Tongue Contact Research Articles

Recording and analysing physical control variables used in clarinet playing: A musical instrument performance capture and analysis toolbox (MIPCAT)

Measuring fine-grained physical interaction between the human player and the musical instrument can significantly improve our understanding of music performance. This article presents a Musical Instrument Performance Capture and Analysis Toolbox (MIPCAT) that can be used to capture and to process the physical control variables used by a musician while performing music. This includes both a measurement apparatus with sensors and a software toolbox for analysis. Several of the components used here can also be applied in other musical contexts. The system is here applied to the clarinet, where the instrument sensors record blowing pressure, reed position, tongue contact, and sound pressures in the mouth, mouthpiece, and barrel. Radiated sound and multiple videos are also recorded to allow details of the embouchure and the instrument’s motion to be determined. The software toolbox can synchronise measurements from different devices, including video sources, extract time-variable descriptors, segment by notes and excerpts, and summarise descriptors per note, phrase, or excerpt. An example of its application shows how to compare performances from different musicians.

The enduring behavioral and neurobiological effects of a flavor cue paired with alcohol drinking during adolescence on the incentive properties of the flavor cue in adulthood in female alcohol-preferring (P) rats

BackgroundAlcohol use disorders (AUDs) affect 15 million people nationwide, 4% of which are adolescents (ages 12–17) and adolescents who binge drink significantly increase their likelihood of suffering from an AUD in adulthood. Research shows that cues (i.e. flavors) paired with alcohol (EtOH) produce significant cue-induced alcohol craving and contribute to relapse in adolescent and adult populations. However, there is a lack of research focused on how cues that accompany EtOH drinking during adolescence, affect EtOH craving later in life. The current study sought to examine the sex- and developmental-dependent effects of adolescent exposure to flavor cues associated with EtOH on operant-lick behavior and cue-induced dopamine (DA) levels within the nucleus accumbens shell (AcbSh; reward structure) in adulthood. MethodsAdolescent alcohol-preferring (P) rats were randomly assigned to one of 4 groups and received 24 hr. access to three bottles on their home cage: Paired: 0.1% blueberry flavor extract (BB) + 15% v/v EtOH and 2 water bottles; Unpaired: 0.1% BB, 15% v/v EtOH, and water; 15% EtOH alone, and 2 water bottles; BB alone and 2 water bottles. Home cage fluid consumption was measured for 2-weeks. On the third week bottles were removed and all animals underwent 9 days of operant training using an operant sipper paradigm. This consisted of two sipper spouts connected to the computer by a lickometer, which registered tongue contacts with the sipper tube (Paired: BB+EtOH or water; Unpaired BB or EtOH; EtOH alone: EtOH or water; BB alone: BB or water). When the fixed ratio (FR) requirement for number of licks/tongue contacts was met, a liquid delivery solenoid dispensed 0.05 ml of fluid into the sipper tube. Following the final operant session all rats remained in their home-cage for approximately 40 days until adulthood at which point they were returned to the operant chambers and tested for appetitive and consummatory behavior in response to the flavor cue (all rats: BB or water; NO EtOH). Two weeks after the final operant session all rats underwent microdialysis testing to examine cue-induced DA levels in the AcbSh. Results: Data indicated that animals in the paired group exhibited a significantly greater level of licking at the BB sipper and a significantly greater level of DA release in response to the flavor cue compared to the other groups. ConclusionsOverall, the data suggest that cues paired with EtOH during adolescence may produce persistent changes to the behavioral and neurobiological mechanisms that contribute to an increased risk of developing an AUD later in life.

Palatal Electrotactile Display Outperforms Visual Display in Tongue Motor Learning.

