Visual Reaction Time Task Research Articles

The role of general cognitive skills in integrating visual and linguistic information during sentence comprehension: individual differences across the lifespan

Individuals exhibit massive variability in general cognitive skills that affect language processing. This variability is partly developmental. Here, we recruited a large sample of participants (N = 487), ranging from 9 to 90 years of age, and examined the involvement of nonverbal processing speed (assessed using visual and auditory reaction time tasks) and working memory (assessed using forward and backward Digit Span tasks) in a visual world task. Participants saw two objects on the screen and heard a sentence that referred to one of them. In half of the sentences, the target object could be predicted based on verb-selectional restrictions. We observed evidence for anticipatory processing on predictable compared to non-predictable trials. Visual and auditory processing speed had main effects on sentence comprehension and facilitated predictive processing, as evidenced by an interaction. We observed only weak evidence for the involvement of working memory in predictive sentence comprehension. Age had a nonlinear main effect (younger adults responded faster than children and older adults), but it did not differentially modulate predictive and non-predictive processing, nor did it modulate the involvement of processing speed and working memory. Our results contribute to delineating the cognitive skills that are involved in language-vision interactions.

The effect of complex cognitive context on the dynamic stability during gait initiation in older women.

Changes in cognitive control are considered potential factors affecting voluntary motor movements during gait initiation (GI). Simulating environments with higher cognitive resource demands have an effect on the stability of GI task performance, which is of significant importance for assessing fall risk in the older adults and devising fall risk management measures in multiple environments. This study aims to reveal the influence of complex cognitive competitive environment with increased cognitive demands on the dynamic stability during GI in the older women. Twenty-three older females and twenty-three younger females performed walking tests under three conditions: voluntary initiation (SI), visual light reaction time task (LRT), and cognitive interference + visual light reaction time task (C + LRT). Eight cameras (Qualisys, Sweden, model: Oqus 600) and three force plates (Kistler, Switzerland, model: 9287C) are used to obtain kinematic and kinetic data. To recorde the trajectory of center of pressure (CoP) and the position of the foot placement, and compute the anterior-posterior (A-P) and medio-lateral (M-L) dynamic stability at the onset and end moments of the single-leg support by means of center of mass (CoM) and gait spatiotemporal parameters. Older women responded to the effect of complex environments involving cognitive competition on body stability by prolonging the lateral displacement time of the CoP during the anticipatory postural adjustments (APAs) phase, reducing step length and velocity, and increasing step width and foot inclination angle. Complex initiation environments lead to competition for cognitive resources in the brain, resulting in decreased stability of GI motor control in older adults. The higher the complexity of the cognitive resource demands environment, the lower the stability of GI in older adults, and the greater the effect on their M-L stability at the onset of stepping.

Effect of Plyometric Exercises Versus Speed Agility Quickness Training on Agility, Speed, Power, Dynamic Balance and Reaction Time in Amateur Badminton Players

Background: Badminton being one of the most popular and fastest racket sport, demands the players to have different skills and fitness level in-order to excel. Skills like power, agility, speed, dynamic balance and reaction time are few of them. Aim: This study aims to compare the effect of plyometric exercises versus speed agility quickness (SAQ) training on agility, speed, power, dynamic balance and reaction time in badminton players. Methods: An experimental study was conducted in 36 amateur badminton player who were divided in 3 groups with 12 participants in each - Plyometric training group, SAQ training group and control group. All received intervention for 6 weeks. The outcome measures used were a) agility- Illinois agility test, b) speed- 30 meters’ sprint test, c) power- vertical jump test, d) dynamic balance- modified star excursion balance test and e) Reaction time- simple visual reaction time task. Statistical analysis: Statistical analysis was performed using SPSS software, version 24. Paired t test was used to compare pre-post differences in each group. Intergroup comparison was evaluated using ANOVA test. Results: Plyometric group showed a significant improvement in the agility, speed, power, posterolateral and posteromedial directions in modified star excursion balance test and reaction time using paired t test. Speed Agility Quickness group revealed significant difference in speed, agility, all three directions in modified star excursion balance test. In control group, significant improvement was seen only in anterior and posteromedial directions in modified star excursion balance test. There was significant difference between the groups in agility, power and speed using ANOVA test. Further post hoc analysis revealed that plyometric and SAQ group showed no statistically significant difference when compared with each other except for power which showed more improvement in the plyometric group. Conclusion: Both plyometric and SAQ training were equally effective in improving speed and agility in badminton players. Power was seen to be improved more in plyometric group. Hence, these training protocols can be used as evidence-based approach to improve skills in badminton players for optimal performance. KEYWORDS: plyometric, SAQ, badminton players, power, agility, speed, dynamic balance, reaction time.

