King-Devick Test Research Articles

노인 뇌졸중 환자의 단속성 안구운동, 일상생활 수행능력 및 인지기능의 상관성

This study aimed to analyze the correlation between saccadic eye movement, activities of daily living, and cognitive function in elderly patients with stroke, that could help establish interventions in clinical settings.
 This study included 32 elderly patients with stroke who were admitted to a medical center. The King-Devick test (K-D test), Korean version of the Modified Barthel Index (K-MBI), and Korean version of the Montreal Cognitive Assessment (MoCA-K) were used as evaluation tools. The correlation between evaluation scores was analyzed using Pearson’s correlation coefficient.
 The correlations between the total scores of the K-D test, K-MBI, and MoCA-K were statistically significant (p<0.01).
 In addition, the K-D test showed statistically significant correlations with personal hygiene, bathing, feeding, toilet, stair climbing, dressing, chair/bed transfer, ambulation, and wheelchair use in the K-MBI and visuospatial/executive, naming, delayed recall, and orientation in the MoCA-K.
 This study showed a correlation between saccadic eye movement, activities of daily living, and cognitive function in elderly patients with stroke. In the future, such studies with larger sample would help to establish interventions in clinical settings.

Fifteen minutes of high intensity running can impair performance on concussion testing; Implications for on-field diagnosis in sport.

To examine the effects of 15 min of high intensity treadmill running on concussion testing assessed by the King-Devick test. Prospective Cohort Study. Participants self-selected to either a running or a control group. At baseline both groups were assessed using the King-Devick concussion test. The running group then completed 15-minutes of treadmill running at rating of perceived exertion of 7-9/10 while the control group sat quietly. Both groups repeated the King-Devick test following that 15-minute period. Participants (n = 84 men, 53 women) were divided in two groups; running or control. Both groups, on average, had significant improvement after 15 min (suggesting a learning effect). Comparisons between the baseline and re-assessment scores indicated impaired performance was more common following high intensity treadmill running (n = 23 participants, 34.3%) compared to the control group (n = 10 participants, 14.3%, p = 0.006, OR = 3.44 [95%CI 1.40-8.50]). Four participants in the running group worsened their score at reassessment by more than 3 s compared to no participants in the control group. After 15 min of high intensity treadmill running, 1 in 3 participants scored a slower time at follow-up or committed a mistake compared to baseline. Implications for clinical practise include: the recommendation that baseline tests be conducted at rest and after high intensity exercise to provide accurate comparisons to assist in clinical decision making; and a cut-off of >3 s may be a clinically useful difference between resting baseline and re-assessment using the King-Devick test.

King-Devick testing and concussion recovery time in collegiate athletes.

To assess whether the King-Devick (KD) test is useful as a prognostic test for prolonged concussion symptoms by examining the relationship between a) change in performance on KD test from baseline to within two days post-injury and b) the absolute KD time at post-concussion testing, with an outcome of time to return to play (RTP). Prospective Cohort Study. Collegiate varsity athletes in the Concussion Assessment, Research, and Education (CARE) Consortium completed baseline and post-injury King-Devick tests from 2014 to 2018. Two exposures were evaluated: 1) change in KD score from baseline to within two days post-injury and 2) absolute KD score within two days post-injury, adjusted for baseline KD. We used Cox proportional hazards models to analyze the relationships between these exposures and time to RTP post-concussion. A total of 309 concussion injuries were included. Median baseline KD score was 40.0 s (IQR: 35.8, 45.2). Median post-injury KD score was 45.8 s (IQR: 39.8, 57.1). Median number of days until RTP in this cohort was 11 (IQR: 8, 17). Post-injury KD score adjusted for baseline KD had a stronger association with time to RTP duration (HR: 0.99 (0.98, 1.00), p = 0.03) than the difference in KD score from baseline to post-injury (HR: 0.99 (0.99, 1.00), p = 0.07). Higher post-injury KD scores are associated with longer RTP. The association between KD post-concussion test and longer RTP warrants further investigation to assess the utility of the KD for prognostication in a clinical setting.

Monitoring the acute and subacute recovery of cognitive ocular motor changes after a sports-related concussion.

