The project described was supported by the National Center for Research Resources, Grant UL1 RR024975-01, and is now at the National Center for Advancing Translational Sciences, Grant 2 UL1 TR000445-06. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

1. Assessment of Response to Light Touch
<ol>
	<li>Place the electrode net (e.g.&#160;128-channels geodesic sensor net) on child or infant&#39;s head. Adjust sensors for full contact using warm saline solution. If on a child, ensure child is sitting comfortably in parent or caregiver lap. If on an infant, ensure that infant is lightly swaddled and either held in caregiver&#39;s arms or in a supine position in an open crib.</li>
	<li>Position a 1 mm nozzle 0.5 cm below the tip of the index finger of the tested hand. Place finger for a young child or palm for an infant in a mold holder and secure with Velcro tape proximal and distal to joint to ensure consistent distance from nozzle to the finger or hand. It is absolutely essential that the child maintains the proper finger position throughout the testing session. Ensure this by periodically assessing finger and hand placement and having child with caregiver if young. If testing an infant, stop protocol if infant cries and provide comfort before restarting. If testing young child, ask caregiver to provide comfort and reassurance throughout the short testing period.</li>
	<li>Start air compressor at 40 psi through regulator to supply valve inputs for tactile stimuli.</li>
	<li>Run stimulus delivery program.
	<ol>
		<li>For the tested hand, present 60 puff stimuli randomly interspersed with 60 sham trials (an air puff delivered via a separate nozzle pointed away from the finger).</li>
		<li>Do not present more than two repetitions of a puff or sham in a row. Vary the inter-trial intervals randomly between 2,000-2,500 msec. The purpose of this is to reduce habituation, where a stimulus is no longer perceived. The total time for a sequence of 120 trials should be 4.5-5 min.</li>
		<li>Run the identical protocol again for the other hand if studying asymmetrical somatosensory disorders.</li>
	</ol>
	</li>
	<li>For protocols not requiring attention to stimulus no further set up is needed. This applies to infant testing. For enhancement of attention in young children (which results in larger specific ERP peaks in recording), provide a task.
	<ol>
		<li>Task example for 5-year-olds: Describe air puffs as &#34;bubbles&#34; blown by &#34;fish&#34; in a &#34;fish tank&#34; (a decorated box concealing the puffer apparatus). Ask children to guess whether each &#34;bubble&#34; is delivered by a blue or a red &#34;fish&#34;. Tell the child that they do not need to and should not say anything while they are performing this task (see set up with mock aquarium in Figure 1).</li>
	</ol>
	</li>
</ol>
2. Assessment of Response to Multisensory Protocol (Auditory-tactile Simultaneous vs. Summed Individual Responses)
<ol>
	<li>Run through steps 1.1-1.3 as described above. Stimuli are described in Table 1.</li>
	<li>Run the stimulus delivery program (e.g.&#160;in E-Prime software). For the tested hand, an auditory-tactile paradigm can present the following 4 stimuli randomly, with 60 trials/ stimulus: puff , puff-/ga/, /ga/-sham, sham. Again, to limit the possibility of habituation, do not present more than two repetitions of a puff or sham in a row in any condition, and vary the inter-trial intervals randomly between 2,000-2,500 msec. Each sequence of 240 trials should take between 9-10 min.</li>
	<li>Run identical protocol over for the other hand.</li>
	<li>Provide a soundless age-appropriate cartoon at initiation of protocol and continue it throughout the procedure to prevent increase in motor artifacts from restlessness, and to decrease the background from large patient-generated delta waves when they are bored. For example, in 5-year olds, we used a loop of 20 min&#160;of a purchased video, played on mute and restarted before each subject was tested. No attention to stimulus is needed, therefore the looped cartoon provides a visual background disconnected from the stimuli.</li>
