VISUAL IMPAIRMENTS IN CHILDREN WITH CEREBRAL PALSY

Background: Autism spectrum disorder (ASD) is a heterogeneous behavioral disorder that is characterized by qualitative deficits in social communication and interaction and restricted, repetitive behavioral patterns, activities, and interests. For an optimum outcome in children with autism, early intervention (preferably before three years of age) is essential. Hence, there is a critical need to improve the awareness of ASD to enable earlier detection and intervention. The present study aims at achieving the following: (1) Investigating neural transmission within the visual system using visual evoked potentials (VEPs) as an index of the myelination process of the visual pathway. (2) Correlating the changes in the VEPs with the clinical severity of autism. (3) Investigating the possible gender differences in VEPs in autistic children. Materials and Methods: The study was conducted on 60 preschool children (11 females and 49 males) who were recruited from the autism center and the pediatric neurology ward and who met the DSM-V criteria for autism in the Pediatric Hospital for the period from 12 December 2019 to 1 June 2021. Their mean age was 4.5±1.17 years. Another 50 (40 males and 10 females) age- and gender-matched normally developed children served as the control group. Both groups were subjected to a detailed history, as well as complete physical and neurological examinations. The VEPs were assessed for all of them. The autistic children were excluded from the study if they had any motor, visual impairment, inborn errors of metabolism, epilepsy, other chronic medical or neurological disorders, or if they were taking medications during the period of study. Results: The P100 wave latency of the VEPs was significantly prolonged in both eyes of autistic children as compared with that of the control group. The N75-P100 amplitude was significantly lower in the left but not the right eye of patients when compared with those of normally developed children. Neither the P100 wave latency nor the N75-P100 amplitude of both eyes was associated with the gender or severity of illness. Conclusion: There are distinct changes in VEPs in autistic children, especially the abnormal prolongation of conduction time, suggesting that autistic children may have brainstem and visual pathway dysfunction. Gender and disease severity score have no impact on VEPs.

Pattern-reversal visual evoked potentials (VEP) were recorded from 22 patients (mean age 33.7 years) with Friedreich's ataxia, 15 of whom also had a detailed neuro-ophthalmological assessment prior to the VEP examination. None had noted symptomatic visual impairment. Eleven of the 15 (73 per cent) examined clinically had one or more neuro-ophthalmic abnormality and 14/22 (64 per cent) had an abnormal VEP study which was always binocular and comprised absent responses, or most commonly, increased P100 component latencies. The maximum P100 latency was 143 ms and the group mean was 118 ms. The P100 amplitude was also generally reduced particularly in those patients with latencies less than 115 ms (upper limit of normal), while in those with latencies above the normal range there was a significant inverse correlation between the P100 amplitude and latency. The waveform, temporal dispersion and interocular differences were normal in almost all patients with identifiable responses, including those with prolonged VEP latencies. Electroretinograms recorded from three selected patients were either normal or minimally abnormal and suggested secondary rather than primary retinal involvement. The only VEP parameter to correlate with either the duration of the generalized disease or the visual acuity was the P100 amplitude. A good correlation was found between the VEP and the clinical neuro-ophthalmic findings. Temporal pallor of the optic disc was most often associated with an abnormal VEP result and impaired visual acuity or colour vision were uncommon in the absence of VEP abnormalities. The VEP changes and those obtained from 24 age- and acuity-matched cases of demyelinating optic neuritis are contrasted and the probable pathophysiology is discussed. Two main conclusions emerge from this study. First, there is a high incidence of asymptomatic visual pathway involvement in Friedreich's ataxia which can be demonstrated by both clinical and VEP examination. Secondly, the VEP changes in Friedreich's ataxia differ from those found in typical demyelinating optic neuropathy and are consistent with progressive nerve fibre loss and associated slowing of conduction, indicating that the visual pathway is affected by the same widespread process of axonal degeneration found throughout the nervous system.