Identifying when recovery from a sports-related concussion (SRC) has occurred remains a challenge in clinical practice. This study investigated the utility of ocular motor (OM) assessment to monitor recovery post-SRC between sexes and compared to common clinical measures. From 139 preseason baseline assessments (i.e. before they sustained an SRC), 18 (12 males, 6 females) consequent SRCs were sustained and the longitudinal follow-ups were collected at 2, 6, and 13 days post-SRC. Participants completed visually guided, antisaccade (AS), and memory-guided saccade tasks requiring a saccade toward, away from, and to a remembered target, respectively. Changes in latency (processing speed), visual-spatial accuracy, and errors were measured. Clinical measures included The Sports Concussion Assessment Tool, King-Devick test, Stroop task, and Digit span. AS latency was significantly longer at 2 days and returned to baseline by 13-days post-SRC in females only (P < 0.001). Symptom numbers recovered from 2 to 6 days and 13 days (P < 0.05). Persistently poorer AS visual-spatial accuracy was identified at 2, 6 and 13 days post-SRC (P < 0.05) in both males and females but with differing trajectories. Clinical measures demonstrated consistent improvement reminiscent of practice effects. OM saccade assessment may have improved utility in tracking recovery compared to conventional measures and between sexes.

Computer-based Eye-tracking Analysis of King-Devick Test Differentiates Persons With Idiopathic Normal Pressure Hydrocephalus From Cognitively Unimpaired.

Functional defects in eye movements and reduced reading speed in neurodegenerative diseases represent a potential new biomarker to support clinical diagnosis. We investigated whether computer-based eye-tracking (ET) analysis of the King-Devick (KD) test differentiates persons with idiopathic normal pressure hydrocephalus (iNPH) from cognitively unimpaired [control (CO)] and persons with Alzheimer's disease (AD). We recruited 68 participants (37 CO, 10 iNPH, and 21 AD) who underwent neurological examination, the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological test battery (CERAD-NB), and a Clinical Dementia Rating interview. The KD reading test was performed using computer-based ET. We analyzed the total time used for the reading test, number of errors, durations of fixation and saccade, and saccade amplitudes. The iNPH group significantly differed from the CO group in the KD test mean total time (CO 69.3 s, iNPH 87.3 s; P ≤0.009) and eye-tracking recording of the mean saccade amplitude (CO 3.6 degree, iNPH 3.2 degree; P ≤0.001). The AD group significantly differed from the CO group in each tested parameter. No significant differences were detected between the iNPH and AD groups. For the first time, we demonstrated altered reading ability and saccade amplitudes in patients with iNPH.

Unique Contributions of the King-Devick and Vestibular/Ocular Motor Screening: A Critically Appraised Topic

Focused Clinical Question: Is there a relationship between performance on the King-Devick test and the vestibular/ocular motor screening in youth and young adults? Clinical Bottom Line: There was insufficient evidence to definitively determine if there is a relationship between performance on the King-Devick test and vestibular/ocular motor screening in youth and young adults.

An Analysis Of In-game Collegiate Baseball Hitting Performance Following Sports Vision Training

