Elina Liukkonen

Magnetoencephalography in presurgical evaluation of children with the Landau-Kleffner syndrome

Summary: Purpose: Our aim was (a) to localize the primary epileptogenic cortex for possible multiple subpial transsection in four children with the Landau‐Kleffner syndrome (LKS), and (b) to evaluate the impact of magnetoencephalography (MEG) in the localizing process.

Long‐term outcome of 32 children with encephalopathy with status epilepticus during sleep, or ESES syndrome

Purpose:  To prospectively evaluate the efficacy of drug treatment and long‐term cognitive outcome in children with encephalopathy with status epilepticus during sleep (ESESS).

Proton Spectroscopic Imaging Shows Abnormalities in Glial and Neuronal Cell Pools in Frontal Lobe Epilepsy

Summary:  Purpose: Proton magnetic resonance spectroscopic imaging (1H MRSI) can lateralize the epileptogenic frontal lobe by detecting metabolic ratio abnormalities in frontal lobe epilepsy (FLE). We used 1H MRS to lateralize and localize the epileptogenic focus, and we also sought to characterize further the metabolic abnormality in FLE.

The effect of surgery in encephalopathy with electrical status epilepticus during sleep

Purpose:  We analyzed clinical and electroencephalography (EEG) outcomes of 13 patients with pharmacoresistant encephalopathy with electrical status epilepticus during sleep (ESES) following epilepsy surgery.

Treatment of electrical status epilepticus in sleep: A pooled analysis of 575 cases

Epileptic encephalopathy with electrical status epilepticus in sleep (ESES) is a pediatric epilepsy syndrome with sleep‐induced epileptic discharges and acquired impairment of cognition or behavior. Treatment of ESES is assumed to improve cognitive outcome. The aim of this study is to create an overview of the current evidence for different treatment regimens in children with ESES syndrome.

Neuropsychological characteristics of five children with the Landau-Kleffner syndrome: Dissociation of auditory and phonological discrimination

The Landau-Kleffner Syndrome (LKS) is characterized by acquired receptive aphasia and EEG abnormality with onset between the ages of 3 and 8 years. This study presents neuropsychological assessments in 5 children with LKS. The aims were (1) to specify the neuropsychological deficits characteristic of these children; and (2) to clarify the nature of the receptive aphasia by comparing nonverbal and verbal auditory discrimination. Receptive aphasia was present in all children. Retardation, poor motor coordination, hyperkinesia, and conduct problems were frequent but variable. All children exhibited a dissociation between the discrimination of environmental sounds and phonological auditory discrimination, the latter being more impaired than the former. This suggests that the primary deficit of the receptive aphasia is an impairment of auditory phonological discrimination rather than a generalized auditory agnosia.

Dravet syndrome: New potential genetic modifiers, imaging abnormalities, and ictal findings

Dravet syndrome is an autosomal dominant epileptic encephalopathy of childhood, which is caused mainly by SCN1A and PCHD19 mutations. Although Dravet syndrome is well recognized, the causes of acute encephalopathy are still elusive, and reported data on ictal electroencephalography (EEG) and structural brain abnormalities are scarce.

Cognitive deficits after cryptogenic infantile spasms with benign seizure evolution

Between 1989 and 1994, 18 children with cryptogenic infantile spasms ‐ defined by normal development before onset of spasms, symmetrical hypsarrhythmia or multifocal spikes, and typical spasms on presentation, and no abnormal findings on aetiological studies including neuroradiology ‐were diagnosed and treated. To assess the risk of cognitive impairment later in life, 15 of these 18 children whose spasms completely resolved within the first year of life were studied. Age at onset of spasms varied between 4.4 and 9.8 months (mean 6.5 months). Children were effectively treated with adrenocorticotrophic hormone (10 children), pyridoxine (three), vigabatrin (one), or sodium valproate (one). Spasms lasted between 11 and 138 days (mean 50 days) and stopped between the age of 6.3 and 10.2 months(mean 8.1 months). EEGs normalized between the age of 7.1 and 13.2 months (mean 9.4 months). Early development was assessed on presentation and within a few months after spasms had stopped. A detailed neuropsychological assessment was performed between the age of 4.0 and 5.9 years. Twelve children had normal intelligence; specific cognitive deficits were found in five. Three children had mild learning disability. Abnormal developmental status at age 8 to 15 months after complete resolution of spasms and EEG abnormalities was associated with cognitive deficits at age 4 to 6 years.

Semiautomatic quantification of spiking in patients with continuous spikes and waves in sleep: sensitivity to settings and correspondence to visual assessment.

OBJECTIVE To define the optimal analysis protocol for semiautomatic quantification of spike index (SI) in continuous spikes and waves in sleep (CSWS). METHODS Ten overnight EEGs (nine patients) with abundant spiking were used to quantify SI with a previously published semiautomatic quantification based on spike detection with BESA software. We studied (i) dependency of SI on maximal interspike interval (maxISI) defining the continuous discharge, (ii) sensitivity of SI to variations in the spike search protocol, and (iii) stability of SI over time. Finally, the semiautomatic method was compared with the quantification based on visual scoring by two neurophysiologists. RESULTS MaxISI of 3s appeared to yield the best combination of sensitivity and stability in SI quantification. The SI of the first hour of sleep did not differ significantly from the SI of the whole night. Mean error of the semiautomatic method compared to visual scoring was only seven percentage units. CONCLUSIONS Semiautomatic quantification of SI functions well with maxISI of 3s, and the first hour of sleep represents the whole night SI with a clinically relevant accuracy. SIGNIFICANCE This method opens a possibility for objective quantification of near-continuous epileptiform spiking during sleep, and it supports the use of shorter epochs for quantitative assessment of CSWS.