Incomplete tongue motor control is a common yet challenging issue among individuals with neurotraumas and neurological disorders. In development of the training protocols, multiple sensory modalities including visual, auditory, and tactile feedback have been employed. However, the effectiveness of each sensory modality in tongue motor learning is still in question. The objective of this study was to test the effectiveness of visual and electrotactile assistance on tongue motor learning, respectively. Eight healthy subjects performed the tongue pointing task, in which they were visually instructed to touch the target on the palate by their tongue tip as accurately as possible. Each subject wore a custom-made dental retainer with 12 electrodes distributed over the palatal area. For visual training, 3×4 LED array on the computer screen, corresponding to the electrode layout, was turned on with different colors according to the tongue contact. For electrotactile training, electrical stimulation was applied to the tongue with frequencies depending on the distance between the tongue contact and the target, along with a small protrusion on the retainer as an indicator of the target. One baseline session, one training session, and three post-training sessions were conducted over four-day duration. Experimental result showed that the error was decreased after both visual and electrotactile trainings, from 3.56 ± 0.11 (Mean ± STE) to 1.27 ± 0.16, and from 3.97 ± 0.11 to 0.53 ± 0.19, respectively. The result also showed that electrotactile training leads to stronger retention than visual training, as the improvement was retained as 62.68 ± 1.81% after electrotactile training and 36.59 ± 2.24% after visual training, at 3-day post training.

Electropalatographic Therapy and Speech Production for Children With Down Syndrome

Purpose Children with Down syndrome (DS) demonstrate speech sound disorders, which impact speech intelligibility in academic and social settings across the life span. The purpose of this technical report is to determine the effects of electropalatographic (EPG) therapy on speech productions for children with DS receiving school-based speech-language therapy services. EPG is a form of visual feedback that displays timing and location of the tongue's contact with the palate during productions of individual phonemes. Method Authors completed a comprehensive literature search to locate articles that investigated the treatment effects of EPG for children with DS. Using the PICO (population, intervention, control, and outcomes) format, we sought in the research to answer “Do children 3–18 years of age with Down syndrome (P), who receive EPG therapy (I) compared to same-age peers with Down syndrome who do not receive EPG therapy (C) show improvement on speech sound production (O)?” Results Three studies met the inclusion criteria and were critically appraised. Two studies were single-subject designs, and one study was a randomized controlled study. Results revealed that EPG therapy improved speech sound production of target phonemes (/s/, /ʃ/, /k/, and /g/) with no transfer to speech intelligibility. Conclusions The results may further the understanding of EPG therapy as a treatment approach, particularly in older individuals with DS receiving school-based speech-language therapy services. Prior to adopting EPG as a treatment approach, clinicians should consider treatment intensity and students' cognitive abilities. Additional research is needed on the long-term effects and generalization of EPG therapy.

A Novel Tongue Pressure Measurement Instrument with Wireless Mobile Application Control Function and Disposable Positioning Mouthpiece.

This study developed a novel chair-side tongue pressure (TP) measuring instrument with a disposable positioning mouthpiece controlled using a smartphone application (APP), denoted as the TP wireless application (TPWA). The mouthpiece was designed with a palate-shaped air balloon containing a tongue contact bump and a plastic bite positioning tube. Fatigue load testing was performed to evaluate mouthpiece durability by applying 700 displacement cycles (50 times a day for one week during training, with twice the safety factor) on the air balloon. The main component used in developing this instrument was a silicon pressure sensor equipped with wireless Bluetooth connection. Young (52 adults; mean age = 20.23 ± 2.17) and elderly (40 adults; mean age = 72.60 ± 7.03) individuals participated in the test with the new instrument, with the results compared to those of a commercial device. The TPWA mouthpiece fatigue test showed that mean response pressures were maintained at 12 kPa. No significant (p > 0.05) differences were found during testing repetitions 0–10 and 701–710. There were no significant differences in the maximum TP values presented between the test sequences using different instruments for young and elderly participants. The TPWA results showed that TP values gradually decreased with increasing age (40.77 kPa for young and 16.55 kPa for elderly participants). The maximum TP for males (43.51 kPa) was significantly larger than that for females (35.14 kPa) in the young group, but an opposite trend was seen in the elderly group (12.97 for males and 17.59 for females). Thus, this study developed a novel chair-side TP measurement instrument with Bluetooth wireless mobile application control. A durable positioning oral mouthpiece was approved for measuring pressure sufficiently, reliably, and precisely for TP screening.