Vision training (VT) programs can be utilized to enhance perception and eye-hand coordination to potentially improve sports performance. There is general support for VT improving athletic performance, but limited research is present for in-game performance improvements, particularly for collegiate baseball. PURPOSE: To evaluate for potential benefits of a VT program on collegiate baseball team hitting performance. If beneficial, VT may be used to supplement standard baseball practice to further improve hitting performance. METHODS: The Northwestern College (NWC) varsity baseball team, a member of the NAIA Greater Plains Athletic Conference (GPAC), performed VT exercises including Brock string, King-Devick test for saccades, long-distance saccades, and near-far training in 18 sessions during the 2019 season. In-game hitting statistics for the 2018 and 2019 seasons were retrospectively collected for all GPAC teams. Two-proportion z-tests were used to compare batting average and slugging percentage between NWC and the GPAC during the 2018 and 2019 seasons. RESULTS: The overall win-loss record of NWC was 30-20 in 2018 (1st place) and 23-25 in 2019 (6th place). Three starting hitters from the 2018 team remained on the team for the 2019 season. The 2018 GPAC batting average was .280 and NWC’s was 6th in the conference at .288 (p = .261). The 2019 GPAC batting average was .281 and NWC led the conference at .304 (p = .034). Batting averages for the GPAC and NWC did not differ between the 2018-19 seasons (p = .417 and p = .171, respectively). The 2018 GPAC slugging percentage was .388 and NWC was 3rd in the conference at .423 (p = .005). The 2019 GPAC slugging percentage was .393 and NWC was 2nd in the conference at .435 (p = .001). The slugging percentages for the GPAC and NWC did not differ between the 2018-19 seasons (p = .233 and p = .261, respectively). CONCLUSIONS: The team batting average was significantly better than the conference average during the season with VT despite losing six starting hitters from the prior season. These differences were not observed in the season before VT. Slugging percentage improved only minimally with VT. These outcomes suggest that VT may improve the in-game batting performance of collegiate baseball players and confirm previous research on the effects of VT on collegiate baseball hitting.

Effect of Concussion on Reaction Time and Neurocognitive Factors: Implications for Subsequent Lower Extremity Injury.

BackgroundRecent evidence has demonstrated that athletes are at greater risk for a lower extremity injury following a return-to-sport (RTS) after sport-related concussion (SRC). The reason for this is not completely clear, but it has been hypothesized that persistent deficits in neurocognitive factors may be a contributing factor.Hypothesis/PurposeThis study assessed simple reaction time, processing speed, attention, and concentration in a group of athletes, post-concussion upon clearance for RTS for potential deficits that may result in slower reaction time, processing speed, attention, and concentration. The researchers hypothesized that the concussion group would demonstrate worse scores on both assessments compared to a sex-, age-, and sport-matched cohort.Study DesignCase-controlled studyMethodsTwelve participants who had suffered a SRC and eight healthy individuals who were matched to the concussed group by age, sex, and sport were evaluated. Those with a concussion had been cleared for RTS by a licensed healthcare provider. Each participant underwent neurocognitive tests that included a simple reaction time test (SRT) and the King-Devick Test (K-D). Independent t-tests were performed to compare the groups with significance set a priori at p<0.05.ResultsThere was a significant difference (p =0.024) between groups for SRT with the concussed group demonstrating a better SRT than the control group. There were no significant differences (p =0.939) between the groups for the K-D.ConclusionWith no significant differences between groups in the K-D assessment and, surprisingly, the concussed group having a better SRT compared to the healthy group, our hypothesis was not supported.Clinical RelevanceThese specific measures, compounded with extensive post-concussion time lapse until RTS clearance, may have limited capacity in revealing potential persistent deficits in relevant neurocognitive characteristics.Level of EvidenceLevel of Evidence 3

Developmental Eye Movement (DEM) and King-Devick (K-D) Performance in Multiple Sclerosis.

Eye movement disorders have been reported in patients with multiple sclerosis (MS) as saccadic disturbances. Several methods have been described for the assessment of saccades, including the K-D and DEM tests. The performance of these tests also involves attention, language, and other brain areas which have been reported to be altered in MS patients. The aim of the study was to determine how developmental eye movement (DEM) and King-Devick (K-D) tests are affected in MS-patients. It was also to analyze whether a resolved episode of optic neuritis (ON) has a negative influence. Subjects with MS showed worse outcomes (higher times) in DEM test (72 (26) s and a K-D test (56 (22) s compared to healthy subjects (64 (7) s and 55 (11) s, respectively). However, a previous ON episode did not worsen the MS-times of DEM (80 (33) s or of K-D (62 (33) s. Horizontal saccades with the DEM showed differences between subjects with MS (with and without ON) and healthy ones (p < 0.05), whereas no such differences were found in the vertical saccades. According to the DEM instructions, MS patients would present heterogeneous oculomotor and non-visual disturbances. Regarding the K-D test, only the third card (the most complex one) showed differences (p < 0.05) between groups. These tests can capture impairment of attention, language, and other areas that correlate with suboptimal brain function in addition to the oculomotor dysfunctions present in subjects with MS.

