We acknowledge all the participants, volunteers, and others involved in the study. We are grateful to Sandra Stolzenbach W&#230;hrens and Wender Bredie (University of Copenhagen) for designing the squares used in the present gratings orientation test. This research was funded by the University of Milan, Piano di sostegno alla ricerca 2018.

An informed, written consent has been signed by all participants. This study was approved by the Ethics Committee of the University of Milan (n. 48/19) and conducted in accordance with the Declaration of Helsinki.
1. Training of experimenters
<ol>
	<li>Take the grating tool and apply a force of 100 g on a sponge placed on a scale. 
	NOTE: Refer to Figure 1 for the schematic of the grating tool used in this study</li>
	<li>Repeat this procedure at least 10 times to reduce variation in the force applied by the grating on the subjects&#39; tongues during testing, both within and across experimenters.</li>
</ol>
2. Assessment procedure
NOTE: Conduct the assessment of tactile acuity following the required health and safety standard to guarantee the subject&#39;s safety (e.g., mask, gloves, and lab coat).
<ol>
	<li>Display all gratings (0.20 mm, 0.25 mm, 0.50 mm, 0.75 mm, 1.00 mm, 1.25 mm) (Figure 2) on a table out of sight of the participant.</li>
	<li>Seat the participant in a comfortable chair and inform them that they can leave the experiment at any time.</li>
	<li>Inform the participant that they will be blindfolded during the experiment and asked to stick out their tongue in a comfortable and relaxed way.</li>
	<li>Prior to the beginning of the experiment, familiarize the subjects with the procedure using the largest grating (1.25 mm) to demonstrate the force applied (100 g for 3 s).</li>
	<li>Notify the participants that they can take a sip of water whenever deemed appropriate.</li>
	<li>Apply each grating onto the subjects&#39; tongue (anterior region of the tongue just around the midline).</li>
	<li>After each touch, ask the subjects to indicate, using their hands, the tool&#39;s orientation (either horizontal or vertical) and their degree of sureness (sure, unsure). Subjects must guess if they do not know.</li>
	<li>After each touch, record all the answers (horizontal, vertical, sure, not sure) for each subject on a spreadsheet (Supplemental Table 1).</li>
	<li>Repeat each grating as many times as deemed necessary for the R-Index cut-off selected, for instance, 6 times, 3 horizontally, and 3 vertically (Supplemental Table 1).</li>
	<li>Sterilize each grating after testing each participant (refer to section 4). 
	NOTE: The tongue should protrude gently from the mouth without effort by the volunteers to avoid excessive fatigue, which would lead to an alteration in their performance results. It is important to note that the higher the repetitions by grating, the more reliable the measurement16.</li>
</ol>
3. Cleaning protocol
<ol>
	<li>Prepare a solution consisting of 20 mL of sodium hypochlorite (see Table of Materials) diluted in 1 L of water according to the manufacturer&#39;s instructions.</li>
	<li>Manually shake the solution for a few seconds.</li>
	<li>Fill 6 cups with approximately 20 mL of the disinfectant solution to fully immerse each tool in the solution.</li>
	<li>Place each tool in the corresponding cup.</li>
	<li>Let the tools soak for 15-20 min.</li>
	<li>Rinse the tools with plenty of water according to the manufacturer&#39;s instructions and scrub them with a toothbrush to ensure removing any sodium hypochlorite residue.</li>
	<li>Allow the tools to air dry.</li>
</ol>
4. R-index calculation
<ol>
	<li>Create a response matrix for each volunteer and for all the tools (Figure 3) based on the response frequencies used to calculate the R-index using the following equation: 
	<img alt="Equation 1" src="/files/ftp_upload/62898/62898eq01.jpg" /> 
	NOTE: R-index expresses individual tactile sensitivity for each tool16. R- index is based on SDT17 and represents an estimated probability of discerning a target stimulus (i.e., the signal) from an alternative stimulus (i.e., the noise). The signal and the noise correspond to the correct or incorrect identification of the horizontal-vertical orientation of the grating. Four response options for both signal and noise can occur: &#34;horizontal-sure&#34;, &#34;horizontal-unsure&#34;, &#34;vertical-unsure&#34; and &#34;vertical-sure&#34;16. R-index values range between 0-1. A higher R-index value indicates better discrimination.</li>
</ol>
5. Sensitivity and threshold determination by the R-index estimates
<ol>
	<li>To determine whether a subject can discriminate the orientation of each tool, calculate the cut-off using a table of critical values for R-index significance tests18 
	NOTE: Considering the present example, corresponding to 36 presentations (i.e., each grating presented 6 times, 3 horizontal and 3 vertical), the cut-off value for discrimination is set to 0.7426 according to the one-sided R-index critical values for &#945; = 0.0518.</li>
	<li>If a sufficiently high number of tools is used (e.g., six different grating dimensions)19, derive R-index threshold estimations.</li>
	<li>To calculate the threshold for each subject, interpolate the two R-indices immediately below and above of the cut-off value20.</li>
</ol>

