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Aim: Dystonia in childhood has many causes. Imaging may suggest corticospinal tract dysfunction with or without coexistent basal ganglia damage. There are very few published neurophysiological studies on children with dystonia; one previous study has focused on primary dystonia. We investigated central motor conduction in 62 children (34 males, 28 females; age range 3-19y, mean age 10y 8mo, SD 4y 8mo) with severe dystonia to evaluate corticospinal tract integrity before consideration for deep brain stimulation., Method: Distal motor and F-wave latencies were measured in the ulnar and/or posterior tibial nerves. Transcranial magnetic stimulation was applied over the motor cortex and motor-evoked potentials were recorded in the activated abductor digiti minimi and/or abductor hallucis muscles. Central motor conduction time (CMCT) was calculated using the F-wave method., Results: CMCT was normal in 50 out of 62 patients; 12 patients showed prolonged CMCT to upper and/or lower limbs. Most children with severe primary and secondary dystonia had normal CMCT, indicating corticospinal tract integrity despite abnormal imaging in 42 out of 50 patients. Abnormal CMCT was found in two out of 12 patients with normal imaging., Interpretation: This study provides new CMCT data for children with severe primary and secondary dystonia. Over 50% of children with evidence of periventricular white-matter damage from magnetic resonance imaging had normal CMCT, challenging traditional pathophysiological models. This is consistent with recent diffusion tensor imaging in children with periventricular white-matter damage, showing disruption of sensory connections rather than corticospinal tract damage. CMCT helps refine our understanding of imaging changes in complex motor disorders of childhood., (© The Authors. Developmental Medicine & Child Neurology © 2011 Mac Keith Press.)

Several brain malformations have been described in rare patients with the deletion 22q11.2 syndrome (DEL22q11) including agenesis of the corpus callosum, pachygyria or polymicrogyria (PMG), cerebellar anomalies and meningomyelocele, with PMG reported most frequently. In view of our interest in the causes of PMG, we reviewed clinical data including brain-imaging studies on 21 patients with PMG associated with deletion 22q11.2 and another 11 from the literature. We found that the cortical malformation consists of perisylvian PMG of variable severity and frequent asymmetry with a striking predisposition for the right hemisphere (P = 0.008). This and other observations suggest that the PMG may be a sequela of abnormal embryonic vascular development rather than a primary brain malformation. We also noted mild cerebellar hypoplasia or mega-cisterna magna in 8 of 24 patients. Although this was not the focus of the present study, mild cerebellar anomalies are probably the most common brain malformation associated with DEL22q11.

Introduction: Non-invasive measures of corticospinal tract (CST) integrity may help to guide clinical interventions, particularly in children and young people (CAYP) with motor disorders. We compared diffusion tensor imaging (DTI) metrics extracted from the CST generated by tensor and non-tensor based tractography algorithms. Methods: For a group of 25 CAYP undergoing clinical evaluation, the CST was reconstructed using (1) deterministic tensor-based tractography algorithm, (2) probabilistic tensor-based, and (3) constrained spherical deconvolution (CSD)-derived tractography algorithms. Results: Choice of tractography algorithm significantly altered the results of tracking. Larger tracts were consistently defined with CSD, with differences in FA but not MD values for tracts to the pre- or post-central gyrus. Differences between deterministic and probabilistic tensor-based algorithms were minimal. Non-tensor reconstructed tracts appeared to be more anatomically representative. Examining metrics along the tract, difference in FA values appeared to be greatest in voxels with predominantly single-fibre orientations. Less pronounced differences were seen outwith of these regions. Conclusion: With an increasing interest in the applications of tractography analysis at all stages of movement disorder surgery, it is important that clinicians remain alert to the consequences of choice of tractography algorithm on subsequently generated tracts, including differences in volumes, anatomical reconstruction, and DTI metrics, the latter of which will have global as well as more regional effects. Tract-wide analysis of DTI based metrics is of limited utility, and a more segmental approach to analysis may be appropriate, particularly if disruption to a focal region of a white matter pathway is anticipated. [ABSTRACT FROM AUTHOR]