Shortening of Saccades as a Possible Easy-to-Use Biomarker to Detect Risk of Alzheimer’s Disease

Background:Wide-ranging functional defects in eye movements have been reported in Alzheimer’s disease (AD) dementia. The detection of abnormal eye movements and reading problems may identify persons at risk of AD when clear clinical symptoms are lacking.Objective:To examine whether computer-based eye-tracking (ET) analysis of King-Devick (KD) test results differentiates cognitively healthy persons from persons with minor problems in cognitive testing or diagnosed mild AD.Methods:We recruited 78 participants (57 non-demented, 21 with mild AD) who underwent neurological examination, the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological test battery (CERAD-NB), and a Clinical Dementia Rating (CDR) interview. The non-demented participants were further divided into control (normal CERAD subtests, mean MMSE = 28) and objective mild cognitive impairment (MCI; decline in at least one CERAD memory score, mean MMSE = 27) groups. The KD reading test was performed using computer-based ET. The total time used for the reading test, errors made, fixation and saccade durations, and saccade amplitudes were analyzed.Results:We found significant differences between the control, objective MCI, and AD groups in regard to the mean saccade amplitude (3.58, 3.33, and 3.21 ms, respectively, p < 0.03) and duration (27.1, 25.3, and 24.8 ms, respectively, p < 0.05). The KD error scores in the AD group differed significantly (p < 0.01) from the other groups.Conclusion:Computed ET analysis of the KD test may help detect persons with objective MCI early when clear clinical symptoms are lacking. The portable device for ET is easy to use in primary health care memory clinics.

뇌졸중 환자의 단속성 안구운동 훈련을 위한 프로그램 개발 및 효과성 검증

This study developed a saccadic eye movement training program and attempted to verify its effectiveness as a tool for training saccadic eye movements in stroke patients.&#x0D; This study included 26 stroke patients. The subjects were classified into an experimental group and a control group through random allocation, and the King-Devick test was administered as the pre-test. After the pre-test, the experimental group performed an existing occupational therapy intervention and a saccadic eye movement training program intervention for a total of 16 sessions. The control group underwent existing occupational therapy and additional occupational therapy interventions. After four weeks, the experimental and control groups were re-tested.&#x0D; The time and number of errors in the King-Devick test before and after intervention in both groups showed statistically significant differences (p&lt;.05), and both parameters in the King-Devick test decreased after the intervention. In addition, the time and number of errors in the King-Devick test in the experimental group after the intervention were significantly lower than those in the control group (p&lt;.05).&#x0D; This study showed that the saccadic eye movement training program had a positive effect on saccadic eye movements in stroke patients.

Machine learning to predict sports-related concussion recovery using clinical data.

Sport-related concussions (SRCs) are a concern for high school athletes. Understanding factors contributing to SRC recovery time may improve clinical management. However, the complexity of the many clinical measures of concussion data precludes many traditional methods. This study aimed to answer the question, what is the utility of modeling clinical concussion data using machine-learning algorithms for predicting SRC recovery time and protracted recovery? This was a retrospective case series of participants aged 8 to 18 years with a diagnosis of SRC. A 6-part measure was administered to assess pre-injury risk factors, initial injury severity, and post-concussion symptoms, including the Vestibular Ocular Motor Screening (VOMS) measure, King-Devick Test and C3 Logix Trails Test data. These measures were used to predict recovery time (days from injury to full medical clearance) and binary protracted recovery (recovery time > 21 days) according to several sex-stratified machine-learning models. The ability of the models to discriminate protracted recovery was compared to a human-driven model according to the area under the receiver operating characteristic curve (AUC). For 293 males (mean age 14.0 years) and 362 females (mean age 13.7 years), the median (interquartile range) time to recover from an SRC was 26 (18-39) and 21 (14-31) days, respectively. Among 9 machine-learning models trained, the gradient boosting on decision-tree algorithms achieved the best performance to predict recovery time and protracted recovery in males and females. The models' performance improved when VOMS data were used in conjunction with the King-Devick Test and C3 Logix Trails Test data. For males and females, the AUC was 0.84 and 0.78 versus 0.74 and 0.73, respectively, for statistical models for predicting protracted recovery. Machine-learning models were able to manage the complexity of the vestibular-ocular motor system data. These results demonstrate the clinical utility of machine-learning models to inform prognostic evaluation for SRC recovery time and protracted recovery.