</ol>
3. Software and Equipment Set Up
<ol>
	<li>To program the software, set up two serial commands sent by the stimulus control application. One identifies the puff, the other the sham. Have the stimulus control application send the commands to a microcontroller.</li>
	<li>Have the microcontroller generate a TTL pulse (e.g. 20 msec duration) to the corresponding digital output channel. This output must be split into two lines, one for the digital input to the EEG recording system and one to the solenoid-gated air valves. Mark the opening of both valves in the EEG data stream.</li>
	<li>Measure the pulse to puff latency for both real and sham conditions with an oscilloscope and a microphone. These should be uniform, and in the order of 10-15 msec. Adjust for the latency post-recording.</li>
	<li>Calculate the force exerted at the nozzle in PSI using a manometer and by measuring the nozzle diameter. Use the formula F(N) = Pressure*Area. For example, the force exerted from a 1 mm radius nozzle at 6 psi yields F(N) = 0.03 lbs.</li>
	<li>To modify the control application for the multisensory protocol, send two serial commands identifying a real puff or sham to the microcontroller as well as a recorded speech sound or silence. Note: In our paradigm we have used the computer generated, accent-neutral /ga/ sound, among others such as /da/, /du/, /bu/, etc.</li>
	<li>Present auditory stimuli through a speaker placed at midline, 2 ft in front of the subject.</li>
	<li>Align the sound onset timing to be simultaneous with the onset of the puff or with the delay measured in step 3.3, depending on which condition is desirable to the tester.</li>
</ol>
4. Data Acquisition and Preparation
<ol>
	<li>Choose filters and references settings to sample data based on standard ERP methodologies. Here, use a 1,000 Hz with filters set to 0.1-400 Hz. During data collection, refer all electrodes to Cz and rereferenced them offline to an average reference.</li>
	<li>To segment the data, filter the recorded data with desired filters and segmenting. For this study use a 0.3-40 Hz bandpass filter and segment the ongoing EEG based on the stimulus onset to include a 200 msec prestimulus baseline and a 500 msec post-stimulus interval.</li>
	<li>Perform quality control of the data. Screen each segment for motor and ocular artifacts such as high frequency muscle activity, using computer algorithms included in the ERP software. Follow this screen by a manual review.</li>
	<li>The automated screening criteria are set as follows in this protocol but can be modified: for eye channels, voltage &#62;140 &#181;V = eye blink and voltage &#62;55 &#181;V = eye movements.</li>
	<li>Correct data from contaminated trials using an ocular artifact correction tool. Note: Any channel with voltage &#62;200 &#181;V is considered of poor quality. If &#62;15 channels are of poor quality, we chose to discard the entire trial for reproducibility reasons.</li>
	<li>Average ERPs. Rereference them to an average reference and then perform baseline-correction based on criteria chosen in step 4.2. Extract mean amplitude and peak latencies for various peaks, extrapolated from grand average waveforms of predefined populations. Note: In our case, we based the following on established literature of older children&#39;s response to median nerve stimulation10-14. We used P50 (30-80 msec), N70 (50-100 msec), P100 (80-150 msec), N140 (130-230 msec), and P2 (250-350 msec) peaks.</li>
	<li>Include only data from electrodes overlapping preset locations (Figure 2). Derive data for individual electrodes and average within each cluster.</li>
</ol>

