Reaction Time Latency Research Articles

Altered individual behavioral and EEG parameters are related to the EDSS score in relapsing-remitting multiple sclerosis patients.

Functional neuroanatomy of cognitive impairment in multiple sclerosis is currently still a challenge. During the progression of the disease, several cognitive mechanisms deteriorate thus diminishing the patient’s quality of life. A primary objective in the cognitive assessment of multiple sclerosis (MS) patients is to find reliable measures utilizing diverse neuroimaging techniques. Moreover, especially relevant in the clinical environment is finding technical approaches that could be applied to individual participants and not only for group analysis. A 64-channel electroencephalographic recording (EEG) was made with thirty participants divided into three groups of equivalent size (N = 10) (healthy control, low-EDSS (1–2.5) and moderate-EDSS (4–6)). Correlation analysis was applied to multiple measures: behavior, neuropsychological tests (Paced Auditory Serial Addition Test, 3 seconds (PASAT-3s) and the Symbol Digit Modality Test (SDMT)), Expanded Disability Status Scale (EDSS), even-related potential (P3) and event-related desynchronization (ERD) parameters and the correlation scores between individual participant’s P3/ERD maps and the healthy grand average P3/ERDmaps. Statistical analysis showed that diverse parameters exhibited significant correlations. A remarkable correlation was the moderate score found between SDMT and EDSS (r = −0.679, p = 0.0009). However, the strongest correlation was between the value of integrated measures (reaction time, P3 and ERD latency) and EDSS (r = 0.699, p = 0.0006). In regard to correlations for grand average maps between groups, the P3 component exhibited a lower score according to a more deteriorated condition (higher EDSS). In contrast, ERD maps remained stable with an increase of EDSS. Lastly, a Z-transformation of individual values of all variables included in the study exhibited heterogeneity in cognitive alterations in the multiple sclerosis participants.

Visuo-oculomotor Function and Reaction Times in Athletes with and without Concussion.

Oculomotor tests in concussion commonly show impairment in smooth pursuit and saccadic function. Honing in on the systems likely to be affected by concussion will streamline use of oculomotor function as a supplemental diagnostic and prognostic tool, as well as improve our understanding of the pathophysiology of concussion. This study investigates oculomotor function between concussed and healthy collegiate athletes and determines measurement test-retest reliability of those tools. Eighty-seven healthy athletes were recruited from a U.S. Division 1 sports university and completed a 30-minute vestibular ocular testing battery in an enclosed rotary chair system equipped with 100-Hz eye-tracking goggles. Forty-three individuals completed the battery twice. Twenty-eight individuals with a current diagnosis of concussion also completed the battery. All participants were aged 18 to 24 years. Bivariate statistical tests examined differences in scores across groups, and intraclass coefficients were computed to test reliability. Concussed individuals had significantly longer saccadic, visual, and dual-task reaction times and reduced saccadic accuracy. There was no difference in optokinetic reflex gain, but few concussed individuals tolerated the task. Reaction time latencies and optokinetic gain show moderate test-retest reliability. Smooth pursuit tasks and saccadic accuracies showed poor test-retest reliability. Saccadic latency was the most sensitive oculomotor function to change after concussion and was reliable over time. Saccadic accuracy was significantly lower in the concussed group but had poor retest reliability. Optokinetic gain may warrant more investigation because of its high test-retest reliability and symptom provocation in concussion, despite not showing a significant difference between groups.

Comparing the Relative Strengths of EEG and Low-Cost Physiological Devices in Modeling Attention Allocation in Semiautonomous Vehicles.

As semiautonomous driving systems are becoming prevalent in late model vehicles, it is important to understand how such systems affect driver attention. This study investigated whether measures from low-cost devices monitoring peripheral physiological state were comparable to standard EEG in predicting lapses in attention to system failures. Twenty-five participants were equipped with a low-fidelity eye-tracker and heart rate monitor and with a high-fidelity NuAmps 32-channel quick-gel EEG system and asked to detect the presence of potential system failure while engaged in a fully autonomous lane changing driving task. To encourage participant attention to the road and to assess engagement in the lane changing task, participants were required to: (a) answer questions about that task; and (b) keep a running count of the type and number of billboards presented throughout the driving task. Linear mixed effects analyses were conducted to model the latency of responses reaction time (RT) to automation signals using the physiological metrics and time period. Alpha-band activity at the midline parietal region in conjunction with heart rate variability (HRV) was important in modeling RT over time. Results suggest that current low-fidelity technologies are not sensitive enough by themselves to reliably model RT to critical signals. However, that HRV interacted with EEG to significantly model RT points to the importance of further developing heart rate metrics for use in environments where it is not practical to use EEG.

