Here we present a protocol for acquiring and recording electroencephalographic (EEG) signals from neurodivergent children before, during, and after participating in dolphin-assisted therapy (DAT) sessions.
Method Article
Here we present a protocol for acquiring and recording electroencephalographic (EEG) signals from neurodivergent children before, during, and after participating in dolphin-assisted therapy (DAT) sessions.
This protocol details the essential steps for acquiring and recording electroencephalographic (EEG) signals in neurodivergent children before, during, and after participating in Dolphin-Assisted Therapy (DAT) sessions. Its main objective is to provide consistent and reliable data that allow for an accurate assessment of brain activity at various stages of the therapeutic process. The protocol establishes a clear framework for comparing the obtained EEG signals, ensuring that each recording meets the standards required for effective analysis and interpretation. To this end, a comprehensive approach is used that combines electronic tools and mathematical methods, such as power spectral analysis, to identify changes in children's brain activity during the intervention. Furthermore, the replicability of the results is ensured, favoring validity and consistency in scientific studies related to the therapy. This protocol, by standardizing data acquisition, seeks to optimize therapeutic outcomes and provide a solid basis for comparing different studies on the impact of DAT on childhood neurodiversity. Furthermore, it provides a robust system for future research, facilitating objective interpretation of therapy effects and improving interventions.
The cultural differences between various human groups largely depend on their cognitive abilities. While some individuals can adapt to these cultural norms, others often face marginalization. Therefore, it is essential for these individuals to participate in sessions that promote their integration into human society1.
Children with neurodevelopmental disorders, such as attention deficit hyperactivity disorder (ADHD) or autism spectrum disorder (ASD), often require a combination of physical and alternative therapies for comprehensive and effective rehabilitation2,3. It is important to note that, in addition to conventional therapies, alternative therapies have been developed to holistically address the physical, emotional, and spiritual aspects of patients. These therapies aim to complement traditional approaches and promote a more complete recovery2,4. When recommended by health professionals, these therapies can serve as valuable complements to conventional medicine3.
One alternative therapy that has garnered increasing public interest due to its advancements in pain relief and improvement in learning skills in children with disabilities is Dolphin-Assisted Therapy (DAT)5. This therapy leverages the interaction between humans and dolphins, typically pregnant or nursing bottlenose dolphins, in an aquatic environment to improve the quality of life of children with different abilities.
Currently, DAT lacks a fully standardized method, as variations have been observed in the processes applied to patients, therapists and/or specialists involved, session duration and frequency, as well as the type of dolphin and its training to achieve therapeutic effects6,7,8. According to Jette et al.9, the standardization of these therapies enhances data collection for research, as consistent data collection allows for comparative studies and the development of new evidence-based therapeutic strategies.
The absence of a standardized data capture system in DAT complicates the objective evaluation of its effects, limiting the comparability of results across studies. Despite the growing popularity of DAT, the methodological framework used to monitor patient changes varies considerably depending on the institution and research team, resulting in inconsistent and even contradictory outcomes10,11.
This variability has raised concerns within the scientific community, as there are no reliable parameters to measure therapeutic efficacy in terms of cognitive, emotional, or behavioral improvements in patients12. The lack of standards also affects the development of rigorous protocols, potentially leading to biased interpretations of results obtained in different DAT studies.
Variability in electroencephalographic (EEG) signal acquisition procedures, such as electrode placement, equipment calibration, and environmental conditions, can introduce inconsistencies in the results, complicating the interpretation of therapeutic effects and comparisons across studies13,14. Therefore, it is essential to standardize the data capture process for EEG signals in these therapies to obtain more accurate and reliable data, thereby contributing to the optimization of therapeutic practices and providing solid evidence of the effectiveness of DAT.
A standardized protocol promotes greater transparency in studies. When uniform methods are used, data and procedures can be shared more openly and effectively, allowing other researchers to verify and validate results. This is particularly important in emerging or underexplored fields, where researchers heavily rely on the replication and validation of previous studies to advance the understanding of the subject15.
