The time-course of visual scanning behaviour of paramedicine students upon arrival at a simulated emergency call

BACKGROUND

Limited knowledge exists regarding how paramedics acquire an understanding of the scene they encounter upon arrival, despite their need to quickly gather information for effective clinical decision-making. This study examined visual scanning behaviour during the early stages of simulated emergency calls.

METHODS

Eye movements of 10 paramedicine students were recorded during simulated calls conducted in both a high-fidelity classroom setting and a full sensory immersion setting.

RESULTS

Students focused on similar areas in both settings, with most time spent looking at the patient rather than distractors such as room features or other people. Analysis of gaze behaviour across the first five minutes revealed a more nuanced pattern: attention initially gravitated towards distractors but decreased as students became familiar with their surroundings and focused on the task at hand. This pattern was consistent across both simulation settings, indicating that information-seeking strategies may be independent of scene complexity.

CONCLUSIONS

Expertise relies on the ability to differentiate between relevant and irrelevant information. Given the unpredictable nature of their work, paramedics must continuously adapt their understanding of a scene from the moment they enter it. Understanding how this skill develops may help identify expert strategies to inform training of novice paramedics.

EXPRESS: The effect of anxiety and its interplay with social cues when perceiving aggressive behaviours

Contextual cues and emotional states carry expectations and biases that are used to attribute meaning to what we see. In addition, emotional states, such as anxiety, shape our visual systems, increasing overall, and particularly threat-related, sensitivity. It remains unclear, however, how anxiety interacts with additional cues when categorizing sensory input. This is especially important in social scenarios where ambiguous gestures are commonplace, thus requiring the integration of cues for a proper interpretation. To this end, we decided to assess how states of anxiety might bias the perception of potentially aggressive social interactions, and how external cues are incorporated in this process. Participants (N = 71) were tasked with signalling the presence of aggression in ambiguous social interactions. Simultaneously, an observer (facial expression) reacted (by showing an emotional expression) to this interaction. Importantly, participants performed this task under safety and threat of shock conditions. Decision measures and eye tracking data were collected. Our results showed that threat of shock did not affect sensitivity nor criterion when detecting aggressive interactions. The same pattern was observed for response times. Drift diffusion modelling analysis, however, suggested quicker evidence accumulation when under threat. Lastly, dwell times over the observer were higher when under threat, indicating a possible association between anxiety states and a bias towards potentially threat-related indicators. Future probing into this topic remains a necessity to better explain the current findings.

Visual Perception in Children with a History of Hypoglycemia due to Hyperinsulinism

Objectives

Hyperinsulinism refers to improper insulin secretion in the presence of low plasma glucose, causing severe and persistent hypoglycemia in infants and children. The brain's occipital lobe, which includes the visual and plays an essential role in visual perception is specifically sensitive to hypoglycemia-induced damage. The present study aims to investigate the visual perception in children suffering from hyperinsulinism and to compare it with the control group.

Materials & Methods

This cross-sectional control study, conducted in 2020 in Isfahan, Iran, involved 20 children aged 4-13 years with hyperinsulinism and 20 healthy children of the same age and gender for comparison. In both groups, the measuring instrument was the Test of Visual Perceptual Skills (non-motor) Third Edition.

Results

The mean visual perceptual quotient in the case and control groups was 80.50±26.74 and 116.50±7.56 (p-value<0.001), respectively. The results overall indicated that children suffering from hyperinsulinism were weaker than healthy children in all areas of visual perception.

Conclusion

Based on the obtained results, it is recommended that children suffering from hyperinsulinism be screened regarding visual perceptual disorders since this screening may be helpful in initiating different rehabilitation programs among these patients.

The Role of Visual Factors in Dyslexia

What are the causes of dyslexia? Decades of research reflect a determined search for a single cause where a common assumption is that dyslexia is a consequence of problems with converting phonological information into lexical codes. But reading is a highly complex activity requiring many well-functioning mechanisms, and several different visual problems have been documented in dyslexic readers. We critically review evidence from various sources for the role of visual factors in dyslexia, from magnocellular dysfunction through accounts based on abnormal eye movements and attentional processing, to recent proposals that problems with high-level vision contribute to dyslexia. We believe that the role of visual problems in dyslexia has been underestimated in the literature, to the detriment of the understanding and treatment of the disorder. We propose that rather than focusing on a single core cause, the role of visual factors in dyslexia fits well with risk and resilience models that assume that several variables interact throughout prenatal and postnatal development to either promote or hinder efficient reading.