<ol>
	<li>Guinard, J. X., Mazzucchelli, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+sensory+perception+of+texture+and+mouthfeel.">The sensory perception of texture and mouthfeel.</a> Trends in Food Science &amp; Technology. 7 (7), 213-219 (1996).</li><li>Jeltema, M., Beckley, J., Vahalik, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Food+texture+assessment+and+preference+based+on+mouth+behavior.">Food texture assessment and preference based on mouth behavior.</a> Food Quality and Preference. 52, 160-171 (2016).</li><li>Scott, C. L., Downey, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Types+of+food+aversions:+animal,+vegetable,+and+texture.">Types of food aversions: animal, vegetable, and texture.</a> The Journal of Psychology. 141 (2), 127-134 (2007).</li><li>Laureati, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individual+differences+in+texture+preferences+among+European+children:+Development+and+validation+of+the+Child+Food+Texture+Preference+Questionnaire+(CFTPQ).">Individual differences in texture preferences among European children: Development and validation of the Child Food Texture Preference Questionnaire (CFTPQ).</a> Food Quality and Preference. 80, 103828 (2020).</li><li>de Lavergne, M. D., Derks, J. A., Ketel, E. C., de Wijk, R. A., Stieger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eating+behaviour+explains+differences+between+individuals+in+dynamic+texture+perception+of+sausages.">Eating behaviour explains differences between individuals in dynamic texture perception of sausages.</a> Food Quality and Preference. 41, 189-200 (2015).</li><li>Engelen, L., de Wijk, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+processing+and+texture+perception.">Oral processing and texture perception.</a> Food Oral Processing: Fundamentals of Eating and Sensory Perception. 8, 157-176 (2012).</li><li>Stokes, J. R., Boehm, M. W., Baier, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+processing,+texture+and+mouthfeel:+From+rheology+to+tribology+and+beyond.">Oral processing, texture and mouthfeel: From rheology to tribology and beyond.</a> Current Opinion in Colloid &amp; Interface Science. 18 (4), 349-359 (2013).</li><li>Engelen, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+receptors.">Oral receptors.</a> Food Oral Processing: Fundamentals of Eating and Sensory Perception. , 15-38 (2012).</li><li>Yackinous, C., Guinard, J. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relation+between+PROP+taster+status+and+fat+perception,+touch,+and+olfaction.">Relation between PROP taster status and fat perception, touch, and olfaction.</a> Physiology &amp; Behavior. 72 (3), 427-437 (2001).</li><li>Etter, N. M., Breen, S. P., Alcala, M. I., Ziegler, G. R., Hayes, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+midline+lingual+point-pressure+somatosensation+using+Von+Frey+hair+monofilaments.">Assessment of midline lingual point-pressure somatosensation using Von Frey hair monofilaments.</a> Journal of Visualized Experiments: JoVE. (156), (2020).</li><li>Essick, G. K., Chen, C. C., Kelly, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+letter-recognition+task+to+assess+lingual+tactile+acuity.">A letter-recognition task to assess lingual tactile acuity.</a> Journal of Oral and Maxillofacial Surgery. 57 (11), 1324-1330 (1999).</li><li>Essick, G. K., Chopra, A., Guest, S., McGlone, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lingual+tactile+acuity,+taste+perception,+and+the+density+and+diameter+of+fungiform+papillae+in+female+subjects.">Lingual tactile acuity, taste perception, and the density and diameter of fungiform papillae in female subjects.</a> Physiology &amp; Behavior. 80 (2-3), 289-302 (2003).</li><li>Van Boven, R. W., Johnson, K. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+limit+of+tactile+spatial+resolution+in+humans:+grating+orientation+discrimination+at+the+lip,+tongue,+and+finger.">The limit of tactile spatial resolution in humans: grating orientation discrimination at the lip, tongue, and finger.</a> Neurology. 44 (12), 2361 (1994).