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The authors declare that they have no competing financial interests.

This novel combination of air puff and ERP (referred to as the &#34;Puffer system&#34;) to measure cortical processing of light touch and tactile-auditory responses is well tolerated by young children with disabilities and by infants. This holds true for unisensory and multisensory versions, and whether the attentional component is added or not in the case of young children. The reasons for the success of this methodology in assessing a young and vulnerable population are due to both the use of an innocuous tactile stimu...

The study of developing cortical sensory processes is essential to understanding the basis for most higher order functions. Sensory experiences are responsible for much of the brain&#39;s organization through infancy and childhood, laying the foundation for complex processes such as cognition, communication, and motor development1-3. Most pediatric studies of sensory processes focus on auditory and visual domains, mainly because these stimuli are easiest to develop, standardize, and test. However, tactile processing is of particular interest in infants and children as it is the first sense to develop in the fetus4,5, and somatosensory information is integral to the function of other cortical systems (e.g. motor, memory, associative learning, limbic)6. Current methods assessing somatosensory processing are limited by the choice of tactile stimulus. A common choice is direct electrical median nerve stimulation7,8, with the potential for discomfort. Other effective methods use active tasks such as discrimination, recognition, and localization of stimuli, requiring both attention and high levels of comprehension9. All of these methods are therefore limited in their use in young children and infants.
Therefore, our goal was to develop a tactile paradigm that addresses these limitations by being noninvasive and reducing the need for a subject&#39;s active participation. Additionally, it needed to have a standardized level of stimulation and a sham-control. For this we developed the &#34;puffer&#34; system, a dual-channel, timed, and calibrated air-puff delivery system, allowing us to measure the effects of light touch in infants and other vulnerable populations.
Functional MRI studies showed that stimulation by puffs of air activates sensory cortices, although the length and challenges of such studies, such as immobilization, lengthy sessions, and anxiety-provoking settings make them difficult to perform in young children. Therefore, we combined our novel delivery system with Event-Related Potential (ERP) methodology in order to provide temporal resolution of sensory processing of light touch in a brief, child-friendly testing session.
This new paradigm offers the needed flexibility to study sensory processing in diverse populations, ages and clinical settings. It also has the advantage of being compatible with auditory stimuli, allowing for multisensory assessments. Until now, accurate and reliable tactile assessment has not been possible in infants or in children who are unable to reliably respond due to intellectual/language disorders. This methodology aims to fill this gap&#160;in order to aid in early identification of sensory processing deficits and intervention during a period of maximal brain plasticity. Improvements in sensory processing in infancy may influence the cascade of neurodevelopmental
The following procedures are all included in Vanderbilt Institutional Review Board approved protocols.

<table><tbody><tr><td>Geodesic sensor net</td><td>EGI, Inc., Eugene, OR</td><td>depends on size</td><td></td></tr><tr><td>Net Station EEG software v. 4.2</td><td>EGI, Inc., Eugene, OR</td><td>NA</td><td></td></tr><tr><td>E-Prime stimulus control application</td><td>PST, Inc. Pittsburgh, PA</td><td>NA</td><td></td></tr><tr><td>Manometer (model 6 in, 0-60 psi)</td><td>H. O. Trerice Co, Oak Park, MI</td><td></td><td></td></tr><tr><td>Custom Puffer setup</td><td>Nathalie Maitre</td><td></td><td></td></tr></tbody></table>

quantitative assessment of cortical auditory-tactile processing in children with disabilities

Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology to quantitatively assess children&#39;s cortical processing of light touch, speech sounds and the multisensory processing of the 2 stimuli, without requiring active subject participation or causing children discomfort. To accomplish this we developed a dual channel, time and strength calibrated air puff stimulator that allows both tactile stimulation and sham control. We combined this with the use of event-related potential methodology to allow for high temporal resolution of signals from the primary and secondary somatosensory cortices as well as higher order processing. This methodology also allowed us to measure a multisensory response to auditory-tactile stimulation.

Assessment of light touch (Figure 3): 
Characteristics of the cortical response to tactile stimulation using the Puffer system: The patterns of peaks in response to the puff are very similar to the cortical responses obtained using median nerve stimulation in normal adults10,11. The early response (P50, N70, P100 peaks) primarily reflects activity in the primary sensory cortex12 and does not require awareness of stimulation....

Watch this Scientific Journal Video about Quantitative Assessment of Cortical Auditory-tactile Processing in Children with Disabilities at JoVE.com

Quantitative Assessment of Cortical Auditory-tactile Processing in Children with Disabilities

Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology to quantitatively assess infants and children&#39;s cortical processing of light touch, speech sounds, and the multisensory processing of the 2 stimuli, without requiring active subject participation or causing discomfort in vulnerable patients.

Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology ...

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10.7K Views.  Vanderbilt University. Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology to quantitatively assess infants and children's cortical processing of light touch, speech sounds, and the multisensory processing of the 2 stimuli, without requiring active subject participation or causing discomfort in vulnerable patients.

Video: Quantitative Assessment of Cortical Auditory-tactile Processing in Children with Disabilities

Cortical Source Analysis of High-Density EEG Recordings in Children

EEG is traditionally described as a neuroimaging technique with high temporal and low spatial resolution. Recent advances in biophysical modelling and signal processing make it possible to exploit information from other imaging modalities like structural MRI that provide high spatial resolution to overcome this constraint1. This is especially useful for investigations that require high resolution in the temporal as well as spatial domain. In addition, due to the easy application and low cost of EEG recordings, EEG is often the method of choice when working with populations, such as young children, that do not tolerate functional MRI scans well. However, in order to investigate which neural substrates are involved, anatomical information from structural MRI is still needed. Most EEG analysis packages work with standard head models that are based on adult anatomy. The accuracy of these models when used for children is limited2, because the composition and spatial configuration of head tissues changes dramatically over development3.&#160;
In the present paper, we provide an overview of our recent work in utilizing head models based on individual structural MRI scans or age specific head models to reconstruct the cortical generators of high density EEG. This article describes how&#160;EEG recordings are acquired, processed, and analyzed with pediatric populations at the London Baby Lab, including laboratory setup, task design, EEG preprocessing, MRI processing, and EEG channel level and source analysis.&#160;