Residential exposure to urban traffic is associated with the poorer neurobehavioral health of Ecuadorian schoolchildren

PurposeWe investigated whether chronic traffic-generated air pollution containing fine and ultrafine particulate matter is associated with reduced neurobehavioral performance and behavioral dysfunction in urban Ecuadorian schoolchildren. Also, we examined the effect of child hemoglobin and sociodemographic risk factors on these neurocognitive outcomes. MethodsA convenience sample of healthy children aged 8–14 years attending public schools were recruited in Quito, Ecuador. Child residential proximity to the nearest heavily trafficked road was used as a proxy for traffic-related pollutant exposure. These included high exposure (<100 m), medium exposure (100–199 m) and low exposure (≥ 200 m) from the nearest heavily trafficked road. The Behavioral Assessment and Research System (BARS), a computerized test battery assessing attention, memory, learning and motor function was used to evaluate child neurobehavioral performance. The Child Behavior Checklist (CBCL/6-18) was used to assess child behavioral dysfunction as reported by mothers. The data were analyzed using multiple linear regression. ResultsChildren with the highest residential exposure to traffic pollutants (< 100 m) had significantly longer latencies as measured by match to sample (b = 410.27; p = 0.01) and continuous performance (b = 37.90; p = 0.02) compared to those living ≥ 200 m away. A similar but non-significant association was observed for reaction time latency. Children living within 100 m of heavy traffic also demonstrated higher scores across all CBCL subscales although only the relationship with thought problems (p = 0.05) was statistically significant in the adjusted model. ConclusionThe study findings suggest that children living within 100 m of heavy traffic appear to experience subtle neurobehavioral deficits that may result from fine and ultrafine particulate matter exposure.

Cortical thickness, neurocognitive, and body composition effects of fasting during Ramadan.

Background:We aimed to study the anatomical, physiological, and cognitive function of healthy individuals practicing fasting during the month of Ramadan. Measurements were taken 1 week before and 2 weeks after Ramadan fasting.Materials and Methods:Twelve healthy male individuals (mean age ± standard error of the mean: 34.3 ± 2.9 years; body mass index: 26.26 ± 1.4 kg/m2) were assessed for various parameters before and after Ramadan fasting. All the tests were performed in the morning. Body composition characteristics were assessed by bioelectrical impedance analysis using a commercially available body composition analyzer. For neurocognitive analysis, participants underwent the stop signal task (SST), pattern recognition memory task (PRM), and spatial working memory strategy (SWM) from the Cambridge Neuropsychological Test Automated Battery. T1-weighted, 1 mm-thick magnetic resonance images were also acquired.Results:Anthropometric analysis showed a significant decrease in body weight, fat-free mass (FFM), trunk FFM, and trunk predicted muscle mass, while the other body composition parameters did not exhibit any changes. The stop signal reaction time (SSRT) latency (ms) (P > 0.05) and PRM did not show any significant difference before and after fasting. SWM task (P < 0.05) improved significantly after fasting. Cortical thickness data of the whole brain were not significantly different after fasting at any brain location. There was a significant correlation between the left amygdala and the SWM strategy (r2 = 0.518) and between fat and brain segmentation volume (r2 = 0.375).Conclusion:Our pilot data suggest that Ramadan fasting leads to weight loss and FFM reductions and improve cognitive function.

Differences in Reaction Time Latency Error on the ANAM4 Across Three Computer Platforms

To investigate the difference of reaction time (RT) measurement on the ANAM4 across three different computer platforms.

