Visual effects of concussion: A review

Response Rate Patterns in Adolescents With Concussion Using Mobile Health and Remote Patient Monitoring: Observational Study

Background

A concussion is a common adolescent injury that can result in a constellation of symptoms, negatively affecting academic performance, neurobiological development, and quality of life. Mobile health (mHealth) technologies, such as apps for patients to report symptoms or wearables to measure physiological metrics like heart rate, have been shown to be promising in health maintenance. However, there is limited evidence about mHealth engagement in adolescents with a concussion during their recovery course.

Objective

This study aims to determine the response rate and response rate patterns in concussed adolescents reporting their daily symptoms through mHealth technology. It will also examine the effect of time-, demographic-, and injury-related characteristics on response rate patterns.

Methods

Participants aged between 11-18 years (median days since injury at enrollment: 11 days) were recruited from the concussion program of a tertiary care academic medical center and a suburban school's athletic teams. They were asked to report their daily symptoms using a mobile app. Participants were prompted to complete the Post-Concussion Symptom Inventory (PCSI) 3 times (ie, morning, afternoon, and evening) per day for 4 weeks following enrollment. The primary outcome was the response rate pattern over time (by day since initial app use and the day since injury). Time-, demographic-, and injury-related differences in reporting behaviors were compared using Mann Whitney U tests.

Results

A total of 56 participants were enrolled (mean age 15.3, SD 1.9 years; n=32, 57% female). The median response rate across all days of app use in the evening was 37.0% (IQR 27.2%-46.4%), which was significantly higher than the morning (21.2%, IQR 15.6%-30.5%) or afternoon (26.4%, IQR 21.1%-31.5%; P<.001). The median daily response was significantly different by sex (female: 53.8%, IQR 46.2%-64.2% vs male: 42.0%, IQR 28.6%-51.1%; P=.003), days since injury to app use (participants starting to use the app >7 days since injury: 54.1%, IQR 47.4%-62.2% vs starting to use the app ≤7 days since injury: 38.0%, IQR 26.0%-53.3%; P=.002), and concussion history (participants with a history of at least one prior concussion: 57.4%, IQR 44.5%-70.5% vs participants without concussion history: 42.3%, IQR 36.8%-53.5%; P=.03). There were no significant differences by age. Differences by injury mechanism (sports- and recreation-related injury: 39.6%, IQR 36.1%-50.4% vs non-sports- or recreation-related injury: 30.6%, IQR 20.0%-42.9%; P=.04) and initial symptom burden (PCSI scores greater than the median score of 47: 40.9%, IQR 35.2%-53.8% vs PCSI scores less than or equal to the median score: 31.9%, IQR 24.6%-40.6%; P=.04) were evident in the evening response rates; however, daily rates were not statistically different.

Conclusions

Evening may be the optimal time to prompt for daily concussion symptom assessment among concussed adolescents compared with morning or afternoon. Multiple demographic- and injury-related characteristics were associated with higher daily response rates, including for female participants, those with more than 1 week from injury to beginning mHealth monitoring, and those with a history of at least one previous concussion. Future studies may consider incentive strategies or adaptive digital concussion assessments to increase response rates in populations with low engagement.

Pupillary dynamics, accommodation and vergence in concussion

Concussion, which is usually associated with head injuries, has received considerable attention in recent years because of its possible long-term cognitive and visual consequences. The review summarised the mild traumatic brain injury literature. Pupillary dynamics, which are primarily mediated by the autonomic nervous system, play an important function in regulating the amount of light entering the eye, but they can be dramatically impacted after a concussion. This can result in aberrant pupillary responses, which may have ramifications for light sensitivity, a common post-concussion symptom. In concussed individuals, accommodation and vergence - the visual processes responsible for focusing on near and distant objects - might be interrupted, potentially leading to fuzzy vision, eyestrain, and difficulty with tasks that require precise visual coordination. Understanding the delicate interplay between these three components of vision in the setting of concussions is critical for creating more targeted diagnostic and rehabilitative techniques, ultimately enhancing the quality of life for those who have had head injuries.

Reliability of a Smooth Pursuit Eye-Tracking System (EyeGuide Focus) in Healthy Adolescents and Adults

Mild traumatic brain injury (mTBI) is the most common brain injury, seen in sports, fall, vehicle, or workplace injuries. Concussion is the most common type of mTBI. Assessment of impairments from concussion is evolving, with oculomotor testing suggested as a key component in a multimodality diagnostic protocol. The aim of this study was to evaluate the reliability of one eye-tracking system, the EyeGuide Focus. A group of 75 healthy adolescent and adult participants (adolescents: n = 28; female = 11, male = 17, mean age 16.5 ± 1.4 years; adults n = 47; female = 22; male = 25, mean age 26.7 ± 7.0 years) completed three repetitions of the EyeGuide Focus within one session. Intraclass correlation coefficient (ICC) analysis showed the EyeGuide Focus had overall good reliability (ICC 0.79, 95%CI: 0.70, 0.86). However, a familiarization effect showing improvements in subsequent trials 2 (9.7%) and 3 (8.1%) was noticeable in both cohorts (p < 0.001) with adolescent participants showing greater familiarization effects than adults (21.7% vs. 13.1%). No differences were observed between sexes (p = 0.69). Overall, this is the first study to address the concern regarding a lack of published reliability studies for the EyeGuide Focus. Results showed good reliability, suggesting that oculomotor pursuits should be part of a multimodality assessment protocol, but the observation of familiarization effects suggests that smooth-pursuit testing using this device has the potential to provide a biologically-based interpretation of the maturation of the oculomotor system, as well as its relationship to multiple brain regions in both health and injury.

