The impact of traumatic brain injury on inhibitory control processes assessed using a delayed antisaccade task.

It has been well established that traumatic brain injury (TBI) can affect cognitive function such as attention, working memory and executive functions. In the present study, we further investigated TBI-related changes in cognitive functions by investigating the ability to reorient visuospatial attention using a modified antisaccade task. Performing an antisaccade requires disengaging attention, inhibiting a reflexive saccade, and then engaging attention to execute a voluntary saccade in a direction opposite to a peripheral target. Particularly we quantified the time (latency), and accuracy (directional and disinhibition errors) of 26 TBI and 33 normal participants in making an antisaccade after a variable period of delay (0, 0.0625, 0.125, 0.250, 0.500 or 1.0 s). Changing the delay period allowed to systematically quantify the temporal and spatial characteristics of preparing and initiating an antisaccade and whether this process is affected by TBI. TBI participants took longer (approximately 33-66 ms for variable delays) to generate correct delayed antisaccades and showed increased directional errors (2-11 % for variable delays) and increased disinhibition prosaccade errors (2-6 % for variable delays) compared to controls. However, both groups made similar disinhibition antisaccade errors. These findings indicate that TBI participants required a longer time to process information, and a possible poorer response inhibition and poor spatial information processing due to head injury.

Changes in the components of visual attention following traumatic brain injury: A systematic review and meta-analysis.

PURPOSE: We conducted a systematic review and meta-analysis to understand the impact of traumatic brain injury (TBI) on visual attention and whether different components and processes of visual attention (such as selective, sustained, divided, and covert orientation of visual attention) are affected following brain injury. METHODS: A literature search between January 1980 to May 2021 was conducted using Medline, Scopus, PubMed, and Google Scholar databases was undertaken for studies that assessed visual attention using different tasks that target specific or multiple components of visual attention. Three hundred twenty-nine potentially relevant articles were identified, and 20 studies met our inclusion criteria. RESULTS: A total of 123 effect sizes (ES) were estimated from 20 studies that included 519 patients with TBI and 530 normal participants. The overall combined ES was statistically significant and large (ES = 0.92), but with high heterogeneity (Q = 614.83, p < 0.0001, I2 = 80.32%). Subgroup analysis showed that the impact of TBI severity, with the ES for moderate-severe TBI significantly higher than mild TBI (t (112) = 3.11, p = 0.002). Additionally, the component of visual attention was differentially affected by TBI (F (2, 120) = 10.25, p<0.0001); the ES for selective attention (ES = 1.13) and covert orientation of visual attention (ES = 1.14) were large, whilst for sustained attention, the ES was medium at 0.43. A subgroup analysis comparing outcome measures showed that reaction time (ES = 1.12) was significantly more affected compared to performance accuracy (ES = 0.43), F (1, 96) = 25.98, p<0.0001). CONCLUSION: Large and significant deficits in visual attention was found following TBI which can last for years after the initial injury. However, different components of visual attention were not affected to the same extent, with selective visual attention and orientation of visual attention most affected following TBI.

Evaluating the extent of change in near point of convergence in traumatic brain injury: a systematic review and meta-analysis.

OBJECTIVE: Traumatic brain injury (TBI) causes significant impact on visual system. This study reports the impact of TBI on the near point of convergence (NPC) measure in individuals with mild TBI. METHODS: A systematic review and meta-analysis were conducted for studies that quantified NPC changes in mild TBI. The relevant studies were searched using search engines such as PubMed, EMBASE, Medline and Google Scholar. Thirty studies fulfilled the criteria for systematic review while twelve studies were included in the meta-analysis from 444 patients with mild TBI and 881 controls. RESULTS: This study showed a large and significant impact of head injury on the clinical measure of NPC in patients with mild TBI with a combined effect size of 0.98(95% CI: 0.67-1.29) and significantly moderate heterogeneity (Q(18) = 60.84,P = .001,I2 = 72.06%). Moderator analysis and subgroup analysis showed no difference in effect size with age and post-injury period. CONCLUSIONS: This study demonstrated that NPC is largely affected by the impact of TBI. Given the ease with which it can be measured and without the need of specialists and dedicated equipment, NPC measure might provide a supplementary measure of oculomotor function in addition to less sensitive and more subjective questionnaires and personal reports.