Spatial learners display enhanced oculomotor performance

ABSTRACTAttention is important during navigation processes that rely on a cognitive map, as spatial relationships between environmental landmarks need to be selected, encoded, and learned. Spatial learners navigate using this process of cognitive map formation, which relies on the hippocampus. Conversely, response learners memorise a series of actions to navigate, which relies on the caudate nucleus. The present study aimed to investigate the relationship between spatial learning and oculomotor performance. We tested 23 response learners and 23 spatial learners, as determined by the 4-on-8 virtual maze, on an antisaccade task with a gap and emotional visual stimulus manipulation. Spatial learners displayed decreased saccadic reaction time latencies compared to response learners. Performance cost from the gap manipulation was significantly higher in response learners. These results could represent an attentional practice effect through the use of spatial strategies during navigation or a more global increase in cognitive function amongst spatial learners.

A Large-Scale Reanalysis of Childhood Fitness and Inhibitory Control

The aim of this study was to reanalyze several datasets to investigate the relation of childhood aerobic fitness on cognition via a number of task performance outcomes and the P3 event-related brain potential component during a modified flanker task, which modulates inhibitory control demands. In a sample of 702 preadolescent children (ages 8–11; 342 females), demographic measures of age, sex, IQ, socioeconomic status, and pubertal status were considered along with aerobic fitness (i.e., VO2peak%). Correlational analyses were conducted to determine the influence of the demographic variables and aerobic fitness on inhibitory control outcomes of response accuracy, reaction time (RT), response variability, interference control, cognitive strategies, P3 amplitude, and P3 latency. Subsequent hierarchical regression analyses were performed with significant demographic factors in the first step and aerobic fitness in the final step. Results indicated that after accounting for significant demographic variables specific to each dependent outcome, aerobic fitness was positively related to response accuracy, with no such relations observed for response speed (RT) for congruent and incongruent conditions of the flanker task. However, greater aerobic fitness was associated with less RT variability and lower accuracy interference. In terms of cognitive strategies, greater fitness was also associated with better discrimination accuracy as well as faster and better quality of information uptake. Across a 15-site region of interest around the topographic maximum, findings indicated that aerobic fitness was positively associated with larger P3 amplitude during incongruent trials. No such relation was observed for P3 latency. Relying on a large aggregated dataset, we demonstrated that aerobic fitness may be particularly beneficial to the allocation of attentional resources, as indexed by P3 amplitude as well as response accuracy and intraindividual variability. These findings, while generalized across inhibitory control demands, were especially related to trials that required greater amounts of inhibition. Thus, aerobic fitness may benefit brain and behavioral outcomes during childhood and has public health implications for the role of childhood physical activity on aspects of cognition that underlie scholastic performance and lifelong effective functioning.

Intraindividual Variability in Inhibition and Prospective Memory in Healthy Older Adults: Insights from Response Regularity and Rapidity

Successful prospective memory (PM) performance relies on executive functions, including inhibition. However, PM and inhibition are usually assessed in separate tasks, and analytically the focus is either on group differences or at most on interindividual differences. Conjoint measures of PM and inhibition performance that take into account intraindividual variability (IIV) are thus missing. In the present study, we assessed healthy older adults’ level of performance and IIV in both inhibition and PM using a classical Go/NoGo task. We also created a prospective Go/NoGo version that embeds a PM component into the task. Using dynamic structural equation modeling, we assessed the joint effects of mean level (), an indicator of amplitude of fluctuations in IIV (or net IIV; intraindividual standard deviation, iSD), and an indicator of time dependency in IIV (the autoregressive parameter ) in reaction times (RTs) on inhibition and PM performance. Results indicate that higher inhibition failure, but not IIV, predicted PM errors, corroborating the current literature on the involvement of prepotent response inhibition in PM processes. In turn, fastest RT latency () and increased net IIV (iSD) were consistently associated with prepotent response inhibition failure, while coherence in RT pattern () was beneficial to inhibition performance when the task was novel. Time-dependent IIV () appears to reflect an adaptive exploration of strategies to attain optimal performance, whereas increased net IIV (iSD) may indicate inefficient sustained cognitive processes when performance is high. We discuss trade-off processes between competing tasks.

