Predictive Processing During Cue-Outcome Associative Learning in Autistic Children.

PURPOSE: Predictive coding theories posit that autism is characterized by an over-adjustment to prediction errors, resulting in frequent updates of prior beliefs. Atypical weighting of prediction errors is generally considered to negatively impact the construction of stable models of the world, but may also yield beneficial effects. In a novel associative learning paradigm, we investigated whether unexpected events trigger faster learning updates in favour of subtle but fully predictive cues in autistic children compared to their non-autistic counterparts. We also explored the relationship between children's language proficiency and their predictive performances. METHODS: Anticipatory fixations and explicit predictions were recorded during three associative learning tasks with deterministic or probabilistic contingencies. One of the probabilistic tasks was designed so that a fully predictive but subtle cue was overshadowed by a less predictive salient one. RESULTS: Both autistic and non-autistic children based their learning on the salient cue, and, contrary to our predictions, showed no signs of updating in favour of the subtle cue. While both groups demonstrated associative learning, autistic children made less accurate explicit predictions than their non-autistic peers in all tasks. Explicit prediction performances were positively correlated with language proficiency in non-autistic children, but no such correlation was observed in autistic children. CONCLUSION: These results suggest no over-adjustment to prediction errors in autistic children and highlight the need to control for general performance in cue-outcome associative learning in predictive processing studies. Further research is needed to explore the nature of the relationship between predictive processing and language development in autism.

Self-Recording of Eye Movements in Amyotrophic Lateral Sclerosis Patients Using a Smartphone Eye-Tracking App.

Introduction: Amyotrophic lateral sclerosis (ALS) can affect various eye movements, making eye tracking a potential means for disease monitoring. In this study, we evaluated the feasibility of ALS patients self-recording their eye movements using the "EyePhone," a smartphone eye-tracking application. Methods: We prospectively enrolled ten participants and provided them with an iPhone equipped with the EyePhone app and a PowerPoint presentation with step-by-step recording instructions. The goal was for the participants to record their eye movements (saccades and smooth pursuit) without the help of the study team. Afterward, a trained physician administered the same tests using video-oculography (VOG) goggles and asked the participants to complete a questionnaire regarding their self-recording experience. Results: All participants successfully completed the self-recording process without assistance from the study team. Questionnaire data indicated that participants viewed self-recording with EyePhone favorably, considering it easy and comfortable. Moreover, 70% indicated that they prefer self-recording to being recorded by VOG goggles. Conclusion: With proper instruction, ALS patients can effectively use the EyePhone to record their eye movements, potentially even in a home environment. These results demonstrate the potential for smartphone eye-tracking technology as a viable and self-administered tool for monitoring disease progression in ALS, reducing the need for frequent clinic visits.

Performance and eye movement patterns of industrial design students reading sustainable design articles.

Sustainable design education plays a crucial role in cultivating sustainability awareness and competencies among students studying industrial design. This research investigates their sustainability levels, reading performance when engaging with articles, and fixation patterns during reading. 60 industrial design students participated in the study. We evaluated their sustainability levels using the Sustainable Consumption Measurement Scale. After reading both theoretical and case article, they completed tests assessing their recall and perspective scores. We collected eye-tracking data to analyze fixation duration and conducted lag sequential analysis on fixation transitions. Students were categorized into higher and lower sustainability groups based on their sustainability scores. Female students demonstrated higher sustainability levels, and students with design experience performed better in the higher sustainability group. While recall scores did not differ significantly, the higher sustainability group exhibited elevated perspective scores in theory article. Perspective scores were generally higher for case article compared to theory article. The higher sustainability group exhibited longer fixation durations in theory article, while the case article had longer fixation durations on images. Fixation transition patterns varied between theoretical and case article, with the former featuring transitions from images to texts, and the latter demonstrating transitions between images. This study provides valuable insights into sustainable design education for students studying industrial design.

Visual Attention to Evolutionarily Relevant Information by Heterosexual Men and Women While Viewing Mock Online Dating Profiles.