Listening Effort in Hearing Aid Users: Is It Related to Hearing Aid Use and Satisfaction?

Listening effort is primarily reflective of real-world performance. Therefore, it is crucial to evaluate the listening effort to predict the performance of hearing aid (HA) users in their daily lives. This study aimed to investigate the relationship between listening effort, daily HA use time, and HA satisfaction. This is a cross-sectional study. Thirty-three bilateral behind-the-ear HA users (17 females and 16 males) between 19 and 37 years were participated. All participants had bilateral, symmetric, moderate sensorineural hearing loss and at least 6 months of experience using HAs. The pure-tone average thresholds (PTA) of the participants' left and right ears were 55.34 ± 4.38 and 54.85 ± 5.05, respectively. First, daily HA use times of the last 30 days were derived from data logging. Second, participants were asked to fill in the Satisfaction with Amplification in Daily Life Scale questionnaire (SADL). Lastly, participants performed the dual-task paradigm to evaluate listening effort. The dual-task paradigm consisted of a primary speech recognition task that included three different individualized signal-to-noise ratio (SNR) conditions, that is, SNR100, SNR80, and SNR50, which the participant could understand 100, 80, and 50% of the speech, respectively. The secondary task was a visual reaction time task that required participants to press the key in response to a visual probe (an image of a white or red rectangle). Multiple linear regression analyses were used to model the effect of factors (daily HA use time and HA satisfaction) on reaction times (RT) of each three individualized SNR sessions. Mean daily HA use time of the participants was 5.72 ± 4.14 hours. Mean RTs of SNR50, SNR80, and SNR100 conditions were 1,050.61 ± 286.49, 893.33 ± 274.79, and 815.45 ± 233.22 ms, respectively. Multiple linear regression analyses showed that daily HA use time and HA satisfaction are significantly related to listening effort in all SNR conditions. For SNR80 condition; F (2,30) = 47.699, p < 0.001, with an adjusted R 2 of 0.745. As far as we know, this study is the first to demonstrate a strong link between listening effort, daily HA use time, and HA satisfaction. Evaluating listening effort following the HA fitting session may provide preliminary information about the treatment success of HA.

The Impact of Acute Tinnitus on Listening Effort: A Study Based on Clinical Observations of Sudden Sensorineural Hearing Loss Patients.

This study investigates the relationship between listening effort and acute tinnitus over the clinical course of sudden sensorineural hearing loss (SSNHL) before and after treatment. Thirty SSNHL patients with acute tinnitus were enrolled in this prospective study. Each patient was evaluated before treatment and after 1 and 3 months of follow-up. Listening effort was evaluated in the unaffected ears in two conditions (with and without background noise) using a dual-task paradigm, which included a primary (speech recognition) task and a secondary (visual reaction time) task. Tinnitus severity was assessed with the Tinnitus Handicap Inventory (THI). It was observed that background noise significantly increased listening effort in SSNHL patients with acute tinnitus before and after treatment. THI scores and listening effort in quiet conditions (** p = 0.009) were significantly decreased three months after treatment. In an analysis of the relation between tinnitus severity and listening effort, it was found that the THI total score was significantly correlated with listening effort in quiet (* p = 0.0388) and noisy conditions (* p = 0.044) before treatment. We concluded that SSNHL patients with acute tinnitus exerted greater listening effort in the presence of background noise than in quiet conditions. Furthermore, listening effort was reduced as tinnitus improved in SSNHL patients during the three months after treatment. Both before and after 3 months of treatment, patients who were more affected and emotionally distressed by tinnitus tended to exert more listening effort in both quiet and noisy environments.

