Design and Test of an Intraoral Electrode Grid for Tongue High-Density Electromyography.

Tongue motor function is crucial in a wide range of basic activities and its impairment affects quality of life. The electrophysiological assessment of the tongue relies primarily on needle electromyography, which is limited by its invasiveness and inability to capture the concurrent activity of the different tongue muscles. This work aimed at developing an intraoral grid for high-density surface electromyography (HDsEMG) to non-invasively map the electrical excitation of tongue muscles. We developed a grid of 4×8 electrodes deposited over an adhesive 8- µ m thick polyurethane membrane. The testing protocol was conducted on 7 healthy participants and included functional tasks (vowels articulation and tongue movements) aimed at activating different regions of the tongue. The electrical stability of contact was assessed by measuring electrode-tongue impedances before and after the tasks. The spatial amplitude distribution of global EMG and single motor unit action potentials (MUAPs) was characterized. Electrode-tongue impedance magnitude showed no significant changes in the pre-post comparison ( 58±46 k Ω vs. 67±58 k Ω at 50Hz). Contact stability was confirmed by the quality of the signals that allowed to quantify spatiotemporal characteristics of muscle activation during the different tasks. The analysis of the spatial distribution of individual MUAPs amplitude showed that they were confined to relatively small areas on the tongue surface (range: 0.5cm2 -3.9cm [Formula: see text]. A variety of different spatiotemporal MUAP patterns, likely due to the presence of different muscle compartments with different fiber orientations, were observed. Our results demonstrate that the developed electrode grid enables HDsEMG acquisition from the tongue during functional tasks, thus opening new possibilities in tongue muscle assessment both at global and single motor unit level.

Assessing the oral and suprahyoid muscles in healthy adults using muscle ultrasound to inform the swallowing process: a proof-of-concept study.

The oral and suprahyoid muscles are responsible for movements of swallowing. Our study aimed to determine the reproducibility of static and dynamic measurements of these muscles using bedside ultrasound equipment. Forty healthy participants were recruited prospectively. Primary outcomes were evaluation of mass measurements of the anterior bellies of the digastric, mylohyoid, geniohyoid and tongue in B-mode ultrasound. Secondary outcomes were evaluation of geniohyoid muscle layer thickness and function using M-mode. Muscle mass measurements demonstrated little within-participant variability. Coefficient of Variance (CoV) across muscles were: anterior belly digastric (5.0%), mylohyoid (8.7%), geniohyoid (5.0%) and tongue (3.2%). A relationship between sex (r2 = 0.131 p = 0.022) was demonstrated for the geniohyoid muscle, with males having higher transverse Cross Sectional Area (CSA) (14.3 ± 3.6 mm vs. 11.9 ± 2.5 mm, p = 0.002). Tongue size was correlated with weight (r2 = 0.356, p = 0.001), height (r2 = 0.156, p = 0.012) and sex (r2 = 0.196, p = 0.004). Resting thickness of the geniohyoid muscle layer changed with increasing bolus sizes (f = 3.898, p = 0.026). Velocity increased with bolus size (p = < 0.001, F = 8.974). However swallow time and slope distance did not, potentially influenced by higher coefficients of variation. Oral and suprahyoid muscle mass are easily assessed using bedside ultrasound. Ultrasound may provide new information about muscle mass and function during swallowing.

Criterion (Concurrent) Validity and Clinical Utility of the Tongueometer Device.

PURPOSE: Tongue manometry (i.e., tongue pressure measurement) is a commonly used assessment for patients with suspected oral-motor involvement in swallowing disorders. Availability of lingual manometry has changed in recent years, with the introduction of the Tongueometer device being a more affordable tongue manometry system. The purpose of this study was to test concurrent (criterion) validity of the Tongueometer compared to the current standard reference device, the Iowa Oral Performance Instrument (IOPI). METHOD: Adults without dysphagia were recruited for participation in this study. Standard lingual measurements (swallowing-related pressures, maximum isometric pressure [MIP], and maximum isometric endurance) were recorded, with the bulb anteriorly placed, with both devices, in a randomized order. The Bland-Altman method was used to determine concurrent (criterion) validity of these measurements compared to the clinical standard IOPI device. A recently available suggested corrective value by Curtis et al. (2023) was also applied, with comparisons made between devices both with and without the Curtis correction. RESULTS: The final sample included 70 adult participants aged 20-89 years (Mage = 52.3 years). Measures with the Tongueometer device were significantly lower when compared with the same measures taken using the IOPI (p < .01) for all measures including MIP, endurance, and swallow pressures. The correction suggested by Curtis and colleagues did not ameliorate these differences. CONCLUSIONS: The Tongueometer lingual measurements were consistently lower compared to the IOPI. Clinical use of values taken with the Tongueometer device should be compared to normative data published for each specific device. Available features of each device (e.g., display, bulb texture, technology/application) should be considered when selecting which device to use with an individual patient.

