with the Mann-Whitney and Wilcoxon tests (α=.05).

RESULTS

OSA and gustatory function scores did not differ among the tongue lesion and control groups with and without palatal coverage (all P>.05). After palatal coverage, the tongue lesion group took more time to perform the OSA test than the control group (P<.05).

CONCLUSIONS

Neither the presence of tongue lesions nor palatal coverage influenced OS or gustatory function. The OSA test response times were longer for the tongue lesion group after they had received palatal coverage.

Children and adolescents with speech sound disorders are more likely to have orofacial dysfunction and malocclusion

Background

Children with speech sound disorders (SSD) form a heterogeneous group that differs in terms of underlying cause and severity of speech difficulties. Orofacial dysfunction and malocclusions have been reported in children with SSD. However, the association is not fully explored.

Objectives

Our aims were to describe differences in orofacial function and malocclusion between a group of children and adolescents with compared to without SSD and to explore associations between those parameters among the group with SSD.

Methods

A total of 105 participants were included, 61 children with SSD (6.0–16.7 years, mean age 8.5 ± 2.8, 14 girls and 47 boys) and 44 children with typical speech development (TSD) (6.0–12.2 years, mean age 8.8 ± 1.6, 19 girls and 25 boys). Assessments of orofacial function included an orofacial screening test and assessment of bite force, jaw stability, chewing efficiency, and intraoral sensory‐motor function. Possible malocclusions were also assessed.

Result

Children with SSD had both poorer orofacial function and a greater prevalence of malocclusion than children with TSD. Furthermore, children with SSD and poorer orofacial function had a greater risk of malocclusion.

Conclusion

Our result suggests that children with SSD are more prone to having poorer orofacial function and malocclusion than children with TSD. This illustrates the importance of assessing coexisting orofacial characteristics in children with SSD, especially since orofacial dysfunction may be linked to an increased risk of malocclusion. This result highlights the need for a multiprofessional approach.

Beyond language: The unspoken sensory-motor representation of the tongue in non-primates, non-human and human primates

The English idiom "on the tip of my tongue" commonly acknowledges that something is known, but it cannot be immediately brought to mind. This phrase accurately describes sensorimotor functions of the tongue, which are fundamental for many tongue-related behaviors (e.g., speech), but often neglected by scientific research. Here, we review a wide range of studies conducted on non-primates, non-human and human primates with the aim of providing a comprehensive description of the cortical representation of the tongue's somatosensory inputs and motor outputs across different phylogenetic domains. First, we summarize how the properties of passive non-noxious mechanical stimuli are encoded in the putative somatosensory tongue area, which has a conserved location in the ventral portion of the somatosensory cortex across mammals. Second, we review how complex self-generated actions involving the tongue are represented in more anterior regions of the putative somato-motor tongue area. Finally, we describe multisensory response properties of the primate and non-primate tongue area by also defining how the cytoarchitecture of this area is affected by experience and deafferentation.

Predicting feeding-tube dependence in patients following endotracheal extubation: a two-item swallowing screen

BACKGROUND

To meet the surging demands for intubation and invasive ventilation as more COVID-19 patients begin their recovery, clinicians are challenged to find an ultra-brief and minimally invasive screen for postextubation dysphagia predicting feeding-tube dependence persisting for 72 h after extubation.

METHODS

This study examined the predictive validity of a two-item swallowing screen on feeding-tube dependence over 72 h in patients following endotracheal extubation. Intensive-care-unit (ICU) patients (≥ 20 years) successfully extubated after ≥ 48 h endotracheal intubation were screened by trained nurses using the swallowing screen (comprising oral stereognosis and cough-reflex tests) 24 h postextubation. Feeding-tube dependence persisting for 72 h postextubation was abstracted from the medical record by an independent rater. To verify the results and cross-check whether the screen predicted penetration and/or aspiration during fiberoptic endoscopic evaluation of swallowing (FEES), participants agreeing to receive FEES were analyzed within 30 min of screening.

RESULTS

The results showed that 95/123 participants (77.2%) failed the screen, which predicted ICU patients' prolonged (> 72 h) feeding-tube dependence, yielding sensitivity of 0.83, specificity of 0.35, and accuracy of 0.68. Failed-screen participants had 2.96-fold higher odds of feeding-tube dependence (95% CI, 1.13-7.76). For the 38 participants receiving FEES, the swallowing screen had 0.89 sensitivity to detect feeding-tube dependence and 0.86 sensitivity to predict penetration/aspiration, although specificity had room for improvement (0.36 and 0.21, respectively).