Convergent cross-species pro-cognitive effects of RGH-235, a new potent and selective histamine H3 receptor antagonist/inverse agonist

The histamine H3 receptor is a favourable target for the treatment of cognitive deficits. Here we report the in vitro and in vivo profile of RGH-235, a new potent, selective, and orally active H3 receptor antagonist/inverse agonist developed by Gedeon Richter Plc. Radioligand binding and functional assays were used for in vitro profiling. Procognitive efficacy was investigated in rodent cognitive tests, in models of attention deficit hyperactive disorder (ADHD) and in cognitive tests of high translational value (rat touch screen visual discrimination test, primate fixed-foreperiod visual reaction time task). Results were supported by pharmacokinetic studies, neurotransmitter release, sleep EEG and dipsogenia. RGH-235 displayed high affinity to H3 receptors (Ki = 3.0–9.2 nM, depending on species), without affinity to H1, H2 or H4 receptors and >100 other targets. RGH-235 was an inverse agonist ([35S] GTPγS binding) and antagonist (pERK1/2 ELISA), showing favourable kinetics, inhibition of the imetit-induced dipsogenia and moderate effects on sleep-wake EEG. RGH-235 stimulated neurotransmitter release both in vitro and in vivo. RGH-235 was active in spontaneously hypertensive rats (SHR), generally considered as a model of ADHD, and revealed a robust pro-cognitive profile both in rodent and primate tests (in 0.3–1 mg/kg) and in models of high translational value (e.g. in a rodent touch screen test and in non-human primates). The multiple and convergent procognitive effects of RGH-235 support the view that beneficial cognitive effects can be linked to antagonism/inverse agonism of H3 receptors.

Auditory cognition and perception of action video game players

A training method to improve speech hearing in noise has proven elusive, with most methods failing to transfer to untrained tasks. One common approach to identify potentially viable training paradigms is to make use of cross-sectional designs. For instance, the consistent finding that people who chose to avidly engage with action video games as part of their normal life also show enhanced performance on non-game visual tasks has been used as a foundation to test the causal impact of such game play via true experiments (e.g., in more translational designs). However, little work has examined the association between action video game play and untrained auditory tasks, which would speak to the possible utility of using such games to improve speech hearing in noise. To examine this possibility, 80 participants with mixed action video game experience were tested on a visual reaction time task that has reliably shown superior performance in action video game players (AVGPs) compared to non-players (≤ 5 h/week across game categories) and multi-genre video game players (> 5 h/week across game categories). Auditory cognition and perception were tested using auditory reaction time and two speech-in-noise tasks. Performance of AVGPs on the visual task replicated previous positive findings. However, no significant benefit of action video game play was found on the auditory tasks. We suggest that, while AVGPs interact meaningfully with a rich visual environment during play, they may not interact with the games’ auditory environment. These results suggest that far transfer learning during action video game play is modality-specific and that an acoustically relevant auditory environment may be needed to improve auditory probabilistic thinking.

Effect of Different Spectral Power Distributions on Mesopic Visual Performance with Blue Light-filtering Intraocular Lens

ABSTRACT The purpose of this work is to analyze the interaction between the spectral transmittance of old-aged subjects, before and after cataract surgery and blue light-filtering intraocular lens implantation, and the spectral power distribution of common street lamps, under conditions typical of nighttime driving. We analyzed contrast threshold and visual reaction time in off-axis vision at different mesopic illumination conditions provided by high-pressure sodium and metal halide lamps. Three groups of subjects with different spectral transmittances participated: young subjects as control group, old-aged subjects with senile cataracts and the same subjects after cataract surgery and blue light-filtering IOL implantation. A clear interaction appears between the spectral power distribution and the spectral transmittance, depending on the visual task. Transparent ocular media allow benefiting from the greater short-wavelength content of the halide lamp. However, cataracts increase contrast threshold and visual reaction time values and also affects how the spectral power distribution influences these visual tasks. After surgery and intraocular lens implantation, visual performance improves for both lamps and the blue light-filter seems to influence spectral transmittance, which affects visual performance under light provided by greater short-wavelength content lamps. Cataract surgery is responsible for an improvement in contrast threshold and visual reaction time tasks, though blue light-filtering of the intraocular lens seems to prevent the visual system from benefiting from lamps with greater emission at short wavelengths.

Bilingualism and Processing Speed in Typically Developing Children and Children With Developmental Language Disorder.