Smooth Pursuit Eye Movements as a Biomarker for Mild Concussion within 7-Days of Injury.

AIM: Deficits in smooth-pursuit eye movements (SPEM) are often associated with mild traumatic brain injury(TBI). Eye tracking tests serve as a quick objective clinical tool to assess such predictive visual tracking. In this study, SPEM was assessed along circular, horizontal and vertical trajectories in adolescents with concussion and age-matched controls. METHODS: Ninety-one young adolescents with concussion and 140 visually healthy age-matched controls with a mean age of 14 years performed a computerized test of circular, horizontal and vertical tracking task using an eye tracker. Oculomotor tracking was assessed by computing the rate of fixation, saccades and SPEM made while performing the tasks. RESULTS: The predictive visual tracking task was able to differentiate the TBI group from the non-TBI group. The TBI group showed a significant difference in the fixation, saccades and SPEM percentages for circular tracking movement compared to the controls. There was a significant difference in fixation and SPEM % for horizontal and vertical tracking. CONCLUSIONS: Predictive visual tracking, assessed using eye tracking technology, is able to differentiate deficits in oculomotor functions in individuals with and without concussion. The eye tracking technology may serve as a quick objective tool to detect and monitor neural deficits due to TBI.

Visuospatial Attention Allocation as an Indicator of Cognitive Deficit in Traumatic Brain Injury: A Systematic Review and Meta-Analysis.

Traumatic Brain Injury (TBI) is defined by changes in brain function resulting from external forces acting on the brain and is typically characterized by a host of physiological and functional changes such as cognitive deficits including attention problems. In the present study, we focused on the effect of TBI on the ability to allocate attention in vision (i.e., the use of endogenous and exogenous visual cues) by systematically reviewing previous literature on the topic. We conducted quantitative synthesis of 16 selected studies of visual attention following TBI, calculating 80 effect size estimates. The combined effect size was large (g = 0.79, p < 0.0001) with medium heterogeneity (I2 = 68.39%). Subgroup analyses revealed an increase in deficit with moderate-to-severe and severe TBI as compared to mild TBI [F (2, 76) = 24.14, p < 0.0001]. Task type was another key source of variability and subgroup analyses indicated that higher order attention processes were severely affected by TBI [F (2, 77) = 5.66, p = 0.0051). Meta-regression analyses revealed significant improvement in visual attention deficit with time [p(mild) = 0.031, p(moderate-to-severe) = 0.002, p(severe) < 0.0001]. Taken together, these results demonstrate that visual attention is affected by TBI and that regular assessment of visual attention, using a systematic attention allocation task, may provide a useful clinical measure of cognitive impairment and change after TBI.

Reading eye movements in traumatic brain injury / Movimientos oculares durante la lectura en lesiones cerebrales traumáticas

PURPOSE: The aim of this study was to measure the reading eye movements in subjects with traumatic brain injury (TBI) using ReadAlyzer. ReadAlyzer is an objective eye movement recording device that tracks the eye movements while reading. METHODS: Reading eye movements were measured using ReadAlyzer in 30 subjects with TBI (mild, moderate and severe) who had binocular vision and reading related symptoms and 60 asymptomatic controls. RESULTS: There was a significant decrease in reading eye movement parameters in subjects with TBI compared to controls. Reading eye movement parameters are represented in median and interquartile range (IQR). Subjects with TBI presented with an increased number of fixations/100 words (median 137, IQR 106-159) and regressions/100 words (24, 12-36), and reduced reading rate (154, 128-173) words per minute. They also had a lesser grade level equivalent (4.0, 3.0-7.0) and reduced comprehension (70, 60-80) percentage compared to controls (Mann-Whitney U test, p < 0.05). Reading eye movement parameters were also significantly affected in mild and moderate-severe TBI subjects compared to controls (Kruskal-Wallis test, p < 0.05). CONCLUSION: Reading eye movement performance using ReadAlyzer was found to be decreased in traumatic brain injury. Reading assessment may serve as a clinical measure to understand the oculomotor system following TBI