</li><li>Moritz, J., Turk, P., Williams, J. D., Stone-Roy, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perceived+intensity+and+discrimination+ability+for+lingual+electrotactile+stimulation+depends+on+location+and+orientation+of+electrodes.">Perceived intensity and discrimination ability for lingual electrotactile stimulation depends on location and orientation of electrodes.</a> Frontiers in Human Neuroscience. 11, 186 (2017).</li><li>Bach-y-Rita, P., Kaczmarek, K. A., Tyler, M. E., Garcia-Lara, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Form+perception+with+a+49-point+electrotactile+stimulus+array+on+the+tongue:+a+technical+note.">Form perception with a 49-point electrotactile stimulus array on the tongue: a technical note.</a> Journal Of Rehabilitation Research and Development. 35, 427-430 (1998).</li><li>O'Mahony, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+discrimination+tests:+A+user-friendly+treatment+of+response+bias,+rating+and+ranking+R-index+tests+and+their+relationship+to+signal+detection.">Understanding discrimination tests: A user-friendly treatment of response bias, rating and ranking R-index tests and their relationship to signal detection.</a> Journal of Sensory Studies. 7 (1), 1-47 (1992).</li><li>Lee, H. S., Van Hout, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+sensory+and+food+quality:+The+R-index+analysis.">Quantification of sensory and food quality: The R-index analysis.</a> Journal of Food Science. 74 (6), 57-64 (2009).</li><li>Bi, J., O'Mahony, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Updated+and+extended+table+for+testing+the+significance+of+the+R-index.">Updated and extended table for testing the significance of the R-index.</a> Journal of Sensory Studies. 22, 713-720 (2007).</li><li>Bertoli, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+sensitivity,+nutritional+status+and+metabolic+syndrome:+Implication+in+weight+loss+dietary+interventions.">Taste sensitivity, nutritional status and metabolic syndrome: Implication in weight loss dietary interventions.</a> World Journal of Diabetes. 5 (5), 717 (2014).</li><li>Robinson, K. M., Klein, B. P., Lee, S. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Utilizing+the+R-index+measure+for+threshold+testing+in+model+caffeine+solutions.">Utilizing the R-index measure for threshold testing in model caffeine solutions.</a> Food Quality and Preference. 16 (4), 283-289 (2005).</li><li>Appiani, M., Rabitti, N. S., Methven, L., Cattaneo, C., Laureati, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+lingual+tactile+sensitivity+in+children+and+adults:+Methodological+suitability+and+challenges.">Assessment of lingual tactile sensitivity in children and adults: Methodological suitability and challenges.</a> Foods. 9 (11), 1594 (2020).</li><li>Cattaneo, C., Liu, J., Bech, A. C., Pagliarini, E., Bredie, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cross-cultural+differences+in+lingual+tactile+acuity,+taste+sensitivity+phenotypical+markers,+and+preferred+oral+processing+behaviors.">Cross-cultural differences in lingual tactile acuity, taste sensitivity phenotypical markers, and preferred oral processing behaviors.</a> Food Quality and Preference. 80, 103803 (2020).</li><li>Abraira, V. E., Ginty, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+sensory+neurons+of+touch.">The sensory neurons of touch.</a> Neuron. 79 (4), 618-639 (2013).</li><li>Johnson, K. O., Phillips, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+spatial+resolution.+I.+Two-point+discrimination,+gap+detection,+grating+resolution,+and+letter+recognition.">Tactile spatial resolution. I. Two-point discrimination, gap detection, grating resolution, and letter recognition.</a> Journal of Neurophysiology. 46 (6), 1177-1192 (1981).</li><li>Phillips, J. R., Johnson, K. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+spatial+resolution.+II.+Neural+representation+of+bars,+edges,+and+gratings+in+monkey+primary+afferents.">Tactile spatial resolution. II. Neural representation of bars, edges, and gratings in monkey primary afferents.</a> Journal of Neurophysiology. 46 (6), 1192-1203 (1981).</li></ol>