The way people create social connections and access information has been altered greatly by technology in recent decades. Online browsing of visual profiles has become a common means for seeking potential partners for both short- and long-term relationships. Little is known, however, about how people prioritize mate quality information while viewing online profiles. Using eye-tracking methods and self-report, this study investigated how people evaluated profile-based facial attractiveness and text-based financial resources information, represented by income and occupation. Heterosexual male and female participants, aged between 18 and 27 years, viewed opposite-sex profiles while their eye-movements were recorded using a remote eye-tracking camera. In line with current theory, resources information had little effect on men's overall attention to women's faces, whereas women's overall attention to men's faces varied depending on the level of income and occupation. Women evaluated men's faces more when income and occupation were low, regardless of attractiveness. Unexpectedly, however, men marginally increased their attention toward unattractive women who showed a high-level of income and more esteemed occupation. Men self-reported a higher interest in women for a short-term relationship and women self-reported a higher interest in men for a long-term relationship. This work provides a foundation to further examine how people browse profile-based information and to investigate the mate selection process, with real-world implications for online dating app users, profile design, and content.

Evaluating the Usability of mHealth Apps: An Evaluation Model Based on Task Analysis Methods and Eye Movement Data.

Advancements in information technology have facilitated the emergence of mHealth apps as crucial tools for health management and chronic disease prevention. This research work focuses on mHealth apps for the management of diabetes by patients on their own. Given that China has the highest number of diabetes patients in the world, with 141 million people and a prevalence rate of 12.8% (mentioned in the Global Overview of Diabetes), the development of a usability research methodology to assess and validate the user-friendliness of apps is necessary. This study describes a usability evaluation model that combines task analysis methods and eye movement data. A blood glucose recording application was designed to be evaluated. The evaluation was designed based on the model, and the feasibility of the model was demonstrated by comparing the usability of the blood glucose logging application before and after a prototype modification based on the improvement suggestions derived from the evaluation. Tests showed that an improvement plan based on error logs and post-task questionnaires for task analysis improves interaction usability by about 24%, in addition to an improvement plan based on eye movement data analysis for hotspot movement acceleration that improves information access usability by about 15%. The results demonstrate that this study presents a usability evaluation model for mHealth apps that enables the effective evaluation of the usability of mHealth apps.

A dataset on eye movement tracking during the resolution of neuropsychological tests on a screen.

The dataset provides data obtained with eye-tracking while 55 volunteers solved 3 distinct neuropsychological tests on a screen inside a closed room. Among the 55 volunteers, 22 were women and 33 were men, all with ages ranging between 9 and 50, and 5 of whom were diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) [1]. The eye-tracker used for the collection of the data was an EyeTribe, which has a sampling rate of 60 Hz and an average visual angle between 0.5 and 1, which correspond to an on-screen error between 0.5 and 1cm (0.1969 to 0.393 inches aprox) respectively, when the distance to the user is around 60cm (23.62 in) [2], which was the case during the collection of these data. The neuropsychological tests were implemented in a software named NEURO-INNOVA KIDS® [3], which are the following: a domino test adapted from the D-48 intelligence test [4], an adaptation of the MASMI test consisting of unfolded cubes [5], the figures series completion test adapted from [6], and the Poppelreuter figures test [7]. Before each of the tests, a calibration process was performed, ensuring that the visual angle error was less than or equal to 0.5 cm (0.1969 in), which is considered an acceptable calibration. The collective mean duration of the four administered tests amounted to 20 minutes. This dataset exhibits significant promise for potential utilization due to the extensive prevalence of these neuropsychological assessments among healthcare practitioners for evaluating diverse cognitive faculties in individuals. Moreover, it has been empirically established that poor performance on these tests is associated with attention deficits [8].

Exercise-induced inflammation alters the perception and visual exploration of emotional interactions.

