Florence Christiaens

Auditory Neuropathy with Preserved Cochlear Microphonics and Secondary Loss of Otoacoustic Emissions

Auditory neuropathy is defined as absent or severely distorted auditory brainstem responses with preserved otoacoustic emissions and cochlear microphonics. This entity can be found in various circumstances including pre-lingual children. An almost universal characteristic reported from adult patients is the ineffectiveness of traditional hearing aids. Adequate management of pre-lingual cases therefore remains an open problem. This paper describes two pre-lingual children whose follow-up data demonstrated a selective loss of the otoacoustic emissions, whereas the cochlear microphonics remained preserved. In one of the patients, hearing aid fitting as soon as she lost her otoacoustic emissions proved successful. These findings have important implications for the operational definition of the condition, since one must be prepared to encounter cases with absent otoacoustic emissions. The present data also demonstrate that conventional amplification can benefit pre-lingual auditory neuropathy cases, at least once they have lost their otoacoustic emissions.

Mutation of a potassium channel–related gene in progressive myoclonic epilepsy

We investigated a large consanguineous Moroccan family with progressive myoclonic epilepsy (PME) consistent with autosomal recessive inheritance, to describe the phenotype and identify the causal gene.

Oral ketamine in paediatric non-convulsive status epilepticus.

In children, non-convulsive status epilepticus (NCSE) is rare and difficult to treat. Response to steroids and GABAergic medication is variable and often decreases with increasing duration of NCSE. We present our experience with oral ketamine, an NMDA-receptor antagonist, administered to five children with severe epilepsy (Lennox-Gastaut Syndrome, myoclonic-astatic epilepsy, progressive myoclonic epilepsy and Pseudo-Lennox Syndrome) during an episode of NCSE. Resolution of NCSE was documented in all cases clinically and electroencephalographically within 24-48 hours of starting ketamine. No significant side effects were noted.

Nonsurgical cerebellar mutism (anarthria) in two children

Cerebellar mutism (anarthria) is a well-described complication of posterior fossa tumor resection. It is accompanied by a characteristic behavior including irritability and autistic features. This syndrome is typically reversible within days to months. Underlying pathophysiology is unknown. We describe two children who presented with a similar clinical finding after nonsurgical cerebellar involvement, hemolytic-uremic syndrome in one and cerebellitis in the other. Postmortem pathologic findings in the first patient indicated cerebellar ischemic necrosis. Single-photon emission computed tomography in the second patient revealed diffuse cerebellar hypoperfusion with no supratentorial abnormalities, refuting a phenomenon of diaschisis between cerebellar and frontal connections. These findings confirm that this clinical syndrome may occur in a nonsurgical, nontraumatic context. They are consistent with recent integrative hypotheses explaining cerebellar anarthria.

Pediatric phantom vision (Charles Bonnet) syndrome

Visual symptomatology in childhood often presents diagnostic difficulties. Recurrent paroxysmal visual complaints, although typically associated with migraine, may also signal other disorders. We describe a 9-year-old partially sighted male with paroxysmal zoopsias resulting from Charles Bonnet syndrome. This condition is characterized by paroxysmal visual hallucinations occurring in patients with chronic visual impairment, akin to the phantom-limb phenomenon. This pediatric case is the fourth report of this condition. We have reviewed the other cases.

Predictive value of electrophysiology in children with hypoxic coma

Assessment of prognosis of children in hypoxic coma is difficult. The value of clinical evaluation is often limited. The usefulness of electrophysiologic tests has been documented mostly in adults and neonates and in cases of traumatic coma. We reviewed retrospectively 39 consecutive children with nontraumatic hypoxic coma to assess the prognostic value of EEG, visual, and auditory evoked potentials. Correlation between electrophysiology and neurologic outcome after mean follow-up period of 30 months was significant (r(s) = 0.6, P < 0.001). In contrast there was no correlation between Pediatric Risk of Mortality score (PRISM) and outcome (r(s) = -0.42, P = 0.8). Combining magnetic resonance imaging with electrophysiology further enhanced their prognostic value (r(s) = 0.69, P < 0.001). Neuroimaging was highly sensitive but less specific, and electrophysiologic tests were highly specific but less sensitive. We conclude that early electrophysiology can contribute to predicting outcome in pediatric hypoxic coma.

Unilateral cortical necrosis following status epilepticus with hypoglycemia

Isolated status epilepticus or severe hypoglycemia rarely causes irreversible focal neurologic deficits in children. We describe three children who presented with status epilepticus and prolonged hypoglycemia resulting in hemiplegia due to unilateral hemispheric damage. The non-vascular cortical topography of the lesions is consistent with selective neuronal necrosis, confirmed by histopathology in one patient. This suggests increased neuronal vulnerability to necrosis secondary to energy failure resulting from combination of hypoglycemia and status epilepticus.

Crossed cerebellar diaschisis secondary to refractory frontal seizures in childhood

We report a girl with refractory partial seizures since 7 years of age, secondary to right frontal cortical dysplasia, who developed MRI and SPECT abnormalities in the contralateral hemicerebellar cortex. These became more marked, leading to left hemicerebellar atrophy. Crossed cerebellar diaschisis has been described mostly in hemispheric stroke and supratentorial tumours, but less often in epilepsy. It is usually a transient phenomenon. This report shows that crossed cerebellar diaschisis can develop within two years of seizure onset and evolve over time.

Transcranial magnetic stimulation and other evoked potentials in pediatric multiple sclerosis

In children, multiple sclerosis is rare and has some clinical and paraclinical differences compared with adults. The assessment of corticospinal motor tracts is expected to be relevant because of their frequent early involvement in this disease. Reported are the results of transcranial magnetic stimulation in two children who presented at 12 and 9 years of age with clinically probable and definite multiple sclerosis, respectively. In Patient 1 the excitatory cortical threshold for the upper limbs was abnormally raised. In Patient 2 the latency of the motor-evoked potentials was considerably increased for the right tibialis anterior muscle, with a slowing of the central conduction time. Although these abnormalities may be consistent with central conduction impairment, they may alternatively suggest early axonal damage because irreversible axonal lesions occurring at the onset of the disease have recently been reported. Testing of central motor tracts, in addition to visual, auditory, and somatosensory pathways, therefore appears appropriate in the multimodal assessment of pediatric patients with suspected multiple sclerosis.

Motor strategies in standing up in leukomalacic spastic diplegia

In spastic diplegia impaired postural control jeopardizes the organization of whole-body movements. We studied segmental motor patterns involved in standing up from a supine position in ten children with spastic diplegia associated with periventricular leukomalacia and 14 unimpaired children using a visual analysis scale previously devised for developmental research. This approach examines specific movement patterns in upper limbs, axis and lower limbs. We found that children with spastic diplegia use movement patterns described in normal children but with markedly reduced intra- and interindividual variability. One previously undescribed stereotyped lower limb pattern was observed in four patients. This approach can systematically characterize the limited repertoire of movement in patients with spastic diplegia and therefore contribute to a better understanding of motor control.