A standardized data capture system, particularly one based on the use of neurophysiological tools such as electroencephalography, could provide more accurate data on the effects of DAT on the brain activity of neurodivergent patients. Although EEG is a non-invasive and widely used method to study brain activity, its application in monitoring alternative therapies remains inconsistent, affecting the reliability and validity of the data obtained16.
Alternative therapies, such as DAT, offer researchers an opportunity to explore the effects of treatments on patients' brains by analyzing brain signals like EEG, combined with mathematical techniques and artificial intelligence tools to assess the efficacy and efficiency of various interventions.
This study, therefore, describes a proposed testing protocol to evaluate treatment outcomes in México for children diagnosed with neurodevelopmental disorders, incorporating DAT. This proposal was carefully developed in collaboration with Delfiniti México, specialists in human-dolphin interaction, focusing not only on swimming activities but also on dolphin-mediated therapeutic interventions.
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NOTE: The methodology used in this research was approved by the Ethics Committee of the National Polytechnic Institute of México in accordance with the Confidentiality Commitment Letter D/1477/2020. This document endorses the sample collection method and the ethical treatment provided to the bottlenose dolphins by the research team. The responsible use of participant data was ensured, and their consent was obtained for the use of the data in the experiments. Prior to sample collection and device connection, the procedure was thoroughly explained to the participants, who were free to withdraw from the study if they disagreed. Those who agreed to participate signed a written informed consent form. Additionally, participants were informed about the tests to be conducted; however, some did not fully understand the procedures before entering the tank with the cetaceans.
NOTE: This protocol outlines the detailed steps for acquiring and recording electroencephalographic (EEG) signals from neurodiverse children before, during, and after participating in Dolphin-Assisted Therapy (DAT) sessions. This protocol is divided into eight stages.
1. Patient consent
2. Preparation of the environment
| Hydrofone | Sampling Rate 96000 sps |
| Hydrophone Sensitivity 8103 25.41e-6; V/Pa | |
| Charge Converter Sensitivity 2647A 0.001 V/pC | |
| ThinkGear ASIC Module 1 (TGAM1) | Sampling frequency 512 sps |
| Bluetooth V3.0 | |
| Logitech C920 | Sampling frequency18 sps |
| Laptop Windows11 | Model: Machenike T58-V |
| CPU: i7-10870H (2.2GHz-5GHz/ 8Cores) | |
| GPU: NVIDIA Geforce RTX3060 Laptop GPU Dual Channel,Up To 32G | |
| Storage: M.2 PCIE. 2.5" HDD | |
| Screen: 144Hz 15.6 Inch FHD |
Table 1: Materials required for monitoring Dolphin-Assisted Therapy (DAT). This table details the equipment necessary for EEG signal acquisition and recording before, during, and after DAT.
| Equipment calibration | |
| Poor signal | An EEG signal captures electrical currents from activated neurons in the cerebral cortex, detectable by EEG systems. These systems function as brain-computer interfaces (BCI), using surface electrodes placed according to the International 10-20 Positioning System, The ThinkGear TGAM1 IS a non-invasive BCI that records and analyzes neural signals, achieving a precision level of 98 %. This is possible taking into account the data integrity, discarding those samples where the flag or indicator called Poor Quality Value is equal to zero. |
| The attributes of brain wave activity monitored by the sensor are quantified through designated flag values: Signal Flatness (25), Signal Excessiveness (26), Power Ratio (27), and Off-Head Detection (29). Concurrent flag indications are possible; for example, a flag value of 51 for suboptimal signal quality indicates non-compliance with both the flatness and excessiveness criteria. Flag values have been meticulously selected to ensure the uniqueness of each possible combination. In addition, a flag value of 200 is indicative of a state in which the sensor has recorded off-head conditions for a duration of four seconds. | |
| The RAW signal of the time series with a sampling frequency of 512 Hz, which allows sampling up to 256 Hz, thus making it possible to separate the signals into fundamental brain wave bands or rhythms, as well as to eliminate the 60 Hz frequency, due to electromagnetic interference from the AC power line through a 60 Hz Notch filter namely a Band Stop Filter. | |
| Bluetooth connection | To connect a TGAM1 sensor to a PC via Bluetooth, first ensure the sensor is powered on and the PC's Bluetooth is enabled. Pair the sensor by searching for devices in the PC's Bluetooth settings, selecting the TGAM1 sensor, and entering the pairing code (usually "0000" or "1234"). Once paired, open the application that will use the sensor, select it as the input device, and configure the correct COM port if required. Test the connection by verifying data transmission in the application, and troubleshoot by checking range, restarting devices, or updating drivers if needed. |
Table 2: Equipment calibration. This table provides a detailed description of the calibration of the components of the equipment used.
3. Pre-DAT stimulus