A New Approach of Minimizing Midas Touch Problem for a Tracer-Free Tongue-Controlled Assistive Technology

Tongue-controlled assistive technologies (ATs) have a great potential to improve the quality of life for people with severe disabilities. Current tongue-controlled ATs, however, require either a tracer to be attached on the tongue or a complicated gesture/mechanism to avoid issuing commands unintendedly during routine intraoral events (e.g., tongue resting, swallowing, and speaking), which poses a high entry barrier to potential users. In this study, we propose a tracer-free tongue-controlled AT using four optical distance sensors and one ambient light sensor with a multi-sensor data fusion algorithm to distinguish the intended tongue contacts from the unintended ones. Eleven healthy human subjects participated in the study to evaluate the performance using the proposed technology in masking unintendedly-issued commands and navigating a mouse cursor on a computer. The proposed multi-sensor data fusion algorithm could mask 100%, 86.99%, and 99.50% of unintendedly-issued commands during tongue resting, swallowing, and speaking, respectively. The efficacy of the tongue commands in mouse navigation was evaluated by command-issuing task and maze-navigation task. The participants could issue tongue commands in a random order with 97.16±0.94% of accuracy. The completion time and the sum of deviation of the maze-navigation task were 31.36±2.74 s and 9.38±0.85 pixel <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively. The subjects' performance on computer-access tasks, using the proposed tracer-free tongue-controlled technology, is at the level of the performance measured with existing tracer-based tongue-controlled technologies, while securing robustness in masking commands, unintendedly issued during routine intraoral events. Results of this preliminary study suggest that the tracer-free implementation is feasible option for the tongue-controlled ATs.

Tongue position assessment during oral phase deglutition in children with anterior open bite and normal vertical overbite.

Tongue position during deglutition presents great variability and can be assessed clinically or with different techniques. This study aims to determine tongue position during deglutition in children aged 8-16 years with anterior open bite (AOB) and normal vertical overbite (NVO) using a fluorescein technique. A cross-sectional analytical study was conducted to assess tongue contact points during the oral phase of deglutition. A total of 132 children with AOB and 132 children with NVO were included in this study. The difference between tongue contacts in both groups was performed, and the association between tongue position and anterior occlusion was establish. Normal distribution analysis, Parson's Chi-square test (P < 0.05). In AOB, about 28.8% showed tongue contact on the palatal surface of the incisors during the oral phase, 25.8% at the gingival margin, and 22% on the palatal rugae. Regarding NVO, 53% showed contact on the palatal rugae, 28.8% at the gingival margin, and 13.6% at the palatal surface. AOB group presented a higher prevalence of impaired tongue positions compared to NVO controls. The palatal surface was the most frequent contact point in the AOB, whereas tongue showed contact points at the palatal rugae in NVO.

Lingual function in children with anterior open bite: A case-control study

To determine the association between the position of the tongue and phonation among individuals with normal vertical overbite (NVO) and anterior open bite (AOB). This was a case-control study of 132 students with AOB and 132 controls with NVO between the ages of 8 and 16years old. The presence of AOB was determined during a clinical examination using a Boley gauge, phonation (speech) was assessed with an articulation test, which was analysed using a classification table of Spanish consonants spoken in Colombia, and tongue contact during swallowing was determined with the Payne test. Associations were determined between AOB and the position of the tongue upon swallowing and during speech (Chi2 test of independence, Fisher's exact test, and Mann-Whitey U test, P<0.005). Finally, a logistic regression model was performed, with AOB as the dependent variable. We found associations between AOB and the presence of lingual interposition, distortion, lingual thrust, protrusion of the tongue, contact with palatine rugae, and type of dentition (P<0.05). According to the logistic regression model, the presence of lingual thrust (odds ratio (OR): 0.067; 95% confidence interval (CI): 0.009-0.518) and contact with the palatine rugae (OR: 0.420; 0.216-0.818) behave as protective factors associated with the presence of AOB, and the presence of distortion was found to be a risk factor (OR: 10.751; 95%CI: 5.658-20.427). Lingual thrust, interposition, and protrusion are associated with AOB. Lingual thrust and contact of the tongue with the palatine rugae behave as protective factors, and the presence of distortion acts as a risk factor.

