Visual mismatch negativity to masked stimuli presented at very brief presentation rates

Mismatch Negativity (MMN) has been characterised as a ‘pre-attentive’ component of an event-related potential (ERP) that is related to discrimination and error prediction processes. The aim of the current experiment was to establish whether visual MMN could be recorded to briefly presented, backward and forward masked visual stimuli, given both below and above levels of subjective experience. Evidence of visual MMN elicitation in the absence of the ability to consciously report stimuli would provide strong evidence for the automaticity of the visual MMN mechanism. Using an oddball paradigm, two stimuli that differed in orientation from each other, an + and an x were presented on a computer screen. Electroencephalogram (EEG) was recorded from nine participants (six females), mean age 21.4 years. Results showed that for stimuli that were effectively masked at 7ms presentation, there was little variation in the ERPs evoked to standard and deviant stimuli or in the subtraction waveform employed to delineate the visual MMN. At 14 ms stimulus presentation, when participants were able to report stimulus presence, an enhanced negativity at around 175 ms and 305 ms was observed to the deviant and was evident in the subtraction waveform. Although some of the difference observed in the ERPs can be attributed to stimulus characteristics, the use of a ‘lonely’ deviant protocol revealed attenuated visual MMN components at 14 ms stimulus presentation. Overall, results suggest that some degree of conscious attention is required before visual MMN components emerge, suggesting visual MMN is not an entirely pre-attentive process

Visual electrodiagnostics and eye movement recording - World Society of Pediatric Ophthalmology and Strabismus (WSPOS) consensus statement

Visual electrodiagnostics and eye movement recording are important additional clinical tools in evaluation, diagnosing and management of ophthalmic and neurological disorders. Due to their objectiveness and non-invasiveness they can play an important role in pediatric ophthalmology. The WSPOS (World Society of Pediatric Ophthalmology and Strabismus) consensus statement gives insight into basic principles and highlights the clinical application of both visual electrodiagnostic tests and eye movement recording

Homonymous hemianopia in childhood: a systematic scoping review protocol

Introduction Cerebral visual impairment (CVI) is the leading cause of visual impairment in childhood in western countries. This encompasses a heterogeneous group of disorders and a spectrum of types of visual impairments. Research is required to explore specific subtypes of CVI and the specific needs of these groups to provide more individualised patient care. One type of CVI is homonymous hemianopia (HH), the absence of vision on one side due to an insult to the postchiasmal visual pathways in one hemisphere of the brain. The scoping review aims to map the nature, features and volume of the existing literature around HH in infancy, childhood and young adolescence.Methods and analysis We will perform a scoping review of the literature relating to HH in children (0–18 years old). The review will follow the PRISMA extension for scoping reviews checklist to ensure reporting integrity. We will conduct electronic database searches including CENTRAL, CINAHL, MEDLINE (PubMed) and PsycINFO. We will also carry out a ‘grey literature’ and internet search for studies or materials not formally published. Two researchers will independently review abstracts yielded from the search strategy for study inclusion.Dissemination This review will inform health professionals and other stakeholders working within this growing population of children with CVI. Our review will summarise the literature relating to this specific subgroup of CVI, and will identify gaps that require further research and development towards specific care of children with this form of CVI

Serial, Visually-Evoked Potentials for the Assessment of Visual Function in Patients with Craniosynostosis

This study aimed to evaluate the effect of craniofacial surgical intervention on the visual pathway’s function by comparing pre- to post-operative patterned, visually-evoked potentials (pVEP). A retrospective review was conducted on craniosynostosis patients who had pre- and post-craniofacial surgery pVEP testing. The pVEP measured grade in terms of amplitude latency and morphology of the waveforms. The pre- and post-operative results were compared. The study identified 63 patients (mean age at preoperative pVEP of 16.9 months). Preoperatively, 33 patients (52.4%) had abnormal pVEP. Nine patients had evidence of intracranial hypertension, and of those, eight (88.9%) had abnormal pVEP. Within 6 months postoperatively, 24 of 33 patients (72.7%) with abnormal preoperative pVEP developed normal postoperative pVEP, while all 30 patients with normal preoperative VEP maintained their normal results postoperatively. Significant improvements in pVEP latency in patients with broad or delayed latency waveforms was evident for subjects with preoperative grades 2–4 (grade 2, p = 0.015; grade 3, p = 0.029; grade 4; p = 0.007), while significant postoperative increase in amplitude was significant for patients with abnormally low amplitude grade 3 and 5 waveforms (grade 3, p = 0.011; grade 5, p = 0.029). Serial pVEP testing represents a useful tool for the early detection of visual pathway dysfunction and follow up visual pathway function in craniosynostosis. Surgical intervention for craniosynostosis can result in the reversal of preoperative pVEP abnormalities seen in these patients, resulting in the normalization of the pVEP waveform, amplitude and latency, depending on the preoperative pVEP abnormality

Clinical use of the Insight Inventory in cerebral visual impairment and the effectiveness of tailored habilitational strategies

AIM: To investigate the utility of the Insight Inventory (a structured clinical inventory completed by caregivers) for assessment of children with cerebral visual impairment; and to investigate effectiveness of tailored habilitational strategies derived from the responses to the Insight Inventory. METHOD: Fifty-one eligible children (26 males, 25 females; mean age 9y 5mo, SD 3y, range 5-16y) were recruited from Great Ormond Street Hospital, London. They underwent baseline assessment including neuro-ophthalmological and neuropsychological evaluations, and parent- and child-reported ratings on a questionnaire-based measure of quality of life. Parents also completed the Insight Inventory. On the basis of responses to the Inventory, families received individualized habilitational strategies. Follow-up assessments 6 months later included repeating the Insight Inventory and quality of life questionnaires. RESULTS: Correlations were found between the Insight Inventory and the Wechsler Intelligence Scale for Children, Fourth Edition, the Beery-Buktenica Test of Visual-Motor Integration, and the Benton Facial Recognition Test, suggesting that the Insight Inventory is an effective tool to estimate visual-perceptual difficulties. At 6 months follow-up, caregiver reports indicated significant improvements in the quality of life of children below the age of 12 years. INTERPRETATION: The Insight Inventory is a simple questionnaire which covers practical aspects of cognitive visual function in everyday life. It provides in-depth information about the aspects that children struggle with. It can also guide programmes of individualized habilitation strategies, which may enhance the quality of life of younger children. WHAT THIS PAPER ADDS: Questionnaire scores demonstrate biologically plausible correlations with formal neuropsychological tests of visual function. After administration of matched practical habilitational strategies, younger children showed improvement in quality of life and functional vision scores