Saccadic Latency Measures on Oculomotor Tracking and King Devick Testing Performance Measures in Pediatric Concussion Patients

Background:King-Devick (KD) testing has been a reliable clinical tool used to identify changes in rapid eye movements between fixation points (saccades) after concussion. Other clinical tools such as oculomotor tracking (OMT) devices have been used to assess the extent of visual dysfunction in concussion patients to aid diagnosis, subtyping, and symptom management.Purpose:To compare trends in OMT saccadic motion analysis data to KD times/performance in concussed patients.Methods:Retrospective study of 66 pediatric patients (ages 12 to 21) with concussion. KD testing was conducted using standard 3 card protocol with a series of numbers which the patient reads aloud in a specific pattern as fast and accurately as possible without head movement. The length of time to complete each card was noted and the three KD times were averaged, resulting in one mean KD value for each patient. Patients were categorized into either a “Fast” (average KD time from 0 - 20 seconds), n=56, or “Slow” group (average KD time above 20 seconds), n=10. Each patient underwent testing with an OMT device during the same visit (250 Hz video-eye tracker), which measured vertical and horizontal saccadic latencies. Statistical analysis using a paired two sample t-test assuming equal variances compared the OMT data between the slow and fast groups. Exclusion criteria included history of visual disorders, learning disorders, seizure disorder, or intracranial hemorrhage.Results:The slow KD group had an average vertical saccadic latency of 248.88 ms and a horizontal saccadic latency of 214.66 ms (Table 1). The fast KD group had an average vertical saccadic latency of 217 ms and a horizontal saccadic latency of 196.64 ms. A t-test of vertical latency showed a statistically significant difference between slow and fast groups (p value = 0.002). A T-test of horizontal latency resulted in a p value = 0.069, which may support a statistically significant difference with a larger sample size.Conclusion:A potential relationship between patients with slower KD test times and slower horizontal/ vertical saccadic latencies on OMT saccadic analysis may be present. However, these trends will need more testing under larger sample sizes in order to make definitive conclusions.Table 1:Vertical and Horizontal Latency in Fast vs Slow KD patients

Improvement in Postural Control Following Concussion in Adolescent Athletes: From Clinical Presentation to Initiation of Return to Play

Background:Impairments in balance or postural control are common following sport-related concussion (SRC). The Balance Error Scoring System (BESS) is widely utilized to assess static postural stability, but laboratory-based balance measures have been shown to more accurately detect changes in postural control.Hypothesis/Purpose:To determine whether postural control improved between presentation to the sports medicine clinic and return-to-sport (RTS) initiation, and whether this trend mirrored symptom scores and cognitive performance. A secondary aim was to assess whether changes in postural control were more accurately captured with center of pressure (COP) based measures compared to BESS.Methods:Patients diagnosed with a SRC were tested within 10 days of presentation (V0) and when cleared by a physician to begin a RTS protocol (V1). Clinical measures included Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) and the King-Devick (K-D) test. The BESS was performed with eyes closed while standing barefoot on a force platform for 6 conditions: double-limb stance, single-limb stance, and tandem stance on both firm and foam surfaces. BESS scores and total balance time were recorded for each condition, and COP-based measures were computed for both double-limb stance conditions (Table 1). Sample entropy was computed to quantify COP regularity over time with increased values indicating improvement in postural control. Wilcoxon signed-rank tests were performed to determine significance between visits (α<0.05).Results:Forty patients (17 males, 13.8±2.0 years) were included for analysis. ImPACT verbal and visual memory scores improved by 10% and 12%, respectively, total symptom score decreased (V0 18.03±13.85, V1 0.97±2.08; p<0.01), and visual motor speed and reaction time were both 11% faster on the K-D test. For postural control, the BESS indicated significant improvement given the reduction in errors on both surfaces (Firm Total: V0 3.23±2.09, V1 2.25±2.11, p=0.01; Foam Total: V0 7.38±2.05, V1 6.08±1.76, p<0.01; Table 1). Similarly, COP-based measures exhibited better overall balance between visits (Figure 1), primarily in the medial-lateral direction on the firm and the anterior-posterior direction on the foam. Lastly, sample entropy improved between visits, indicating more effective postural control.Conclusion:Significant improvement in postural control was observed during the recovery period which mirrored improvement in symptom scores and cognitive performance. Additionally, while COP-based measures showed similar trends to the BESS, they provided more detailed information in regards to balance recovery. Specifically, findings from the double stance condition highlight the utility of a more advanced assessment of postural control for determining RTS readiness following a SRC.Table 1.COP-based measures of balance performance at diagnosis (V0) and clearance (V1) visitsFigure 1.Representative stabilograms of double stance balance on firm and foam surfaces at diagnosis (V0) and clearance visits (V1)