CONCLUSION

This ultra-brief swallowing screen is sufficiently sensitive to identify high-risk patients for feeding-tube dependence persisting over 72 h after extubation. Once identified, a further assessment and care are indicated to ensure the prompt return of patients' oral feeding.

TRIAL REGISTRATION

NCT03284892, registered on September 15, 2017.

Effect of complete dentures on oral stereognostic ability in edentulous patients: A systematic review

Aim:

Oral stereognosis is an important sensation for a human being to percept any type of materials that are introduced in the oral cavity. It is defined as the ability of an individual to recognize objects using only tactile sensation without using vision, audition, balance, somatic function, taste, or smell. The primary purpose of this review was to evaluate the effect of complete dentures on oral stereognostic ability in edentulous subjects.

Settings and Design:

Systematic review based on PRISMA guidelines.

Materials and Methods:

A systematic search of the electronic databases like PubMed and Web of Science was done using keywords – “stereognosis,” “oral stereognosis,” “complete denture,” and “complete edentulism.” In addition to this, a manual search of references mentioned in the articles and gray literature was done. Data extraction and assessment were done by two independent reviewers.

Statistical Analysis Used:

Qualitative analysis.

Results:

The literature search yielded a total of 61 articles. Thirteen duplicate articles were removed and 36 articles were rejected after initial screening of titles and abstracts. A total of 12 articles were selected for full text reading and 5 of them were included for qualitative analysis.

Conclusion:

All the included studies showed complete denture treatment therapy improved stereognostic ability in terms of correct identification of test pieces and time taken to identify the objects. There is also a direct relationship between the adaptability of dentures and stereognostic ability.

Effects of a swallowing and oral care intervention for patients following endotracheal extubation: a pre- and post-intervention study

Background

For patients who survive a critical illness and have their oral endotracheal tube removed, dysphagia is highly prevalent, and without intervention, it may persist far beyond hospital discharge. This pre- and post-intervention study with historical controls tested the effects of a swallowing and oral care (SOC) intervention on patients’ time to resume oral intake and salivary flow following endotracheal extubation.

Methods

The sample comprised intensive care unit patients (≥ 50 years) successfully extubated after ≥ 48 h endotracheal intubation. Participants who received usual care (controls, n = 117) were recruited before 2015, and those who received usual care plus the intervention (n = 54) were enrolled after 2015. After extubation, all participants were assessed by a blinded nurse for daily intake status (21 days) and whole-mouth unstimulated salivary flow (2, 7, 14 days). The intervention group received the nurse-administered SOC intervention, comprising toothbrushing/salivary gland massage, oral motor exercise, and safe-swallowing education daily for 14 days or until hospital discharge.

Results

The intervention group received 8.3 ± 4.2 days of SOC intervention, taking 15.4 min daily with no reported adverse event (coughing, wet voice, or decreased oxygen saturation) during and immediately after intervention. Participants who received the intervention were significantly more likely than controls to resume total oral intake after extubation (aHR 1.77, 95% CI 1.08–2.91). Stratified by age group, older participants (≥ 65 years) in the SOC group were 2.47-fold more likely than their younger counterparts to resume total oral intake (aHR 2.47, 95% CI 1.31–4.67). The SOC group also had significantly higher salivary flows 14 days following extubation (β = 0.67, 95% CI 0.29–1.06).

Conclusions

The nurse-administered SOC is safe and effective, with greater odds of patients’ resuming total oral intake and increased salivary flows 14 days following endotracheal extubation. Age matters with SOC; it more effectively helped participants ≥ 65 years old resume total oral intake postextubation.