OBJETIVO: El objetivo de este estudio fue medir los movimientos oculares durante el proceso de lectura en sujetos con lesión cerebral traumática (TBI) utilizando ReadAlyzer, un dispositivo de registro objetivo del movimiento del ojo, que rastrea los movimientos oculares durante la lectura. MÉTODOS: Se midieron los movimientos oculares durante la lectura utilizando ReadAlyzer en 30 sujetos con TBI (leve, moderada y grave) con síntomas relacionados con la vision binocular y la lectura, así como en 60 controles asintomáticos. RESULTADOS: Se produjo una disminución significativa de los parámetros del movimiento ocular durante la lectura en los sujetos con TBI, en comparación con los controles. Los parámetros del movimiento ocular durante la lectura se representan como mediana y rango intercuartílico (IQR). Los sujetos con TBI presentaron un incremento del número de fijaciones /100 palabras (137, 106-159) y regresiones/100 palabras (24, 12-36), así como una reducción de la tasa de lectura (154, 128-173) palabras por minuto. También reflejaron un menor grado de equivalencia de nivel (4, 3-7) y una reducción de la comprensión (70, 60-80) porcentual, en comparación con los controles (prueba U de Mann-Whitney, p < 0,05). Los parámetros del movimiento ocular durante la lectura se vieron también significativamente afectados en los pacientes de TBI leve y moderada-severa, en comparación con los controles (prueba de Kruskal-Wallis, p < 0,05). CONCLUSIÓN: Se observó un descenso del desempeño del movimiento ocular durante la lectura, utilizando ReadAlyzer, en las lesiones cerebrales traumáticas. La evaluación de la lectura puede servir como medida clínica para comprender el sistema oculomotor tras una lesión cerebral traumática

Visual profile of acquired brain injury in Indian cohort: a retrospective study.

OBJECTIVE: With the increasing global prevalence of acquired brain injury (ABI), the burden of visual problems as a sequelae to ABI is on the rise. This study reports the visual profile of patients with ABI seen in Neuro-Optometry Clinic (NOC) at a tertiary eye-care center in Southern India. METHODS: A retrospective study was carried out between January 2014 and December 2015. Medical records of patients diagnosed with ABI referred by Neuro-Ophthalmologists to the NOC were reviewed. The detailed history, clinical findings of neuro assessment and management details were recorded. RESULTS: Of the 241 patients with ABI, 208 had Traumatic Brain Injury (TBI) and 33 had Cerebro-Vascular Accident (CVA). The mean (SD) age of patients with TBI was 35 ± 14 years and CVA was 52 ± 16 years. Binocular diplopia (61%) was seen predominantly in TBI due to vertical deviation (31%). Cranial nerve palsy was most common in TBI (55%) than CVA (36%) and visual field defects were most frequently seen in CVA (27%). CONCLUSION: Cranial nerve paresis and restrictive strabismus with diplopia were the most common presentations in TBI and visual field defects in CVA. A neuro-optometric evaluation is recommended to identify visual dysfunctions and provide appropriate management options. ABBREVIATIONS: ABI: Acquired Brain Injury; TBI: Traumatic Brain Injury; CVA: Cerebrovascular Accident; NOC: Neuro-Optometry Clinic; NSBVA: Non-Strabismic binocular vision anomalies; OMD: Oculomotor dysfunction; VFD: Visual field defect; GON: Glaucomatous optic neuropathy.

Reading eye movements in traumatic brain injury.

PURPOSE: The aim of this study was to measure the reading eye movements in subjects with traumatic brain injury (TBI) using ReadAlyzer. ReadAlyzer is an objective eye movement recording device that tracks the eye movements while reading. METHODS: Reading eye movements were measured using ReadAlyzer in 30 subjects with TBI (mild, moderate and severe) who had binocular vision and reading related symptoms and 60 asymptomatic controls. RESULTS: There was a significant decrease in reading eye movement parameters in subjects with TBI compared to controls. Reading eye movement parameters are represented in median and interquartile range (IQR). Subjects with TBI presented with an increased number of fixations/100 words (median 137, IQR 106-159) and regressions/100 words (24, 12-36), and reduced reading rate (154, 128-173) words per minute. They also had a lesser grade level equivalent (4.0, 3.0-7.0) and reduced comprehension (70, 60-80) percentage compared to controls (Mann-Whitney U test, p<0.05). Reading eye movement parameters were also significantly affected in mild and moderate-severe TBI subjects compared to controls (Kruskal-Wallis test, p<0.05). CONCLUSION: Reading eye movement performance using ReadAlyzer was found to be decreased in traumatic brain injury. Reading assessment may serve as a clinical measure to understand the oculomotor system following TBI.