Identifying the duration of emotional stimulus presentation for conscious versus subconscious perception via hierarchical drift diffusion models

To investigate subliminal priming effects, different durations for stimulus presentation are applied ranging from 8 to 30 ms. This study aims to select an optimal presentation span whichleads to a subconscious processing. 40 healthy participants rated emotional faces (sad, neutral or happy expression) presented for 8.3 ms, 16.7 ms and 25 ms. Alongside subjective and objectivestimulus awareness, task performance was estimated via hierarchical drift diffusion models. Participants reported stimulus awareness in 65 % of the 25 ms trials,in 36 % of 16.7 ms trials, and in 2.5 % of 8.3 ms trials.Emotion-dependent responses were reflected in decreased performance (drift rates, accuracy)during sad trials. The detection rate (probability of making a correct response) during 8.3 ms was 12.2 % and slightly above chance level (33.333 % for three response options) during 16.7 ms trials (36.8 %). The experiments suggest a presentation time of 16.7 ms as optimal for subconscious priming. An emotion-specific response was detected during 16.7 ms while the performanceindicates a subconscious processing.

Virtual occlusion effects on the perception of self-initiated visual stimuli

Virtual reality (VR) has established itself as a useful tool in the study of human perception in the laboratory. A recent study introduced a new approach to examine visual sensory attenuation (SA) effects in VR. Hand movements triggered the appearance of Gabor stimuli, which were either presented behind the participant's hand - not rendered in VR ("virtual occlusion") - or elsewhere on the display. Virtual occlusion led to a rightward shift of the psychometric curve, suggesting that self-generated hand movements reduced the perceived contrast of the stimulus. Since such attenuation effects might provide a window into the predictive processing of the sensory and cognitive apparatus, we sought to better understand the nature of the virtual occlusion effects. In our study, the presentation of test stimuli was either self-initiated, self-initiated with a variable delay, or triggered externally; the test stimuli were occluded or not. In conflict with our hypothesis, we found moderate to strong evidence for an absence of any horizontal shifts between the psychometric curves. However, virtual occlusion was associated with a decrease in the slope of the psychometric function. Our results suggest that virtual occlusion attenuated the relative perceptual sensitivity, so that participants had more difficulty discriminating contrast differences when the test stimulus was presented behind the hand. We tentatively conclude that, in the visual domain, the discriminability of stimulus intensity is modified by internal predictive cues (i.e., proprioception), possibly linked to shifts in covert spatial attention.

Differing Characteristics of Human-Shaped Visual Stimuli Affect Clinicians' Dosage of a Spinal Manipulative Thrust on a Low-Fidelity Model: A Cross-Sectional Study

OBJECTIVE

The purpose of this study was to determine whether chiropractic clinicians modulate spinal manipulation (SM) thrust characteristics based on visual perception of simulated human silhouette attributes.

METHODS

We performed a cross-sectional within-participant design with 8 experienced chiropractors. During each trial, participants observed a human-shaped life-sized silhouette of a mock patient and delivered an SM thrust on a low-fidelity thoracic spine model based on their visual perception. Silhouettes varied on the following 3 factors: apparent sex (male or female silhouette), height (short, average, tall), and body mass index (BMI) (underweight, healthy, obese). Each combination was presented 6 times for a total of 108 trials in random order. Outcome measures included peak thrust force, thrust duration, peak preload force, peak acceleration, time to peak acceleration, and rate of force application. A 3-way repeated measures analysis of variance model was used to for each variable, followed by Tukey's honestly significant difference on significant interactions.

RESULTS

Peak thrust force was reduced when apparent sex of the presented silhouette was female (F_1,7 = 5.70, P = .048). Thrust duration was largely invariant, except that a BMI by height interaction revealed a longer duration occurred for healthy tall participants than healthy short participants (F_4,28 = 4.34, P = .007). Compared to an image depicting obese BMI, an image appearing underweight lead to reduced peak acceleration (F_2,5 = 6.756, P = .009). Clinician time to peak acceleration was reduced in short compared to tall silhouettes (t₇ = 2.20, P = .032).

CONCLUSION

Visual perception of simulated human silhouette attributes, including apparent sex, height, and BMI, influenced SM dose characteristics through both kinetic and kinematic measures. The results suggest that visual information from mock patients affects the decision-making of chiropractic clinicians delivering SM thrusts.