Introduction: There is increasing interest in neurosurgical interventions for hypertonicity in children and young people (CAYP), which often presents with a mixture of dystonia and spasticity. Significant spasticity would usually be considered a contraindication for deep brain stimulation (DBS) and more suitably treated with intrathecal baclofen (ITB). We aimed to explore whether white matter microstructure, as measured by Fractional Anisotropy (FA), differed between CAYP selected for DBS compared to ITB surgery. Methods: We retrospectively analysed Diffusion Tensor Imaging for 31 CAYP selected for DBS surgery (14 primary dystonia, 17 secondary dystonia) and 10 CAYP selected for ITB surgery. A voxel-wise comparison of FA values was performed using tract-based spatial statistics, comparing primary and secondary dystonia groups to the ITB group, and the two dystonia groups. Results: Widespread areas of reduced FA were demonstrated in ITB compared to either DBS group and in CAYP with secondary compared to primary dystonia. These changes were not restricted to motor pathways. Region of interest (ROI) analysis from the corticospinal tract (CST) demonstrated groupwise differences but overlapping values at the individual level. Conclusions: DTI measures may contribute to decision making for CAYP selection for movement disorder surgery. Significant differences in CAYP with secondary dystonia selected for DBS surgery compared to CAYP selected for ITB pump implants, suggesting that more extensive white matter injury may be a feature of the spastic motor phenotype. Altered white matter microstructure could potentially explain the reduced responsiveness to interventions such as DBS in secondary compared to primary dystonia. [ABSTRACT FROM AUTHOR]

Background: Accuracy of electrode placement is an important determinant of outcome following deep brain stimulation (DBS) surgery. Data on accuracy of electrode placement into the globus pallidum interna (GPi) in paediatric patients is limited, particularly those with non-primary dystonia who often have smaller GPi. Pallidal DBS is known to be more effective in the treatment of primary dystonia compared with secondary dystonia. Objectives: We aimed to determine if accuracy of pallidal electrode placement differed between primary, secondary and NBIA (neuronal degeneration and brain iron accumulation) associated dystonia and how this related to motor outcome following surgery. Methods: A retrospective review of a consecutive cohort of children and young people undergoing DBS surgery in a single centre. Fused in frame preoperative planning magnetic resonance imaging (MRI) and postoperative computed tomography (CT) brain scans were used to determine the accuracy of placement of DBS electrode tip in Leskell stereotactic system compared with the planned target. The differences along X, Y, and Z coordinates were calculated, as was the Euclidean distance of electrode tip from the target. The relationship between proximity to target and change in Burke-Fahn-Marsden Dystonia Rating Scale at 1 year was also measured. Results: Data were collected from 88 electrodes placed in 42 patients (14 primary dystonia, 18 secondary dystonia and 10 NBIA associated dystonia). Median differences between planned target and actual position were: left-side X-axis 1.05 mm, Y-axis 0.85 mm, Z-axis 0.94 mm and Euclidean difference 2.04 mm; right-side X-axis 1.28 mm, Y-axis 0.70 mm, Z-axis 0.70 mm and Euclidean difference 2.45 mm. Accuracy did not differ between left and right-sided electrodes. No difference in accuracy was seen between primary, secondary or NBIA associated dystonia. Dystonia reduction at 1 year post surgery did not appear to relate to proximity of implanted electrode to surgical target across the cohort. Conclusions: Accuracy of surgical placement did not differ between primary, secondary or NBIA associated dystonia. Decreased efficacy of pallidal DBS in secondary and NBIA associated dystonia is unlikely to be related to difficulties in achieving the planned electrode placement. [ABSTRACT FROM AUTHOR]

To evaluate the usefulness of neuroimaging in children with idiopathic intracranial hypertension, brain magnetic resonance imaging (MRI) scans of children with idiopathic intracranial hypertension and age-matched controls were reviewed. Compared with controls, patients with idiopathic intracranial hypertension had flattening of the posterior sclera in 61% versus 40% of cases, distension of perioptic subarachnoid space in 65% versus 35%, intraocular protrusion of prelaminar optic nerve in 17% versus 0%, tortuosity of optic nerve in 30% versus 5%, and an empty sella in 26% versus 5% of cases. The presence of 3 or more of the MRI features is 95% specific in predicting idiopathic intracranial hypertension. The observed general anesthetic effect on these neuroimaging features are also minimized when multiple features are taken into account. Magnetic resonance imaging features can assist in suspecting the diagnosis of idiopathic intracranial hypertension in children, provided caution is applied when interpreting imaging performed under a general anesthesia. [ABSTRACT FROM AUTHOR]

