Joost Meekes

Verbal memory after epilepsy surgery in childhood.

PURPOSE To investigate verbal memory after epilepsy surgery both group-wise and at the level of individual children, and to assess associations with side of surgery and removal of the temporal lobe. METHODS A prospective controlled study in a consecutive sample of 21 children undergoing epilepsy surgery, with comprehensive assessments of verbal memory before surgery and six, 12 and 24 months after surgery. For each patient, two age- and gender-matched controls were tested at similar intervals. Standardized regression-based (SRB) analysis was applied to compare post-surgical change in individual patients with change in controls. RESULTS Group-wise, average normed scores on verbal memory tests were higher after epilepsy surgery than before, corroborating earlier reports. By dint of empirically based SRB analysis, however, considerable individual differences in post-surgical change were revealed. Children with resections that included the left temporal lobe functioned significantly poorer than predicted on the basis of their pre-surgical performance. In contrast, verbal memory performance after surgery was consistent with pre-surgical baseline in the majority of children with resections that spared the left temporal lobe. CONCLUSIONS Despite cessation of epileptic seizures, verbal memory remains vulnerable in children who required surgery including the left temporal lobe. In most - but not all - children with other types of surgery, post-surgical verbal memory is consistent with their individual pre-surgical base level.

Withdrawal of antiepileptic drugs improves psychomotor speed after childhood epilepsy surgery.

This retrospective study evaluates the impact of postoperative antiepileptic drug (AED) withdrawal on psychomotor speed in seizure-free children, operated for medically refractory epilepsy. Post-surgical medication policy and neuropsychological assessments (performed shortly before and 6, 12 and 24 months after surgery), were evaluated in 57 children (32 female, median age at surgery 13 years). Patients were divided into a withdrawal (n=29) and a no-withdrawal group (n=28). Scores of four psychomotor tests performed at 12 and 24 months after surgery were compared with those of postoperative baseline measurements, performed 6 months after surgery. At 24 months, the withdrawal group had improved significantly more than the no-withdrawal group on three of four tests; reaction time to light (p=0.031), reaction time to sound (p=0.045) and tapping (p=0.003). At 12 months, a non-significant tendency in the same direction was found for both reaction time tests. Drug withdrawal after surgery improves psychomotor speed and may unleash the potential for cognitive improvement.

Visual memory after epilepsy surgery in children: A standardized regression-based analysis of group and individual outcomes

Visual memory is vulnerable to epilepsy surgery in adults, but studies in children suggest no change or small improvements. We investigated visual memory after epilepsy surgery, both group-wise and in individual children, using two techniques to assess change: 1) repeated measures analysis of variance (ANOVA) and 2) an empirically based technique for detecting cognitive change [standardized regression-based (SRB) analysis]. A prospective cohort consisting of 21 children completed comprehensive assessments of memory both before surgery (T0) and 6 (T1), 12 (T2), and 24 months (T3) after surgery. For each patient, two age- and gender-matched controls were assessed with the same tests at the same intervals. Repeated measures ANOVA replicated the results of previous studies reporting no change or minor improvements after surgery. However, group analysis of SRB results eliminated virtually all improvements, indicating that the ANOVA results were confounded by practice effects. Standardized regression-based group results showed that in fact patients scored lower after surgery than would be predicted based on their presurgical performance. Analysis of individual SRB results showed that per visual memory measure, an average of 18% of patients obtained a significantly negative SRB score, whereas, on average, only 2% obtained a significantly positive SRB score. At T3, the number of significantly negative SRB scores outweighed the number of significantly positive SRB scores in 62% of patients. There were no clear associations of clinical variables (including side and site of surgery and postsurgical seizure freedom) with memory outcome. The present analysis revealed that given their individual presurgical functioning, many children obtained disappointing results on some visual memory tests after epilepsy surgery. Comparison of the SRB analysis with ANOVA results emphasizes the importance of empirically based techniques for detecting cognitive effects of epilepsy surgery in childhood.

High-Intensity Chronic Stroke Motor Imagery Neurofeedback Training at Home: Three Case Reports:

Motor imagery (MI) with neurofeedback has been suggested as promising for motor recovery after stroke. Evidence suggests that regular training facilitates compensatory plasticity, but frequent training is difficult to integrate into everyday life. Using a wireless electroencephalogram (EEG) system, we implemented a frequent and efficient neurofeedback training at the patients’ home. Aiming to overcome maladaptive changes in cortical lateralization patterns we presented a visual feedback, representing the degree of contralateral sensorimotor cortical activity and the degree of sensorimotor cortex lateralization. Three stroke patients practiced every other day, over a period of 4 weeks. Training-related changes were evaluated on behavioral, functional, and structural levels. All 3 patients indicated that they enjoyed the training and were highly motivated throughout the entire training regime. EEG activity induced by MI of the affected hand became more lateralized over the course of training in all three patients. The patient with a significant functional change also showed increased white matter integrity as revealed by diffusion tensor imaging, and a substantial clinical improvement of upper limb motor functions. Our study provides evidence that regular, home-based practice of MI neurofeedback has the potential to facilitate cortical reorganization and may also increase associated improvements of upper limb motor function in chronic stroke patients.

Parental education predicts change in intelligence quotient after childhood epilepsy surgery

To know whether change in the intelligence quotient (IQ) of children who undergo epilepsy surgery is associated with the educational level of their parents.

Stimulation of the parietal cortex affects reaching in a patient with epilepsy

A 15-year-old girl with complex partial epilepsy had subdural electrodes implanted. She was tested on reaching tasks during electrocortical stimulation prior to neurosurgery. MRI showed left mesial parietal dysplasia. Stimulation of the superior parietal cortex (electrode pair 37–45, figure, A) during line bisection and visually guided reaching resulted in movement arrest followed by the arm drifting upward (figure, B, …

Recovery After Childhood Traumatic Brain Injury: Vulnerability and Plasticity

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Lexicon before and after epilepsy surgery in adolescents

OBJECTIVE Poor performance on confrontation naming tasks by children and adolescents with pharmacologically intractable epilepsy has been interpreted as indicating impairments of lexicon, that is, the store of words in long-term memory. However, confrontation naming performance crucially depends not only on word knowledge but also on other functions such as fluency. We applied an alternative method to assess lexicon with the aim of tracing deficits in lexicon before and after surgery in adolescents with pharmacologically intractable epilepsy. METHOD Sixteen patients and 32 age- and sex-matched controls completed the Dutch version of the controlled oral word production task. Responses were used to calculate indices of lexical fluency (retrieval efficiency), lexical breadth (vocabulary size), and lexical depth (knowledge of word properties), as well as use of search strategies. RESULTS Adolescents with pharmacologically intractable epilepsy had lower lexical fluency scores than healthy peers, but did not differ from them on the dimensions of lexical breadth and lexical depth. Patients demonstrated reduced use of search strategies. In fact, the difference in lexical fluency between patients and controls disappeared after controlling for Full Scale IQ (obtained using the Dutch version of the 3rd edition of the Wechsler Intelligence Scale for Children (WISC-IIINL; Kort et al., 2005; Wechsler, 2002) or-for older children-the Dutch version of the first edition of the Kaufman Adult and Adolescent Intelligence Test (KAIT; Kaufman & Kaufman, 1993; Mulder, Dekker, & Dekker, 2004) and use of search strategies. In patients, changes in the use of the antiepileptic drug carbamazepine were associated with lexical fluency. CONCLUSION Adolescents with pharmacologically intractable epilepsy differ from their healthy peers mainly in lexical fluency, rather than word knowledge per se. (PsycINFO Database Record