Assessment of Orofacial Esthetics among Different Specialists in Dental Medicine: A pilot study

Objectives

Little is known whether specialists in different dental fields assess orofacial esthetics differently due to various focus of their interest. The aim was to find out if there is a difference in judgement of orofacial esthetics among specialists in three different fields of Dental Medicine, i.e. specialists in Prosthodontics (S-Prosthod), Periodontology (S-Perio), and Orthodontics (S-Ortho).

Material and methods

A total of 69 specialists (23 participants in each group) assessed the same 60 photographs of the lower third of the face of young healthy people with Angle Class I and natural teeth while smiling. Moreover, the assessed anterior teeth on the photographs of similes had to be without any restorations. The assessments were made using 7 out of 8 Items of Orofacial Esthetic Scale (OES). A face profile assessment was not performed. A Likert 1-5 scale was used for assessments (1-the worst score; 5-the best score). Mean values of summary scores as well as of each OES item were calculated for each specialist for further statistical analysis. One-sample Kolmogorov-Smirnov test, descriptive statistics, one-way ANOVA, and Sheffe post-hoc tests were performed.

Results

The specialists in Periodontology gave significantly lowest scores to all 7 items related to orofacial esthetics, while the specialists in Prosthodontics gave the highest scores (p<0.05).

Conclusion

Assessments of orofacial esthetics differ significantly among specialists in Prosthodontics, Periodontology and Orthodontics. Further study is needed to clarify the factors which influence the judgement, and to find out if specific education in certain specialties can modify the assessment.

Effects of Visual Stimuli from Media on the Perception of Dentofacial Esthetics

Objectives

The study explored whether television commercials change the perception of one's own dentofacial attractiveness and to identify if it is influenced by personality traits.

Materials and methods

The sample included 83 participants, aged 19-27 years. The experimental group (N=42) watched commercials portraying famous young individuals with high smile esthetics, bright teeth and no visible malocclusions, while the control group (N=41) watched neutral commercials (without people or visible teeth). The perception of subjects` own orofacial esthetics and its psychosocial effects were assessed a month before the exposure and immediately after it. The subjects` malocclusion severity and personality characteristics (extraversion, conscientiousness, agreeableness, neuroticism, intellect, self-esteem and perfectionism) were assessed.

Results

In their second report, respondents were inclined to report less psychosocial impacts with small differences (ranging from 0-3 scalar points on average) and less significant in the active group compared to neutral group (2 out of 7 vs. 5 out of 7 aspects). Types of visual stimuli were a significant predictor only of changes pertaining to psychological impact of dental esthetics (p=0.045; r=0.221). The intellect moderated perception of smile esthetics, after having been exposed to commercials, accentuated beautiful smiles as a suppressor (ΔR²=0.076; p=0.005; total model R²=0.347; p=0.033). In subjects with higher cognitive abilities, an increase in the self-perceived malocclusion level induced a smaller decrease in psychological impact of dental esthetics as compared to those with lower intellect.

Conclusion

Psychosocial influences of malocclusion are not stable and tend to decrease during time. However, the exposure to a high smile esthetic of other individuals can inhibit that process in persons with more severe malocclusion and higher cognitive abilities.

Correlations between developmental test of visual perception-adolescent and adult and visual evoked potential in people with multiple sclerosis

Background: Optic neuritis (ON) is a common visual sign in multiple sclerosis (MS). Although ON is recovered in most cases, other visual functions such as visual perception are affected and are not fully recovered. The aim of this study is to investigate the relationship between visual evoked potential (VEP) P100 and N70 latencies and visual perception using the Developmental Test of Visual Perception-Adolescent and Adult (DTVP-A) in people with MS. Methods: In this cross-sectional study, 24 people with ON due to MS, aged 18-50 years old took part. In order to assess the visual perception and optic nerve conductivity, the DTVP-A and the VEP were accomplished, respectively. Pearson's product-moment correlation coefficient was used to analyze the data. Results: There was a significant negative correlation between right VEP P100 latency and total score of DTVP-A (r = -0.450, P < 0.05) as well as a significant negative correlation between right VEP P100 latency with visual-motor integration (VMI) subtest of DTVP-A (r = -0.485, P < 0.05). Conclusion: The visual perception has an important role in safety and independent daily activities. Therefore, determining the related factors is essential. Although the findings of the current study revealed a moderate statistical correlation between visual perception and right VEP P100 latency, the small sample size might limit the generalization of our findings; therefore, further study is required to confirm our results.