Analysis of the suprahyoid muscles during tongue elevation: High-density surface electromyography as a novel tool for swallowing-related muscle assessment.

BACKGROUND: High-density surface electromyography (HD-sEMG) has enabled non-invasive analysis of motor unit (MU) activity and recruitment, but its application to swallowing-related muscles is limited. OBJECTIVE: We aimed to investigate the utility of HD-sEMG for quantitatively evaluating the MU recruitment characteristics of the suprahyoid muscles during tongue elevation. METHODS: We measured the sEMG activity of the suprahyoid muscles of healthy participants during tongue elevation using HD-sEMG. Maximum voluntary contraction (MVC) was measured, followed by data collection during sustained and ramp-up tasks to capture suprahyoid muscle activity. Changes in the temporal/spatial MU recruitment patterns within individual suprahyoid muscles were analysed. RESULTS: This study enrolled 16 healthy young adults (mean age: 27.8 ± 5.3 years; eight males and eight females). Increasing muscle force corresponded to a decrease in modified entropy and correlation coefficient and an increase in the coefficient of variation. No significant differences were observed between male and female participants. CONCLUSION: The results of this study, consistent with those observed in other muscles, such as the vastus lateralis muscle, suggest that HD-sEMG is a valuable and reliable tool for quantitatively evaluating MU recruitment in the suprahyoid muscles. This measurement technique holds promise for novel assessments of swallowing function.

What's special about human speech? A student exercise for comparing speech production between humans and chimpanzees.

Modern humans and chimpanzees share a common ancestor on the phylogenetic tree, yet chimpanzees do not spontaneously produce speech or speech sounds. The lab exercise presented in this paper was developed for undergraduate students in a course entitled "What's Special About Human Speech?" The exercise is based on acoustic analyses of the words "cup" and "papa" as spoken by Viki, a home-raised, speech-trained chimpanzee, as well as the words spoken by a human. The analyses allow students to relate differences in articulation and vocal abilities between Viki and humans to the known anatomical differences in their vocal systems. Anatomical and articulation differences between humans and Viki include (1) potential tongue movements, (2) presence or absence of laryngeal air sacs, (3) presence or absence of vocal membranes, and (4) exhalation vs inhalation during production.

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.

Relationship between texture perception and oral function: A preliminary study in young, healthy adults.

BACKGROUND: Oral frailty, characterised by reduced oral function, is associated with systemic health issues in older adults. Although the criteria for diminished oral function often focus on motor and secretory abilities, texture perception also plays a crucial role in health due to its impact on food intake and palatability. OBJECTIVE: This study aimed to explore the relationship between thickness discrimination ability (TDA) and oral motor and secretory functions in healthy young individuals. METHODS: Twenty-eight adults were assessed for texture perception using eight concentrations of aqueous xanthan gum solutions to determine TDA scores. Measurements of occlusal force, masticatory performance, tongue pressure, stimulated salivary flow rate and tongue-lip motor function were conducted. Spearman's correlation analysis was used to evaluate the relationship between TDA scores and oral functions. Participants were divided into high-sensitivity and low-sensitivity groups based on their TDA scores to compare oral function test results. RESULTS: The TDA scores varied among the participants, with higher scores correlating with higher masticatory performance (r = 0.41, p < .05). Masticatory performance in the high-sensitivity group was significantly higher than in the low-sensitivity group (211.9 ± 59.2 mg/dL vs. 157.9 ± 43.0 mg/dL, p = .013), with no significant differences in other oral functions. CONCLUSION: Masticatory performance was correlated with TDA, suggesting a link between the selection function of mastication and thickness discrimination. These findings highlight the potential relevance of texture perception in oral function and indicate the need for further exploration, particularly in older adults with declining oral health.

Artificial Q-Grader: Machine Learning-Enabled Intelligent Olfactory and Gustatory Sensing System.