Thalamic infarction with distinct manifestations is well-described in adults but less well-delineated in children. We report two infants who presented with an apparent life-threatening event (ALTE) with very early magnetic resonance imaging (MRI) demonstrating a unilateral thalamic infarction. Subsequent MRI demonstrated bilateral changes in the brain stem and basal ganglia, which were in keeping with profound hypoxic ischaemic injury. We propose the thalamic infarction to be the primary event precipitating a profound hypoxic ischaemic injury as an alternative explanation to the neuroimaging observation. Conclusion: Thalamic infraction may have a causal role in ALTE. Early and appropriate neuroimaging is required to detect these changes. [ABSTRACT FROM AUTHOR]

We describe a 15-year-old boy who presented with a stroke. Brain MRI imaging showed thalamic and multiple cerebral infarcts. An echocardiogram revealed multiple atrial masses, which were resected. Histological examination confirmed multiple atrial myxomas. Further clinical examination of the patient revealed subtle buccal and peri-oral lentigenes. The diagnosis of Carney complex was made clinically. The patient was subsequently diagnosed with testicular seminomas and a cutaneous angiomyxoma. Genetic investigation revealed a pathological mutation in the PRKAR1A gene. We review the reported manifestations and presentations of Carney complex, along with current diagnostic guidelines. We emphasise the importance of recognising the cutaneous manifestations of this rare autosomal dominantly inherited neoplasia syndrome. [ABSTRACT FROM AUTHOR]

In childhood, central nervous system (CNS) presentations associated with antibodies to voltage-gated potassium channel (VGKC) complex include limbic encephalitis, status epilepticus, epileptic encephalopathy, and autistic regression. We report the cases of two individuals (a 6-year-old male and an 11-year-old female) who presented with an acute-onset explosive seizure disorder with positive VGKC complex antibodies and bilateral basal ganglia changes on magnetic resonance imaging (MRI). Both patients made a complete clinical recovery, without immunotherapy, with resolution of the MRI changes and normalization of the antibody levels. Extended antibody testing, including testing for leucine-rich glioma-inactivated 1 (LGI1), contactin-associated protein 2, and contactin-2 was negative. This could suggest that the clinico-radiological phenotype in our patients may in fact be associated with a novel autoreactive target(s) within the VGKC complex, as may be the case in other children with VGKC complex-mediated CNS disorders. [ABSTRACT FROM AUTHOR]

Objective It is unclear how brain growth with age affects electrode position in relation to target for children undergoing deep brain stimulation surgery. We aimed to model projected change in the distance between the entry point of the electrode into the brain and target during growth to adulthood. Methods Modeling was performed using a neurodevelopmental magnetic resonance imaging database of age-specific templates in 6-month increments from 4 to 18 years of age. Coordinates were chosen for a set of entry points into both cerebral hemispheres and target positions within the globus pallidus internus on the youngest magnetic resonance imaging template. The youngest template was nonlinearly registered to the older templates, and the transformations generated by these registrations were applied to the original coordinates of entry and target positions, mapping these positions with increasing age. Euclidean geometry was used to calculate the distance between projected electrode entry and target with increasing age. Results A projected increase in distance between entry point and target of 5–10 mm was found from age 4 to 18 years. Most change appeared to occur before 7 years of age, after which minimal change in distance was found. Conclusions Electrodes inserted during deep brain stimulation surgery are tethered at the point of entry to the skull. Brain growth, which could result in a relative retraction with respect to the original target position, appears to occur before 7 years of age, suggesting careful monitoring is needed for children undergoing implantation before this age. Reengineering of electrode design could avoid reimplantation surgery in young children undergoing deep brain stimulation. [ABSTRACT FROM AUTHOR]