The authors have nothing to disclose.

Few valid instruments are available for measuring tactile acuity10,11,13,22. Von Frey filaments have been shown to be an adequate method for measuring both skin and oral tactile acuity10,21,22. However, these instruments measure a different dimension of lingual tactile acuity than the gratings orientat...

The texture and mouthfeel of food play an important role in liking1,2,3,4, and while research has found differences in texture perception due to factors such as chewing behavior2,5,&#160;saliva flow, and composition6,7, there are limited methods available to assess variation in oral tactile receptors (mechanoreceptors). The oral cavity houses different types of mechanoreceptors found in the mouth: Merkel receptors, Ruffini cylinders, and Meissner corpuscles8. Mechanoreceptors can be classed into two groups: slowly adapting and rapidly adapting. Slowly adapting mechanoreceptors (Ruffini cylinders and Merkel receptors) produce signals continuously while being stimulated. In contrast, rapidly adapting mechanoreceptors (Meissner&#39;s corpuscles) respond to the beginning and end of stimulation with a signal. Tactile acuity varies widely across tongue surfaces and between individuals, possibly due to differences in mechanoreceptor sensitivity. The location and the number of mechanoreceptors in the oral cavity, the differences in the spatial arrangement/density of the mechanoreceptors (spatial acuity), or the differences in their sensitivity when activated could be the cause of this intra- and inter-individual variability. Several methods to evaluate and screen for variation in mechanoreceptor sensitivity in the oral cavity have been published, including von Frey filaments9,10, letter recognition11,12, grating orientation tests13, and flexible electrode array14,15. The gratings orientation test requires square gratings (Figure 1, Figure 2) with different groove widths to be placed on the tongue of a blindfolded subject. They indicate if subjects perceive the gratings to be in either a horizontal or vertical orientation. Responses are used to calculate average thresholds based on the subject&#39;s ability to discriminate the orientation for the different grating sizes.

<table><tbody><tr><td>Custom-made squares</td><td>University of Reading; University of Copenhagen</td><td></td><td>Squares of 1 cm&lt;sup&gt;2&lt;/sup&gt; from polytetrafluoroethylene (PTFE)</td></tr><tr><td>Disinfenctant solution (20% sodium hypochlorite)</td><td>Amuchina, Angelini S.p.A., Roma, Italy</td><td></td><td></td></tr><tr><td>Eye masks</td><td>Various</td><td></td><td></td></tr><tr><td>Gloves</td><td>Various</td><td></td><td></td></tr><tr><td>Lab coat</td><td>Various</td><td></td><td></td></tr><tr><td>Plastic cup for drinking water</td><td>Various</td><td></td><td></td></tr><tr><td>Excel</td><td>Microsoft</td><td></td><td></td></tr></tbody></table>

assessment of spatial lingual tactile sensitivity using a gratings orientation test