Purpose The aim of the current study was to investigate whether dual language experience modulates processing speed in typically developing (TD) children and in children with developmental language disorder (DLD). We also examined whether processing speed predicted vocabulary and sentence-level abilities in receptive and expressive modalities. Method We examined processing speed in monolingual and bilingual school-age children (ages 8-12 years) with and without DLD. TD children (35 monolinguals, 24 bilinguals) and children with DLD (17 monolinguals, 10 bilinguals) completed a visual choice reaction time task. The Clinical Evaluation of Language Fundamentals, the Peabody Picture Vocabulary Test, and the Expressive Vocabulary Test were used as language measures. Results The children with DLD exhibited slower response times relative to TD children. Response time was not modified by bilingual experience, neither in children with typical development nor children with DLD. Also, we found that faster processing speed was related to higher language abilities, but this relationship was not significant when socioeconomic status was controlled for. The magnitude of the association did not differ between the monolingual and bilingual groups across the language measures. Conclusions Slower processing speed is related to lower language abilities in children. Processing speed is minimally influenced by dual language experience, at least within this age range. Supplemental Material https://doi.org/10.23641/asha.12210311.

Acute fatigue affects reaction times and reaction consistency in Mixed Martial Arts fighters.

Mixed Martial Arts (MMA) is a multielement combat sport where fighters need to quickly react to an opponent’s movements under fatigued conditions. Research indicates that fast reaction time is important in many sports, but the effect of fatigue has shown negative, null, or even positive influences on reaction time. However, few studies have been conducted in a controlled setting, especially using MMA figthers, whose matches are frequently resolved in a split-second. Therefore, this study investigated whether acute neuromuscular fatigue affects reaction and movement times, and their consistency in MMA fighters (N = 45). Before and after an upper-body Wingate test, a simple visual reaction time task was completed. Results showed a significant negative effect of fatigue on the reaction times and their consistency, with longer reactions (1.5% change) and lower consistency (14.7% change) after the Wingate test. Further, greater amounts of fatigue during the Wingate test seemed to negatively affect the consistency of post-Wingate movement time. Due to cumulative fatigue and the dynamic nature of MMA, our data indicate that not only the decrements in aerobic and anaerobic power likely affect a fighter’s performance, but their reaction time and motor time may also be compromised during a fight.

Optic flow and attention alter locomotion differently in the young and old

BackgroundOptic flow is used in the control of walking speed and aids in navigation through space. However, the influence of attention on optic flow processing during locomotion is not known. Research Question: Does attentional focus influence the processing of optic flow during locomotion in young and older adults? MethodsAuditory and visual concurrent reaction time tasks were conducted while walking on a treadmill within an anterior-posterior modulating optic flow field in young and older adults. Optic flow was generated with full field back-projected scenes shown while walking on a treadmill under three conditions: a) optic flow consistent with the treadmill speed, b) slow sinusoidal modulation of the speed (SINE), and c) reversals of optic flow velocity from congruent with walking to the opposite direction (REV). Movement in response to the scenes along with reaction times were measured. ResultsThe optic flow perturbations altered movement on the treadmill. Older adults responded more than young adults during the slowly changing sinusoidal perturbations, but not to the rapid reversing scenes. Our main hypothesis that sensory modality of a concurrent cognitive task influences the processing of optic flow was confirmed for the reversing optic flow condition but not for the sinusoidal optic flow. The impact of optic flow conditions on reaction times was only found during the REV condition, with impact on visual RTs being greater than auditory RTs. SignificanceTaken together, the results suggest attentional focus on sensory modality of concurrent tasks while walking can impact optic flow processing for navigation and control; however, the characteristics of the optic flow (e.g. perturbation speed) play an important role.

Motivated to Gain: Awareness of an Impending Ending and the Ending Effect.

The ending effect describes the phenomenon that individuals are more risk-taking during the final round of a series of risky decision tasks. Previous research suggests that the ending effect might be caused by a motivational shift induced by changes in time perception. However, none of the existing research directly tested the motivational state immediately before the last round of a series of risky decision tasks. To fill in this gap of knowledge, the present study tested whether this motivational shift indeed occurs immediately before the last round. All participants worked on 11 rounds of risky decision tasks, half of them knew that the decision tasks included 11 rounds, whereas the other half did not know. Before the last round of the risky decision tasks, all participants completed a visual reaction time task. It was found that, compared with participants who were not aware of the impending ending, those who knew they were approaching the last round responded to peripherally located character strings appearing immediately after gain-related words slower than those appearing after loss-related words, suggesting that perceived endings lead participants to be more motivated toward gaining rewards. This work provides critical evidence which supports the motivational account of the ending effect proposed in previous research. Such a finding would represent a next step in unpacking the psychological consequences of perceived endings in everyday life.