Portable and personalized artificial intelligence (AI)-driven sensors mimicking human olfactory and gustatory systems have immense potential for the large-scale deployment and autonomous monitoring systems of Internet of Things (IoT) devices. In this study, an artificial Q-grader comprising surface-engineered zinc oxide (ZnO) thin films is developed as the artificial nose, tongue, and AI-based statistical data analysis as the artificial brain for identifying both aroma and flavor chemicals in coffee beans. A poly(vinylidene fluoride-co-hexafluoropropylene)/ZnO thin film transistor (TFT)-based liquid sensor is the artificial tongue, and an Au, Ag, or Pd nanoparticles/ZnO nanohybrid gas sensor is the artificial nose. In order to classify the flavor of coffee beans (acetic acid (sourness), ethyl butyrate and 2-furanmethanol (sweetness), caffeine (bitterness)) and the origin of coffee beans (Papua New Guinea, Brazil, Ethiopia, and Colombia-decaffeine), rational combination of TFT transfer and dynamic response curves capture the liquids and gases-dependent electrical transport behavior and principal component analysis (PCA)-assisted machine learning (ML) is implemented. A PCA-assisted ML model distinguished the four target flavors with >92% prediction accuracy. ML-based regression model predicts the flavor chemical concentrations with >99% accuracy. Also, the classification model successfully distinguished four different types of coffee-bean with 100% accuracy.

Influence of oral motor tasks on postural muscle activity during dynamic reactive balance.

BACKGROUND: Jaw clenching improves dynamic reactive balance on an oscillating platform during forward acceleration and is associated with decreased mean sway speed of different body regions. OBJECTIVE: It is suggested that jaw clenching as a concurrent muscle activity facilitates human motor excitability, increasing the neural drive to distal muscles. The underlying mechanism behind this phenomenon was studied based on leg and trunk muscle activity (iEMG) and co-contraction ratio (CCR). METHODS: Forty-eight physically active and healthy adults were assigned to three groups, performing three oral motor tasks (jaw clenching, tongue pressing against the palate or habitual lower jaw position) during a dynamic one-legged stance reactive balance task on an oscillating platform. The iEMG and CCR of posture-relevant muscles and muscle pairs were analysed during platform forward acceleration. RESULTS: Tongue pressing caused an adjustment of co-contraction patterns of distal muscle groups based on changes in biomechanical coupling between the head and trunk during static balancing at the beginning of the experiment. Neither iEMG nor CCR measurement helped detect a general neuromuscular effect of jaw clenching on the dynamic reactive balance. CONCLUSION: The findings might indicate the existence of robust fixed patterns of rapid postural responses during the important initial phases of balance recovery.

Evaluating Anterior and Posterior Oral Tongue Contributions to Pressure Generation: A Comparison Between Regular and Effortful Saliva Swallows.

PURPOSE: This study determined the contributions of the anterior and posterior tongue regions in tongue pressure generation during regular saliva swallows (SSs) and effortful swallows (ESs) completed under two different instructions. The association between tongue pressure and perceived effort to swallow was also examined. METHOD: Forty healthy adults without swallowing disorders participated in this study, divided into two age groups: 20 younger (Mage = 21.95 years, SD = 4.43) and 20 older (Mage = 70.10 years, SD = 4.30). Simultaneous data acquisition involved submental surface electromyography, tongue manometry, and a visual analog scale across swallowing conditions (SS, ES with tongue emphasis, and ES with pharyngeal squeezing). The main outcome measures were tongue pressure during swallowing and perceived effort to swallow. RESULTS: Overall tongue pressure during ESs with tongue emphasis and with pharyngeal squeezing was greater than that during SSs (R2 = .78, p < .001). Moreover, tongue pressure during the ES with tongue emphasis was greater than that during the ES with pharyngeal squeezing (t = 25.63, p < .001). The posterior tongue region generated more pressure during SSs (R2 = .64, p < .001) and the ES with tongue emphasis (R2 = .55, p < .001) than the anterior tongue. Finally, a positive correlation was found between perceived effort and tongue pressure during swallowing (r = .75, 95% CI [0.72, 0.77]). CONCLUSIONS: Tongue pressure generation was affected by the type of instruction used to elicit ESs, and the posterior tongue showed relatively greater pressure contributions than the anterior tongue for ESs with tongue emphasis and SSs. Furthermore, age-related declines in pressure generation during swallowing were not evidenced in this study, underscoring the ability of healthy older individuals to appropriately modulate lingual pressure during ESs. Last, our results showed that the visual analog scale is a simple tool for rating swallowing effort during ESs, supporting its potential clinical use to train ESs.