A Functional Near Infrared Spectroscopy Investigation of the Physiological Underpinnings of Visual Cognitive Workload After Concussion

Background:In concussion, functional near infrared spectroscopy (fNIRS) has been shown to detect differences in cortical oxygenation during neurocognitive testing, with concussed adults manifesting less task-based cortical activation compared to controls. In addition, fNIRS has identified significantly reduced interhemispheric coherence in adult concussions relative to controls. In addition, adults with greater post-concussive symptom burden demonstrate lower task-related oxygenation in the frontal and dorsolateral prefrontal cortex (DLPFC) and reduced connectivity compared to controls.Hypothesis:The goal of this study was to use fNIRS to identify any differences in visual task-related cortical activation between concussed adolescents and healthy controls while performing a the King-Devick (KD) test.Methods:We enrolled 112 adolescents, ages 12-18 years, with recent concussion and 165 healthy controls as part of a large observational prospective cohort. Participants were provided standardized instructions to read the KD cards while wearing the fNIRS sensor pad. The relative changes in the difference of oxy-and deoxy-hemoglobin concentrations over each task condition for each optode were calculated via the Modified Beer-Lambert Law using local baselines for each task condition period as its beginning. The averaged oxy-hemoglobin concentration changes for each task period were used for statistical analysis of group (e.g., concussed vs healthy) effect.Results:The concussed adolescents (n=112) and healthy controls (n=165) were demographically comparable with respect to age, sex, and race/ethnicity. The concussed group was more likely to have a history of prior concussion (p = <.0001) and migraine (p = .0001) compared to the healthy control group (Table 1). The concussed adolescents were assessed with fNIRS while performing a visual task a median of 10 days after injury (IQR 4-16). The concussed group had significantly lower oxygenation changes that are the difference between oxygenated and deoxygenated hemoglobin as an indicator of task-evoked response, on left lateral prefrontal area (p<.005, FDR q<.005). As expected, there was also a main effect for task condition (cards) at right lateral prefrontal cortex (p<.001, FDR q<.005).Conclusions:fNIRS is able to distinguish concussed adolescents from healthy controls while performing a visual-cognitive task, the K-D test. Injured adolescents with concussion demonstrated a compensatory pattern of cortical activation, suggesting localized brain dysfunction, recruiting from both hemispheres, distinguishing it from the pattern of cortical activation in healthy controls. fNIRS, as a modality, is not only able to differentiate concussion from healthy controls, but also captures the compensatory mechanisms of cortical activation that underlie visual cognitive function after injury.

Visual-Spatial Attentional Performance Identifies Lower Extremity Injury Risk in Adolescent Athletes.

