Giorgio L. Porro

Neonatal posterior cerebral artery stroke: clinical presentation, MRI findings, and outcome

To report the clinical presentation, magnetic resonance imaging (MRI) findings, and follow‐up data of newborn infants with perinatal arterial ischemic stroke in the territory of the posterior cerebral artery (PCA).

Role of visual dysfunction in postural control in children with cerebral palsy.

Introduction: Deficient postural control is one of the key problems in cerebral palsy (CP). Little, however, is known about the specific nature of postural problems of children with CP, nor of the relation between abnormal posture and dysfunction of the visual system. Aim of the study: To provide additional information on the association of abnormalities in postural control and visual dysfunction of the anterior or posterior part of the visual system. Methods: Data resulting from ophthalmologic, orthoptic, neurological, neuro-radiological, and ethological investigations of more than 313 neurologically impaired children were retrospectively analyzed. Results: Abnormal postural control related to ocular and ocular motor disorders consisted of anomalous head control and subsequent abnormal head posture and torticollis. The abnormal postural control related to retrochiasmatical damage of the visual system consisted of a torticollis combined with adjustment of the upper part of the body, as if at the same time adapting to a combination of defects and optimizing residual visual functions. Conclusion: Visual dysfunctions play a distinct role in the postural control of children with CP.

Visual behaviours of neurologically impaired children with cerebral visual impairment: an ethological study

BACKGROUND/AIMS Visual functions of neurologically impaired children with permanent cerebral visual impairment (CVI) can be difficult to determine. This study investigated the behavioural profile of CVI children by means of ethological observations in order to gain a better understanding of their visual functions. METHODS Video registrations of nine subjects who were unable to undergo more orthodox methods of visual function testing were observed and analysed by an ethologist. RESULTS A series of behaviours (direct signs) and supportive or confirming behavioural elements (indirect signs) indicating some visual perception in the children were found. CONCLUSION Detailed ethological observations of visual behaviour were shown to be useful for analysing visual functions of children with permanent CVI.

Quantification of white matter injury following neonatal stroke with serial DTI

Background:Diffusion tensor imaging (DTI) can be used to predict outcome following perinatal arterial ischemic stroke (PAIS), although little is known about white matter changes over time.Methods:Infants with PAIS were serially scanned in the neonatal period (n = 15), at 3 mo (n = 16), and at 24 mo (n = 8). Fractional anisotropy (FA) values in five regions of interest (anterior and posterior limb of the internal capsule, corpus callosum, optic radiation, and posterior thalamic radiation) were obtained and compared with FA values of healthy controls and neurodevelopmental outcome.Results:In the neonatal period, no differences in FA values were found. At 3 mo, the six infants who ultimately developed motor deficits showed lower FA values in all affected regions. Four infants developed a visual field defect and showed lower FA values in the affected optic radiation at 3 mo (0.22 vs. 0.29; P = 0.03). Finally, a correlation between FA values of the corpus callosum at 3 mo and the Griffiths developmental quotients was found (r = 0.66; P = 0.03). At 24 mo, a similar pattern was observed.Conclusion:Neonatal FA measurements may underestimate the extent of injury following PAIS. FA measurements at 3 mo could be considered a more reliable predictor of neurodevelopmental outcome and correlate with DTI findings at 24 mo.

Perimetry in Young and Neurologically Impaired Children The Behavioral Visual Field (BEFIE) Screening Test Revisited