Inter-relationship between visual symptoms, activity limitation and psychological functioning in patients with diabetic retinopathy

AIMS

We explored the direct and indirect impact of restrictions in daily living activities on the relationship between perceived visual symptoms associated with diabetic retinopathy (DR) and psychological functioning.

METHODS

In this prospective, cross-sectional study, 514 tertiary patients with DR (mean age±SD, 60.4±12.6 years; 64% male) answered questions related to nine domains of DR-specific quality of life. These were classified into the following predictor, mediating and outcome variables: visual symptoms (predictor variable); activity limitation, driving, lighting, social restriction, inconvenience, mobility (mediating variables); and emotional distress and concerns (outcome variables). Direct and indirect relationships between study variables were assessed using path analysis, using interval-level person measures derived from Rasch analyses of the study questionnaires.

RESULTS

We found no direct effect of DR-related visual symptoms on emotional distress or concerns. Rather, the association between visual symptoms and emotional distress was mediated (all p<0.05) by mobility (indirect effect=0.07), inconvenience (indirect effect=0.28), activity limitation (indirect effect=0.13) and social restriction (indirect effect=0.11). Similarly, the relationship between DR-related visual symptoms and concerns was mediated by inconvenience (indirect effect=0.36) and social restriction (indirect effect=0.11). Lighting and driving did not have a mediating role.

CONCLUSIONS

The link between vision and psychological functioning outcomes such as emotional distress and concern is complex in patients with DR and mediated by limitations in daily living activities and social factors. Interventions to enhance daily functioning and social interaction may be effective in reducing emotional distress associated with DR-related vision impairment.

Effect of Three Different Core Materials on Masking Ability of a Zirconia Ceramic

OBJECTIVES

Masking ability of a restorative material plays a role in hiding colored substructures; however, the masking ability of zirconia ceramic (ZRC) has not yet been clearly understood in zirconia-based restorations. This study evaluated the effect of three different core materials on masking ability of a ZRC.

MATERIALS AND METHODS

Ten zirconia disc samples, 0.5mm in thickness and 10mm in diameter, were fabricated. A white (W) substrate (control) and three substrates of nickel-chromium alloy (NCA), non-precious gold alloy (NPGA), and ZRC were prepared. The zirconia discs were placed on the four types of substrates for spectrophotometry. The L*, a*, and b* values of the specimens were measured by a spectrophotometer and color change (ΔE) values were calculated to determine color differences between the test and control groups and were then compared with the perceptual threshold. Randomized block ANOVA and Bonferroni test analyzed the data. A significance level of 0.05 was considered.

RESULTS

The mean and standard deviation values of ΔE for NCA, NPGA, and ZRC groups were 10.26±2.43, 9.45±1.74, and 6.70±1.91 units, respectively. Significant differences were found in the ΔE values between ZRC and the other two experimental groups (NCA and NPGA; P<0.0001 and P=0.001, respectively). The ΔE values for the groups were more than the predetermined perceptual threshold.

CONCLUSIONS

Within the limitations of this study, it was concluded that the tested ZRC could not well mask the examined core materials.

Influence of Subclinical Neck Pain on the Ability to Perform a Mental Rotation Task: A 4-Week Longitudinal Study With a Healthy Control Group Comparison

OBJECTIVE

Mental rotation of objects and the frame of reference of those objects are critical for executing correct and skillful movements and are important for object recognition, spatial navigation, and movement planning. The purpose of this longitudinal study was to compare the mental rotation ability of those with subclinical neck pain (SCNP) to healthy controls at baseline and after 4 weeks.

METHODS

Twenty-six volunteers (13 SCNP and 12 healthy controls) were recruited from a university student population. Subclinical neck pain participants had scores of mild to moderate on the Chronic Pain Grade Scale, and controls had minimal or no pain. For the mental rotation task, participants were presented with an object (letter "R") on a computer screen presented randomly in either normal or backwards parity at various orientations (0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°). Participants indicated the object's parity by pressing "N" for normal or "B" for backwards. Each orientation for normal and backward parities was presented 5 times, and the average response time for all letter presentations was calculated for each participant, at baseline and 4 weeks later.

RESULTS

Both groups had overall improved response times from baseline to 4 weeks. Healthy participants had significantly improved response times compared to SCNP, both at baseline (P < .05) and 4 weeks (P < .05).

CONCLUSIONS

Healthy participants performed better than the SCNP group at both time points. Subclinical neck pain may impair the ability to perform a complex mental rotation task involving cerebellar connections, possibly due to altered body schema.