Normative High-Resolution Pharyngeal Manometry: Impact of Age, Size of System, and Sex on Primary Metrics and Pressure Stability.

There have been many reports of normative pharyngeal swallowing pressures using high-resolution pharyngeal manometry, but there is a fair amount of between-subject variance in reported pressure parameters. The purpose of this study was to put forward normative pharyngeal high-resolution manometry measures across the lifespan and investigate the effects of age, size of system, and sex. High-resolution pharyngeal manometry was performed on 98 healthy adults (43 males) between the ages 21 and 89. Pressure duration, maxima, integral, and within-individual variability metrics were averaged over 10 swallows of 10-ml thin liquid. Multiple linear and logistic regressions with model fitting were used to examine how pharyngeal pressures relate to age, pharyngeal size, and sex. Age was associated with tongue base maximum pressure, tongue base maximum variability, and upper esophageal sphincter-integrated relaxation pressure (F3,92 = 6.69; p < 0.001; adjusted R2 = 0.15). Pharyngeal area during bolus hold was associated with velopharynx integral (F1,89 = 5.362; p = 0.02; adjusted R2 = 0.05), and there was no significant model relating pharyngeal pressures to C2-C4 length (p < 0.05). Sex differences were best described by tongue base integral and hypopharynx maximum variability (χ2 = 10.27; p = 0.006; pseudo R2 = 0.14). Normative data reveal the distribution of swallow pressure metrics which need to be accounted for when addressing dysphagia patients, the importance of pressure interactions in normal swallow, and address the relative stability of swallow metrics with normal aging.

Development and growth of median structures in the human tongue: A histological study using human fetuses and adult cadavers.

Glossectomy is a surgical procedure performed to remove all or part of the tongue in patients with cancer. The removal of a significant part of the tongue has a marked effect on speech and swallowing function, as patients may lose not only the tongue muscles but also the median lingual septum (MLS). Therefore, to achieve successful tongue regeneration, it is necessary to investigate the developmental processes of not only the tongue muscles but also the MLS. This study was conducted to clarify the mutual development of the tongue muscles and the MLS in human fetuses. Serial or semi-serial histological sections from 37 embryos and fetuses (aged 5-39 weeks) as well as nine adults were analyzed. The MLS appeared at Carnegie stage 15 (CS15), and until 12 weeks of gestation, abundant fibers of the intrinsic transverse muscle crossed the septum in the entire tongue. However, in near-term fetuses and adults, the contralaterally extending muscles were restricted to the deepest layer just above the genioglossus muscle. This finding indicates that the crossing transverse muscle showed the highest density at mid-term. A thorough understanding of both the MLS and the tongue muscles is necessary for successful tongue regeneration.

Biomechanical and Cortical Control of Tongue Movements During Chewing and Swallowing.

Tongue function is vital for chewing and swallowing and lingual dysfunction is often associated with dysphagia. Better treatment of dysphagia depends on a better understanding of hyolingual morphology, biomechanics, and neural control in humans and animal models. Recent research has revealed significant variation among animal models in morphology of the hyoid chain and suprahyoid muscles which may be associated with variation in swallowing mechanisms. The recent deployment of XROMM (X-ray Reconstruction of Moving Morphology) to quantify 3D hyolingual kinematics has revealed new details on flexion and roll of the tongue during chewing in animal models, movements similar to those used by humans. XROMM-based studies of swallowing in macaques have falsified traditional hypotheses of mechanisms of tongue base retraction during swallowing, and literature review suggests that other animal models may employ a diversity of mechanisms of tongue base retraction. There is variation among animal models in distribution of hyolingual proprioceptors but how that might be related to lingual mechanics is unknown. In macaque monkeys, tongue kinematics-shape and movement-are strongly encoded in neural activity in orofacial primary motor cortex, giving optimism for development of brain-machine interfaces for assisting recovery of lingual function after stroke. However, more research on hyolingual biomechanics and control is needed for technologies interfacing the nervous system with the hyolingual apparatus to become a reality.

Sarcopenia of the longitudinal tongue muscles in rats.