Introduction: The study aimed to investigate whether an exercise-induced pro-inflammatory response alters the perception as well as visual exploration of emotional body language in social interactions. Methods: In a within-subject design, 19 male, healthy adults aged between 19 and 33 years performed a downhill run for 45 min at 70% of their VO2max on a treadmill to induce maximal myokine blood elevations, leading to a pro-inflammatory status. Two control conditions were selected: a control run with no decline and a rest condition without physical exercise. Blood samples were taken before (T0), directly after (T1), 3 h after (T3), and 24 h after (T24) each exercise for analyzing the inflammatory response. 3 h after exercise, participants observed point-light displays (PLDs) of human interactions portraying four emotions (happiness, affection, sadness, and anger). Participants categorized the emotional content, assessed the emotional intensity of the stimuli, and indicated their confidence in their ratings. Eye movements during the entire paradigm and self-reported current mood were also recorded. Results: The downhill exercise condition resulted in significant elevations of measured cytokines (IL6, CRP, MCP-1) and markers for muscle damage (Myoglobin) compared to the control running condition, indicating a pro-inflammatory state after the downhill run. Emotion recognition rates decreased significantly after the downhill run, whereas no such effect was observed after control running. Participants' sensitivity to emotion-specific cues also declined. However, the downhill run had no effect on the perceived emotional intensity or the subjective confidence in the given ratings. Visual scanning behavior was affected after the downhill run, with participants fixating more on sad stimuli, in contrast to the control conditions, where participants exhibited more fixations while observing happy stimuli. Conclusion: Our study demonstrates that inflammation, induced through a downhill running model, impairs perception and emotional recognition abilities. Specifically, inflammation leads to decreased recognition rates of emotional content of social interactions, attributable to diminished discrimination capabilities across all emotional categories. Additionally, we observed alterations in visual exploration behavior. This confirms that inflammation significantly affects an individual's responsiveness to social and affective stimuli.

Combining EEG and eye-tracking in virtual reality: Obtaining fixation-onset event-related potentials and event-related spectral perturbations.

Extensive research conducted in controlled laboratory settings has prompted an inquiry into how results can be generalized to real-world situations influenced by the subjects' actions. Virtual reality lends itself ideally to investigating complex situations but requires accurate classification of eye movements, especially when combining it with time-sensitive data such as EEG. We recorded eye-tracking data in virtual reality and classified it into gazes and saccades using a velocity-based classification algorithm, and we cut the continuous data into smaller segments to deal with varying noise levels, as introduced in the REMoDNav algorithm. Furthermore, we corrected for participants' translational movement in virtual reality. Various measures, including visual inspection, event durations, and the velocity and dispersion distributions before and after gaze onset, indicate that we can accurately classify the continuous, free-exploration data. Combining the classified eye-tracking with the EEG data, we generated fixation-onset event-related potentials (ERPs) and event-related spectral perturbations (ERSPs), providing further evidence for the quality of the eye-movement classification and timing of the onset of events. Finally, investigating the correlation between single trials and the average ERP and ERSP identified that fixation-onset ERSPs are less time sensitive, require fewer repetitions of the same behavior, and are potentially better suited to study EEG signatures in naturalistic settings. We modified, designed, and tested an algorithm that allows the combination of EEG and eye-tracking data recorded in virtual reality.

Effects of attentional deployment training for relieving negative emotion in individuals with subthreshold depression.

OBJECTIVE: As a prodromal stage to major depressive disorder (MDD), subthreshold depression (StD) has a higher prevalence in the population, resulting in a greater healthcare burden. StD individuals' current negative emotion could be moderated by attentional deployment. However, it remains unclear whether attentional deployment training can mitigate subsequent negative emotion in StD individuals. METHODS: Based on 160 participants, we combined decision task (Experiment 1, N = 69), eye-tracking (Experiment 2, N = 40), and EEG (Experiment 3, N = 51) techniques to investigate how one-week attentional deployment (gain-focus, GF) training modulated the emotional processing of negative stimulus and its underlying neural correlates in StD individuals. RESULTS: After one-week GF training, StD individuals significantly reduced the first fixation time and total fixation time on the negative part (missed opportunities) of decision outcome and showed a decrease in emotional sensitivity to missed opportunities. An increase in N1 and decrease in P3 and LPP (late positive potentials) amplitudes, as well as a decrease in alpha oscillation, were observed when StD individuals faced missed opportunities after training. Additionally, the extent of reduction in StD individuals' emotional sensitivity to missed opportunities could be significantly predicted by the degree of decrease in alpha oscillation. CONCLUSION: One-week attentional deployment training could modulate negative emotion in StD individuals and the degree of change in alpha oscillation might act as an objective indicator for the effectiveness of training. SIGNIFICANCE: Our study provides a convenient and effective approach to alleviate the negative emotion of StD individuals.

MRGazer: decoding eye gaze points from functional magnetic resonance imaging in individual space.