Individual thresholds by R-index estimates are calculated using a gratings orientation test (6 different tools of increasing grating size from 0.20-1.25 mm) to assess spatial lingual tactile sensitivity. During the experiment, the subjects are blindfolded and asked to specify the orientation of the grating (either horizontal or vertical) placed on the tongue. R-index is based on Signal Detection Theory (SDT), and it is an estimated probability of correctly identifying a target stimulus (the signal, e.g., the correct orientation) compared to an alternative stimulus (the noise, e.g., the incorrect orientation). Once the R-index values for each subject and each tool dimension are calculated, it is possible to derive the individual threshold by interpolating the two R-indices immediately below and above the established cut-off (typically 75%) based on one-sided R-index critical values. This procedure can be helpful in the medical field to study the association between oral tactile sensitivity, speech clarity, and swallowing disorders, as well as in sensory and consumer studies to explore individual variation in texture perception, food preferences, and eating behavior.

A total of 70 healthy adults (age range = 19-33 years; mean age = 22.0; 52.9% women) were involved in the study, as shown in Appiani et al. (2020)21.
As an example, the R-index distribution by age for square 0.75 mm is reported in Figure 4. Each point represents a different subject. Subjects above the dotted line (cut-off value: 0.7426) are those who correctly identify the orientation of the grating (more sensitive).
<p class="jove_cont...

Watch this Scientific Journal Video about Assessment of Spatial Lingual Tactile Sensitivity using a Gratings Orientation Test at JoVE.com

Assessment of Spatial Lingual Tactile Sensitivity using a Gratings Orientation Test

This work illustrates a standard procedure and threshold determination by the R-index to assess spatial lingual tactile sensitivity using a gratings orientation test.

Individual thresholds by R-index estimates are calculated using a gratings orientation test (6 different tools of increasing grating size from 0.20-1.25 ...

assessment-spatial-lingual-tactile-sensitivity-using-gratings

Research

JoVE Journal

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2.5K Views.  University of Milan. Deze video illustreert een procedure om de gevoeligheid van de ruimtelijke linguale tactiele grootte te beoordelen met behulp van een rasporiëntatietest. Soortgelijke hulpmiddelen zijn gebruikt om tactiele scherpte op lichaamsniveau te meten, en met name op de vingertoppen van de handen. Er bestaan echter weinig methodologische benaderingen om de gevoeligheid op oraal niveau te meten.En specifiek op de tong. Deze procedure kan nuttig zijn in de medische voeding om de associatie tussen...

Video: Assessment of Spatial Lingual Tactile Sensitivity using a Gratings Orientation Test

Measurement of Vibration Detection Threshold and Tactile Spatial Acuity in Human Subjects

Tests that allow the precise determination of psychophysical thresholds for vibration and grating orientation provide valuable information about mechanosensory function that are relevant for clinical diagnosis as well as for basic research. Here, we describe two psychophysical tests designed to determine the vibration detection threshold (automated system) and tactile spatial acuity (handheld device). Both procedures implement a two-interval forced-choice and a transformed-rule up and down experimental paradigm. These tests have been used to obtain mechanosensory profiles for individuals from distinct human cohorts such as twins or people with sensorineural deafness.

Here, we present protocols to determine vibration detection thresholds and tactile acuity using psychophysical methods in man.

Tests that allow the precise determination of psychophysical thresholds for vibration and grating orientation provide valuable information about ...

A Tactile Automated Passive-Finger Stimulator (TAPS)

Although tactile spatial acuity tests are used in both neuroscience research and clinical assessment, few automated devices exist for delivering controlled spatially structured stimuli to the skin. Consequently, investigators often apply tactile stimuli manually. Manual stimulus application is time consuming, requires great care and concentration on the part of the investigator, and leaves many stimulus parameters uncontrolled. We describe here a computer-controlled tactile stimulus system, the Tactile Automated Passive-finger Stimulator (TAPS), that applies spatially structured stimuli to the skin, controlling for onset velocity, contact force, and contact duration. TAPS is a versatile, programmable system, capable of efficiently conducting a variety of psychophysical procedures. We describe the components of TAPS, and show how TAPS is used to administer a two-interval forced-choice tactile grating orientation test.
Corresponding Author: Daniel Goldreich

A Tactile Automated Passive-Finger Stimulator TAPS

We describe a computer-controlled device for investigating the sense of touch: the Tactile Automated Passive-finger Stimulator (TAPS). We describe the components of TAPS, and show how TAPS is used to administer a two-interval forced-choice tactile grating orientation test.