Asymmetric Dopaminergic Degeneration and Attentional Resources in Parkinson's Disease.

Background: Attention is crucial to voluntary perform actions in Parkinson’s disease (PD), allowing patients to bypass the impaired habitual motor control. The asymmetrical degeneration of the dopaminergic system could affect the attentional functions.Objective: To investigate the relationship between the asymmetric dopaminergic degeneration and the attentional resources in Parkinsonian patients with right-side (RPD) and left-side (LPD) motor symptoms predominance.Methods: 50 RPD, 50 LPD, and 34 healthy controls underwent visual (V), auditory (A), and multiple choices (MC) reaction time (RTs) tasks. For PD patients, these tasks were performed before and after a 4-week intensive, motor-cognitive rehabilitation treatment (MIRT). The effectiveness of treatment was evaluated assessing Unified Parkinson’s disease Rating Scale (UPDRS) III and Timed-up and Go Test (TUG).Results: RTs did not differ between PD patients and healthy controls. Before MIRT, no differences between LPD and RPD patients were observed in RTs (p = 0.20), UPDRS III (p = 0.60), and TUG (p = 0.38). No differences in dopaminergic medication were found between groups (p = 0.44 and p = 0.66 before and after MIRT, respectively). After MIRT, LPD patients showed a significant reduction in MC RTs (p = 0.05), V RTs (p = 0.02), and MC-V RTs. A significant association between changes in RTs and improvements in UPDRS III and TUG was observed in LPD patients.Conclusion: attention does not differ among RPD patients, LPD patients and healthy controls. Only LPD patients improved their performances on attentional tasks after MIRT. We argue that the increased early susceptibility of the left nigrostriatal system to degeneration affects differently the cognitive modifiability and the neuroplastic potential. Our results could provide insight into new therapeutic approaches, highlighting the importance to design different treatments for RPD patients and LPD patients.

Orbitofrontal Lesion Alters Brain Dynamics of Emotion-Attention and Emotion-Cognitive Control Interaction in Humans.

Patients with lesion to the orbitofrontal cortex (OFC) experience challenges in emotional control and emotion-guided behaviors. The OFC is known to participate in executive functions and attentional control of emotion and our previous research suggests OFC lesion alters the balance between voluntary and involuntary attention and cognitive control within the context of emotion. To better understand how OFC lesion affects the dynamics and interaction of these functions, we studied EEG and performance of 12 patients with lesion to the OFC and 11 control subjects with intact OFC in a Go/NoGo visual reaction time (RT) task with neutral targets and intervening threat-related emotional distractors (Executive RT Test). Event-related potentials (ERPs), specifically N2P3 peak-to-peak amplitude and the following late positive potential (LPP), were used to measure allocation of attention and cognitive control to emotional distractors. Task performance and Behavior Rating Inventory of Executive Functions—Adult version (BRIEF-A) scores were used to assess executive functions. As expected, the Control group showed increased N2P3 amplitude in the context of threat-related distractors, particularly over the right hemisphere, while LPP was not modulated by these distractors. In contrast, patients with OFC lesion showed no such impact of threat-related distractors on N2P3 amplitude but exhibited increased and prolonged left-lateralized impact of threat on LPP in the Go-condition. In NoGo-condition, the N2P3 amplitude was increased in both groups due to threat, but the impact was seen earlier, i.e., at the N2 peak in the OFC group and later at the P3 peak in Controls. The OFC group committed more errors in the Executive RT Test and reported more problems in BRIEF-A, thus both objective and subjective evidence for challenges in executive functions was obtained in patients with orbitofrontal lesion. Furthermore, the time-course of attention allocation and cognitive control towards task-irrelevant emotional stimuli was altered as evidenced by ERPs. We conclude that orbitofrontal lesion is associated with altered neural dynamics underlying the interaction of involuntary attention to emotion and cognitive control. These alterations in brain dynamics may underlie some of the challenges patients encounter in everyday life when emotional events interact with cognitive demands.

Medications influencing central cholinergic pathways affect fixation stability, saccadic response time and associated eye movement dynamics during a temporally-cued visual reaction time task.

