Visual Evoked Potential Findings and Correlation between Visual Evoked Potential and Clinical Severity in Children with Autism Spectrum Disorder

Aim and objectives: Visual dysfunction in diabetes mellitus (DM) is multifactorial and can be due to vascular disease, and metabolic abnormalities that can affect the retina, optic nerve, and visual pathways. Visual evoked potential (VEP) is an electrophysiological test that can quantify the functional integrity of the visual pathways from the retina via the optic nerves, and optic tracts to the visual cortices. In this study, we aimed to investigate the visual pathway dysfunction among diabetics without retinopathy compared with healthy controls and to look for any correlation with diabetic neuropathy, duration of diabetes, or HbA1c level. Methods: The study included 75 diabetic patients and 75 age and sex-matched controls. VEPs were recorded using the pattern reversal stimulation method on the Medtronic EMG EP machine, and P100 latency and N75-P100 amplitude were recorded in both diabetic patients and healthy controls. Results: Mean P100 latency was significantly prolonged and N75-P100 amplitude significantly reduced among diabetic cases compared to healthy controls (p < 0.001). Among diabetics with peripheral neuropathy, P100 latency was significantly prolonged and N75-P100 amplitude was significantly reduced compared to diabetics without peripheral neuropathy. A significant positive correlation of VEP P100 latency (p < 0.001) and a negative correlation with N75-P100 amplitude (p < 0.001) with duration of disease were also found. Conclusion: VEP changes are observed in diabetics before the development of retinopathy or peripheral neuropathy indicating optic pathway dysfunction, which precedes the development of these complications. Early preclinical visual pathway dysfunction can warrant taking the necessary measures to reduce diabetic complications. Abbreviations: DM = Diabetes Mellitus, VEP = Visual Evoked Potential, HbA1c = Hemoglobin A1 c, MRI = Magnetic Resonance Imaging, EEG = Electroencephalography, P100 = Positive wave peak at latency 100 ms (millisecond), N75 = Negative wave peak at latency 75 ms (millisecond), N145 = Negative wave peak at latency 145 ms (millisecond), OCT = Optical coherence tomography, PRVEP = Pattern Reversal Visual Evoked Potential, NCS = Nerve Conduction Study, SSR = Sympathetic Skin Response, IL1 = Interleukin-1, LIF = Leukemia inhibitory factor, CNTF = Ciliary neurotrophic factor, TNF alpha = Tumor necrosis factor-alpha, TGF-beta = Transforming growth factor-beta.

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.

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.

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.

Aging effect in pattern, motion and cognitive visual evoked potentials

&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Introduction&#x0D; Chronic hyperglycemia of diabetes is associated with dysfunction and failure of various organs, especially the eyes, kidneys, neves, heart and blood vessels. Visual evoked potential (VEP) test evaluates how the visual system responds to light. As it tests the function of the visual pathway from the retina to the occipital cortex, VEP is a useful clinical tool in the diagnosis and documentation of visual impairment in many ophthalmological disorders.&#x0D; Analysis of pattern reversal VEPs may provide early diagnosis of diabetic changes and determine prognosis during treatment. The visual evoked potential is suggested to be a sensitive indicator of functional changes in the visual processing pathway.&#x0D; Aims and Objectives&#x0D; The objective of this study was to establish whether duration of DM has an effect on the VEP measurements, P100 wave latency.&#x0D; Material and methods&#x0D; VEP was recorded in 60 type 2 diabetic patients and compared to 60 age and sex matched normal healthy non-diabetic controls. The patients were divided into three groups based on the duration of diabetes. VEP was recorded with a pc based, two channel, RMS EMG EP MK II machine. Comparison between two groups were done using independent Students’ ‘t’ test.. One way ANOVA (Analysis of Variance) and multiple comparisons were done using post hoc Tukey Multiple Comparison Test to compare the variables between the three study groups. To determine correlation between variables, Pearson's correlation coefficient was used. The mean difference was statistically significant at p&lt;0.05&#x0D; Result&#x0D; P100 wave latency was significantly longer in diabetic patients as compared to normal controls (P&lt;0.001); There was significant reduction in N75-P100 amplitudes in diabetic subjects(p&lt;0.01). Duration of diabetes was found to influence the VEP parameters as statistically significant increase in the mean P100 latency with the duration of the disease.(110.2+6.51 ms in group &lt;3 yrs duration of DM, 113.4 +5.00 ms in 4–6 yrs duration group, 118.2+4.23 ms in 7–10 years duration group) (p&lt; 0.01). On applying, Pearson's correlation coefficient test, significant positive correlation was observed between P100 latency and duration of diabetes. (r = 0.5803; p &lt;0.001).&#x0D; Conclusion&#x0D; It is concluded that diabetes has effect on the visual pathway and changes in VEP response in diabetic patients are correlated with duration of disease. So, VEP can be used for early diagnosis of diabetic changes of the visual pathway.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

To report the flash visual evoked potential (VEP) findings in children with primary congenital glaucoma (PCG) before and after successful surgical control of the intraocular pressure (IOP). The study enrolled children presenting with PCG to the Ophthalmology Department of Alexandria Main University Hospital in the period between June and December 2019. All study participants were subjected to a standard protocol of examination, to confirm the diagnosis of PCG. The child was then referred for flash VEP testing. Peaks were designated as negative and positive waves in a numerical sequence (N1, P1, N2, P2, N3 and P3). The child was then scheduled for surgery within 1week of presentation. Postoperative VEP testing was scheduled as soon as feasible and was conducted in the same way as the preoperative VEP testing. The study was conducted on 11 (four right) eyes of eight (five males) children. The mean ± standard deviation of the age of the study children at presentation and at postoperative VEP testing was 3.5 ± 1.6 and 5.1 ± 3.0months, respectively. The study eyes mean ± standard deviation IOP at presentation and at postoperative VEP testing was 23.0 ± 6.7 and 8.3 ± 2.4mmHg, respectively (p < 0.0001). There were a statistically insignificant reduction in P2 implicit time (p = 0.235) and a statistically insignificant increase in each of N1-P1 (p = 0.15) and N2-P2 (p = 0.67) amplitudes postoperatively than preoperatively. IOP elevation in PCG adversely affects the optic nerve function, but, at least in the short term, has no permanent detrimental effect on the optic nerve function as evidenced by the improvement in the VEP parameters.