Background. Intraoperative monitoring (IOM) of visual evoked potentials (VEPs) is used to inform surgeons about impacts on the visual system in order to prevent iatrogenic visual impairment. The VEP monitoring use become widespread only in the last decade; nowadays, there is no generally accepted methodology for its implementation, and the effectiveness of VEP monitoring and the factors determining it have not been sufficiently studied.Aim. The aim of the study was to investigate the factors influencing the VEP monitoring feasibility and effectiveness.Materials and methods. Data from 240 consecutive neurosurgical operations performed using VEP monitoring were retrospectively reviewed. IOM data (registration parameters, presence and type of VEP changes), patient characteristics (gender and age, tumor type and location, presence of preoperative visual dysfunctions), anesthesia parameters and postoperative changes in vision were studied. Statistical analysis was performed using χ2 and Mann–Whitney tests.Results. VEPs were obtained in 91.3 % of eyes with completely or partially preserved vision. The main factors reducing the chances to record VEPs successfully are preoperative visual disorders and the use of inhalation anesthesia. A personalized approach to the selection of reference electrodes and frequency filtering parameters makes it possible to reduce the number of averagings required for VEP recording and accelerate informing surgeons. With successful monitoring 59.1 % of eyes had no noticeable VEP changes; 5.8 % of eyes had signs of intraoperative improvement; 35.1 % had signs of deterioration. Among the last category, 60.7 % of eyes had full VEPs recovery afterwards. After surgery, new visual disorders were detected in 2.6 % of eyes without signs of intraoperative deterioration, in 6.7 % – with temporary deterioration, and in 19.3 % – with signs of deterioration persisted until IOM is finished. Assessing the sensitivity and specificity of VEP monitoring is hampered by the possibility of complications in the early postoperative period and IOM influence on the course and results of the operation. The proportion of total resections was maximal when VEP monitoring was successful. In the subgroup without preoperative visual impairments, the alarms during monitoring were associated with decrease in proportion of total resections proportion due to increase in proportion of subtotal resections.Conclusion. VEP monitoring with a personalized approach allows effective monitoring of visual functions preservation during neurosurgical operations.

To investigate the effects of high infusion pressure in conjunction with pars plana vitrectomy (PPV) on retinal morphology and function in rabbits. Pars plana vitrectomy was performed under urethane (0.8 mg/kg) anaesthesia in the right eye of albino rabbits following phacoemulsification and aspiration (PEA). The left eyes were not touched. After PEA, the animals were divided into two groups. In six eyes, intraocular pressure (IOP) was increased to 80 mmHg for 30 mins (high-pressure group) and in five eyes IOP was maintained at 40 mmHg for 30 mins (low-pressure group). The IOPs were regulated by the height of the bottle of balanced salt solution (BSS) and monitored with a pressure transducer. After the pressure elevation, vitreous fluid was collected to measure the glutamate concentration. Then, PPV was performed for 15 mins in both groups under an infusion pressure of 40 mmHg. In five additional rabbits, PEA alone was performed in the right eye, and vitreous fluid was collected (PEA group). Functional alterations were assessed by recording visual evoked potentials (VEPs) and electroretinograms (ERGs). Ten days after the IOP changes, the animals were killed with intravenous pentobarbital sodium and the eyes were prepared for histological analysis. Damage to retinal ganglion cells (RGCs) was quantified by counting the number of cells in the ganglion cell layer (GCL). The contralateral eyes in the high-pressure group served as controls (n = 6). The mean implicit time (IT) of the VEPs in the high-pressure group was significantly longer than that before the IOP elevation, by 114-124% (p < 0.05, paired t-test), and also than that of control eyes (p < 0.05, anova followed by t-test). No significant changes in the VEPs were detected in either the low-pressure group or the PEA group. There were significantly fewer cells in the GCL in the high-pressure group (24.7/mm) than in the control animals (41.4/mm; p < 0.05, Dunnett's test). The number of cells in the GCL in the low-pressure and PEA groups did not significantly differ to that in the controls. The amplitudes of the ERG a- and b-waves were not significantly changed (p > 0.05, paired t-test). These results suggest that high infusion pressure in conjunction with PPV leads to morphological and functional changes in the retina. The absence of ERG changes and presence of VEP changes suggest that these changes were due to damage to RGCs, which supports the morphological observations.

