William J. Logan

Neurologic manifestations of pediatric systemic lupus erythematosus.

Central nervous system involvement is a common but rarely reviewed feature of pediatric systemic lupus erythematosus (SLE). We retrospectively reviewed the charts of 91 patients with pediatric SLE and using a standardized data abstraction form documented 40 patients with central nervous system (CNS-SLE) involvement. The mean age of onset of SLE was 13.3 years. In 19 patients the CNS manifestation was a presenting symptom, in 12 patients CNS involvement was present within the first year of diagnosis, and in 9 patients it took up to 7 years for CNS disease to become evident. Nineteen children (48%) manifested neuropsychiatric SLE, which included depression, concentration or memory problems, and frank psychosis. Seizures were present in 8 patients (20%), 6 had cerebral ischemic events (15%), 1 had chorea (3%), 2 had papilledema (5%), and 2 patients had a peripheral neuropathy (5%). Nine patients (22%) had severe headache consistent with lupus headache. Seven children had more than one CNS manifestation. In the investigation of CNS-SLE, computed tomography and/or magnetic resonance imaging scans were helpful in patients with focal ischemic lesions and venous sinus thrombosis. Electroencephalography was abnormal only in 33% of patients with seizure disorders and rarely helpful in patients with diffuse neuropsychiatric symptoms. Single-photon emission computed tomography scans were abnormal in most patients with neuropsychiatric SLE, especially in those with frank psychosis. The lupus anticoagulant was present in the patient with chorea and was frequently present in patients with cerebral vascular events. Long-term outcome was good: only 1 child died of cerebral hemorrhagic infarction and 3 others had significant persistent CNS deficits. The majority of patients (90%) had excellent recovery from CNS-SLE.

Infantile spasms Outcome and prognostic factors of cryptogenic and symptomatic groups

We reviewed the outcome (developmental, neurologic, and seizure) and prognostic factors of 57 cases of infantile spasms (17 cryptogenic, 40 symptomatic). The mean developmental score of the cryptogenic group (71.2 ± 24.2) was significantly higher than that of the symptomatic group (48.4 ± 24.51), as assessed by the Griffith Mental Developmental Scale. A resultant neurologic deficit was present in 23.5% of the cryptogenic group and 75.0% of the symptomatic group. Coexistence of other forms of seizures was observed in 35.3% of the cryptogenic group and 57.5% of the symptomatic group. Outcome was affected by the coexistence of other seizures, presence of neurologic deficit, time lag in initiation of treatment (cognitive outcome only), poor response to ACTH treatment, and persistent EEG abnormality. Character of spasms and time lag in initiation of treatment (seizure outcome only) did not have any significant effect on outcome.

Combined utility of functional MRI, cortical mapping, and frameless stereotaxy in the resection of lesions in eloquent areas of brain in children.

We studied 16 children with lesions in the eloquent brain to determine if the amalgamation of information from functional magnetic resonance imaging (fMRI), frameless stereotaxy, and direct cortical mapping and recording could facilitate the excision of these lesions while minimizing potential neurological deficits. The mean age of the children was 10 years. Fourteen children presented with seizures. All lesions were located in or near eloquent cerebral cortex. fMRI was successful in all patients in delineating the relationship between the lesion and regions of task-activated cortex. The ISG wand was utilized in all cases for scalp and bone flap placement, and for intraoperative localization of the lesion. Direct cortical stimulation or recording of phase reversals with somatosensory evoked potentials helped delineate the central sulcus and language cortex in patients with lesions near the motor or language cortex. Intraoperative electrocorticography (ECoG) was utilized in all patients who presented with seizures to guide the extent of resection of the epileptiform cortex. Ten children had benign cerebral neoplasms, nine of which were totally resected. The other diagnoses included vascular malformations, Sturge-Weber, tuberous sclerosis, Rasmussens encephalitis, and primitive neuroectodermal tumor. Only 1 patient with a left Rolandic AVM developed a new neurological deficit postoperatively. Thirteen of fourteen patients who presented with seizure disorders were rendered either seizure free or improved in terms of seizure control postoperatively. Follow-up has ranged from 12 to 18 months, with a mean follow-up of 15 months. We conclude that the techniques of fMRI, frameless stereotaxy, direct cortical stimulation and recording can be utilized in sequence to accurately localize intracerebral lesions in eloquent brain, and to reduce the morbidity of resecting these lesions in children.