Cross-linguistic lateral bracing: An ultrasound study

Lateral bracing refers to intentional stabilizing of tongue contact with the roof of the mouth along the upper molars or the hard palate. Previous research has found evidence of lateral bracing in individual speakers of six languages [Cheng et al. 2017. Can. Acoust. 45, 186]. The current study examines lateral bracing cross-linguistically at a larger scale using ultrasound technology to image tongue movement. We tracked and measured the magnitude of vertical tongue movement at three positions (left, right, and middle) in the coronal plane over time using Flow Analyzer [Barbosa, 2014. J. Acoust. Soc. Am. 136, 2105] for optical flow analysis. Preliminary results across all languages (Cantonese, English, French, Korean, Mandarin, and Spanish) show that the sides of the tongue are more stable than the center and maintain a relatively high position in the mouth throughout speech. The magnitude of movement at the sides is significantly smaller than at the center of the tongue. Further, lateral releases vary in frequency for different languages. This evidence supports the view that bracing is a physiological property of speech production that occurs irrespective of the language spoken. [Funding from NSERC.]

Use of electropalatography in the treatment of speech disorders in children with Down syndrome: a randomized controlled trial.

Electropalatography (EPG) records details of the location and timing of tongue contacts with the hard palate during speech. It has been effective in treating articulation disorders that have failed to respond to conventional therapy approaches but, until now, its use with children and adolescents with intellectual/learning disabilities and speech disorders has been limited. To evaluate the usefulness of EPG in the treatment of speech production difficulties in children and adolescents with Down syndrome (DS) aged 8-18 years. A total of 27 children with DS were assessed on a range of cognitive and speech and language measures and underwent additional EPG assessment. Participants were randomly allocated to one of three age-matched groups receiving either EPG therapy, EPG-informed conventional therapy or 'treatment as usual' over a 12-week period. The speech of all children was assessed before therapy using the Diagnostic Evaluation of Articulation and Phonology (DEAP) and reassessed immediately post- and 3 and 6 months post-intervention to measure percentage consonants correct (PCC). EPG recordings were made of the DEAP assessment items at all time points. Per cent intelligibility was also calculated using the Children's Speech Intelligibility Measure (CSIM). Gains in accuracy of production immediately post-therapy, as measured by PCC, were seen for all groups. Reassessment at 3 and 6 months post-therapy revealed that those who had received therapy based directly on EPG visual feedback were more likely to maintain and improve on these gains compared with the other groups. Statistical testing showed significant differences between groups in DEAP scores across time points, although the majority did not survive post-hoc evaluation. Intelligibility across time points, as measured by CSIM, was also highly variable within and between the three groups, but despite significant correlations between DEAP and CSIM at all time points, no statistically significant group differences emerged. EPG was an effective intervention tool for improving speech production in many participants. This may be because it capitalizes on the relative strength of visual over auditory processing in this client group. The findings would seem to warrant an increased focus on addressing speech production difficulties in current therapy.

A multilinear tongue model derived from speech related MRI data of the human vocal tract

We present a multilinear statistical model of the human tongue that captures anatomical and tongue pose related shape variations separately. The model is derived from 3D magnetic resonance imaging data of 11 speakers sustaining speech related vocal tract configurations. To extract model parameters, we use a minimally supervised method based on an image segmentation approach and a template fitting technique. Furthermore, we use image denoising to deal with possibly corrupt data, palate surface information reconstruction to handle palatal tongue contacts, and a bootstrap strategy to refine the obtained shapes. Our evaluation shows that, by limiting the degrees of freedom for the anatomical and speech related variations, to 5 and 4, respectively, we obtain a model that can reliably register unknown data while avoiding overfitting effects. Furthermore, we show that it can be used to generate plausible tongue animation by tracking sparse motion capture data.