The correlation between retinal sensitivity assessed by microperimetry and contrast sensitivity in diabetic macular oedema

AIM

To investigate the relationship between contrast sensitivity (CS) and retinal sensitivity (RS) assessed by microperimetry (MP) in diabetic retinopathy (DR) with clinically significant macular oedema (CSME).

METHODS

A retrospective study was performed with 35 eyes of 35 patients with DR and CSME. Retinal thickness (RT) and MP were tested with the spectral SD-optical coherence topography/scanning laser ophthalmoscope system. Mean central RT at the fovea centre's 1 mm zone (CRT) and at the fixation centre's 1 mm zone (FCRT) was measured. RS was tested at the fixation centre, within 2° and 4° areas. CS was measured with six target sizes (6.3°, 4.0°, 2.5°, 1.6°, 1.0°, 0.64°) with a contrast glare tester.

RESULTS

The mean CRT and FCRT were 344.3±136.2 and 359.9±135.5 μm, respectively. Mean log CSs (-log10) with the six target sizes ranged from 0.19 to 1.32. The mean RS at the fixation centre, within 2°, and within 4° area were 8.51±4.81 dB, 8.58±3.88 dB and 9.22±3.56 dB, respectively. RS at all tested areas were significantly correlated to log CS with all target sizes (range, r=0.366-0.755; p=0.0001-0.030). CRT and FCRT were not significantly correlated to log CS or RS.

CONCLUSIONS

CS and RS showed moderately significant correlations in CSME. However, neither CS nor RS was correlated with RT in patients with CSME. It could be that CS and MP are complementary to each other and are useful tools in the evaluation of functional vision.

Temporal resolution of figures and grounds

Recent studies have demonstrated that establishing figure-ground organization influences other perceptual processes. Specifically, figures undergo perceptual processing earlier than ground regions (Lester, Hecht, & Vecera, 2009), and they are processed for longer durations relative to ground regions (Hecht & Vecera, 2011). One potential consequence of figures' extended processing is degraded temporal resolution compared to ground regions. To test this hypothesis, observers completed a modified flicker-fusion task while viewing either displays that contained well-defined figures and grounds or displays that were ambiguous. As evidenced by increased sensitivity for flickering targets on the ground regions, the current results support the claim that figures have poorer temporal resolution than ground regions.

Repetitive tests of visual function improved visual acuity in young subjects

AIMS

To test visual function after repetitive tests of visual acuity (VA) and contrast sensitivity (CS).

METHODS

Ten young female subjects performed repetitive tests of visual functions over ten sessions within 5 weeks. Per week they performed two 30 min sessions of repetitive tests of central VA, CS and vernier acuity (VT) using Michael Bach's Freiburg Vision Test FrACT 3.5.5. FrACT presents an optotype in different spatial frequencies or an optotype with decreasing contrast. Using SPSS Statistics we analysed the correlation between the number of repetitive test sessions and the change in visual function of the total group and of the individuals.

RESULTS/CONCLUSION

After ten sessions, we found a significant improvement in VA, CS and VT. When compared with the initial session, VA increased by 32%, mean CS improved by 40% and mean VT enhanced by 47%. We also found a significant correlation between the number of test sessions and VA (r=-0.374, p<0.01), CS (r=-0.258, p<0.05) and VT (r=-0.379, p<0.01). Individual changes in vision were variable. In eight subjects, VA and CS improved significantly. VT improved in nine subjects. Our data suggest that repetitive tests of visual function may improve VA significantly.

Treatment of Visual Hallucinations in Schizophrenia by Acetylcholinesterase Inhibitors: a case report

Schizophrenia and various neurological disorders have some signs and symptoms. Visual hallucinations are one of such disorders. The related studies in some diseases for example Parkinson Disease and Lewy Body Dementia indicate that Acetylcholine (Ach) plays a significant role in neuropsychiatric manifestation and its association with visual hallucination; therefore, visual hallucinations occur due to the depletion of Ach. Drug therapies such as Cholinesterase inhibitors (ChEIs) for increasing Ach level may be beneficial in treating visual hallucination. AchEI's have been used in the treatment of visual hallucinations in Dementia and Parkinson's Disease. We thought that a similar Ach depletion may cause visual hallucinations in patients with schizophrenia and may provide a target for drug treatment. We had a patient with schizophrenia whose psychotic symptoms responded to the treatment plan, but her visual hallucination did not. However, the patient's visual hallucination successfully responded to Rivastigmine (AchEI).This case illustrates the use of an AchEI in the treatment of refractory visual hallucinations in a patient with schizophrenia.