Although tactile spatial acuity tests are used in both neuroscience research and clinical assessment, few automated devices exist for delivering ...

Biology

Assessment of Midline Lingual Point-Pressure Somatosensation Using Von Frey Hair Monofilaments

Detection and discrimination threshold estimates for oral point pressure are assessed using Von Frey Hair monofilaments. Consistent with previously published protocols, threshold estimates are determined using a two-interval forced choice (2-IFC) paradigm with a three down/one up approach. Detection threshold estimates determine the mean force in which a participant can identify the presence of pressure. During the detection threshold procedure, the participant is instructed to choose which of two sequentially presented observation intervals contained the tactile test stimulus. If the participant performs three correct detections in a row (i.e., 3 &#39;hits&#39;), the researcher decreases the stimulus to the next lower target force level. With one incorrect detection (a &#39;miss&#39;), the researcher increases the force delivered to the next higher level. This threshold estimation approach is known as a 3-down/1-up adaptive staircase. Reponses are recorded on a paper ballot, and a participant&#39;s estimated threshold is defined as the geometric mean of five reversals. During the discrimination threshold procedure, the participant is asked to make a choice between two serially presented stimuli as to which is the &#34;harder&#34; or &#34;stronger&#34; pressure. The same scoring of &#39;hits&#39;, &#39;misses&#39;, and stopping points are used. Detection and discrimination testing for oral point pressure at tongue midline takes approximately 20 min to complete. Using these commercially-available clinical tools, individual touch sensation profiles for the midline tongue can be achieved in a relatively time and cost effective means.

This work describes a standard method to assess tactile sensation at the midline of the tongue tip. Using Von Frey Hair (VFH) monofilaments, this protocol provides estimates of detection and discrimination threshold estimates for oral point pressure (OPP).

Detection and discrimination threshold estimates for oral point pressure are assessed using Von Frey Hair monofilaments. Consistent with previously ...

Tactile Semiautomatic Passive-Finger Angle Stimulator (TSPAS)

Passive tactile perception is the ability to passively and statically perceive stimulus information coming from the skin; for example, the ability to sense spatial information is the strongest in the skin on the hands. This ability is termed tactile spatial acuity, and is measured by the tactile threshold or discrimination threshold. At present, the two-point threshold is extensively used as a measure of tactile spatial acuity, although many studies have indicated that critical deficits exist in two-point discrimination. Therefore, a computer-controlled tactile stimulus system was developed, the tactile semiautomated passive-finger angle stimulator (TSPAS), using the tactile angle discrimination threshold as a new measure for tactile spatial acuity. The TSPAS is a simple, easily operated system that applies raised angle stimuli to a subject&#39;s passive fingerpad, while controlling movement speed, distance, and contact duration. The components of the TSPAS are described in detail as well as the procedure to calculate the tactile angle discrimination threshold.

Tactile Semiautomatic Passive-Finger Angle Stimulator TSPAS

Presented is the tactile semiautomated passive-finger angle stimulator TSPAS, a new way to assess tactile spatial acuity and tactile angle discrimination using a computer-controlled tactile stimulus system that applies raised angle stimuli to a subject&#39;s passive fingerpad, while controlling for movement speed, distance, and contact duration.

Passive tactile perception is the ability to passively and statically perceive stimulus information coming from the skin; for example, the ability to ...

An Automated Assessment of Visual Acuity in Infants and Toddlers

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Visual acuity measurement is an important visual function test to perform in infancy and childhood. However, accurate visual acuity measurement in infants is difficult because of deficiencies in their communication ability. This paper presents a novel automated method to assess visual acuity in children (5-36 months old). This method, the automated acuity card procedure (AACP), uses a webcam for eye tracking and recognizes children's watching behaviors automatically. A two-choice preferential-looking test is performed when the tested child watches the visual stimuli shown on a high-resolution digital display screen. When the tested child watches the stimuli, their facial pictures are recorded by the webcam. These pictures are used by the set computer program to analyze their watching behavior. With this procedure, the child's eye movement responses to different stimuli are measured, and their visual acuity is assessed without communication. By comparing the results with grating acuity obtained by Teller Acuity Cards (TACs), AACP performance is deemed comparable to that of TACs.