In recent years, there has been increasing interest in estimating the cortical sources of scalp measured electrical activity for cognitive neuroscience experiments. This article describes how high density EEG is acquired and how recordings are processed for cortical source estimation in children from the age of 2 years at the London Baby Lab.

EEG is traditionally described as a neuroimaging technique with high temporal and low spatial resolution. Recent advances in biophysical modelling and ...

Practical Methodology of Cognitive Tasks Within a Navigational Assessment

This paper describes an approach for measuring navigation accuracy relative to cognitive skills. The methodology behind the assessment will thus be clearly outlined in a step-by-step manner. Navigational skills are important when trying to find symbols within a speech-generating device (SGD) that has a dynamic screen and taxonomical organization. The following skills have been found to impact children&#8217;s ability to find symbols when navigating within the levels of an SGD: sustained attention, categorization, cognitive flexibility, and fluid reasoning1,2. According to past studies, working memory was not correlated with navigation1,2.
The materials needed for this method include a computerized tablet, an augmentative and alternative communication application, a booklet of symbols, and the Leiter International Performance Scale-Revised (Leiter-R)3. This method has been used in two previous studies. Robillard, Mayer-Crittenden, Roy-Charland, Minor-Corriveau and B&#233;langer1 assessed typically developing children, while Rondeau, Robillard and Roy-Charland2 assessed children and adolescents with a diagnosis of Autism Spectrum Disorder. The direct observation of this method will facilitate the replication of this study for researchers. It will also help clinicians that work with children who have complex communication needs to determine the children&#8217;s ability to navigate an SGD with taxonomical categorization.

Children who have complex communication needs can benefit from the use of a speech-generating device (SGD). Cognitive skills were identified as having an impact on the ability to navigate between levels of SGDs. This protocol describes the steps needed for Speech-language Pathologists to assess cognitive skills and navigational abilities.

This paper describes an approach for measuring navigation accuracy relative to cognitive skills. The methodology behind the assessment will thus be ...

Infant Auditory Processing and Event-related Brain Oscillations

Rapid auditory processing and acoustic change detection abilities play a critical role in allowing human infants to efficiently process the fine spectral and temporal changes that are characteristic of human language. These abilities lay the foundation for effective language acquisition; allowing infants to hone in on the sounds of their native language. Invasive procedures in animals and scalp-recorded potentials from human adults suggest that simultaneous, rhythmic activity (oscillations) between and within brain regions are fundamental to sensory development; determining the resolution with which incoming stimuli are parsed. At this time, little is known about oscillatory dynamics in human infant development. However, animal neurophysiology and adult EEG data provide the basis for a strong hypothesis that rapid auditory processing in infants is mediated by oscillatory synchrony in discrete frequency bands. In order to investigate this, 128-channel, high-density EEG responses of 4-month old infants to frequency change in tone pairs, presented in two rate conditions (Rapid: 70 msec ISI and Control: 300 msec ISI) were examined. To determine the frequency band and magnitude of activity, auditory evoked response averages were first co-registered with age-appropriate brain templates. Next, the principal components of the response were identified and localized using a two-dipole model of brain activity. Single-trial analysis of oscillatory power showed a robust index of frequency change processing in bursts of Theta band (3 - 8 Hz) activity in both right and left auditory cortices, with left activation more prominent in the Rapid condition. These methods have produced data that are not only some of the first reported evoked oscillations analyses in infants, but are also, importantly, the product of a well-established method of recording and analyzing clean, meticulously collected, infant EEG and ERPs. In this article, we describe our method for infant EEG net application, recording, dynamic brain response analysis, and representative results.