Deficits in saccades and smooth-pursuit eye movements in adults with traumatic brain injury: a systematic review and meta-analysis.

PURPOSE: To conduct a review of literature and quantify the effect that traumatic brain injury (TBI) has on oculomotor functions (OM). METHODS: A systematic review and meta-analysis was conducted from papers that objectively measured saccades and smooth-pursuit eye movements in mild and severe TBI. RESULTS: The overall impact of TBI on OM functions was moderate and significant with an effect size of 0.42 from 181 OM case-control comparisons. The heterogeneity, determined using the random effect model, was found to be significant (Q (180) = 367, p < 0.0001, I2 = 51) owing to the variety of OM functions (reflexive saccades, antisaccades, memory-guided saccades, self-paced saccades and pursuits) measured and varying post-injury periods.The overall effect on OM functions were similar in mild and severe TBI despite differences in combined effect size of various OM functions. OM functions involving complex cognitive skills such as antisaccades (in mild and severe TBI) and memory-guided saccades (in mild TBI) were the most adversely affected, suggesting that OM deficits may be associated with cognitive deficits in TBI. CONCLUSION: TBI often results in long-standing OM deficits. Experimental measures of OM assessment reflect neural integrity and may provide a sensitive and objective biomarker to detect OM deficits following TBI.

Changes in stimulus and response AC/A ratio with vision therapy in Convergence Insufficiency / Cambios del ratio AC/A estímulo y respuesta tras con terapia visual en casos de Insuficiencia de Convergencia

Purpose: To evaluate the changes in the stimulus and response Accommodative Convergence to Accommodation (AC/A) ratio following vision therapy (VT) in Convergence Insufficiency (CI). Methods: Stimulus and response AC/A ratio were measured on twenty five CI participants, pre and post 10 sessions of VT. Stimulus AC/A ratio was measured using the gradient method and response AC/A ratio was calculated using modified Thorington technique with accommodative responses measured using WAM-5500 open-field autorefractor. The gradient stimulus and response AC/A cross-link ratios were compared with thirty age matched controls. Results: Mean age of the CI and control participants were 23.3 ± 5.2 years and 22.7 ± 4.2 years, respectively. The mean stimulus and response AC/A ratio for CI pre therapy was 2.2 ± 0.72 and 6.3 ± 2.0 PD/D that changed to 4.2 ± 0.9 and 8.28 ± 3.31 PD/D respectively post vision therapy and these changes were statistically significant (paired t-test; p < 0.001). The mean stimulus and response AC/A ratio for controls was 3.1 ± 0.81 and 8.95 ± 2.5 PD/D respectively. Conclusions: Stimulus and response AC/A ratio increased following VT, accompanied by clinically significant changes in vergence and accommodation parameters in subjects with convergence insufficiency. This represents the plasticity of the AC/A crosslink ratios that could be achieved with vision therapy in CI (AU)

Objetivo: Evaluar los cambios de la relación convergencia acomodativa/acomodación (AC/A) estímulo y respuesta, tras terapia visual (TV) en casos de Insuficiencia de Convergencia (CI). Métodos: Se midieron las relaciones AC/A de estímulo y respuesta en veinticinco participantes, tras realizar sesiones previas y posteriores de TV. La relación AC/A de estímulo se midió utilizando el método gradiente, y la relación AC/A de respuesta se calculó utilizando la técnica modificada de Thorington, midiendo las respuestas acomodativas con un autorrefractómetro de campo abierto WAM-5500. Se compararon las relaciones cruzadas AC/A gradiente estímulo y respuesta con treinta controles emparejados por edad. Resultados: La edad media del grupo con CI y el grupo control fue de 23,3 ± 5,2 años y 22,7 ± 4,2 años, respectivamente. La relación media AC/A de estímulo y respuesta para CI previa a la terapia fue de 2,2 ± 0,72 y 6,3 ± 2 PD/D, cuyos valores fueron de 4,2 ± 0,9 y 8,28 ± 3,31 PD/D respectivamente tras la terapia visual. Dichos cambios fueron estadísticamente significativos (prueba de t pareada; p < 0,001). La relación media AC/A de estímulo y respuesta para los controles fue de 3,1 ± 0,81 y 8,95 ± 2,5 PD/D. Conclusiones: La relación AC/A de estímulo y respuesta se incrementó tras la TV, junto a cambios clínicamente significativos en lo que respecta a vergencia y parámetros de acomodación en los pacientes con insuficiencia de convergencia. Esto representa la plasticidad de las referencias cruzadas AC/A, que podría alcanzarse con terapia visual en los casos de CI (AU)