Author Spotlight: An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System  

In this paper, we present a novel automated method for assessing visual acuity in infants and toddlers by using an eye-tracking system.

Visual acuity measurement is an important visual function test to perform in infancy and childhood. However, accurate visual acuity measurement in infants ...

New Methods to Study Gustatory Coding

The sense of taste allows animals to detect chemicals in the environment, giving rise to behaviors critical for survival. When Gustatory Receptor Neurons (GRNs) detect tastant molecules, they encode information about the identity and concentration of the tastant as patterns of electrical activity that then propagate to follower neurons in the brain. These patterns constitute internal representations of the tastant, which then allow the animal to select actions and form memories. The use of relatively simple animal models has been a powerful tool to study basic principles in sensory coding. Here, we propose three new methods to study gustatory coding using the moth Manduca sexta. First, we present a dissection procedure for exposing the maxillary nerves and the subesophageal zone (SEZ), allowing recording of the activity of GRNs from their axons. Second, we describe the use of extracellular electrodes to record the activity of multiple GRNs by placing tetrode wires directly into the maxillary nerve. Third, we present a new system for delivering and monitoring, with high temporal precision, pulses of different tastants. These methods allow the characterization of neuronal responses in vivo directly from GRNs before, during and after tastants are delivered. We provide examples of voltage traces recorded from multiple GRNs, and present an example of how a spike sorting technique can be applied to the data to identify the responses of individual neurons. Finally, to validate our recording approach, we compare extracellular recordings obtained from GRNs with tetrodes to intracellular recordings obtained with sharp glass electrodes.

We present three new methods to study gustatory coding. Using a simple animal, the moth Manduca sexta (Manduca), we describe a dissection protocol, the use of extracellular tetrodes to record the activity of multiple gustatory receptor neurons, and a system for delivering and monitoring precisely timed pulses of tastants.

The sense of taste allows animals to detect chemicals in the environment, giving rise to behaviors critical for survival. When Gustatory Receptor Neurons ...

Neuroscience

In Vivo Evaluation of the Mechanical and Viscoelastic Properties of the Rat Tongue

The tongue is a highly innervated and vascularized muscle hydrostat on the floor of the mouth of most vertebrates. Its primary functions include supporting mastication and deglutition, as well as taste-sensing and phonetics. Accordingly, the strength and volume of the tongue can impact the ability of vertebrates to accomplish basic activities such as feeding, communicating, and breathing. Human patients with sleep apnea have enlarged tongues, characterized by reduced muscle tone and increased intramuscular fat that can be visualized and quantified by magnetic resonance imaging (MRI). The abilities to measure force generation and viscoelastic properties of the tongue constitute important tools for obtaining functional information to correlate with imaging data. Here, we present techniques for measuring tongue force production in anesthetized Zucker rats via electrical stimulation of the hypoglossal nerves and for determining the viscoelastic properties of the tongue by applying passive Lissajous force/deformation curves.

In Vivo Evaluation of the Mechanical and Viscoelastic Properties of the Rat Tongue

We describe a surgical procedure in an anesthetized rat model for determining the muscle tone and viscoelastic properties of the tongue. The procedure involves specific stimulation of the hypoglossal nerves and application of passive Lissajous force/deformation curves to the muscle.

The tongue is a highly innervated and vascularized muscle hydrostat on the floor of the mouth of most vertebrates. Its primary functions include ...