Anticholinergic medications largely exert their effects due to actions on the muscarinic receptor, which mediates the functions of acetylcholine in the peripheral and central nervous systems. In the central nervous system, acetylcholine plays an important role in the modulation of movement. This study investigated the effects of over-the-counter medications with varying degrees of central anticholinergic properties on fixation stability, saccadic response time and the dynamics associated with this eye movement during a temporally-cued visual reaction time task, in order to establish the significance of central cholinergic pathways in influencing eye movements during reaction time tasks. Twenty-two participants were recruited into the placebo-controlled, human double-blind, four-way crossover investigation. Eye tracking technology recorded eye movements while participants reacted to visual stimuli following temporally informative and uninformative cues. The task was performed pre-ingestion as well as 0.5 and 2h post-ingestion of promethazine hydrochloride (strong centrally acting anticholinergic), hyoscine hydrobromide (moderate centrally acting anticholinergic), hyoscine butylbromide (anticholinergic devoid of central properties) and a placebo. Promethazine decreased fixation stability during the reaction time task. In addition, promethazine was the only drug to increase saccadic response time during temporally informative and uninformative cued trials, whereby effects on response time were more pronounced following temporally informative cues. Promethazine also decreased saccadic amplitude and increased saccadic duration during the temporally-cued reaction time task. Collectively, the results of the study highlight the significant role that central cholinergic pathways play in the control of eye movements during tasks that involve stimulus identification and motor responses following temporal cues.

Learning to search. The importance of eye movements in the decrease of response times during a visual choice reaction time task

Reaction times are often used as an indicator of the efficiency of the processes in thecentral nervous system. While extensive research has been conducted on the possibleresponse time correlates, the role of eye movements in visual tasks is yet unclear. Here wereport data to support the role of eye movements during visual choice reaction time training.Participant performance, reaction times, and total session duration improved. Eyemovementsshowed expected changes in saccade amplitude and resulted in improvementin visual target searching.

Related Factors and Predictors of Cognitive Dysfunction in Chronic Kidney Disease on Maintenance Hemodialysis in Nigeria.

Background:Previous studies suggest a high frequency of cognitive impairment (CI) in persons with chronic kidney disease (CKD); however, factors associated with CI and predictors of CI in persons with CKD remain largely unclear. The aim of this study was to determine the factors associated with CI and predictors of CI in CKD patients on maintenance hemodialysis.Materials and Methods:The first stage of the study included recruitment of 100 apparently healthy participants aimed at determining the reference values. The second stage of the study included eighty CKD patients on maintenance hemodialysis. The iron psychology (FEPSY) was used to assess the memory, psychomotor speed, concentration, and attention using simple auditory reaction time (ART) and visual reaction time (VRT) tasks, recognition memory tests (RMT), finger tapping task (FTT), and binary choice task (BCT).Results:Using normative values generated in this study, 41 (51.3%) and 43 (53.8%) CKD patients had abnormal scores on ART dominant (D) and nondominant (ND) sides, respectively. Forty (50%) and 42 (52.5%) patients had abnormal scores on VRT D and ND sides, respectively. Twenty-one (26.3%) and 68 (85%) had abnormal scores on BCT and computer-assisted visual scanning task, respectively. Sixty-four (80%) and 65 (81.3%) had abnormal scores on RMT (words) and RMT, respectively. Fifty-two (65%) and 48 (60%) patients had abnormal scores on D and ND sides of (FTT), respectively. Factors associated with psychomotor speed impairment were duration of CKD from diagnosis (P = 0.0001 and 0.043 in D and ND ART, respectively), duration on dialysis (P = 0.0001 across board in D and ND ART as well as in D and ND VRT, respectively), and plasma urea (PU) and plasma creatinine (PCr) (P < 0.05). Factors found to be associated with memory impairment included age (P = 0.045 and 0.025 on words and figures RMT, respectively), PU (P = 0.002 and 0.005 on words and figures RMT, respectively), and PCr (P = 0.012 and 0.040 on words and figures RMT, respectively). Duration on dialysis (P = 0.032) and PCr (P = 0.001) were associated with attention and concentration. Only psychomotor speed was independently predicted by duration of CKD.Conclusion:Factors associated with psychomotor speed impairment were duration of CKD, duration on dialysis, and PU and PCr while age, PU, and PCr were associated with memory. Duration on dialysis and PCr were associated with attention and concentration. Only psychomotor speed was independently predicted by duration of CKD.

Psychometric Functions of Dual-Task Paradigms for Measuring Listening Effort.