Trial registration

NCT02334774, registered on January 08, 2015

Preliminary exploration for evaluating acuity of oral texture perception

Despite the important role of oral texture perception in feeding and nutritional homeostasis, its impairment has not been of particular clinical interest, and no clinical protocol is available to evaluate its acuity. This preliminary study aimed to establish a method to evaluate the acuity of oral texture perception. Because texture perception is regarded as reflecting integrity of the sensorimotor system of the jaw and mouth, we hypothesized that the ability to perceive various aspects of food texture would correlate with each other, and tested our hypothesis in 11 healthy adults. First, we prepared three types of test foods with different dominant textures, each of which comprised a series of stimuli with different ingredient concentrations; we used these test foods in discrimination tests involving pairwise comparison. Tests performed using the up-down staircase method revealed significant correlation among the discrimination thresholds for three test foods, suggesting that acuities of texture perception correlated with each other across different textural attributes. Second, we examined the associations between the acuity of texture perception and some aspects of mechanical sensation of the tongue: tactile and two-point discrimination thresholds, as well as the graininess recognition threshold. The acuity of texture perception of the subjects whose sensitivity was low for at least one of these aspects of mechanical sensation (n = 5) was significantly lower than that exhibited by the other subjects (Wilcoxon rank-sum test, p = 0.0417). We concluded that oral texture perception ability can be evaluated by discrimination tests for specific aspects of texture, using appropriate test foods.

Association of Post-extubation Dysphagia With Tongue Weakness and Somatosensory Disturbance in Non-neurologic Critically Ill Patients

Objective

To prospectively assess the association between impoverished sensorimotor integration of the tongue and lips and post-extubation dysphagia (PED).

Methods

This cross-sectional study included non-neurologic critically ill adult patients who required endotracheal intubation and underwent videofluoroscopic swallowing study (VFSS) between October and December 2016. Participants underwent evaluation for tongue and lip performance, and oral somatosensory function. Demographic and clinical data were retrieved from medical records.

Results

Nineteen patients without a definite cause of dysphagia were divided into the non-dysphagia (n=6) and the PED (n=13) groups based on VFSS findings. Patients with PED exhibited greater mean duration of intubation (11.85±3.72 days) and length of stay in the intensive care unit (LOS-ICU; 13.69±3.40 days) than those without PED (6.83±5.12 days and 9.50±5.96 days; p=0.02 and p=0.04, respectively). The PED group exhibited greater incidence of pneumonia, higher videofluoroscopy swallow study dysphagia scale score, higher oral transit time, and lower tongue power and endurance and lip strength than the non-dysphagia groups. The differences in two-point discrimination and sensations of light touch and taste among the two groups were insignificant. Patients intubated for more than 7 days exhibited lower maximal tongue power and tongue endurance than those intubated for less than a week.

Conclusion

Duration of endotracheal intubation, LOS-ICU, and oromotor degradation were associated with PED development. Oromotor degradation was associated with the severity of dysphagia. Bedside oral performance evaluation might help identify patients who might experience post-extubation swallowing difficulty.

Tongue weakness and somatosensory disturbance following oral endotracheal extubation

The tongue plays important roles in mastication, swallowing, and speech, but its sensorimotor function might be affected by endotracheal intubation. The objective of this pilot study was to describe disturbances in the sensorimotor functions of the tongue over 14 days following oral endotracheal extubation. We examined 30 post-extubated patients who had prolonged (≥48 h) oral endotracheal intubation from six medical intensive care units. Another 36 patients were recruited and examined from dental and geriatric outpatient clinics served as a comparison group. Tongue strength was measured by the Iowa Oral Performance Instrument. Sensory disturbance of the tongue was measured by evaluating light touch sensation, oral stereognosis, and two-point discrimination with standardized protocols. Measurements were taken at three time points (within 48 h, and 7 and 14 days post-extubation) for patients with oral intubation but only once for the comparison group. The results show that independent of age, gender, tobacco used, and comorbidities, tongue strength was lower and its sensory functions were more impaired in patients who had oral intubation than in the comparison group. Sensory disturbances of the tongue gradually recovered, taking 14 days to be comparable with the comparison group, while weakness of the tongue persisted. In conclusion, patients with oral endotracheal intubation had weakness and somatosensory disturbances of the tongue lasting at least 14 days from extubation but whether is caused by intubation and whether is contributed to postextubation dysphagia should be further investigated.

The perception of materials through oral sensation

This paper presents the results of a multimodal study of oral perception conducted with a set of material samples made from metals, polymers and woods, in which both the somatosensory and taste factors were examined. A multidimensional scaling analysis coupled with subjective attribute ratings was performed to assess these factors both qualitatively and quantitatively. The perceptual somatosensory factors of warmth, hardness and roughness dominated over the basic taste factors, and roughness was observed to be a less significant sensation compared to touch-only experiments. The perceptual somatosensory ratings were compared directly with physical property data in order to assess the correlation between the perceived properties and measured physical properties. In each case, a strong correlation was observed, suggesting that physical properties may be useful in industrial design for predicting oral perception.