Medicine

Taste Exam: A Brief and Validated Test

The emerging importance of taste in medicine and biomedical research, and new knowledge about its genetic underpinnings, has motivated us to supplement classic taste-testing methods in two ways. First, we explain how to do a brief assessment of the mouth, including the tongue, to ensure that taste papillae are present and to note evidence of relevant disease. Second, we draw on genetics to validate taste test data by comparing reports of perceived bitterness intensity and inborn receptor genotypes. Discordance between objective measures of genotype and subjective reports of taste experience can identify data collection errors, distracted subjects or those who have not understood or followed instructions. Our expectation is that fast and valid taste tests may persuade researchers and clinicians to assess taste regularly, making taste testing as common as testing for hearing and vision. Finally, because many tissues of the body express taste receptors, taste responses may provide a proxy for tissue sensitivity elsewhere in the body and, thereby, serve as a rapid, point-of-care test to guide diagnosis and a research tool to evaluate taste receptor protein function.

This protocol measures human taste responses and includes a brief anatomical assessment, a short taste test, and a validation method using the subject&#39;s reported sensation and taste receptor genotype.

The emerging importance of taste in medicine and biomedical research, and new knowledge about its genetic underpinnings, has motivated us to supplement ...

Testing of all Six Semicircular Canals with Video Head Impulse Test Systems

Throughout the last decade, there has been a rapid development of existing test procedures and methods evaluating the human vestibular system. In 2009 and 2013, commercially available video Head Impulse Testing (vHIT) has enabled clinicians to examine the function of all three paired semicircular canals within the vestibular system. The vHIT test has revolutionized vestibular testing and, at many clinics and hospitals around the world, this test is now considered the most important initial test of vertiginous patients. There are several manufacturers of vHIT systems around the world. A test protocol for two of the most widespread vHIT systems, EyeSeeCam and ICS Impulse, will be presented. Included in this protocol is a description of the two different test methods termed 2D vHIT testing and 3D vHIT testing. The vHIT system includes a lightweight goggle with accompanying software. The test is fast (5-10 min) and can be done with minimal discomfort to the person being examined. However, there are many steps of the test, and each of these steps may alter the final test results, if the individual steps of the test are not performed correctly. It is therefore of paramount importance that the examiner is familiar with the potential noise and/or artifact triggers. Systematic training of future examiners before performing vHIT in a clinical setting and compliance with this protocol may minimize these challenges of the test. The vHIT test is not just a &#8220;plug and play&#8221; test. However, if carried out correctly, this test offers excellent objective assessment of the function of the high frequency domain of the vestibular system. It has a very high positive predictive value and offers a specificity very close to one hundred percent.

This protocol describes how to correctly perform the video head impulse test with two separate test systems commonly used worldwide. Both the 2D and 3D video head impulse test methods are described.

Throughout the last decade, there has been a rapid development of existing test procedures and methods evaluating the human vestibular system. In 2009 and ...

Assessment of Static Graviceptive Perception in the Roll-Plane using the Subjective Visual Vertical Paradigm

Vestibular disorders are among the most common syndromes in medicine. In recent years, new vestibular diagnostic systems have been introduced that allow the examination of all semicircular canals in the clinical setting. Assessment methods of the otolithic system, which is responsible for the perception of linear acceleration and perception of gravity, are far less in clinical use. There are several experimental approaches for measuring the perception of gravity. The most frequently used method is the determination of the subjective visual vertical. This is usually measured with the head in an upright position. We present here an assessment method for testing otolith function in the roll plane. The subjective visual vertical is measured in the head upright position as well as with head inclination of &#177; 15&#176; and &#177; 30&#176; in the roll plane. This extended functional paradigm is an easy-to-perform clinical test of otolith function and ensures increased information content for the detection of impaired graviceptive perception.

The perception of gravity is commonly determined by the subjective visual vertical in the head upright position. The additional assessment at head tilts of &#177; 15&#176; and &#177; 30&#176; in the roll plane ensures increased information content for the detection of impaired graviceptive perception.

Vestibular disorders are among the most common syndromes in medicine. In recent years, new vestibular diagnostic systems have been introduced that allow ...

Assessment of Spatial Lingual Tactile Sensitivity using a Gratings Orientation Test

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