IMPORTANCE Visual field examination in young or neurologically impaired children is a challenge. As a result, the Behavioral Visual Field (BEFIE) Screening Test was developed in 1995. OBJECTIVES To evaluate the applicability of the BEFIE test in a large population of young or neurologically impaired children, its reliability and consistency of findings across time, and its potential diagnostic value compared with standard conventional perimetry. DESIGN, SETTING, AND PARTICIPANTS The BEFIE tests were performed at an academic tertiary center and measured the peripheral visual field extension in degrees by observing an individuals response to a stimulus on a graded arc that moved from the periphery to the center of the visual field along different meridians. Patient files from all children who underwent this test were retrospectively analyzed. In total, 1788 BEFIE tests were performed in 835 children (median age, 3.4 years). MAIN OUTCOMES AND MEASURES Reliability and results of all tests were longitudinally evaluated. The diagnostic value of the BEFIE test was assessed by comparing monocular BEFIE test results with those of standard conventional perimetry in children who underwent both. RESULTS Of 1788 tests, 74% (95% CI, 72%-76%) were considered reliable from the age of 4 months and older, with increasing success with higher ages; 56% reliable in children younger than 1 year; 71% reliable in children between 1 and 2 years; and more than 75% reliable in children 2 years and older (Spearman r = 0.506; P = .11). Peripheral visual field defects were found in 28% (95% CI, 25%-31%) of all first reliable tests. In 75% of children who underwent serial testing, results were consistent and there were good explanations in the case of discrepancies. Comparison of monocular BEFIE tests with standard conventional perimetry results in 147 eyes yielded a positive predictive value of 98% (95% CI, 94%-100%), negative predictive value of 66% (95% CI, 56%-75%), specificity of 98% (95% CI, 95%-100%), sensitivity of 60% (95% CI, 50%-71%), and superior sensitivity of 80% (95% CI, 70%-91%) when only absolute peripheral visual field defects at standard conventional perimetry were accounted for. CONCLUSIONS AND RELEVANCE These data suggest that the BEFIE test is a valuable tool to detect peripheral visual field defects when standard conventional perimetry cannot be performed in young or neurologically impaired children.

Development of visual function in hemihydranencephaly

This study reports on the findings of longitudinal follow‐up of visual function in a 12‐year‐old girl affected by congenital right hemihydranencephaly. This extremely rare unilateral brain malformation allowed the authors to gather new information on neuronal plasticity and functional compensations of the visual system across a period of 10 years. An extension of the preserved right visual hemifields above the middle line and strategical eye or head positions developed to increase visual functions are discussed. In addition, ophthalmological and orthoptical findings, as well as the development of monocular grating and linear acuity, are described.

Epilepsy surgery provides new insights in retinotopic organization of optic radiations. A systematic review.

Purpose of review Visual field defects (VFDs) produced by temporal lobe resections provide valuable information on the retinotopic organization of the optic radiations. The results of this systematic review of the literature will be translated into a revised – and evidence-based – map of the retinotopic anatomy of the anterior optic radiations. Recent findings Recent studies provide best evidence by combining automatic static perimetry and modern imaging techniques. VFDs occur in 83% of patients undergoing temporal lobectomy. There is a significant correlation between size of resection and amount of VFD. Most defects appear incongruous. Macular involvement is seen in more than 50% of cases. The inferolateral defect border is of a sloping nature and sometimes crosses the horizontal meridian. On the basis of these findings, the classical theory on the retinotopic anatomy of the optic radiation should be revised. Summary This article systematically reviews the literature on VFDs after temporal lobe resection. Frequency, size, congruity, macular involvement and defect borders are related to size of resection. The classical theory on the retinotopic organization of the anterior optic radiations should be revised.

Visual function and compensatory mechanisms for hemianopia after hemispherectomy in children

Little is known about the functional visual outcome of children after hemispherectomy. Several case reports have described an anomalous head posture (AHP) and exotropia (XT) contralateral to the side of early brain damage, as possible compensatory mechanisms (CMs) for homonymous hemianopia (HH). The aim of this study was to determine visual outcome and the prevalence of such CMs in hemispherectomized children.

Longitudinal follow-up of grating acuity in children affected by cerebral palsy: Results of a 5 year study

Purpose To analyse the natural course of visual acuity in subjects affected by cerebral palsy.Methods During the past 5 years, 16 children underwent repeated grating acuity measurements using the acuity card procedure. At the end of the follow-up final grating acuity was compared with linear acuity obtained using standard optotypes.Results A good or moderate improvement in grating acuity was shown by 14 subjects. However, the general development of grating acuity showed a protracted course and early values did not correlate with final grating acuity (r = 0.20). Moreover, most of the children showed subnormal vision when measured with standard optotypes.Conclusion Clinicians should remain optimistic about the potential for some visual development in children affected by cerebral palsy. However, great caution should be exercised in extrapolating information from early grating acuity measurements. Regular assessments with the acuity card procedure are necessary in order to gain an insight into the natural course of visual development in children affected by cerebral palsy.

Bilateral population receptive fields in congenital hemihydranencephaly

Congenital hemihydranencephaly (HH) is a very rare disorder characterised by prenatal near‐complete unilateral loss of the cerebral cortex. We investigated a patient affected by congenital right HH whose visual field extended significantly into the both visual hemifields, suggesting a reorganisation of the remaining left visual hemisphere. We examined the early visual cortex reorganisation using functional MRI (7T) and population receptive field (pRF) modelling.