Strategies to identify lower extremity musculoskeletal (LEMSK) injury risk have been informed by prospectively identified biomechanical and neuromuscular risk factors. Emergent evidence suggests that cognitive and oculomotor performance may also contribute to LEMSK injury. The purpose of this study was to determine whether prospective cognitive and oculomotor measures identify adolescent athletes who sustain an in-season LEMSK injury. Prospective longitudinal study. Controlled laboratory and athletic event settings. Four hundred eighty-eight adolescent male football and female soccer athletes aged 13 to 18 years. Preseason baseline cognitive and oculomotor performance: Attention Network Task (ANT), cued task switching, King-Devick test, and near point of convergence. Incidence of LEMSK sprains and strains during a single competitive season. Attention Network Task-orienting network reaction time (RT) was the only cognitive or oculomotor measure significantly associated with LEMSK injury [B = 1.015, 95% confidence interval (CI): 1.01-1.024, P < 0.01]. Every 10 milliseconds increase in orienting network RT was associated with a 15% increased risk for LEMSK injury. Athletes demonstrating an orienting network RT ≥ 32.8 milliseconds had a higher risk for LEMSK injury relative to athletes below the cut-point (relative risk, 2.62; 95% CI, 1.52-4.52; odds ratio, 3.00; 95% CI, 1.63-5.52). Deficits in visual-spatial components of attention were associated with 2.62 times greater risk for LEMSK injury in adolescent athletes. The present results add evidence to suggest that visual-spatial attentional processing contributes to LEMSK injury and may supplement previously established LEMSK injury risk assessments.

An investigation into the measurement properties of the King-Devick Eye Tracking system

Objectives Eye tracking has been gaining increasing attention as a possible assessment and monitoring tool for concussion. The King-Devick test (K-DT) was expanded to include an infrared video-oculography-based eye tracker (K-D ET). Therefore, the aim was to provide evidence on the reliability of the K-D ET system under an exercise condition. Methods Participants (N = 61; 26 male, 35 female; age range 19-25) were allocated to an exercise or sedentary group. Both groups completed a baseline K-D ET measurement and then either two 10-min exercise or sedentary interventions with repeated K-D ET measurements between interventions. Results The test-retest reliability of the K-D ET ranged from good to excellent for the different variables measured. The mean ± SD of the differences for the total number of saccades was 1.04 ± 4.01 and there was an observable difference (p = 0.005) in the trial number. There were no observable differences for the intervention (p = 0.768), gender (p = 0.121) and trial (p = 0.777) for average saccade’s velocity. The mean ± SD of the difference of the total fixations before and after intervention across both trials was 1.04 ± 3.63 and there was an observable difference in the trial number (p = 0.025). The mean ± SD of the differences for the Inter-Saccadic Interval and the fixation polyarea before and after intervention across both trials were 1.86 ± 22.99 msec and 0.51 ± 59.11 mm2 and no observable differences for the intervention, gender and trial. Conclusion The results provide evidence on the reliability of the K-D ET, and the eye-tracking components and demonstrate the relationship between completion time and other variables of the K-D ET system. This is vital as the use of the K-DT may be increasing and the combination of the K-DT and eye tracking as one single package highlights the need to specifically measure the reliability of this combined unit.

Late Exercise Tolerance Testing Using a Dynamic High Intensity Interval Multidirectional Movement Protocol

Analyze the utility of a 5-step exertional rehab protocol (ERP) that included High Intensity Interval Multi-Directional Movement (HIIT-MD) or step 5. We assessed the incidence and etiologies of exercise intolerance (EI) during Step 5 in concussed patients who tolerated maximal linear exertion. Exertional testing can be used to determine appropriate levels of exercise tolerance (ET) in concussed patients. Traditionally linear modalities have been used to determine max ET prior to clearance. HIIT-MD protocols can be the next appropriate step to bridge clearance for more dynamic activities. Retrospective chart review included 130 step 5 trials for EI; of those, 72 had pre/postexercise King Devick (KD) and force plate (FP) testing. Patients were 10-59 years old and clinic visits occurred 2019-2020. EI rate was recorded and failure reason was documented by our clinic's concussion specialist. The difference between pre/post exercise KD and FP was investigated. Of 130 step 5 trials, 21.54% failed due to EI. Reason for EI included the onset of symptoms (82.1%), followed by signs of dysautonomia (39.3%). Symptoms and dysautonomia combined were noted in 35.7% of those with EI. Symptoms appeared in combination with another marker 69.6% of the time. The average change in KD times pre/post exercise testing was +2.52 seconds longer in the EI group compared to -2.45 seconds shorter in the ET group (p = 0.62). The EI group demonstrated an average change of 0.36 deg/sec sway velocity increase after exercise compared to 0.13 deg/sec in the ET group (p = 0.93). There is evidence for the utility of a HITT-MD protocol for dynamic exercise/sports clearance. Exercise testing progression and concussion clearance should include a dynamic HITT-MD protocol to ascertain no late phase dynamic EI. Dysautonomia and/or vestibulocular aggravation may be contributors to late phase EI. If EI exists, identifying and targeting underlying causes can aid optimal recovery.

