The aim of this study was to evaluate the incidence of visual function abnormalities in children with infantile hemiplegia, and the relation between visual abnormalities and type of lesion, as shown by brain MRI. Visual function was tested (grating acuity, visual field size, binocular optokinetic nystagmus [OKN], and ocular movements) in a group of 47 children with congenital or early acquired hemiplegic cerebral palsy (mean age 25 months, range 8 to 52 months). The cohort was subdivided into four groups according to MRI findings: brain malformations (n=5), abnormalities of the periventricular white matter (n=20), cortical-subcortical lesions (n=16), and non-progressive postnatal brain injuries (n=6). More than 80% of the children showed abnormal results in at least one visual test: acuity was the least impaired function, while visual field and OKN were abnormal in more than 50% of the cohort. No specific correlation could be identified between the type and timing of the lesions and visual function. Unlike adults with stroke, visual field defects were not always related to contralateral damage in the optic radiations or in the visual cortex. These results indicate that visual abnormalities are common in children with hemiplegia, and that they cannot always be predicted by MRI. All children with hemiplegia need a detailed assessment of visual function.
SUMMARY To identify brain lesions most often associated with cerebral visual impairment (CVI) after neonatal encephalopathy and to evaluate the prognostic value of MRI for visual outcome, the authors reviewed visual assessments and brain MRI of 80 infants and young children with documented perinatal hypoxic‐ischaemic and/or haemorrhagic insults. MRIs were classified according to the severity of lesions at the optic radiations and at the visual cortex; visual acuity was tested with the acuity card procedure. Among the 48 children found to have a CVI, 42 had moderate to severe lesibns of the optic radiations and 19 had lesions of the visual cortex. In both cases visual acuity was statically correlated with MRI grading, but the damage at the optic radiations was the better predictor. Early detection of abnormal MR findings in the visual cortex and. especially, at the optic radiations may indicate which infants with neonatal encephalopthy should receive longitudinal visual assessment and specific rehabilitation and educational management. RÉSUMÉ Corrélations entre les troubles cérébraux de la vision et les IRM chez les enfants avec encéphalopathie néonatale Dans le but d'identifier les lésions cérébrales le plus souvent associées à un trouble visucl cérébral (CVI) après une encéphalopathie néonatale ct d'evaluer la valeur pronostique de l'IRM pour le devenir visuel, les auteurs ont passé en revue l'évaluation visuclle et les IRM cérébrales de 80 nourrissons et jeunes enfants avec antécédents d'agression périnatale hypoxo‐ischémiquc et/ou hémorragiquc. Les IRM furent classées en fonction de la séverité des lésions dc radiations optiques et du cortex visuel; l'acuité visuelle fut appréciée par les échelles habituelles d'acuité. Parmi les 48 enfants avec CVI, 42 avaient des lésions modérées à sévères des radiations optiques et 42 avaienr des lésions du cortex visucl. Dans les deux cas, l'acuité visuclle était corrélée avec l'importancc des manifestations IRM mais l'atteinte des radiations optiques était le meilleur prédicteur. La détection précoce d'anomalies IRM du cortex visuel et, spécialement des radiations optiques, peut indiquer que les nourrissons avec encéphalopathie néonatale devraient bénéficier d'un suivi de la fonction visuelle, d'une rééducation spécifique et d'une prise en charge éducative. ZUSAMMENFASSUNG Korrelatkm zwischen cerebraler Sehstörung und Magnet Resonitanz Tomographic bei Kindern mit neonataler Enzeplialopathie Die Autoren untersuchten bei 80 Säuglingen und Klcinkindern mit dokumentierten perinatalen hypoxish‐ischämischen und/oder hämorrhagischen Insulten die visuellen Untersuchungs‐ und Hirn‐ MRI Befunde, urn Hirnläsionen, die nach neonataler Enzephalopathie am haufigstcn mit cerebralen Sehstörungen (CVI) einhergehen, zu bestimmen und urn den prognostischen Wert des Hirn‐MRI für den visuellen Outcome zu beurteilen. Die MRIs wurden nach dem Schweregrad der Läsionen an den Sehbahnen und am visuellen Cortex klassifiziert; die Sehschärfe wurde anhand der Acuity Card Procedure festgestellt. Von den 48 Kindern, bei denen eine CVI diagnostiziert wurde, hatten 42 mäßige bis schwere Läsionen an den