Hexose transport in L6 muscle cells. Kinetic properties and the number of [3H]cytochalasin B binding sites

(1) Myoblasts in culture (L6 cell line) were used as an in vitro model system, to study the kinetic and pharmacological properties of hexose transport in skeletal muscle tissue. (2) Uptake of 2-deoxy-D-[3H]glucose into L6 cells grown in monolayer culture was judged rate limiting since: (2) The time course of sugar uptake extrapolated to zero, (b) a parallel inhibition of hexose uptake and phosphorylation was caused by cytochalasin B, and (c) very little backflow of the hexose was detected. (3) Uptake of 2-deoxy-D-[3H]glucose by cells in monolayers was linear for at least 20 min and it was stimulated by countertransport. The Kt value was 0.83 mM. Cytochalasin B inhibited uptake non-competitively, and half maximal inhibition was achieved at 0.3 microM. Cytochalasin E (up to 5 microM) did not affect 2-deoxy-D-[3H]glucose uptake. (4) L6 myoblasts, detached by trypsinization, retained the hexose transport activity. Kt in detached cells was 0.96 mM. V was 3.2 nmol/min per mg protein, and half maximal inhibition was observed with 0.25 microM cytochalasin B. (5) [3H]Cytochalasin B binding to detached cells showed saturable and non-saturable components. The former could be further separated into cytochalasin E-sensitive binding (probably associated to cytoskeletal proteins) and cytochalasin E-insensitive binding, a fraction of which was inhibited by D-glucose. The D-glucose sensitive sites amount to 16.3 pmol/mg protein, and showed a Kd of 0.49 microM, which is in close agreement with the Ki of cytochalasin B inhibition of hexose uptake. These sites probably are equivalent to the hexose carrier molecules, and are present at a density of 6.8 . 10(6) sites/cell.

Cortical Reorganization After Modified Constraint-Induced Movement Therapy in Pediatric Hemiplegic Cerebral Palsy

Constraint-induced movement therapy improves motor function in the affected hand of children with hemiplegic cerebral palsy and results in cortical changes in adults with stroke. This study measured clinical improvement and cortical reorganization in a child with hemiplegia who underwent modified constraint-induced movement therapy for 3 weeks. Clinical, functional magnetic resonance imaging and magnetoencephalography measurements were done at baseline, after therapy, and 6 months after therapy. Modified constraint-induced movement therapy resulted in clinical improvement as measured by the Pediatric Motor Activity Log. Functional magnetic resonance imaging showed bilateral sensorimotor activation before and after therapy and a shift in the laterality index from ipsilateral to contralateral hemisphere after therapy. Magnetoencephalography showed increased cortical activation in the ipsilateral motor field and contralateral movement evoked field after therapy. Cortical reorganization was maintained at the 6-month follow-up. This is the first study to demonstrate cortical reorganization after any version of constraint-induced movement therapy in a child with hemiplegia.

Cerebral Arteriopathy in Children With Neurofibromatosis Type 1

OBJECTIVE: Cerebrovascular abnormalities are serious but underrecognized complications of neurofibromatosis type 1 (NF1). The aim of this study was to investigate the prevalence, clinical presentation, imaging findings, and prognosis of cerebral arteriopathies in childhood NF1. METHODS: Patients followed at the NF1 clinic at the Hospital for Sick Children, Toronto, Ontario, Canada, between 1990 and 2007 were studied. Patients with confirmed NF1 diagnosis and neuroimaging results were included. All neuroimaging studies were reviewed for the presence of arteriopathy by 2 study pediatric neuroradiologists blinded to clinical information. Clinical records of children with cerebral arteriopathy were reviewed. RESULTS: Among 419 children with confirmed NF1, 266 (63%) received neuroimaging. Among children with neuroimaging results, 17 had cerebral arteriopathy (minimum prevalence rate of 6%). Among the 35 patients who received magnetic resonance angiography (MRA), arteriopathy was more common in patients with NF1 with optic gliomas (11 of 21) compared with those without optic glioma (4 of 14). Forty-seven percent of children developed focal deficits months to years after the diagnosis of the arteriopathy. Follow-up at a mean of 7 years after diagnosis of arteriopathy showed that 35% (6 of 17) had progressive arteriopathy requiring revascularization surgery. Seven patients received aspirin for primary stroke prevention. On retrospective review of imaging studies, a mean delay of 51 months to clinical radiographic reporting of these findings was observed. CONCLUSIONS: The prevalence of cerebral arteriopathy in children with NF1 in this study was at least 6% and was associated with young age and optic glioma. Arteriopathy causes stroke with resultant neurologic deficits. Medical and/or surgical interventions may prevent these complications. Therefore, the addition of vascular imaging (MRA/conventional angiography) to brain imaging studies for early detection of arteriopathy should be considered for children with NF1, particularly young patients with optic glioma.