Strabismic amblyopia affects decision processes preceding saccadic response

Amblyopia is a developmental disorder of vision associated with abnormal visual stimulation during early childhood. It is known that amblyopia may affect not only spatial vision parameters but also oculomotor behavior. Several previous studies showed that increased saccadic reaction time (latency) may be present in amblyopic subjects. In our recent work, we have demonstrated that not only amblyopic but also a dominant eye may show increased saccadic latency in strabismic individuals. Since saccadic latency can be considered as a decision time, we have applied LATER (Linear Approach to Threshold with Ergodic Rate) decision model to find out how developmental impairment of visual input affects visual decision-making processes, as well as to verify whether amblyopia affects also the cortical ability to inhibit more primitive, early saccadic responses during our modified delayed saccade task. Ten subjects with strabismic amblyopia and twelve control subjects were examined. As we expected, strabismic amblyopes showed decreased rate of rise of the neural decision signal for all viewing conditions as compared to controls. In addition, the comparison between the strabismic and anisometropic groups revealed that the amblyopic eye in strabismic subjects showed decreased rate of rise of the decision signal as compared to amblyopic eye in anisometropic subjects. Although we speculated that amblyopia may reduce the ability of cortical control and favor more reflexive, early saccadic actions to occur, our findings did not confirm this hypothesis. This study provide further evidence that amblyopia is associated with cortical deficits which affect the cortical decision about saccade initiation.

Characteristics of the cognitive evoked potentials in elderly people with cognitive decline

Results of research of cognitive visual evoked potentials at elderly women with various level of cognitive decline are shown in article. Both relevance of the early diagnostics of cognitive disorders and expedience of using of methods of functional neurovisualization to reveal higher cortical dysfunctions are shown also. To appraise cognitive functions we applied express-method of evaluating of cognitive functions during normal aging. According to results of this test two groups were created: the 1st - women without cognitive disorders, the 2nd - with mild cognitive impairment. The evoked potentials were registered for all participants with using of 128-channel system GES-300. Latency of P300-wave and reaction time were calculated. According to temporary characteristics of P300-wave it has been revealed that the group with cognitive decline differed in longer latent period in centro-temporo-parietal area of the left hemisphere, and also longer reaction time. However, latency of P300 in central-parietal areas of the right hemisphere was less than one at persons of the control group. These changes reflect dysfunction of structures of a medial temporal lobe which is expressed mainly by the memory disorders.

Using Eye Movements to Assess Language Comprehension in Toddlers Born Preterm and Full Term

To assess language skills in children born preterm and full term by the use of a standardized language test and eye-tracking methods. Children born ≤32 weeks' gestation (n = 44) were matched on sex and socioeconomic status to children born full term (n = 44) and studied longitudinally. The Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) were administered at 18 months (corrected for prematurity as applicable). The Looking-While-Listening Task (LWL) simultaneously presents 2 pictures and an auditory stimulus that directs the child's attention to one image. The pattern of eye movements reflects visual processing and the efficiency of language comprehension. Children born preterm were evaluated on LWL 3 times between 18 and 24 months. Children born full term were evaluated at ages corresponding to chronological and corrected ages of their preterm match. Results were compared between groups for the BSID-III and 2 LWL measures: accuracy (proportion of time looking at target) and reaction time (latency to shift gaze from distracter to target). Children born preterm had lower BSID-III scores than children born full term. Children born preterm had poorer performance than children born full term on LWL measures for chronological age but similar performance for corrected age. Accuracy and reaction time at 18 months' corrected age displaced preterm-full term group membership as significant predictors of BSID-III scores. Performance and rate of change on language comprehension measures were similar in children born preterm and full term compared at corrected age. Individual variation in language comprehension efficiency was a robust predictor of scores on a standardized language assessment in both groups.

Startle reveals decreased response preparatory activation during a stop-signal task.