Premorbid Primary Headache and Vestibular and Oculomotor Baseline Assessments in Collegiate Athletes.

The purpose of this study was to determine the effects of premorbid headache status on vestibular and oculomotor baseline tests in collegiate club athletes. Retrospective case-control study. Sport Concussion Laboratory. Collegiate club athletes with a self-reported premorbid headache history (n = 32, 19.50 ± 1.98 years, and 31% women) and age-sex-sport-matched controls (n = 32, 19.56 ± 1.47 years, and 31% women) without a self-reported headache history were included. Participants were grouped based on a self-reported headache history at baseline. Controls were randomly matched to self-reported headache participants by age, sex, and sport. Vestibular/ocular motor screen (VOMS) baseline symptoms, symptom provocation, near point of convergence (NPC) distance, and King-Devick (K-D) test time were compared between groups. Athletes with a self-reported headache history at baseline are 3.82 times more likely to have abnormal NPC scores (P = 0.032) and 4.76 times more likely to have abnormal K-D test times (P = 0.014) than those without a headache history. There was no difference in VOMS baseline symptoms or symptom provocation between groups (P > 0.05). Club collegiate athletes with a headache history were more likely to screen as abnormal during a vestibular/ocular motor function assessment than athletes without a history of headaches. Healthcare professionals should screen for pre-existing headache during baseline concussion assessments before test interpretation. A premorbid headache history at preseason baseline assessment may influence vestibular and oculomotor function, and care should be taken when interpreting these individuals' tests.

Oculometric Feature Changes During Acute Hypoxia in a Simulated High-Altitude Airdrop Scenario.

BACKGROUND: Severe acute hypoxia results in a rapid deterioration of cognitive functioning and thus poses a risk for human operations in high altitude environments. This study aimed at investigating the effects of oxygen system failure during a high-altitude high-opening (HAHO) parachute jump scenario from 30,000 ft (9144 m) on human physiology and cognitive performance using a noncontact eye-tracking task.METHODS: Nine healthy male volunteers (ages 27-48) were recruited from the Norwegian Special Operations Commandos. Eye-tracking data were collected to derive information on cognitive performance in the context of rapid dynamic changes in pressure altitude while performing a modified King-Devick test. The baseline data was collected at 8000 ft (2438 m) while breathing 100% oxygen during decompression. For every test, the corresponding arterial blood gas analysis was performed.RESULTS: The study subjects endured severe hypoxia, which resulted in significant prolongations of fixation time (range: 284.1-245.6 ms) until 23,397 ft (131 m) and fixation size (range: 34.6-32.4 mm) until 25,389 ft (7739 m) as compared to the baseline (217.6 ± 17.8 ms and 27.2 ± 4.5 mm, respectively). The increase in the saccadic movement and decrease in the saccadic velocity was observed until 28,998 ft and 27,360 ft (8839 and 8339 m), respectively.DISCUSSION: This is the first study to investigate cognitive performance from measured oculometric variables during severe hypobaric hypoxia in a simulated high-altitude airdrop mission scenario. The measurement of altered oculometric variables under hypoxic conditions represents a potential avenue to study altered cognitive performance using noncontact sensors that can derive information and serve to provide the individual with a warning from impending incapacitation.Pradhan GN, Ottestad W, Meland A, Kåsin JI, Høiseth LØ, Cevette MJ, Stepanek J. Oculometric feature changes during acute hypoxia in a simulated high-altitude airdrop scenario. Aerosp Med Hum Perform. 2021; 92(12):928-936.