The tongue is a muscular hydrostat, with lingual movements occurring during breathing, chewing, swallowing, vocalization, vomiting, coughing and grooming/sexual activities. In the elderly, reduced lingual dysfunction and weakness contribute to increased risks of obstructive sleep apnea and aspiration pneumonia. In Fischer 344 (F344) rats, a validated model of aging, hypoglossal motor neuron death is apparent, although there is no information regarding tongue strength. The intrinsic tongue muscles, the superior and inferior longitudinal, transversalis and verticalis exist in an interdigitated state. Recently, we established a method to measure the specific force of individual intrinsic tongue muscle, accounting for the tissue bulk that is not in the direction of uniaxial force. In the longitudinal muscles of 6- (n = 10), 18- (n = 9) and 24-month-old (n = 12) female and male F344 rats, we assessed specific force, fatigability, fiber type dependent cross-sectional area (CSA) and overall CSA. Muscle force and fatigue was assessed ex vivo using platinum plate simulation electrodes. Tongue muscles were frozen in melting isopentane, and transverse sections cut at 10 µm. Muscle fiber type was classified based on immunoreactivity to myosin heavy chain (MyHC) isoform antibodies. In H&E stained muscle, CSA and uniaxial muscle contributions to total tongue bulk was assessed. We observed a robust ∼30% loss of longitudinal specific force, with reductions in overall longitudinal muscle fiber CSA and specific atrophy of type IIx/IIb fibers. It will be important to investigate the mechanistic underpinnings of hypoglossal motor neuron death and tongue muscle weakness to eventually provide therapies for age-associated lingual dysfunctions.

Tongue, palatal, hyoid and pharyngeal muscle activity during chewing, swallowing, and respiration.

OBJECTIVE: Chewing, swallowing, and respiration are synchronized oropharyngeal functions. This study aimed to analyze the dynamics and coordination during natural chewing and swallowing in relation to respiratory phases. DESIGN: Eight oropharyngeal muscles in minipigs were recorded using electromyography, X-ray fluoroscopy, and nasopharyngeal dynamics. Chewing cycles and swallowing episodes were analyzed for timing and activity amplitude along respiratory cycles. Digastric and middle pharyngeal constrictor were used as zero-points for timing analysis in chewing cycles and swallowing episodes, respectively. The beginning of these cycles and episodes were used as the zero-point for timing analysis in respiration during feeding. RESULTS: The timing of jaw closing (57.8%) was longer than opening (42.2%) during chewing. Muscle activity occurred 20% later than digastric onsets and 15% earlier than jaw closing phase. Duration of muscle activity was shorter in ipsilateral than contralateral sides except for palatal muscles. Pharyngeal, palatal, and hyoid muscles showed longer durations than tongue muscles in jaw opening (p < 0.05). Palatal and hyoid muscles showed 2-phased activity in chewing while hyoid muscles showed higher amplitude in chewing and swallowing than other muscles. About 80% of the chewing cycles and swallowing episodes occurred in expiration. Nasopharyngeal airflow velocity increased from jaw opening to swallowing while airflow pressure decreased. CONCLUSION: These findings indicate key activity of palatal and pharyngeal muscles mostly in chewing. The respiratory cycle changes in chewing and swallowing simultaneously with the activation of the tongue, palatal, and pharyngeal muscles. These findings will be useful for further understanding the mechanisms in swallowing and breathing disorders.

Assessing Mode-Switching Strategies for Assistive Robotic Manipulators Using a Preliminary Version of the Novel Non-invasive Tongue-Computer Interface.

The inductive tongue-computer interface allows individuals with tetraplegia to control assistive devices. However, controlling assistive robotic arms often requires more than 14 different commands, which cannot always fit into a single control layout. Previous studies have separated the commands into modes, but few have investigated strategies to switch between them. In this feasibility study, we compare the efficiency of switching modes using buttons, swipe gestures and double taps using a preliminary version of a new non-invasive mouthpiece unit (nMPU), which includes an integrated activation unit and a single sensor board. Three participants controlled a JACO assistive robot to pick up a bottle using different mode-switching strategies. Compared with switching modes with buttons, switching modes with swipes and double taps increased the task completion time by 21% and 58% respectively. Therefore, we recommend that configurations with multiple modes for the non-invasive tongue-computer interface include buttons for mode-switching.Clinical relevance- Cumbersome mode-switching strategies can lower a control interface's responsiveness and contribute to end-user abandonment of assistive technologies. This study showed that using buttons to switch modes is more reliable. Moreover, this study will inform the development of future control layouts with improved usability.