Quantitative examination of isometric tongue protrusion forces in children with oro-facial dysfunctions or myofunctional disorders.

Oro-facial dysfunctions (OFD) or oro-facial myofunctional disorders in children lead to severe problems in teeth and jaw position, articulation, chewing and swallowing. The forces of the tongue, the central muscle for articulation, chewing and swallowing are focused on in several studies. In this examination, isometric tongue protrusion forces (TPF) of children with OFD and controls were compared. Thirty participants with OFD and 30 controls were presented a target force level as a straight line on a monitor that they were supposed to match by generating an isometric tongue force for different target levels (0.25N and 0.5N). Correlations of the severity of OFD (symptom score) with the capacities of the TPF 0.25N and 0.5N were calculated. Statistical differences were obvious in TPF variability and the accuracy, depending on the weight. Tongue contact time, expressed as per cent (TCT, total contact: 100%), was significantly lower in children with OFD (P=.005). Mean and median TPF was not different between groups. The predictive value of TPF for OFD revealed a level of 58.6% for TPF 0.25N and 74.5% for TPF 0.5N. Correlations of the severity of OFD were seen for some parameters. Subjects with OFD show significantly lower competencies in accuracy and endurance of tongue protrusion forces. This may have a high impact on phenotyping children with OFD and influence therapeutical approaches.

Efficacy of Electropalatography for Treating Misarticulation of /r/.

The purpose of the present study was to document the efficacy of electropalatography (EPG) for the treatment of rhotic errors in school-age children. Despite a growing body of literature using EPG for the treatment of speech sound errors, there is little systematic evidence about the relative efficacy of EPG for rhotic errors. Participants were 5 English-speaking children aged 6;10 to 9;10, who produced /r/ at the word level with < 30% accuracy but otherwise showed typical speech, language, and hearing abilities. Therapy was delivered in twice-weekly 30-min sessions for 8 weeks. Four out of 5 participants were successful in achieving perceptually and acoustically accurate /r/ productions during within-treatment trials. Two participants demonstrated generalization of /r/ productions to nontreated targets, per blinded listener ratings. The present findings support the hypothesis that EPG can improve production accuracy in some children with rhotic errors. However, the utility of EPG is likely to remain variable across individuals. For rhotics, EPG training emphasizes one possible tongue configuration consistent with accurate rhotic production (lateral tongue contact). Although some speakers respond well to this cue, the narrow focus may limit lingual exploration of other acceptable tongue shapes known to facilitate rhotic productions.

How clarinettists articulate: The effect of blowing pressure and tonguing on initial and final transients.

Articulation, including initial and final note transients, is important to tasteful music performance. Clarinettists' tongue-reed contact, the time variation of the blowing pressure P¯mouth, the mouthpiece pressure, the pressure in the instrument bore, and the radiated sound were measured for normal articulation, accents, sforzando, staccato, and for minimal attack, i.e., notes started very softly. All attacks include a phase when the amplitude of the fundamental increases exponentially, with rates r ∼1000 dB s(-1) controlled by varying both the rate of increase in P¯mouth and the timing of tongue release during this increase. Accented and sforzando notes have shorter attacks (r∼1300 dB s(-1)) than normal notes. P¯mouth reaches a higher peak value for accented and sforzando notes, followed by a steady decrease for accented notes or a rapid fall to a lower, nearly steady value for sforzando notes. Staccato notes are usually terminated by tongue contact, producing an exponential decrease in sound pressure with rates similar to those calculated from the bandwidths of the bore resonances: ∼400 dB s(-1). In all other cases, notes are stopped by decreasing P¯mouth. Notes played with different dynamics are qualitatively similar, but louder notes have larger P¯mouth and larger r.