In a stop-signal task participants are instructed to initiate a movement in response to a go signal, but to inhibit this movement if an infrequent stop signal is presented after the go. Reaction time (RT) in a stop-signal task is typically longer compared with that in a simple RT task, which may be attributed to a reduced readiness to initiate the response caused by the possibility of having to inhibit the response. The purpose of this experiment was to probe the preparatory activation level of the motor response during a stop-signal task using a startling acoustic stimulus (SAS), which has been shown to involuntarily trigger sufficiently prepared responses at a short latency. Participants completed two separate tasks: a simple RT task, followed by a stop-signal RT task. During both tasks, an SAS (120 dB) was pseudorandomly presented concurrently with the go signal. As expected, RT during the simple RT task was significantly shorter than during the stop-signal task. A significant reduction in RT was noted when an SAS was presented during the simple RT task; however, during the stop-signal task, an SAS resulted in either a significant speeding or a moderate delay in RT. Additionally, the subset of SAS trial responses with the shortest RT latencies produced during the stop-signal task were also delayed compared with the short-latency SAS trial responses observed during the simple RT task. Despite evidence that a response was prepared in advance of the go signal during a stop-signal task, it appears that the amount of preparatory activation was reduced compared with that achieved during a simple RT task.

Prolongation of ERP latency and reaction time (RT) in simultaneous EEG/fMRI data acquisition

BackgroundRecording EEG and fMRI data simultaneously inside a fully-operating scanner has been recognized as a novel approach in human brain research. Studies have demonstrated high concordance between the EEG signals and hemodynamic response. However, a few studies reported altered cognitive process inside the fMRI scanner such as delayed reaction time (RT) and reduced and/or delayed N100 and P300 event-related brain potential (ERP) components. New methodThe present study investigated the influence of electromagnetic field (static magnetic field, radio frequency (RF) pulse, and gradient switching) and experimental environment on posterior N100 and P300 ERP components in four different settings with six healthy subjects using a visual oddball task: (1) classic fMRI acquisition inside the scanner (e.g., supine position, mirror glasses for stimulus presentation), (2) standard behavioral experiment outside the scanner (e.g., seated position, keyboard response), (3) controlled fMRI acquisition inside the scanner (e.g., organic light-emitting diode (OLED) goggles for stimulus presentation) inside; and (4) modified behavioral experiment outside the scanner (e.g., supine position, OLED goggles). ResultsThe study findings indicated that the experimental environment in simultaneous EEG/fMRI acquisition could substantially delay N1P, P300 latency, and RT inside the scanner, and was associated with a reduced N1P amplitude. Comparison with existing methodsThere was no effect of electromagnetic field in the prolongation of RT, N1P and P300 latency inside the scanner. N1P, but not P300, latency was sensitive to stimulus presentation method inside the scanner. ConclusionFuture simultaneous EEG/fMRI data collection should consider experimental environment in both design and analysis.

Improvement in symptom severity, cognitive assessment, processing speed, reaction time and visual acuity in a professional hockey player with a prior concussion