To collect data on refractive errors and visual impairment in adults with an intellectual disability (ID) in the Netherlands. A randomized sample of 2100 participants was drawn from a base population of 9000 adults with intellectual disabilities in the Netherlands. This article reports on the first 900 participants. All participants underwent a protocol-based on-site ophthalmological assessment carried out by skilled investigators. Co-operation was classified according to the number of tests that could be carried out reliably and was good or excellent in 80% of subjects, average in 13% and poor in 7%. Refraction could be reliably assessed in 505/900 (56%) subjects. There was an increased risk of visual impairment in all subgroups compared to the general Dutch population. Visual acuity (VA) was related to the level of ID, but refractive errors were not. New spectacles were prescribed in 106 cases (12%). Of 374 people in whom both monocular VA and the refractive error of the right eye could be reliably assessed, 153 (41%) had a pretest prescription, 16 (10%) of which we found to be inadequate. Of the 221 participants without a pretest prescription, 41 (19%) benefited from correction. Only 38/84 (45%) subjects aged 50 years or older, who could benefit from correction for near vision, had near spectacles. New correction increased the mean distant VA significantly from 0.44 to 0.65 (p < 0.0005). With some adaptations, visual screening is feasible in a majority of adults with ID. Visual impairment and refractive errors are much more prevalent in adults with ID than in the normal population. Accurate spectacle correction resulted in significant improvement in distant VA.

Cerebral lesions in premature infants are usually found in the periventricular area, closely related to the optic tracts. Therefore, we have developed a simple set-up which allows repetive measurements of visual evoked potentials (VEP) during the first hours of life leaving the infants undisturbed in the incubator. Stimulation by single flashes during periods of quiet spontaneous EEG activity results in distinct VEPs. In 20 “healthy” newborns (27-34 gw) the latency decreased over a few hours coinciding with the increase in core temperature and with the recovery from slight respiratory- and/or metabolic acidosis. No changes in VEPs were observed in 4 infants with arterial hypotension (m-BP down to 20 mmHg) nor in 5 infants with hypocarbia (pCO2 down to 1.3 KPa). However, in 4 hypoxic infants (a-pO2 down to 2.5 KPa) the latency increased and the amplitude decreased markedly. Finally, in 9 premature infants with asymptomatic hypoglycemia (0.0-1.3; median 0.7 mmol/1) no effects on VEPs were detectable.Conclusion: Repetitive investigations of VEPs immediately after birth appear to be a reliable method of monitoring the cerebral function. Only hypoxia was observed to induce marked changes in VEP and thereby in cerebral metabolism. Asymptomatic hypoglyoemia, however, even when severe, did surprisingly not affect VEP.

Five children with a history of preterm birth (mean gestational age of 27 weeks; birth weight 870-1,380 g) and perinatal post-hemorrhagic hydrocephalus were examined ophthalmologically at ages ranging from 4-11 years. An extended visual evoked potentials (VEPs) examination was simultaneously performed, using pattern-reversal, motion-onset, and cognitive visual stimuli. Although 3 of the 10 eyes displayed about normal visual acuity (> or =0.9), all of the examined eyes were abnormal for at least one variant of the tested VEPs. Pathological changes in VEPs (missing responses, shape abnormalities due to delayed VEPs maturation, prolonged peak latencies, and reduced amplitudes) were roughly proportional to both gestational age and reduction in visual acuity. A more severe pathology was found in the motion-onset VEPs (in all five subjects - nine eyes) when compared to the pattern-reversal VEPs (in four subjects - eight eyes). These observations suggest that the magnocellular system/dorsal stream of the visual pathway (which is particularly activated in response to motion stimuli) may be more frequently affected in preterm children than the parvocellular system/ventral stream (tested mostly by the standard pattern-reversal VEPs). This pilot study may encourage further testing of the combined pattern and motion-related VEPs examinations in preterm children as a way of detecting hidden cortical/cerebral visual impairment (CVI).