An eye to the future: Acute and long-term neuro-ophthalmological and neurological complications of COVID-19

COVID-19 has had a significant impact on the global population and has produced compelling evidence of non-pulmonary organ dysfunction, including the nervous system. It is vital that specialists in ophthalmology and neurology are informed of the potential complications of COVID-19 and gain a deeper understanding of how COVID-19 can cause diseases of the nervous system. In this review we detail four possible mechanisms by which COVID-19 infection may result in neurological or neuro-ophthalmological complications: (1) Toxic and metabolic effects of severe pulmonary COVID-19 disease on the neural axis including hypoxia and the systemic hyper-inflammatory state, (2) endothelial dysfunction, (3) dysimmune responses directed again the neuroaxis, and (4) direct neuro-invasion and injury by the virus itself. We explore the pathological evidence for each of these and how they may link to neuro-ophthalmological disorders. Finally, we explore the evidence for long-term neurological and neuro-ophthalmological complications of COVID-19, with a focus on neurodegeneration.

Anticipatory head control mechanisms in response to impact perturbations: An investigation of club rugby players with and without a history of concussion injury

OBJECTIVES

The primary objective of this study was to examine rugby players anticipatory and compensatory head control during predictable and unpredictable impact events.

METHODS

An observational cross-sectional study design. Fifty-one (17_healthy 34_concussion) male rugby players were exposed to external predictable and unpredictable impact perturbations at mid-chest level. Surface EMG of the upper-trapezius (UT), splenius-capitis (Spl) and sternocleidomastoid (Scm) was recorded and analysed across three temporal epochs typical for anticipatory and compensatory postural control. Synchronized sagittal head-kinematics were measured from high-speed video (500 fps). Nonparametric tests were used to examine within and between group effects.

RESULTS

Anticipatory head control was evident in predictable conditions, expressed by early posterior head displacement and activation of the Spl. Compared to unpredictable conditions, muscle amplitudes were significantly lower, as was head acceleration. Compared to Healthy, the Concussion athletes lacked early activation of the Spl, exhibited delayed anticipatory head adjustments and experienced higher head accelerations in predictable conditions.

CONCLUSION

Rugby players with concussion injuries have significant deficits in cervical spinal motor control. The concussed motor control strategy leads to higher inertial head accelerations and delayed anticipatory head displacements. Effects may persist for two or more years following injury, which may indicate re-injury vulnerability in these athletes.

Evaluation and Utility of the King-Devick With Integrated Eye Tracking as a Diagnostic Tool for Sport-Related Concussion

Background

Eye-tracking technology for detecting eye movements has been gaining increasing attention as a possible assessment and monitoring tool for sport-related concussion (SRC).

Purpose

To determine the diagnostic accuracy of a rapid number-naming task with eye tracking, the King-Devick Eye Tracking (K-D ET) assessment, in identifying SRC.

Study Design

Cohort study.

Methods

One female and 1 male team of United States collegiate rugby-15 players competing during the 2018 season were recruited. Variables assessed were total saccades, saccade velocity, total fixations, fixation duration, fixation polyarea, and test duration. A generalized estimating equation was used to examine group (concussion vs nonconcussion), time (baseline vs postinjury/postseason), and sex-based differences for each outcome measure. In addition, the different components of diagnostic accuracy of the K-D ET were calculated.

Results

Baseline K-D ET assessment for 49 participants (25 male, 24 female) were assessed at the beginning of the season, with 28 participants who did not sustain a head injury during the season completing the postseason assessments and 6 participants completing a postinjury (suspected concussion) assessment. Significant differences were observed between concussed and nonconcussed groups for total saccades (P = .024), fixation duration (P = .007), and fixation polyarea (P = .030), with differences from baseline to follow-up observed for saccade velocity (P = .018) in both groups. Sex-based differences were noted for total fixations (P = .041), fixation polyarea (P = .036), and completion time (P = .035). No significant Group × Time interactions were noted. The K-D ET test duration indicated high specificity (0.86) but not high sensitivity (0.40). No other variables reported high sensitivity or specificity.

Conclusion

Other than completion time of the K-D ET test, no K-D ET oculomotor parameter was highly sensitive or specific in the diagnosis of concussion in this study.

Synaptic plasticity in self-powered artificial striate cortex for binocular orientation selectivity

Get in-depth understanding of each part of visual pathway yields insights to conquer the challenges that classic computer vision is facing. Here, we first report the bioinspired striate cortex with binocular and orientation selective receptive field based on the crossbar array of self-powered memristors which is solution-processed monolithic all-perovskite system with each cross-point containing one CsFAPbI₃ solar cell directly stacking on the CsPbBr₂I memristor. The plasticity of self-powered memristor can be modulated by optical stimuli following triplet-STDP rules. Furthermore, plasticity of 3 × 3 flexible crossbar array of self-powered memristors has been successfully modulated based on generalized BCM learning rule for optical-encoded pattern recognition. Finally, we implemented artificial striate cortex with binocularity and orientation selectivity based on two simulated 9 × 9 self-powered memristors networks. The emulation of striate cortex with binocular and orientation selectivity will facilitate the brisk edge and corner detection for machine vision in the future applications.

Designing efficient bio-inspired vision systems remains a challenge. Here, the authors report a bio-inspired striate visual cortex with binocular and orientation selective receptive field based on self-powered memristor to enable machine vision with brisk edge and corner detection in the future applications.