Event Abstract Back to Event Improvement in symptom severity, cognitive assessment, processing speed, reaction time and visual acuity in a professional hockey player with a prior concussion Matthew M. Antonucci1, 2, 3*, Paul E. Link2, 3, Frederick R. Carrick1, 4 and Derek A. Barton2, 3 1 Carrick Institute, Clinical Neuroscience, United States 2 Plasticity Brain Centers, Neurorehabilitation, United States 3 NeuroSynergy Associates, PA, Neurorehabilitation, United States 4 Harvard Medical School and Harvard-Macy MGH Institute of Health Professions, USA, Medical Education, United States Background: A 23-year-old, male, right hand dominant/left-hand stick holding, hockey player with a history of concussion presents with occasional lightheadedness, fogginess, and a constant feeling of being in a “daze”. His Graded Symptom Checklist (GSC) severity was 48/162. His Standard Assessment of Concussion (SAC) was 26/30, Trails A (TA) 13.6 seconds, Trails B (TB) was 31.2, Trails AB difference (TA-B) was 17.6. His Simple Reaction Time (sRT) was 300 milliseconds, Processing Speed (PS) was 83 symbols matched correctly in 2 minutes, Choice Reaction Time (cRT) latency was 387 milliseconds and his Visual Acuity line difference (VA) was 1.2 on intake. Methods: A five-day, multimodal program of receptor based neurological rehabilitation was administered three times per day, one hour per session. Each session consisted of electrical non-invasive nerve stimulation, neuromuscular reeducation exercises, vision therapy exercises, vestibular rehabilitation exercises, hand-eye coordination exercises, and off-vertical axis rotations. Results: Following conclusion of five days of treatment there were significant improvements in GSC (-95.9%), SAC (+10.4%), TA (-22.1%), TB (34.6%), TB-A (-31.4%), PS (+8.8%), sRT latency (-21.33%), cRT latency (-13.2%), and VA (-83.33%). Conclusion: Short duration, multimodal, intensive programs of receptor based neurological rehabilitation may be a viable method to improve neurological integrity and performance in individuals with Post-Concussive Syndrome. The authors suggest further investigation into short duration, multi-modal, intensive approaches to restoring neurological function in individuals suffering from mild traumatic brain injury (mTBI) Keywords: concussion rehabilitation, standard assessment of concussion, Trail Making Test (TMT), Reaction Time, MTBI Conference: International Symposium on Clinical Neuroscience: Clinical Neuroscience for Optimization of Human Function, Orlando, United States, 7 Oct - 9 Oct, 2016. Presentation Type: Poster Presentation Topic: Abstracts ISCN 2016 Citation: Antonucci MM, Link PE, Carrick FR and Barton DA (2016). Improvement in symptom severity, cognitive assessment, processing speed, reaction time and visual acuity in a professional hockey player with a prior concussion. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: Clinical Neuroscience for Optimization of Human Function. doi: 10.3389/conf.fneur.2016.59.00058 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Sep 2016; Published Online: 07 Sep 2016. * Correspondence: Dr. Matthew M Antonucci, Carrick Institute, Clinical Neuroscience, Cape Canaveral, United States, drnucci@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Matthew M Antonucci Paul E Link Frederick R Carrick Derek A Barton Google Matthew M Antonucci Paul E Link Frederick R Carrick Derek A Barton Google Scholar Matthew M Antonucci Paul E Link Frederick R Carrick Derek A Barton PubMed Matthew M Antonucci Paul E Link Frederick R Carrick Derek A Barton Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Using Reaction Time and Equal Latency Contours to Derive Auditory Weighting Functions in Sea Lions and Dolphins.

Subjective loudness measurements are used to create equal-loudness contours and auditory weighting functions for human noise-mitigation criteria; however, comparable direct measurements of subjective loudness with animal subjects are difficult to conduct. In this study, simple reaction time to pure tones was measured as a proxy for subjective loudness in a Tursiops truncatus and Zalophus californianus. Contours fit to equal reaction-time curves were then used to estimate the shapes of auditory weighting functions.

Improvement in symptom severity, cognitive assessment, and choice reaction time in a college professor with post-concussive syndrome.

Event Abstract Back to Event Improvement in symptom severity, cognitive assessment, and choice reaction time in a college professor with post-concussive syndrome. Matthew M. Antonucci1, 2, 3*, Paul E. Link2, 3, Derek A. Barton2, 3 and Frederick R. Carrick1, 4 1 Carrick Institute, Clinical Neuroscience, United States 2 Plasticity Brain Centers, Neurorehabilitation, United States 3 NeuroSynergy Associates, PA, Neurorehabilitation, United States 4 Harvard Medical School and Harvard-Macy MGH Institute of Health Professions, Medical Education, United States Background: A 42-year-old, college professor, with a history of concussion following a motor vehicle accident, presented with symptoms of headache, neck pain, balance problems, fatigue, low energy and trouble driving. Graded Symptom Checklist (GSC) severity was 33/162. Trails A (TA) and Trails B (TB) had scores of 27.0 seconds and 32.9 seconds respectively. Choice Reaction Time (cRT) latency was 424 milliseconds. Methods: A five-day, multimodal program of receptor based neurological rehabilitation was administered three times per day, one hour per session. Each session consisted of electrical somatosensory stimulation, vestibular rehabilitation exercises, neuromuscular reeducation exercises, hand-eye coordination exercises, vision therapy exercises and off-vertical axis rotations. Results: Following conclusion of five days of treatment there were improvements in GSC (-75%), decreased TA (-37%) and TB (-10%), and cRT latency (-15.8%). Conclusion: Short duration, multimodal, intensive programs of receptor based neurological rehabilitation may be a viable method to improve neurological integrity and performance in individuals with Post-Concussive Syndrome. The authors suggest further investigation into short duration, multi-modal, intensive approaches to restoring neurological function in individuals suffering from mild traumatic brain injury (mTBI) Keywords: concussion rehabilitation, Off-vertical axis rotation, cognitive processing, Trail Making Test (TMT), MTBI, Vestibular Rehabilitation Conference: International Symposium on Clinical Neuroscience: Clinical Neuroscience for Optimization of Human Function, Orlando, United States, 7 Oct - 9 Oct, 2016. Presentation Type: Poster Presentation Topic: Abstracts ISCN 2016 Citation: Antonucci MM, Link PE, Barton DA and Carrick FR (2016). Improvement in symptom severity, cognitive assessment, and choice reaction time in a college professor with post-concussive syndrome.. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: Clinical Neuroscience for Optimization of Human Function. doi: 10.3389/conf.fneur.2016.59.00095 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Sep 2016; Published Online: 07 Sep 2016. * Correspondence: Dr. Matthew M Antonucci, Carrick Institute, Clinical Neuroscience, Cape Canaveral, United States, drnucci@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Matthew M Antonucci Paul E Link Derek A Barton Frederick R Carrick Google Matthew M Antonucci Paul E Link Derek A Barton Frederick R Carrick Google Scholar Matthew M Antonucci Paul E Link Derek A Barton Frederick R Carrick PubMed Matthew M Antonucci Paul E Link Derek A Barton Frederick R Carrick Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The Effects of Repeated Testing, Simulated Malingering, and Traumatic Brain Injury on Visual Choice Reaction Time.