Eye-tracking research has proven valuable in understanding numerous cognitive functions. Recently, Frey et al. provided an exciting deep learning method for learning eye movements from functional magnetic resonance imaging (fMRI) data. It employed the multi-step co-registration of fMRI into the group template to obtain eyeball signal, and thus required additional templates and was time consuming. To resolve this issue, in this paper, we propose a framework named MRGazer for predicting eye gaze points from fMRI in individual space. The MRGazer consists of an eyeball extraction module and a residual network-based eye gaze prediction module. Compared to the previous method, the proposed framework skips the fMRI co-registration step, simplifies the processing protocol, and achieves end-to-end eye gaze regression. The proposed method achieved superior performance in eye fixation regression (Euclidean error, EE=2.04°) than the co-registration-based method (EE=2.89°)， and delivered objective results within a shorter time (~0.02 second/volume) than prior method (~0.3 second/volume). The code is available at https://github.com/ustc-bmec/MRGazer.

Estimating Cognitive Workload Using Task-Related Pupillary Responses in Simulated Drilling in Cochlear Implantation.

OBJECTIVES: Training of temporal bone drilling requires more than mastering technical skills with the drill. Skills such as visual imagery, bimanual dexterity, and stress management need to be mastered along with precise knowledge of anatomy. In otorhinolaryngology, these psychomotor skills underlie performance in the drilling of the temporal bone for access to the inner ear in cochlear implant surgery. However, little is known about how psychomotor skills and workload management impact the practitioners' continuous and overall performance. METHODS: To understand how the practitioner's workload and performance unfolds over time, we examine task-evoked pupillary responses (TEPR) of 22 medical students who performed transmastoid-posterior tympanotomy (TMPT) and removal of the bony overhang of the round window niche in a 3D-printed model of the temporal bone. We investigate how students' TEPR metrics (Average Pupil Size [APS], Index of Pupil Activity [IPA], and Low/High Index of Pupillary Activity [LHIPA]) and time spent in drilling phases correspond to the performance in key drilling phases. RESULTS: All TEPR measures revealed significant differences between key drilling phases that corresponded to the anticipated workload. Enlarging the facial recess lasted significantly longer than other phases. IPA captured significant increase of workload in thinning of the posterior canal wall, while APS revealed increased workload during the drilling of the bony overhang. CONCLUSION: Our findings contribute to the contemporary competency-based medical residency programs where objective and continuous monitoring of participants' progress allows to track progress in expertise acquisition. Laryngoscope, 2024.

Infant attention to rhythmic audiovisual synchrony is modulated by stimulus properties.

Musical interactions are a common and multimodal part of an infant's daily experiences. Infants hear their parents sing while watching their lips move and see their older siblings dance along to music playing over the radio. Here, we explore whether 8- to 12-month-old infants associate musical rhythms they hear with synchronous visual displays by tracking their dynamic visual attention to matched and mismatched displays. Visual attention was measured using eye-tracking while they attended to a screen displaying two videos of a finger tapping at different speeds. These videos were presented side by side while infants listened to an auditory rhythm (high or low pitch) synchronized with one of the two videos. Infants attended more to the low-pitch trials than to the high-pitch trials but did not display a preference for attending to the synchronous hand over the asynchronous hand within trials. Exploratory evidence, however, suggests that tempo, pitch, and rhythmic complexity interactively engage infants' visual attention to a tapping hand, especially when that hand is aligned with the auditory stimulus. For example, when the rhythm was complex and the auditory stimulus was low in pitch, infants attended to the fast hand more when it aligned with the auditory stream than to misaligned trials. These results suggest that the audiovisual integration in rhythmic non-speech contexts is influenced by stimulus properties.

Advancements in eye movement measurement technologies for assessing neurodegenerative diseases.

Eye movements have long been recognized as a valuable indicator of neurological conditions, given the intricate involvement of multiple neurological pathways in vision-related processes, including motor and cognitive functions, manifesting in rapid response times. Eye movement abnormalities can indicate neurological condition severity and, in some cases, distinguish between disease phenotypes. With recent strides in imaging sensors and computational power, particularly in machine learning and artificial intelligence, there has been a notable surge in the development of technologies facilitating the extraction and analysis of eye movements to assess neurodegenerative diseases. This mini-review provides an overview of these advancements, emphasizing their potential in offering patient-friendly oculometric measures to aid in assessing patient conditions and progress. By summarizing recent technological innovations and their application in assessing neurodegenerative diseases over the past decades, this review also delves into current trends and future directions in this expanding field.