The purpose of the study was to characterize the psychometric functions that describe task performance in dual-task listening effort measures as a function of signal to noise ratio (SNR). Younger adults with normal hearing (YNH, n = 24; experiment 1) and older adults with hearing impairment (n = 24; experiment 2) were recruited. Dual-task paradigms wherein the participants performed a primary speech recognition task simultaneously with a secondary task were conducted at a wide range of SNRs. Two different secondary tasks were used: an easy task (i.e., a simple visual reaction-time task) and a hard task (i.e., the incongruent Stroop test). The reaction time (RT) quantified the performance of the secondary task. For both participant groups and for both easy and hard secondary tasks, the curves that described the RT as a function of SNR were peak shaped. The RT increased as SNR changed from favorable to intermediate SNRs, and then decreased as SNRs moved from intermediate to unfavorable SNRs. The RT reached its peak (longest time) at the SNRs at which the participants could understand 30 to 50% of the speech. In experiments 1 and 2, the dual-task trials that had the same SNR were conducted in one block. To determine if the peak shape of the RT curves was specific to the blocked SNR presentation order used in these experiments, YNH participants were recruited (n = 25; experiment 3) and dual-task measures, wherein the SNR was varied from trial to trial (i.e., nonblocked), were conducted. The results indicated that, similar to the first two experiments, the RT curves had a peak shape. Secondary task performance was poorer at the intermediate SNRs than at the favorable and unfavorable SNRs. This pattern was observed for both YNH and older adults with hearing impairment participants and was not affected by either task type (easy or hard secondary task) or SNR presentation order (blocked or nonblocked). The shorter RT at the unfavorable SNRs (speech intelligibility < 30%) possibly reflects that the participants experienced cognitive overload and/or disengaged themselves from the listening task. The implication of using the dual-task paradigm as a listening effort measure is discussed.

Gestalt Perceptual Organization of Visual Stimuli Captures Attention Automatically: Electrophysiological Evidence

The visual system leverages organizational regularities of perceptual elements to create meaningful representations of the world. One clear example of such function, which has been formalized in the Gestalt psychology principles, is the perceptual grouping of simple visual elements (e.g., lines and arcs) into unitary objects (e.g., forms and shapes). The present study sought to characterize automatic attentional capture and related cognitive processing of Gestalt-like visual stimuli at the psychophysiological level by using event-related potentials (ERPs). We measured ERPs during a simple visual reaction time task with bilateral presentations of physically matched elements with or without a Gestalt organization. Results showed that Gestalt (vs. non-Gestalt) stimuli are characterized by a larger N2pc together with enhanced ERP amplitudes of non-lateralized components (N1, N2, P3) starting around 150 ms post-stimulus onset. Thus, we conclude that Gestalt stimuli capture attention automatically and entail characteristic psychophysiological signatures at both early and late processing stages.HighlightsWe studied the neural signatures of the automatic processes of visual attention elicited by Gestalt stimuli. We found that a reliable early correlate of attentional capture turned out to be the N2pc component. Perceptual and cognitive processing of Gestalt stimuli is associated with larger N1, N2, and P3

Gaze shifts during dual-tasking stair descent.

To investigate the role of vision in stair locomotion, young adults descended a seven-step staircase during unrestricted walking (CONTROL), and while performing a concurrent visual reaction time (RT) task displayed on a monitor. The monitor was located at either 3.5 m (HIGH) or 0.5 m (LOW) above ground level at the end of the stairway, which either restricted (HIGH) or facilitated (LOW) the view of the stairs in the lower field of view as participants walked downstairs. Downward gaze shifts (recorded with an eye tracker) and gait speed were significantly reduced in HIGH and LOW compared with CONTROL. Gaze and locomotor behaviour were not different between HIGH and LOW. However, inter-individual variability increased in HIGH, in which participants combined different response characteristics including slower walking, handrail use, downward gaze, and/or increasing RTs. The fastest RTs occurred in the midsteps (non-transition steps). While gait and visual task performance were not statistically different prior to the top and bottom transition steps, gaze behaviour and RT were more variable prior to transition steps in HIGH. This study demonstrated that, in the presence of a visual task, people do not look down as often when walking downstairs and require minimum adjustments provided that the view of the stairs is available in the lower field of view. The middle of the stairs seems to require less from executive function, whereas visual attention appears a requirement to detect the last transition via gaze shifts or peripheral vision.