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360
Abstracts
SY-06-5
Epileptic channelopathies in man and mouse
J. Noebels
Department of Neurology, Baylor College of Medicine,
Houston, TX, USA
Inherited disorders of ion channels are now the single
most common known cause of idiopathic generalized
epilepsy. Despite this rapid progress in gene discovery,
we are only beginning to understand their intriguing pathophysiology.
Channelopathy phenotypes arise in both the
developing and mature central nervous system, and show
remarkable clinical diversity, including tonic/clonic,
absence, and myoclonic epilepsy, as well as other episodic
neurological disorders. The mutations target both voltageand
ligand-gated channels, and produce disease by altering
the biophysical properties of the pore subunit or by modifying
auxiliary subunits that regulate membrane insertion,
modulation, and localization of the channel complex. In
almost all cases, the direct result is to prolong intrinsic
membrane depolarisation or impair synaptic transmission.
Recent studies in orthologous mouse models suggest that
the mechanisms for age-dependent epileptogenesis in these
inherited errors are more complex than initially realized.
Despite widespread expression, only certain neural
networks are vulnerable at various developmental stages,
presumably accounting for phenotypic diversity. The selectivity
is explained by the differential contributions of individual
channels to the excitability and firing behavior, and
by the presence of compensatory subunits. As one example,
generalized spike-wave absence epilepsy is seen in a
cluster of four mutant mouse models, each representing a
subunit of the brain voltage-gated calcium channel. In two
of these models (a1a and b4), the compensatory subunits
have been identified, and their absence in thalamic neurons
contributes to thalamocortical synchrony. We have recently
identified further downstream cellular plasticity in thalamic
low threshold calcium currents that may also directly
contribute to the seizure phenotype.
SY-7
What Happens to a Child at Risk for Developmental
Delay/Disability
SY-07-1
Introduction
S. Harel
Division of Pediatrics, The Institute For Child Development
and Pediatrics Neurology, Tel Aviv, Israel
Abstract not submitted
SY-07-2
School age outcomes of pre-school children diagnosed
with either global developmental delay or specific
language impairment
M. Shevell, A. Majnemer, R. Platt
Montreal Children’s Hospital-McGill University, Canada
The objective of this study is to describe prospectively the
school age (6–7 years) functional and developmental
outcomes in a cohort of children diagnosed previously
with either a global developmental delay or a specific
language impairment. Two cohorts have been assembled:
(a) global developmental delay (n ¼ 99); and (b) specific
language impairment (n ¼ 72). These cohorts were initially
assessed and diagnosed at a mean age of 37.6 and 43.3
months, respectively. Functional, developmental and
language outcomes were assessed in each cohort between
the ages of 6–7 years using a variety of measures. These
included the Battelle Developmental Inventory, Vineland
Adaptive Behavior Scale, WeeFIM, Child Health Questionnaire,
Parenting Stress Index, Child Behavior Checklist/4–
18, Expressive One-Word Picture Vocabulary Test and the
Peabody Picture Vocabulary Test-Revised. Outcomes on
each of these measures for each cohort in this ongoing
study will be described and co-related with factors identified
at initial intake to establish the possibility and strength of
prognostic variables.
SY-07-3
Cerebral visual disorders in children with brain lesions:
outcome and correlation with neuroimaging
G. Cioni, A. Guzzetta, F. Tinelli
Division of Child Neurology and Psychiatry, Stella Maris
Scientific Institute and University of Pisa, I Calambrone,
Pisa, Italy
Children with brain lesions of antenatal or perinatal
onset are at high risk for early disturbances of their visual
development, detectable since the first months of life by
means of new behavioural and electrophysiological techniques.
Several studies have reported that various aspects of
visual function, such as visual acuity, visual fields, optokinetic
nystagmus, fixation shift, and perception of movement
are often impaired in these children. A strong
correlation between the results of visual assessment, and
cognitive and motor development also has been also
reported, suggesting a crucial role for visual function in
the early development. Long-term follow-up of these children
have revealed subtle neuropsychological disorders.
Neuroimaging techniques, and brain MRI in particular,
are useful in predicting the occurrence and extent of visual
impairment. However, the correlation between imaging
findings and function is not always consistent. This is probably
due to the involvement of the complex extra-striatal