Improving Tongue Command Accuracy: Unlocking the Power of Electrotactile Feedback Training.

People with spinal cord injury or neurological disorders frequently require aid in performing daily tasks. Utilizing hand-free assistive technologies (ATs), particularly tongue-controlled ATs, may offer a feasible solution as the tongue is controlled by a cranial nerve and remains functional in the presence of spinal cord injury. However, existing intra-oral ATs require a significant level of training to accurately issuing these commands. To minimize the training process, we have designed intuitive tongue commands for our Multifunctional intraORal Assistive technology (MORA). Our prior works demonstrated that electrotactile feedback outperformed visual feedback in tasks involving tongue motor learning. In this study, we implement electrical stimulation (E-stim) as electrotactile feedback on the tongue to teach new tongue commands of MORA, and quantitatively analyze the efficacy of the electrotactile feedback in command accuracy and precision. The random command task was adopted to evaluate tongue command accuracy with 14 healthy participants. The average sensors contacted per trial dropped significantly from 1.57 ± 0.15 to 1.16 ± 0.05 with electrotactile feedback. After training with electrotactile feedback, 83% of the trials were completed with only one command having been activated. These results suggest that E-stim enhanced both the accuracy and precision of subjects' tongue command training. The results of this study pave the way for the implementation of electrotactile feedback as an accurate and precise command training technique for MORA.

Flexibility for Intensity Dosing in Lingual Resistance Exercises: A Large Randomized Clinical Trial in Typically Aging Adults as Proof of Principle.

OBJECTIVE: The objective of this study was to determine the effect of intensity dosing during tongue exercise on tongue pressure generation, adherence, and perceived effort. DESIGN: This was a five-site, prospective, randomized clinical trial. Outcome measures were obtained across multiple baselines, biweekly during exercise, and 4-weeks post-intervention. SETTING: The general community at each study site. PARTICIPANTS: Typically aging adults between 55-82 years of age with no history of neurological or swallowing disorders. Eighty-four volunteers completed the study. INTERVENTIONS: Participants were randomly assigned to one of four exercise groups: (a) maximum intensity/no biofeedback, (b) progressive intensity/no biofeedback, (c) maximum intensity/biofeedback, and (d) progressive intensity/biofeedback. Half of the participants completed a maintenance exercise program. OUTCOME MEASURES: Maximum isometric pressure (MIP), regular effort saliva swallow pressure, adherence, and the Borg Rating of Perceived Exertion Scale. RESULTS: All exercise protocols were efficacious for gains in MIP (large effect sizes; Cohen's d). Group 3 made gains in regular effort saliva swallow pressure (medium effect size). There was a significant change in perceived exertion for regular effort saliva swallow pressure at 8 weeks. Tongue pressure gains were maintained at 1 month, regardless of maintenance group status. Mean adherence across groups was high. CONCLUSIONS: All groups improved pressure generation. Intensity dosing differences did not affect strength gains, adherence, or detraining. Regular effort saliva swallow pressure may be most responsive to maximum intensity with biofeedback. The findings suggest flexibility in approach to tongue exercise protocols. Tongue muscles may differ from limb muscles in terms of dose response and neuroplasticity principles.

[Conspicuous Conditions of the Tongue: Normal Variants vs. Pathological Findings].

INTRODUCTION: With its sensitivity, taste buds and complex anatomical structure of various muscles, the tongue is a central organ for speaking, tasting and food intake, especially oral food transport, chewing and swallowing. Changes in the tongue 's condition are frequent and often lead to uncertainty among patients and eventually to a visit to the family doctor, to the ear, nose and throat specialist, dentist or maxillofacial surgeon. The question whether the condition of the tongue is a lesion requiring treatment or just a variant can quite often prove a major challenge. The differential diagnoses are wide-ranging from harmless changes to alarming signs of disease. The time and duration of occurrence, the accompanying symptoms such as a burning sensation or taste disorders as well as risk factors such as nicotine and alcohol consumption are important anamnestic elements. Possible causes can be malnutrition, systemic diseases, inflammatory processes or malignancies. Accordingly, a blood test and a smear or a biopsy may be necessary as the first diagnostic step. The aim of this review is to explain the different types and causes of tongue problems and to explain in which cases further clarifications are necessary.