Diabetic retinopathy (DR) is a microvascular complication associated with diabetes mellitus. Pregnancy is a major risk factor for DR in diabetic women. Recent evidenced suggests that in course of DR functional changes including damage of pre-ganglionic and ganglionic cells in retina precede structural microvascular changes. A number of studies in the past have highlighted the role of pattern visual evoked potential (VEP) in detecting such functional changes. However, the study of VEP changes in diabetic pregnancies remains unexplored. This case series has the objective of exploring VEP changes in symptomatic OVD cases, who had no signs of DR on fundoscopy. We present two cases of overt diabetic women who complaint of straining of eyes, headache, and difficulty in reading during pregnancy. Complete ophthalmic examination was done in both the cases followed by a VEP test. VEP test was done as a part of a research project. The ethical clearance for the project was obtained from the Institute’s Ethics Committee before the commencement of the study. Fundoscopic examination in both cases revealed that the retina was within normal limits with no signs of retinopathy. In Case 1, P100 latency was increased for the left eye and was normal for the right eye during the first visit. While P100 latency was increased for both left and right eye during the second visit. There was a substantial increase in P100 latency for both eyes in second visit as compared to first visit. In Case 2, P100 latency was increased for both left and right eye and amplitude decreased for the left eye. This is a case series consisting of symptomatic overt diabetic pregnant women who had increased P100 latency despite no signs of retinopathy in fundoscopy. The previous studies have reported that multiple follow-ups with ophthalmoscopy may not be cost-effective in diabetic pregnant women. VEP provides a window for detection of early functional changes that may help identify at risk patients for follow-up and early intervention.

Visual evoked potential (VEP) is used as a means of intraoperative visual function monitoring. It remains unclear, however, whether intraoperative VEP monitoring is a means of real-time visual function monitoring that has satisfactory effectiveness and sensitivity. To evaluate this, the relationships between VEP waveform changes in endoscopic transsphenoidal surgery and postoperative visual function were analyzed retrospectively. Intraoperative VEP monitoring was carried out during 82 endoscopic transnasal transsphenoidal surgeries for 164 eyes at Nara Medical University Hospital, Nara, Japan under total intravenous anesthesia. Red light flash stimulation was provided to each eye independently. The VEP recording and postoperative visual function were then analyzed. In 160 of 164 eyes (98%), steady VEP monitoring was performed. Stable VEP was acquired from eyes with a corrected visual acuity >0.1. VEP was not recorded in four eyes that had a corrected visual acuity under 0.05. A transient VEP decrease was observed in 26 eyes, 8 of which had improved visual acuity and 18 of which had no change in visual acuity. A permanent gradual VEP decrease occurred in eight eyes; this finding did not correspond to a change in visual function. The visual acuity of the patients who underwent the transsphenoidal operation in our study did not worsen. Intraoperative monitoring of VEP predicts postoperative visual function, and a reversible change in VEP indicates that visual function will be preserved. Intraoperative VEP monitoring will be mandatory for surgeries harboring a risk of visual impairment.

Pattern reversal visual evoked potentials (VEPs) with checks of 50' and 12' were recorded in 15 patients with idiopathic unilateral macular hole. VEPs from the affected eyes were reduced in amplitude compared with those from the fellow eyes, especially with checks of 12' (percentage of the amplitude in the affected eye to that in the fellow eye was 86% +/- 19% with checks of 50' and 61% +/- 35% with checks of 12'). The latencies showed no statistically significant difference between the affected and the fellow eyes, although a marked interocular delay was found in a few patients. The degree of amplitude reduction and interocular delay had no relation to the size of the macular hole or visual acuity. The effects of experimental scotomata of various sizes on the VEPs, which were evaluated in nine normal subjects, were also variable among the subjects. We conclude that although the macula predominantly participates in the pattern VEP, an estimation of the extent of macular pathology from the VEP changes may be difficult because the VEP changes induced by a macular hole have wide individual variation and have no relation to the size of the hole.