Choice reaction time (CRT), the time required to discriminate and respond appropriately to different stimuli, is a basic measure of attention and processing speed. Here, we describe the reliability and clinical sensitivity of a new CRT test that presents lateralized visual stimuli and adaptively adjusts stimulus onset asynchronies using a staircase procedure. Experiment 1 investigated the test–retest reliability in three test sessions performed at weekly intervals. Performance in the first test session was accurately predicted from age and computer-use regression functions obtained in a previously studied normative cohort. Central processing time (CentPT), the difference between the CRTs and simple reaction time latencies measured in a separate experiment, accounted for 55% of CRT latency and more than 85% of CRT latency variance. Performance improved significantly across the three test sessions. High intraclass correlation coefficients were seen for CRTs (0.90), CentPTs (0.87), and an omnibus performance measure (0.81) that combined CRT and minimal SOA z-scores. Experiment 2 investigated performance in the same participants when instructed to feign symptoms of traumatic brain injury (TBI): 87% produced abnormal omnibus z-scores. Simulated malingerers showed greater elevations in simple reaction times than CRTs, and hence reduced CentPTs. Latency-consistency z-scores, based on the difference between the CRTs obtained and those predicted based on CentPT latencies, discriminated malingering participants from controls with high sensitivity and specificity. Experiment 3 investigated CRT test performance in military veterans who had suffered combat-related TBI and symptoms of post-traumatic stress disorder, and revealed small but significant deficits in performance in the TBI population. The results indicate that the new CRT test shows high test–retest reliability, can assist in detecting participants performing with suboptimal effort, and is sensitive to the effects of TBI on the speed and accuracy of visual processing.

Startle activation is additive with voluntary cortical activation irrespective of stimulus modality

When a startling acoustic stimulus (SAS) is presented during a simple reaction time (RT) task, it can trigger the prepared response through an involuntary initiation pathway. Previous research modelling the effects of presenting a SAS at various intervals following a non-startling auditory imperative signal (IS) suggested that involuntary initiation-related neural activation is additive with the voluntary initiation processes. The current study tested the predictions of this additive model when the SAS and IS are of different modalities by using a visual rather than auditory go-signal. Because voluntary RT latencies are delayed for visual stimuli compared to acoustic stimuli, it was hypothesised that the time course of additive activation would be similarly delayed. Participants performed 150 RT trials requiring a targeted 20° wrist extension task with a SAS presented 0–125ms following a visual go-signal. Results were not different to those predicted by an additive model (p=0.979), yet were significantly different to those predicted by a horse-race model (p=0.037), indicating a joint contribution of voluntary and involuntary activation, even when the IS and SAS are of different modalities. Furthermore, the results indicated that voluntary RT differences due to stimulus modality are attributable to processes that occur prior to the increase in initiation-related activation.