Lingual tactile acuity and food texture preferences among children and their mothers

Despite anecdotal reports of children being more sensitive to texture than adults, and of texture being one of the main drivers of food aversions, there is a paucity of scientific knowledge on the influence of texture perception on food choice in children. The primary goals of this study were to assess the use of a modified letter-identification task to study lingual tactile acuity, one aspect of oral sensitivity, in children and to examine age-related differences in sensitivity. The secondary goal was to explore whether lingual tactile acuity and age relate to various measures of food choice and preference. To this end, children 7-10 years old (31 girls, 21 boys) and their mothers were tested using identical procedures. To assess lingual tactile acuity, children and mothers were asked to use the tips of their tongues to identify raised alphabetical letters of varying size (2.5-8.0 mm) on Teflon strips. To relate lingual tactile acuity to food texture preferences, a forced-choice questionnaire assessed preferences for foods similar in flavor but different in texture (e.g., smooth versus crunchy peanut butter). Children were able to complete the lingual acuity task as well as their mothers and took less time to assess each letter stimulus (p < 0.001); however, there were no age-related differences in lingual acuity (p = 0.14). Age, but not lingual acuity, related to food texture preferences: mothers preferred harder foods (p < 0.001) and those containing more particles (p < 0.04) than did children, although children's preferences became more adult-like with increasing age. The availability of a rapid, child-friendly method for assessing oral sensitivity opens up new possibilities of examining differences in oral tactile perceptions across the life span. That food preferences changed with age and were not related to oral sensitivity underscores the fact that factors such as experience, culture and family food practices have a significant impact on children's food texture preferences.

Oral sensation and function: a comparison of patients with innervated radial forearm free flap reconstruction to healthy matched controls

BACKGROUND

Limited evidence exists for the use of innervated radial forearm free flap (RFFF) reconstruction of hemiglossectomy defects. This study reports on sensation, mastication, and speech outcomes for patients with innervated RFFF reconstruction of the anterior two-thirds of the tongue.

METHODS

Sensation, mastication, and speech intelligibility were assessed in 8 patients and age- and sex-matched controls.

RESULTS

Sensation of intact tongue tissue after reconstruction of the hemitongue did not differ from controls. Although some sensory ability was restored to patients' reconstructed tongue, differences existed between the patient group and controls. However, whole mouth sensations resulted in similar sensory ability as controls. Whereas patients demonstrated adequate masticatory and speech ability, differences existed between patients and controls.

CONCLUSION

Although some sensory ability is preserved in patients who have had tongue reconstruction with an innervated RFFF, functional outcomes such as masticatory ability and speech intelligibility may be affected in some patients.

Decrease in stereognostic ability of the tongue with age

Rehabilitation of eating and swallowing functions from the viewpoint of quality of life should attempt to restore not only the physical, but also sensory function. As the size and shape of the intra-oral bolus of food provides oral sensory information important for eating and swallowing, we investigated the stereognostic ability of the tongue in 269 young adults (mean age: 24.5 years) and 60 seniors (mean age: 80.5 years); all of whom had no eating or swallowing complaints. Assessment of the stereognostic ability involved identifying 20 differently shaped test pieces placed in the oral cavity. The young adults identified a significantly higher number of differently shaped test pieces than the seniors (mean correct number of responses: 16.5 and 10.1 respectively; P < 0.001). Gender and the presence of palatal covers did not have any significant effect on stereognostic ability. The test pieces were categorized into six groups based on the shape. When the young adults misidentified a piece, they often selected another piece within the same group, almost never selecting a piece from another group. The seniors, however, chose test pieces from different groups. Moreover, to determine whether stereognosis could be improved through training, we conducted training involving four senior subjects in their 80s, who correctly identified 10 or fewer pieces. After the training, the number of correct answers increased significantly (P < 0.05). These findings indicate that seniors show decreased stereognostic ability of the tongue compared with young adults and suggest the possibility of recovering the ability using our training method.

Dysphagia in the elderly

The capacity to swallow or eat is a basic human need and can be a great pleasure. Older adults look forward to sharing mealtimes and participating in social interactions. The loss of capacity to swallow and dine can have far-reaching implications. With age, the ability to swallow undergoes changes that increase the risk for disordered swallowing, with devastating health implications for older adults. With the growth in the aging population, dysphagia is becoming a national health care burden and concern. Upward of 40% of people in institutionalized settings are dysphagic. There is a need to address dysphagia in ambulatory, acute care, and long-term care settings.