Figure 1: International 10-20 system for the placement of extracranial electrodes. The sensor must make contact at the FP1 point23. Please click here to view a larger version of this figure.

Figure 2: Use of electroencephalographic device. This Figure shows the correct way to place the EEG device. Please click here to view a larger version of this figure.

Figure 3: Acquisition and recording of EEG signals before DAT. This Figure shows the process of acquiring EEG signals before therapy starts. Please click here to view a larger version of this figure.
4. DAT stimulus

Figure 4: Acquisition and recording of EEG signals during DAT. This Figure shows the process of acquiring EEG signals during therapy. Please click here to view a larger version of this figure.
5. Post-DAT stimulus

Figure 5: Acquisition and recording of EEG signals after DAT. This Figure shows the process of acquiring EEG signals after therapy. Please click here to view a larger version of this figure.
6. Acquiring EEG data

Figure 6: EEG processing. Processing raw EEG data is controlled by a user interface to promote intuitive understanding in relation to a perception-action cycle. Please click here to view a larger version of this figure.

Figure 7: The integrated development environment (IDE) for EEG signal. The system will display available resources on the computer, including connected devices like webcams and EEG acquisition hardware. Please click here to view a larger version of this figure.

Figure 8: System configuration window. Displays the System Configuration Window, where devices are set up and customized. Please click here to view a larger version of this figure.

Figure 9: Patient information window. Shows the Patient Information Window, used for entering essential details like name, diagnosis, and experiment parameters. Please click here to view a larger version of this figure.

Figure 10: Start data sampling. This Figure shows the initiate data acquisition by activating the EEG sampling section. Please click here to view a larger version of this figure.

Figure 11: Complete sample taken from the patient. The figure shows when the software has completed the capture of the patient's samples. Please click here to view a larger version of this figure.
7. Analyzing EEG data

Figure 12: data analysis window. This Figure shows the analysis section of the main interface. Please click here to view a larger version of this figure.
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Figure 13: Results from EEG processing. Outputs generated by the system, showing the raw data and the processed EEG signals (A), the signal processing through the FFT periodogram (B), the spectrogram (C) and the band-pass filtered spectrogram (D). Please click here to view a larger version of this figure.
8. Communication of results
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This study describes the process of acquisition and analysis of EEG signals through a simulated UI in IDE, complemented by the application of a standardized method for data collection. This approach provides a reference framework that facilitates comparability between studies and ensures reproducibility, enabling other researchers to replicate the procedures and obtain consistent results in various contexts.
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Dolphin-assisted therapy (DAT) emerged as a therapeutic modality for individuals with autism and developmental24,25. DAT offers life-enriching, fresh experiences to participants, stimulating interest and sensory engagement in an arresting backdrop25,26. However, there are several limitations that affect the interpretation of the efficacy of DAT, including the demands for controlled experimental desi...
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The authors have nothing to disclose.
This article is supported by the National Polytechnic Institute (Instituto Politécnico Nacional) of México through project No. 20250776, granted by the Secretariat of Research and Postgraduate (Secretaría de Investigación y Posgrado), Secretaría de Ciencia, Humanidades, Tecnología e Innovación (SECIHTI). Additionally, the research described in this work was conducted at the Center for Computing Research (Centro de Investigación en Computación). It should be noted that this research is a major part of the doctoral thesis entitled Estandarización de la recolección de señales EEG de niños neurodivergentes durante Terapias Asistidas por Delfines, bajo el Paradigma de la Ciencia de Sistemas, supported by the work of Brenda Lorena Flores Hidalgo, work directed by Dr. Oswaldo Morales Matamoros and Dr. Jesús Jaime Moreno Escobar. Furthermore, support has been received through the scholarship granted with CVU 1145035 by the Secretaría de Ciencia, Humanidades, Tecnología e Innovación (SECIHTI).
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| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| Charge Converter | Hottinger Brüel & Kjær | Sensitivity 2647A 0.001 V/pC Sampling frequency 512 sps | |
| Hydrofone | Hottinger Brüel & Kjær | 8103 | Sampling Rate 96000 sps Sensitivity 8103 25.41e-6; V/Pa |
| Laptop Windows11 | Machenike | Machenike T58-V | CPU: i7-10870H (2.2GHz-5GHz/ 8Cores) GPU: NVIDIA Geforce RTX3060 Laptop GPU Dual Channel,Up To 32G Storage: M.2 PCIE. 2.5" HDD Screen: 144Hz 15.6 Inch FHD |
| ThinkGear ASIC Module 1 | NeuroSky | TGAM1 | Bluetooth V3.0 |
| Webcam | Logitech | C920 | Sampling frequency18 sps |
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