Exploring the technological dimension of Autonomous sensory meridian response-induced physiological responses.

Background: In recent years, the scientific community has been captivated by the intriguing Autonomous sensory meridian response (ASMR), a unique phenomenon characterized by tingling sensations originating from the scalp and propagating down the spine. While anecdotal evidence suggests the therapeutic potential of ASMR, the field has witnessed a surge of scientific interest, particularly through the use of neuroimaging techniques including functional magnetic resonance imaging (fMRI) as well as electroencephalography (EEG) and physiological measures such as eye tracking (Pupil Diameter), heart rate (HR), heartbeat-evoked potential (HEP), blood pressure (BP), pulse rates (PR), finger photoplethysmography (PPG), and skin conductance (SC). This article is intended to provide a comprehensive overview of technology's contributions to the scientific elucidation of ASMR mechanisms. Methodology: A meticulous literature review was undertaken to identify studies that have examined ASMR using EEG and physiological measurements. The comprehensive search was conducted across databases such as PUBMED, SCOPUS, and IEEE, using a range of relevant keywords such as 'ASMR', 'Autonomous sensory meridian response', 'EEG', 'fMRI', 'electroencephalography', 'physiological measures', 'heart rate', 'skin conductance', and 'eye tracking'. This rigorous process yielded a substantial number of 63 PUBMED and 166 SCOPUS-related articles, ensuring the inclusion of a wide range of high-quality research in this review. Results: The review uncovered a body of research utilizing EEG and physiological measures to explore ASMR's effects. EEG studies have revealed distinct patterns of brain activity associated with ASMR experiences, particularly in regions implicated in emotional processing and sensory integration. In physiological measurements, a decrease in HR and an increase in SC and pupil diameter indicate relaxation and increased attention during ASMR-triggered stimuli. Conclusions: The findings of this review underscore the significance of EEG and physiological measures in unraveling the psychological and physiological effects of ASMR. ASMR experiences have been associated with unique neural signatures, while physiological measures provide valuable insights into the autonomic responses elicited by ASMR stimuli. This review not only highlights the interdisciplinary nature of ASMR research but also emphasizes the need for further investigation to elucidate the mechanisms underlying ASMR and explore its potential therapeutic applications, thereby paving the way for the development of novel therapeutic interventions.

Assessment of Oculomotor Functions as a Biomarker in Mild Traumatic Brain Injury.

Mild traumatic brain injury (mTBI), or concussion, is a major public health problem, and ambiguity still exists regarding its diagnosis. While functional magnetic resonance imaging (fMRI) has been identified as a helpful screening tool for concussion, its limited accessibility in clinical or field settings necessitates a more efficient alternative. Oculomotor function deficit is an often-reported pathology in mTBI. Due to the neuroanatomical overlap between eye-movement circuitry and mTBI pathophysiology, visual deficits are expected. In this study, we investigate the possibility of using an oculomotor assessment tool for finding biomarkers in concussion. We used fMRI with tasks evaluating oculomotor functions: smooth pursuit (SP), saccades, anti-saccades, and optokinetic nystagmus (OKN). Before the scanning, the testing with a system of virtual reality goggles with integrated eye- and head-tracking was used where subjects performed the same tasks as those used in fMRI. Twenty-nine concussed symptomatic adults (CSA) within 1-month postconcussion and 29 age- and sex-matched healthy controls (HCS) were tested to examine blood oxygen level-dependent (BOLD) fMRI alterations associated with performances in oculomotor function after mTBI and evaluate the efficacy of the oculomotor assessment in detecting oculomotor and gaze deficits following mTBI. Comparing CSA with HCS, significant differences were observed in anti-saccades and OKN performance. CSA group exhibited elevated %BOLD signal change on each task compared with HCS: in the superior frontal gyrus during the smooth pursuit, inferior frontal gyrus during the saccades, putamen and dorsolateral prefrontal cortex (DLPFC) during the anti-saccades, and lingual gyrus and IFG during the OKN. Key findings include the following: (1) oculomotor deficits in concussed subjects compared with controls, (2) abnormal activation patterns in areas related to the regulation and control of oculomotor movements, suggesting concussion-induced disruptions, and (3) the potential of oculomotor assessment as a promising approach for mTBI biomarkers, with anti-saccades and OKN identified as the most sensitive tasks.