The Victorians were still faster than us. Commentary: Factors influencing the latency of simple reaction time.

Woods et al. (2015) claim that secular Simple Reaction Time (SRT) slowing (Woodley et al., 2013), disappears once modern studies are corrected for software and hardware lag, and once Galton's data are corrected for fastest-response selection. Here, this is challenged with a reanalysis of the secular slowing of SRT in the UK amongst large (N > 500), population-representative age-matched (≊18–30 years) studies. Starting with Galton's sample, this is assigned the simulated value estimated by Dodonova and Dodonov (2013, who like Woods et al. were critical of secular SRT slowing, owing to measurement issues) on the basis that he collected the fastest of three trials (207.5 ms). The two sexes in Galton's study are combined (as in Woods et al.), raising the weighted sample mean to 208.5 ms. Next is the Wilkinson and Allison (1989) study, which attempted to replicate Galton's study one century later, collecting SRTs as part of an exhibit in the London Science Museum. An electronic chronoscope recorded SRTs on magnetic tape, and sampled over eight trials with micro-processor-determined variable foreperiods. The mean SRT value for the 1189 participants aged between 20 and 29 is 245 ms. The presence of long and variable foreperiods necessitates a penalty of 10 ms (Dodonova and Dodonov, 2013). Another 10 ms should be deducted based on key-pressing time (Dodonova and Dodonov, 2013), reducing the mean to 225 ms. The studies of Deary and Der (2005) and Der and Deary (2006) are also included. The first utilized the highly representative Scottish Twenty-07 cohort. Dodonova and Dodonov (2013) identified a 53 ms lag stemming from liquid crystal stimulus onset delay. This is subtracted from the weighted average of the two sexes (300.8 ms), along with another 10 ms for key-pressing time. The resultant mean is 237.8 ms. Dodonova and Dodonov (2013) cleaned the male data in the Der and Deary (2006) study, collected from the representative UK Health and Lifestyle Survey, by removing cases for which SRT standard deviations exceeded those for choice RT. This reduced the N from 834 to 661, and also reduced the mean from 300 to 284 ms. The estimate was also penalized for LCD onset delay and key-pressing time, reducing the mean to 221 ms. When the SRT value for the female sample is penalized equivalently the resulting value is 239 ms. In order to simulate the female N for the purposes of taking a weighted average of both sexes, the actual female N is reduced in proportion to the male N (79.3% = 881), yielding a weighted mean of 230.9 ms for a combined sample-size of 1472. Table ​Table11 presents the data used in the analysis. Table 1 SRT means, sample sizes and sampling years for four large, age-matched UK samples. Consistent with Dodonova and Dodonov (2013), N-weighted regression is employed, as the only data on sample variability is sample size. Figure ​Figure11 illustrates the secular trend in British SRT spanning 100 years. Figure 1 Secular SRT slowing across four large, representative studies from the UK spanning a century. Bubble-size is proportional to sample size. Combined N = 6622. The secular slowing between UK studies is statistically significant (β = 0.97; 95% CI = 0.969–0.971, N = 6622), at +22.8 ms a century. Additional evidence for generational SRT slowing comes from Verhaeghen (2014), who suggested that the ratio of longitudinal to cross-sectional age-related slowing might indicate generational changes in processing speed. Verhaeghen reports ratios for two SRT studies (0.91 and 1.15), implying both secular losses and gains. For the study of Deary and Der (2005), the SRT ratios are “censored because they were excessively large” (p. 256). In this study, the ratio of the cross-sectional slowing trend (taking the weighted average of all paired between-cohort differences rescaled in terms of change per decade for males and females), to the weighted average decadal longitudinal slowing trend for both the males and females is 0.73, for an N of 1926 (cf. Woodley et al., 2014, for a detailed reanalysis of this dataset utilizing curve-fitting). The weighted average of the three SRT “Verhaeghen ratios” is 0.9 (N = 4078)—tentatively consistent with generational declines (i.e., a ratio of < 1). In conclusion, Woods et al. (2015) have undoubtedly made an important contribution to the debate concerning the role of software and hardware lag in the inflation of contemporary estimates of SRT, however, the evidence for generational SRT slowing remains quite compelling.