Background: The increasing prevalence of gestational diabetes mellitus (GDM) during pregnancy has opened the opportunity to study its short- and long-term effects on maternal ophthalmic health. Visual evoked potential (VEP) is a non-invasive electrophysiological test that detects functional disturbances along the visual pathway before the physical signs of diabetic retinopathy (DR) can set in. This longitudinal study is aimed at the assessment of changes in VEP in GDM during different stages of pregnancy and 6-12 weeks after parturition by comparing it with normoglycemic controls.Design and method: Diagnosed cases of GDM were recruited along with normoglycemic controls at 24-28 weeks of gestation. Each participant was required to attend two follow-up appointments at 32-38 weeks of gestation and 6-12 weeks after parturition. A blood sample was taken in a fasting state to record biochemical parameters. VEP was recorded using Neuropack S1 MEB-9400 electrodiagnostic equipment (Nihon Kohden, Tokyo, Japan) in a dark room by providing pattern reversal stimuli to each eye.Results: A total of 29 participants (15 in the control group and 14 in the GDM group) completed the entire study procedure. The observed mean P100 latency of both eyes in the GDM group was recorded longer as compared to that in the control group at baseline and during late pregnancy. Although the mean P100 latency saw a significant decline in postpartum visits as compared to that in late pregnancy, the values were higher than in the control group. P100 latency at baseline correlated significantly to serum advanced glycated end products' (AGE’S) levels in the GDM group.Conclusion: Our study findings reflect that the diagnosis of GDM is associated with significant changes in VEP during and after pregnancy as compared to that of healthy pregnant women.

To estimate prospectively late ocular manifestations in patients after aneurysmal subarachnoid hemorrhage (SAH) treated with aneurysm clipping. Forty-six patients (12 men and 34 women), 23-69 years of age, were included in this study. A conventional ophthalmological examination, visual evoked potentials (VEPs), and static perimetry were performed on all patients. The mean interval between the onset of SAH and the aforementioned examination was 1.9 ± 1.3 years (range 0.5-5 years). The following were compared between patients with affected and non-affected visual fields as well as between those with normal and abnormal VEPs: sex, age, time from SAH to surgery, Hunt and Hess scale, Glasgow Coma Scale, Glasgow Outcome Scale, grading of SAH according to the Fisher scale, and the size and site of aneurysm. Visual field defects were found in 23 patients (50%). In all of these patients, both eyes were affected. The most frequent type of visual field defects were: constricted field (47.8%), multiple peripheral foci (26.1%), and superior field defect (17.4%). There was no significant relationship between the analyzed factors and the occurrence of visual field defects, although statistical significance was almost observed in respect to the Fisher scale (p = 0.055). Deterioration in VEPs was observed in nine patients (19.6%). In the group of patients with abnormal VEPs, the time from onset of SAH to surgery was 2.6 ± 1.8 days, whereas in the group of patients with normal VEPs this time amounted to 6.4 ± 2.4 days (p = 0.02). In patients with no changes in VEPs, the mean Fisher score was significantly higher than in the group with abnormal VEPs (2.8 ± 0.6 vs 2.0 ± 0.4 respectively, p = 0.04). Visual field defects and VEP deterioration are frequent late ocular manifestations of SAH treated with aneurysm clipping. Damage to the visual pathway correlates with the severity of SAH and timing of aneurysmal surgery.

Background: Hypertensive retinopathy is one of the most common complications of hypertension. Hypertension can cause changes in vascular endothelium including hyalinization, which can lead to demyelination of the optic nerve and results in conduction abnormalities in the visual pathway. Visual evoked potential (VEP), a non-invasive neurophysiological technique, is useful in detecting the changes in functional integrity in the visual pathway. The present study was done to compare the changes in the VEP between normotensive and hypertensive individuals. Aims and Objectives: This study aims to compare the VEP changes among normotensive and hypertensive individuals. Materials and Methods: The study was conducted in 30 normotensive and 30 hypertensive subjects (BP ≥140/90 mmHg, according to JNC-7 classification) with normal visual acuity. VEP was recorded using the pattern reversal stimulation technique. The peak latencies of the waves N75, P100, and N145 were measured. Results: There was a statistically significant prolonged N75 (P < 0.05), P100 (P < 0.05), and N145 (P < 0.05) latencies in hypertensive individuals when compared to normotensives. Conclusion: VEP changes occur in hypertensive patients before the development of hypertensive retinopathy. Thus, VEP can be used as a routine screening test for hypertensive individuals, and it can also be used as a better prognostic tool during the treatment of hypertensive retinopathy.