Sehbahnen und 19 Läsionen des visuellen Cortex. In beiden Fällen bestand eine statistische Korrelation zwischen Sehschärfe und MRI‐Grading, die Schädigung der Sehbahnen hatte aber die bessere prognostische Aussagekraft. Durch frühzeitige Erkennung abnormer MRI Befunde im visuellen Cortex und besondcr an den Sehbahnen kann festgelegt werden, welche Kinder mit neonataler Enzephalopathie langfristigc Sehprüfungen, sowie besondere Rehabilitation und Schulförderung bekommen sollten. RESUMEN Correlación entre la alteración visual cerebral y la imagen por resonancia magnética en niños con encepfalopatia neonatal Para identificar lesiones cerebrales mayormente asociadas a alteración visual cerebral (AVC) después de una encefalopatiá neonatal y para evaluar el valor pronóstico de la IRM con respecto al curso de la visión, los autores revisaron las evaluaciones visuales y la IRM de 80 lactantes y niños pequeños que habian sufrido, documentadamente, en la época perinatal una hipoxic‐isquemia y/o una haemorragia cerebrales. La IRM se clasificó de acuerdo con la gravedad de las lesiones a nivel de las rediaciones ópticas y del córtex visual; la agudeze visual se examinó por el procedimiento de las targetas de agudeza. Entre los 48 niños con AVC, 42 tenian lesiones de moderadas a graves de las radiaciones ópticas y 19 del córtex visual. En ambos casos la agudeza visual estaba estadísticamente correlacionada con el grado de alteración de la IRM, pero la alteración de las radiaciones ópticas constituía un mejor predictor. La detectión precoz de anomalías IRM en el córtex visual, y especialmente en las radiaciones ópticas, puede indicar qué niños con encefalopatía neonatal deben recibir una evaluatión visual longitudinal, así como una rehabilitación específica y manejo educativo.
The aim of this study was to evaluate the incidence of visual function abnormalities in children with infantile hemiplegia, and the relation between visual abnormalities and type of lesion, as shown by brain MRI. Visual function was tested (grating acuity, visual field size, binocular optokinetic nystagmus [OKN], and ocular movements) in a group of 47 children with congenital or early acquired hemiplegic cerebral palsy (mean age 25 months, range 8 to 52 months). The cohort was subdivided into four groups according to MRI findings: brain malformations (n=5), abnormalities of the periventricular white matter (n=20), cortical‐subcortical lesions (n=16), and non‐progressive postnatal brain injuries (n=6). More than 80% of the children showed abnormal results in at least one visual test: acuity was the least impaired function, while visual field and OKN were abnormal in more than 50% of the cohort. No specific correlation could be identified between the type and timing of the lesions and visual function. Unlike adults with stroke, visual field defects were not always related to contralateral damage in the optic radiations or in the visual cortex. These results indicate that visual abnormalities are common in children with hemiplegia, and that they cannot always be predicted by MRI. All children with hemiplegia need a detailed assessment of visual function.
Abstract The classical definition of cortical blindness in both adults and children refers to complete loss of vision, including appreciation of light and dark, loss of OKN with preservation of pupillary responses, normal eye motility and normal retina on examination. Cerebral visual impairment (CVI) is now recommended as a better term. Complete blindness is rare in these patients. Most of them have some residual vision, which it is often difficult to test because they show inattention and variability in their visual performance. Secondly, ‘cerebral’ seems to be a more appropriate term than ‘cortical’. Visual impairment is secondary to a cerebral disease from multiple causes (e.g. infection, trauma, cerebrovascular disease, etc.), involving retrochiasmatic visual pathways but not necessarily the visual cortex. According to the timing of the cerebral injury, CVI in children can be classified as congenital or acquired. The latter can be caused by meningitis, encephalitis, head trauma, hydrocephalus, or metabolic derangements. Occipital infarctions are often observed in these cases. Congenital CVI includes visual loss caused by malformations, intrauterine infections or perinatal hypoxic ischaemic encephalopathy (HIE). HIE is the most common cause of CVI, and is often accompanied by other motor and cognitive impairment owing to the diffuse nature of this pathology.