High-density electroencephalography (dEEG) is being used increasingly to study brain development and plasticity in the early years of life. Here we present an application of sophisticated analysis techniques that builds on traditional EEG recording to understand the oscillatory dynamics of rapid auditory processing in the infant brain.

Rapid auditory processing and acoustic change detection abilities play a critical role in allowing human infants to efficiently process the fine spectral ...

Testing Sensory and Multisensory Function in Children with Autism Spectrum Disorder

In addition to impairments in social communication and the presence of restricted interests and repetitive behaviors, deficits in sensory processing are now recognized as a core symptom in autism spectrum disorder (ASD). Our ability to perceive and interact with the external world is rooted in sensory processing. For example, listening to a conversation entails processing the auditory cues coming from the speaker (speech content, prosody, syntax) as well as the associated visual information (facial expressions, gestures). Collectively, the &#8220;integration&#8221; of these multisensory (i.e., combined audiovisual) pieces of information results in better comprehension. Such multisensory integration has been shown to be strongly dependent upon the temporal relationship of the paired stimuli. Thus, stimuli that occur in close temporal proximity are highly likely to result in behavioral and perceptual benefits &#8211; gains believed to be reflective of the perceptual system&#39;s judgment of the likelihood that these two stimuli came from the same source. Changes in this temporal integration are expected to strongly alter perceptual processes, and are likely to diminish the ability to accurately perceive and interact with our world. Here, a battery of tasks designed to characterize various aspects of sensory and multisensory temporal processing in children with ASD is described. In addition to its utility in autism, this battery has great potential for characterizing changes in sensory function in other clinical populations, as well as being used to examine changes in these processes across the lifespan.

We describe how to implement a battery of behavioral tasks to examine the processing and integration of sensory stimuli in children with ASD. The goal is to characterize individual differences in temporal processing of simple auditory and visual stimuli and relate these to higher order perceptual skills like speech perception.

In addition to impairments in social communication and the presence of restricted interests and repetitive behaviors, deficits in sensory processing are ...

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 ...

Event-related Potentials During Target-response Tasks to Study Cognitive Processes of Upper Limb Use in Children with Unilateral Cerebral Palsy

Unilateral Cerebral Palsy (CP) is a neurodevelopmental disorder that is a very common cause of disability in childhood. It is characterized by unilateral motor impairments that are frequently dominated in the upper limb. In addition to a reduced movement capacity of the affected upper limb, several children with unilateral CP show a reduced awareness of the remaining movement capacity of that limb. This phenomenon of disregarding the preserved capacity of the affected upper limb is regularly referred to as Developmental Disregard (DD). Different theories have been postulated to explain DD, each suggesting slightly different guidelines for therapy. Still, cognitive processes that might additionally contribute to DD in children with unilateral CP have never been directly studied. The current protocol was developed to study cognitive aspects involved in upper limb control in children with unilateral CP with and without DD. This was done by recording event-related potentials (ERPs) extracted from the ongoing EEG during target-response tasks asking for a hand-movement response. ERPs consist of several components, each of them associated with a well-defined cognitive process (e.g., the N1 with early attention processes, the N2 with cognitive control and the P3 with cognitive load and mental effort). Due to its excellent temporal resolution, the ERP technique enables to study several covert cognitive processes preceding overt motor responses and thus allows insight into the cognitive processes that might contribute to the phenomenon of DD. Using this protocol adds a new level of explanation to existing behavioral studies and opens new avenues to the broader implementation of research on cognitive aspects of developmental movement restrictions in children.

Several children with unilateral Cerebral Palsy seem to disregard the preserved capacity of their affected upper limb. This Developmental Disregard is extensively described in the literature but the involved cognitive processes have not been studied. To study underlying cognitive factors of upper limb control, an event-related potential protocol was developed.

Unilateral Cerebral Palsy (CP) is a neurodevelopmental disorder that is a very common cause of disability in childhood. It is characterized by unilateral ...