Changes in stimulus and response AC/A ratio with vision therapy in Convergence Insufficiency.

PURPOSE: To evaluate the changes in the stimulus and response Accommodative Convergence to Accommodation (AC/A) ratio following vision therapy (VT) in Convergence Insufficiency (CI). METHODS: Stimulus and response AC/A ratio were measured on twenty five CI participants, pre and post 10 sessions of VT. Stimulus AC/A ratio was measured using the gradient method and response AC/A ratio was calculated using modified Thorington technique with accommodative responses measured using WAM-5500 open-field autorefractor. The gradient stimulus and response AC/A cross-link ratios were compared with thirty age matched controls. RESULTS: Mean age of the CI and control participants were 23.3±5.2 years and 22.7±4.2 years, respectively. The mean stimulus and response AC/A ratio for CI pre therapy was 2.2±0.72 and 6.3±2.0 PD/D that changed to 4.2±0.9 and 8.28±3.31 PD/D respectively post vision therapy and these changes were statistically significant (paired t-test; p<0.001). The mean stimulus and response AC/A ratio for controls was 3.1±0.81 and 8.95±2.5 PD/D respectively. CONCLUSIONS: Stimulus and response AC/A ratio increased following VT, accompanied by clinically significant changes in vergence and accommodation parameters in subjects with convergence insufficiency. This represents the plasticity of the AC/A crosslink ratios that could be achieved with vision therapy in CI.

Natural history of idiopathic abducens nerve paresis in a young adult / Historia natural de paresia idiopática del nervio abducens en un adulto joven

The natural history of idiopathic abducens nerve paresis and the role of conservative management such as vision training during the recovery process is not well documented in the literature to the best of our knowledge. This case report presents the natural recovery process of idiopathic abducens nerve paresis in a young adult and the role of vision therapy in the recovery process (AU)

Hasta la fecha, la historia natural de la paresia idopática del nervio abducens y la función de un tratamiento conservador como la terapia visual durante el proceso de recuperación no se hallan bien documentadas en la literatura. Este informe de un caso presenta el proceso de recuperación natural de la paresia idiopática del nervio abducens en un adulto joven, así como la función de la terapia visual en el proceso de recuperación (AU)

Natural history of idiopathic abducens nerve paresis in a young adult.

The natural history of idiopathic abducens nerve paresis and the role of conservative management such as vision training during the recovery process is not well documented in the literature to the best of our knowledge. This case report presents the natural recovery process of idiopathic abducens nerve paresis in a young adult and the role of vision therapy in the recovery process.

Acute adult onset comitant esotropia associated with accommodative spasm.

PURPOSE: Acute onset comitant esotropia associated with spasm of accommodation in children and adults is a rare clinical condition. When occurring with pupillary miosis and restricted ocular motility, it is referred to as "spasm of near reflex" (SNR) and may require neurological investigation. The natural history of SNR depends on its etiology. There is little information in the literature regarding the long-term follow-up of SNR and the stability of visual signs and symptoms following cessation of treatment. We report a case of SNR in an otherwise healthy young male, and discuss the presentation, clinical investigations, management, response to treatment, and 1-year follow-up. CASE REPORT: A 23-year-old male patient reported to the clinic with sudden onset of blurred vision, inward deviation of the eyes, and binocular diplopia. On examination, he was diagnosed to have acute onset esotropia resulting from SNR. He was treated with cycloplegic medications and vision therapy. The condition resolved following 1 year and there has been no recurrence. CONCLUSIONS: Acute adult onset esotropia occurring with accommodative spasm responds favorably to cycloplegic medications but may need a longer course of treatment for successful resolution and stability.