The Role of Motion Extrapolation in Amphibian Prey Capture

Sensorimotor delays decouple behaviors from the events that drive them. The brain compensates for these delays with predictive mechanisms, but the efficacy and timescale over which these mechanisms operate remain poorly understood. Here, we assess how prediction is used to compensate for prey movement that occurs during visuomotor processing. We obtained high-speed video records of freely moving, tongue-projecting salamanders catching walking prey, emulating natural foraging conditions. We found that tongue projections were preceded by a rapid head turn lasting ∼ 130 ms. This motor lag, combined with the ∼ 100 ms phototransduction delay at photopic light levels, gave a ∼ 230 ms visuomotor response delay during which prey typically moved approximately one body length. Tongue projections, however, did not significantly lag prey position but were highly accurate instead. Angular errors in tongue projection accuracy were consistent with a linear extrapolation model that predicted prey position at the time of tongue contact using the average prey motion during a ∼ 175 ms period one visual latency before the head movement. The model explained successful strikes where the tongue hit the fly, and unsuccessful strikes where the fly turned and the tongue hit a phantom location consistent with the fly's earlier trajectory. The model parameters, obtained from the data, agree with the temporal integration and latency of retinal responses proposed to contribute to motion extrapolation. These results show that the salamander predicts future prey position and that prediction significantly improves prey capture success over a broad range of prey speeds and light levels. Neural processing delays cause actions to lag behind the events that elicit them. To cope with these delays, the brain predicts what will happen in the future. While neural circuits in the retina and beyond have been suggested to participate in such predictions, few behaviors have been explored sufficiently to constrain circuit function. Here we show that salamanders aim their tongues by using extrapolation to estimate future prey position, thereby compensating for internal delays from both visual and motor processing. Predictions made just before a prey turn resulted in the tongue being projected to a position consistent with the prey's pre-turn trajectory. These results define the computations and operating regimen for neural circuits that predict target motion.

Coordination in oro-pharyngeal biomechanics during human swallowing

In swallowing, the tongue contacts against the hard palate to generate pressure for propelling a bolus from the oral cavity into the pharynx. Meanwhile, the hyoid and larynx move upward and forward to facilitate the bolus from the pharynx into the esophagus. It has been well known that sequential coordination between those actions is critical for safety accomplishment of swallowing. However, the absence of noninvasive assessment for it limits the detection to the physiological symptom of dysphagia. We applied a sensor sheet on the hard palate to measure tongue contact pressure and a bend sensor on the frontal neck to monitor the laryngeal movement, which was synchronized with hyoid motion for assessing the coordination between both actions in 14 healthy male subjects when swallowing 5ml of water. The sequential order of tongue pressure and hyoid movement was successfully displayed. Tongue pressure was produced after slight movement of the hyoid and closely to the hyoid elevation, then reached a maximum when the hyoid stabilized in the most anterior–superior position, and ceased concurrently with the onset of hyoid descent. Additionally, the synchronized data from both sensors showed positive correlations between identified time points on the laryngeal signal waveform and onset, peak and offset of tongue pressure. Our sensing system successfully showed the coordination between tongue pressure production and hyoid motion, and could be a simple and noninvasive method for clinicians to evaluate the oral and pharyngeal stages of swallowing.

Tongue adhesion in the horned frog Ceratophrys sp.

Frogs are well-known to capture elusive prey with their protrusible and adhesive tongues. However, the adhesive performance of frog tongues and the mechanism of the contact formation with the prey item remain unknown. Here we measured for the first time adhesive forces and tongue contact areas in living individuals of a horned frog (Ceratophrys sp.) against glass. We found that Ceratophrys sp. generates adhesive forces well beyond its own body weight. Surprisingly, we found that the tongues adhered stronger in feeding trials in which the coverage of the tongue contact area with mucus was relatively low. Thus, besides the presence of mucus, other features of the frog tongue (surface profile, material properties) are important to generate sufficient adhesive forces. Overall, the experimental data shows that frog tongues can be best compared to pressure sensitive adhesives (PSAs) that are of common technical use as adhesive tapes or labels.