Changes in event-related potentials with stimulant medication in children with attention deficit hyperactivity disorder

Thirty-two children with attention deficit hyperactivity disorder (ADHD) undergoing a 4 week double-blind medication assessment (methylphenidate) and 32 normal controls were studied using event-related potentials (ERPs). The ERPs were recorded from 13 active electrodes during a visual feature detection task. Significant age effects were found in N2, P3a and P3b latencies, that did not interact with group. The P3a and P3b latencies were significantly longer in the ADHD children on baseline testing; there were no latency differences between the groups of children when the normal controls were compared with the ADHD children on their optimal drug dosage (as determined by extensive behavioural and cognitive assessments). There were no significant distributional effects either between groups, or with the ADHD children as a function of medication; there were also no significant differences in reaction time measures. Thus, only the ERPs reflected slowed processing in the ADHD children that normalized on appropriate medication.

Pediatric Constraint-Induced Movement Therapy Is Associated With Increased Contralateral Cortical Activity on Functional Magnetic Resonance Imaging:

The mechanism behind constraint-induced movement therapy (constraint therapy) success is unknown. Study objectives were to evaluate cortical change after modified constraint therapy and explore a novel approach to quantify developmental disregard. Five participants underwent modified constraint therapy. Functional magnetic resonance imaging (MRI) and clinical measures were done pretreatment and posttreatment. Developmental disregard indices were calculated. Four participants showed clinical improvement posttreatment. Functional MRI laterality indices were variable pretreatment and exclusively contralateral among participants posttreatment. The disregard index range was —12.9 to 62.6 among participants. Disregard indices were correlated with change scores after treatment on the Pediatric Motor Activity Log amount of use domain (r = .93, P = .02), Assisting Hand Assessment (r = .93, P = .02), and grip strength (r = .92, P = .03). Study results suggest that a shift to or persistence of contralateral cortical activity for affected hand movement is important for constraint therapy mechanism of action; and developmental disregard may be a predictor of positive response to treatment.

Neonatal Guillain-Barré syndrome

A term female infant had the clinical manifestations and accompanying electrophysiologic studies to fulfill the criteria of Guillain-Barré syndrome. At birth, she presented with generalized hypotonia, paucity of lower limb movements, and diminished muscle stretch reflexes. At 3 weeks of age, motor nerve conduction studies demonstrated evidence of demyelination and axonal involvement. Progressive clinical improvement was observed beginning at the age of 2 weeks with subsequent normalization of clinical examinations and nerve conduction studies. To our knowledge, this patient is the youngest reported with Guillain-Barré syndrome.

The Hospital for Sick Children, Toronto, Longitudinal ERG study of children on vigabatrin.

The purpose of this longitudinal study was to identify changes in ERG responses associated with vigabatrin treatment. We accomplished this by recording longitudinally ERGs in children before and during vigabatrin treatment and comparing results between children on vigabatrin monotherapy and those taking additional anticonvulsive medications. Thirty-three children on vigabatrin therapy were tested; the duration between visits was approximately 6 months. Thirteen children were assessed initially before starting vigabatrin therapy and seven were assessed soon after (age range 1.5–126 months, median 6 months). The remaining 13 patients were already on vigabatrin at the time of initial visit (age range 6.5–180 months, median 16 months). ERGs were tested using the standard protocol established by the International Society for Clinical Electrophysiology of Vision, with Burian-Allen bipolar contact-lens electrodes. In addition to standard responses we recorded photopic oscillatory potentials (OPs). All 33 patients were tested longitudinally on at least two occasions and 11 were tested on three occasions. For children whose only anticonvulsive drug was vigabatrin there was a significant curvature (quadratic function, p<0.05) of the predicted cone b-wave amplitude with time; exhibited as increase in b-wave amplitude followed by subsequent decrease. Descriptive data demonstrated the same pattern in the group taking anticonvulsive medications in addition to vigabatrin. In most children the flicker amplitude declined between 6 months and 1 year of vigabatrin treatment. Our data demonstrated that rod responses, which may be abnormal before initiation of vigabatrin, did not change substantially with vigabatrin treatment.