Background: Visual impairments are associated with cerebral palsy (CP). They enhance functional limitations in children with CP. Objective: The objective of the study was to determine the types of visual impairments in children with CP, and thus the importance of early evaluation and intervention to improve the quality of life. Materials and Methods: Children with CP (n=775) attending the child development clinic from 2012 to 2017 were included in the study. Thorough antenatal, natal, postnatal, and developmental history were recorded. Complete demographic data, anthropometry and general physical, and neurological examination findings were recorded. All patients were advised neuroimaging (computed tomography/magnetic resonance imaging) and hearing and ophthalmological assessment. Results: Of the 775 patients, 270 (34.8%) patients had squint (including convergent and divergent). Detailed fundoscopic and visual evoked potentials (VEP) examination was done in 382 patients. Non-apparent abnormalities (VEP and fundus changes) were seen in 121 patients (31.7%) among 382 tested. Of those 121 patients, VEP changes and fundus changes were seen in 62 and 41 patients, respectively. Refractive errors were detected in 25 patients. Of the total patients assessed for ophthalmological ailments, 129 (33.7%) patients were completely normal. Conclusion: Visual impairments are associated in large percentage of CP patients. Early evaluation and intervention are emphasized to improve the quality of life in these patients.

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.

Visual evoked potential (VEP) is a technique used to assess the brain's electrical response to visual stimuli. The aims of this study were to examine neural transmission within the visual pathway through VEP testing in preschool children with autism spectrum disorder (ASD) and compare it to age-matched controls, as well as search for a correlation between the VEP parameters and the symptoms of ASD. Participants were composed of ASD children (9 males) and typically developing children (8 males and 4 females), aged between 3 and 5 years. Checkerboards were chosen as the pattern-reversal VEP. The clinical severity of ASD was assessed using the Autism Treatment Evaluation Checklist (ATEC) and the Vineland Adaptive Behavior Scales 2nd edition (VABS-II). Our findings demonstrated that children with ASD had significantly longer N145 latency compared to the controls. A longer N145 latency correlated with a higher score of ATEC within the sensory/cognitive awareness subdomain. In addition, a slower N145 response was also associated with a lower VABS-II score within the socialization domain. The correlation between longer VEP latency and abnormal behaviors in children with ASD suggests a delayed neural communication within other neural circuits, apart from the visual pathway. These lines of evidence support the possibility of using VEP, along with clinical parameters, for the assessment of ASD severity.

Autism spectrum disorder (ASD) is a developmental disorder characterized by persistent deficits in social communication and interaction. Speech is an important form of social communication. Prosody (e.g. vocal pitch, rhythm, etc.), one aspect of the speech signal, is crucial for ensuring information about the emotionality, excitability, and intent of the speaker, is accurately expressed. The objective of this study was to gain a better understanding of how auditory information is used to regulate speech prosody in autistic and non-autistic children, while exploring the relationship between the prosodic control of speech and social competence. Eighty autistic (M = 8.48 years, SD = 2.55) and non-autistic (M = 7.36 years, SD = 2.51) participants produced vocalizations while exposed to unaltered and frequency altered auditory feedback. The parent-report Multidimensional Social Competence Scale was used to assess social competence, while the Autism-Spectrum Quotient and the Autism Spectrum Rating Scales were used to assess autism characteristics. Results indicate that vocal response magnitudes and vocal variability were similar across autistic and non-autistic children. However, autistic children produced significantly faster responses to the auditory feedback manipulation. Hierarchical multiple regressions indicated that these faster responses were significantly associated with poorer parent-rated social competence and higher autism characteristics. These findings suggest that prosodic speech production differences are present in at least a subgroup of autistic children. These results represent a key step in understanding how atypicalities in the mechanisms supporting speech production may manifest in social-communication deficits, as well as broader social competence, and vice versa. Autism Res 2020, 13: 1880-1892. © 2020 International Society for Autism Research and Wiley Periodicals LLC LAY SUMMARY: In this study, autistic and non-autistic children produced vowel sounds while listening to themselves through headphones. When the children heard their vocal pitch shifted upward or downward, they compensated by shifting their vocal pitch in the opposite direction. Interestingly, autistic children were faster to correct for the perceived vowel sound changes than their typically developing peers. Faster responses in the children with ASD were linked to poorer ratings of their social abilities by their parent. These results suggest that autistic and non-autistic children show differences in how quickly they control their speech, and these differences may be related to the social challenges experienced by autistic children.

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.

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.

Correlation between optical coherence tomography, pattern electroretinogram, and visual evoked potentials in open-angle glaucoma patients.

The Predictive Role of Intraoperative Visual Evoked Potentials in Visual Improvement After Endoscopic Pituitary Tumor Resection in Large and Complex Tumors: Description and Validation of a Method