Impact of lingual plates on the interocclusal free way space: a pilot study

Palatal augmentation prostheses are commonly used in the treatment for dysphagia. By lowering the palatal contours, the tongue contact is increased and thus the bolus propulsion facilitated. However, the unfavourable weight of such appliances may be avoided when using lingual plates. Hence, the aim of this study is to investigate the effect of two different types of lingual plates on the vertical dimension in rest position. Eleven healthy dentate subjects with an average age of 35.5 years (26-60 years) volunteered in this pilot study. The vertical overbites were measured on plaster models. Two different designs of the experimental lingual plates were tested in this pilot study (P-type & D-type). The inter-occlusal freeway space was measured using the electromagnetic K7 jaw-tracking system (Myotronics, U.S.A.), while the subjects were seated in an upright position. They were asked to close from rest position into maximum intercuspation for about 2 s. Recordings were performed without the plates and subsequently with each of the two plate designs in situ. All recordings were performed three times and the second closing movement of each recording was used for the analysis. After averaging the repetitions without experimental lingual plates, with P-type and D-type plates, the differences were analysed using a Kruskall-Wallis test. The results showed no significantly increased freeway space while using both types of lingual plates. Hence, it can be concluded that any altered tongue pressure during swallowing with lingual plates is not related to an increase in vertical dimension.

Differences in biomechanical features of tongue pressure production between articulation and swallow

Summary The purpose of this study was to compare the tongue pressure against the hard palate during the articulation of a monosyllable with that during swallowing. The participants were 20 healthy adults without swallowing or articulation disorder (10 men and 10 women, mean age ± standard deviation: 22·5 ± 0·9 years). Tongue pressure during articulation of [ki] (articulatory pressure) and during dry swallowing (swallowing pressure) was recorded by a 0·1-mm-thick sensor sheet with five measuring points attached to the hard palate. Biomechanical parameters such as maximal magnitude, duration, integrated value and slope gradient were compared between articulatory pressure and swallowing pressure at each measuring point. Although swallowing pressure was produced at each measuring point, articulatory pressure was found only in the posterior circumferential parts of the hard palate and was smaller in magnitude (14·9-16·7% of swallowing pressure) and integrated value, which meant the amount of work by tongue pressing (7·0-7·9%), shorter in duration (26·6-31·8%) and shallower in slope gradient, which meant the speed of tongue pressing (26·9-27·4%). Maximal magnitude was closely correlated with duration (R(2) = 0·386) and slope gradient (R(2) = 0·843) for articulatory pressure. These results first show the biomechanical differences between articulation and swallowing in terms of tongue contact with the hard palate. The findings suggest that tongue pressure measurement might be a useful investigation for patients with tongue motor disorder.

Surface tension helps a tongue grab liquid

Capitalizing on the opportunities presented by the surface tension of aqueous liquids against air shows natural selection at its most creative. The paper in PNAS by Rico-Guevara and Rubega (1) describes how protruded hummingbird tongues curl lengthwise into a pair of tubes containing nectar. As a tongue contacts nectar on its lower surface or is withdrawn from full submersion, the surface tension of the residual air–nectar interface draws the sides of the tubes up into nearly complete cylinders. Together with the hydrophilic surface of the tongue, lengthwise stiffening rods ensure proper reshaping with no need for muscular activity. After retraction, subsequent protrusion through a tighter bill aperture strips the tongue of the fluid. Neither capillarity nor active pumping needs to take place, and therefore, the high viscosity from the concentrated sugar in the nectar does not present a problem. Viscosity may minimize lengthwise leakage from the cylinders, while viscosity rises steeply with increasing concentrations of sugar, and therefore, surface tension changes much less.