Comparing Functional Trend and Learning among Groups in Intensive Binary Longitudinal Eye-Tracking Data using By-Variable Smooth Functions of GAMM.

This paper presents a model specification for group comparisons regarding a functional trend over time within a trial and learning across a series of trials in intensive binary longitudinal eye-tracking data. The functional trend and learning effects are modeled using by-variable smooth functions. This model specification is formulated as a generalized additive mixed model, which allowed for the use of the freely available mgcv package (Wood in Package 'mgcv.' https://cran.r-project.org/web/packages/mgcv/mgcv.pdf , 2023) in R. The model specification was applied to intensive binary longitudinal eye-tracking data, where the questions of interest concern differences between individuals with and without brain injury in their real-time language comprehension and how this affects their learning over time. The results of the simulation study show that the model parameters are recovered well and the by-variable smooth functions are adequately predicted in the same condition as those found in the application.

Eye-Tracking Analyses of a Coach's Pointing Gestures Timed With Speech: Implications for Players' Recall of Basketball Tactical Instructions.

Coaches often use pointing gestures alongside their speech to reinforce their message and emphasize important concepts during instructional communications, but the impact of simultaneous pointing gestures and speech on learners' recall remains unclear. We used eye-tracking and recalled performance to investigate the impact of a coach's variously timed pointing gestures and speech on two groups of learners' (novices and experts) visual attention and recall of tactical instructions. Participants were 96 basketball players (48 novice and 48 expert) who attempted to recall instructions about the evolution of a basketball game system under two teaching conditions: speech accompanied by gestures and speech followed by gestures. Overall, the results showed that novice players benefited more from instructional speech accompanied by gestures than from speech followed by gestures alone. This was evidenced by their greater visual attention to the diagrams, demonstrated through a higher fixation count and decreased saccadic shifts between the coach and the diagrams. Additionally, they exhibited improved recall and experienced reduced mental effort, despite having the same fixation time on the diagrams and equivalent recall time. Conversely, experts benefited more from instructional speech followed by gestures, indicating an expertise reversal effect. These results suggest that coaches and educators may improve their tactical instructions by timing the pairing of their hand gestures and speech in relation to the learner's level of expertise.

Evaluating the validity of eye-tracking tasks and stimuli in detecting high-risk infants later diagnosed with autism: A meta-analysis.

Gaze abnormalities are well documented in infants at elevated risk for autism spectrum disorder (ASD). However, variations in experimental design and stimuli across studies have led to mixed results. The current meta-analysis aimed to identify which type of eye tracking task and stimulus are most effective at differentiating high-risk infants (siblings of children with ASD) who later meet diagnosis criteria from low-risk infants without familial autism. We synthesized 35 studies that used eye tracking to investigate gaze behavior in infants at high genetic risk for autism before 2 years of age. We found that stimulus features, regions of interest (ROIs) and study quality moderated effect sizes across studies. Overall, dynamic stimuli and socially-relevant regions in the social stimuli (i.e. the target and activity of characters' shared focus) reliably detected high-risk infants who later develop ASD. Attention disengagement task and stimuli depicting interactions between human and nonhuman characters could identify high-risk infants who later develop ASD and those who have autism-related symptoms but do not meet the diagnostic criteria as well. These findings provide sensitive and reliable early markers of ASD, which is helpful to develop objective and quantitative early autism screening and intervention tools.

Application to combine questioning, stimulus presentation and external measurements in a real-life music eye tracking experiment.

Studying people in real-life situations, such as making music in a vocal group, requires flexible and integrative measurement technology. Therefore, a digital browser-based survey instrument was developed for this study. It was designed to seamlessly introduce questions on participants' mobile devices through external control immediately after relevant events, aiming to achieve high accuracy in self-administered situational questions. In addition, chronological synchronization with supplementary measurements (here eye-tracking and audio recording) was incorporated. Digital features of this web app offer convenient integration into everyday situations, synchronous interviewing of multiple people, and gathering time-based data. Due to the numerous possibilities of the browser-based development interface, various other application areas can be opened up. The contribution of this article is:-App - explanation and offer for use-Feasibility report on the implementation of the app in an eye-tracking study with vocal groups.