Due to the proximity of craniopharyngioma to the optic apparatus, one of the most common complications after surgery is visual deterioration. Intraoperative visual evoked potential (VEP), as a means of real-time visual function monitoring, has been integrated into transsphenoidal surgery for pituitary adenoma to predict postoperative visual outcome. Compared with pituitary tumor, craniopharyngioma often adheres to optic nerves, with increased risk of postoperative visual impairment. Furthermore, extended endoscopic endonasal surgery (EEES) can provide direct visualization of the surgical plane between the craniopharyngioma and the optic nerves, which contributes to analysis of the mechanism of real-time VEP changes during surgery. Therefore, VEP monitoring applied during EEES for craniopharyngioma may have more clinical value. However, only 9 patients who underwent EEES with VEP monitoring for craniopharyngioma have been sporadically reported to date. In this paper, the authors present the largest series to date analyzing the clinical value of VEP to predict postoperative visual outcome in adult patients with craniopharyngioma. Sixty-five adult patients who underwent EEES with intraoperative VEP monitoring for primary craniopharyngioma were retrospectively reviewed. The association between changes in VEP amplitude and postoperative visual outcome was determined. In addition, other potential prognostic factors with regard to postoperative visual outcomes were included in the analysis. Gross-total resection was achieved in 59 patients (90.8%). Reproducible and stable VEP was recorded in 128 of 130 eyes (98.5%). During surgery, VEP remained stable in 108 eyes, 10 (9.3%) of which had new visual acuity (VA) and/or visual field (VF) defects after surgery. Transient VEP decrease was recorded in 15 eyes, 4 (26.7%) of which had visual deterioration. Of the 5 eyes with permanent VEP decrease, 3 (60%) experienced postoperative visual impairment. Permanent VEP decrease (OR 19.868, p = 0.007) and tight adhesion (OR 6.104, p = 0.040) were independent adverse factors for postoperative VA deterioration. Tight adhesion (OR 7.150, p = 0.002) and larger tumor volume (OR 1.066, p = 0.001) were significant risk factors for postoperative VF defects. Intraoperative VEP monitoring can serve as a real-time warning to guide surgeons to avoid postoperative visual impairment. It effectively predicted VA changes in adult patients with craniopharyngioma after EEES. Tight adhesion and larger tumor volume were also strong predictors of postoperative visual impairment.

Despite increasingly frequent and longer lasting hypoxic episodes during progressive labor, the neonate is alert and vigorous at birth. We investigated whether high levels of PGs during the perinatal period assist in preserving neural function after such "stressful" hypoxic events. Visual evoked potentials (VEPs) and electroretinograms (ERGs) were recorded before and 45 min after mild moderate asphyxic hypoxia (two 4-min asphyxic-hypoxic periods induced by interrupting ventilation at 8-min intervals) in newborn piglets <12 h old treated or not treated with inhibitors of PG synthase (ibuprofen or diclofenac) with or without PG analogs. At 45 min after the hypoxic episode, P2 and b-wave amplitudes were slightly decreased and latencies were delayed. These changes in the VEP and ERG returned to near normal by 120 min. Ibuprofen and diclofenac decreased brain and retinal PG levels and markedly intensified 45 min after hypoxia-induced changes in VEP and ERG, but cerebral and retinal blood flows improved. Combined treatment with PG synthase inhibitor in combination with 16,16-dimethyl-PGE(2) (a PGE(2) analog), but not with PGI(2) and PGF(2alpha) analogs, and in combination with the EP(2) receptor agonist butaprost (but not EP(1) or EP(3) agonists), prevented ibuprofen- and diclofenac-aggravated postasphyxia electrophysiological changes. In conclusion, high levels of PGE(2) in nervous tissue, via actions on EP(2) receptors, seem to contribute to preservation of neural function in the perinate subjected to frequent hypoxic events.