Behavioral Assessment of Hearing in 2 to 4 Year-old Children: A Two-interval, Observer-based Procedure Using Conditioned Play-based Responses

Collecting reliable behavioral data from toddlers and preschoolers is challenging. As a result, there are significant gaps in our understanding of human auditory development for these age groups. This paper describes an observer-based procedure for measuring hearing sensitivity with a two-interval, two-alternative forced-choice paradigm. Young children are trained to perform a play-based, motor response (e.g., putting a block in a bucket) whenever they hear a target signal. An experimenter observes the child&#39;s behavior and makes a judgment about whether the signal was presented during the first or second observation interval; the experimenter is blinded to the true signal interval, so this judgment is based solely on the child&#39;s behavior. These procedures were used to test 2 to 4 year-olds (n = 33) with no known hearing problems. The signal was a 1,000 Hz warble tone presented in quiet, and the signal level was adjusted to estimate a threshold corresponding to 71%-correct detection. A valid threshold was obtained for 82% of children. These results indicate that the two-interval procedure is both feasible and reliable for use with toddlers and preschoolers. The two-interval, observer-based procedure described in this paper is a powerful tool for evaluating hearing in young children because it guards against response bias on the part of the experimenter.

This paper describes a procedure for measuring hearing sensitivity in 2 to 4 year-old children. Children are trained to perform play-based responses when they hear a target signal. Thresholds are then estimated in a two-interval, two-alternative forced-choice paradigm, based on observations of the child&#39;s behaviors.

Collecting reliable behavioral data from toddlers and preschoolers is challenging. As a result, there are significant gaps in our understanding of human ...

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.

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 ...

Sound Source Localization Testing in Single-sided Deafness Following Bone Conduction Intervention

Single-sided deafness (SSD), where there is severe to profound hearing loss in one ear and normal hearing in the other, is a prevalent auditory condition that significantly impacts the quality of life for those affected. The ability to accurately localize sound sources is crucial for various everyday activities, including speech communication and environmental awareness. In recent years, bone conduction intervention has emerged as a promising solution for patients with SSD, offering a non-invasive alternative to traditional air conduction hearing aids. However, the effectiveness of bone conduction devices (BCDs), especially in terms of improving sound localization abilities, remains a topic of considerable interest.
Here, we present a protocol to assess the impact of bone conduction intervention on sound localization ability in patients with SSD. The protocol includes the experimental setup (a sound-treated room and a semicircular array of loudspeakers), stimuli, and data analysis methods. Participants indicate the perceived direction of noise bursts, and their responses are analyzed using root mean square error (RMSE) and bias. The results of sound localization testing before and after bone conduction intervention are reported and compared. Despite no significant differences, most patients (71%) had a localization bias clearly toward the intervention side after bone conduction intervention. The study concludes that bone conduction intervention can promptly enhance certain sound localization skills in patients with SSD, offering evidence to support the efficacy of BCDs as a treatment for SSD.

We present a protocol to evaluate the impact of bone conduction intervention on sound localization ability in patients with single-sided deafness (SSD). This protocol can be applied to assess the efficacy of bone conduction devices in restoring sound localization abilities and improving the overall quality of life for individuals with SSD.

Single-sided deafness (SSD), where there is severe to profound hearing loss in one ear and normal hearing in the other, is a prevalent auditory condition ...

Assessment of Audio-Tactile Sensory Substitution Training in Participants with Profound Deafness Using the Event-Related Potential Technique

This paper examines the application of electroencephalogram-based methods to assess the effects of audio-tactile substitution training in young, profoundly deaf (PD) participants, with the aim of analyzing the neural mechanisms associated with vibrotactile complex sound discrimination. Electrical brain activity reflects dynamic neural changes, and the temporal precision of event-related potentials (ERPs) has proven to be key in studying time-locked processes while performing behavioral tasks that involve attention and working memory. 
The current protocol was designed to study electrophysiological activity in PD subjects while they performed a continuous performance task (CPT) using complex-sound stimuli, consisting of five different animal sounds delivered through a portable stimulator system worn on the right index finger. As a repeated-measures design, electroencephalogram (EEG) recordings in standard conditions were performed before and after a brief training program (five 1 h sessions over 15 days), followed by offline artifact correction and epoch averaging, to obtain individual and grand-mean waveforms. Behavioral results show a significant improvement in discrimination and a more robust P3-like centroparietal positive waveform for the target stimuli after training. In this protocol, ERPs contribute to the further understanding of learning-related neural changes in PD subjects associated with audio-tactile discrimination of complex sounds.

This protocol is designed to explore underlying learning-related electrophysiological changes in subjects with profound deafness after a short training period in audio-tactile sensory substitution by applying the event-related potential technique.