Surgical versus medical treatment for severe epilepsy: consequences for intellectual functioning in children and adults. A follow-up study

IQ changes after pediatric epilepsy surgery: a systematic review and meta-analysis

OBJECTIVE

This systematic review aimed to assess the intellectual outcome of children who underwent surgery for epilepsy.

METHODS

A systematic review of electronic databases was conducted on December 3, 2021, for PubMed and January 11, 2022, for Web of Science. The review was conducted according to the PRISMA guidelines. The included studies reported on intelligence quotient (IQ) or developmental quotient (DQ) before and after epilepsy surgery in children. Studies were included, if the patients had medically intractable epilepsy and if the study reported mainly on curative surgical procedures. We conducted a random-effects meta-analysis to determine the mean change of IQ/DQ.

RESULTS

Fifty-seven studies reporting on a total of 2593 patients met the inclusion criteria. The mean age at surgery was 9.2 years (± 3.44; range 2.4 months-19.81 years). Thirty-eight studies showed IQ/DQ improvement on a group level, 8 yielded stable IQ/DQ, and 19 showed deterioration. Pooled analysis revealed a significant mean gain in FSIQ of + 2.52 FSIQ points (95% CI 1.12-3.91). The pooled mean difference in DQ was + 1.47 (95% CI - 6.5 to 9.5). The pooled mean difference in IQ/DQ was 0.73 (95% CI - 4.8 to 6.2). Mean FSIQ gain was significantly higher in patients who reached seizure freedom (+ 5.58 ± 8.27) than in patients who did not (+ 0.23 ± 5.65). It was also significantly higher in patients who stopped ASM after surgery (+ 6.37 ± 3.80) than in patients who did not (+ 2.01 ± 2.41). Controlled studies showed a better outcome in the surgery group compared to the non-surgery group. There was no correlation between FSIQ change and age at surgery, epilepsy duration to surgery, and preoperative FSIQ.

SIGNIFICANCE

The present review indicates that there is a mean gain in FSIQ and DQ in children with medically intractable epilepsy after surgery. The mean gain of 2.52 FSIQ points reflects more likely sustainability of intellectual function rather than improvement after surgery. Seizure-free and ASM-free patients reach higher FSIQ gains. More research is needed to evaluate individual changes after specific surgery types and their effect on long-term follow-up.

Unveiling the potential of perampanel and pregabalin in addressing pentylenetetrazole-induced electrographic alterations and neurobehavioral anomalies

Chemical kindling is broadly used experimental model to investigate novel treatments on the process of epileptogenesis and coexisting behavioral comorbidities. The current study aimed to investigate the low dose perampanel (PER) (0.125 and 0.5 mg/kg) and pregabalin (PG) (15 mg/kg) as standalone treatments and in combination on kindling-induced seizure progression with concurrent electroencephalographic alterations. Mice were subjected to pentylenetetrazole (PTZ)-induced kindling followed by neurobehavioral assessment for anxiety-like activity and cognitive deficit through behavioral experiments. The monotherapy with PER at 0.5 mg/kg and PG at 15 mg/kg delayed the kindling process but PRP+PG yielded pronounced benefits and hindered the development of seizures of higher severity. PER+PG combination relieved the animals from anxiety-like behavior in various employed anxiogenic tests. Furthermore, the kindling-associated cognitive deficit was protected by PER+PG combination as increased alteration behavior, discrimination index and latencies to enter the dark zone were noted in y-maze, object recognition and passive avoidance tests, respectively while shorter escape latencies were noted in water maze. The brain samples of kindled mice had elevated malondialdehyde and reduced catalase, superoxide dismutase and glutathione peroxidase enzymes while treatment with PER and PG combination shielded the mice from heightened kindling-associated oxidative stress. Overall, the findings of the present study illustrate that concurrent administration of PER and PG effectively hindered the process of epileptogenesis by protecting neuronal excitability and brain oxidative stress. The results predict the dominance of PER and PG combination over monotherapy which might serve as an effective novel combination to combat drug resistance and behavioral disorders in epileptic patients.

Seizures' impact on cognition and quality of life in childhood cancer survivors

BACKGROUND

The objective of this study was to determine the impact of seizure-related factors on neurocognitive, health-related quality of life (HRQOL), and social outcomes in survivors of childhood cancer.

METHODS

Survivors of childhood cancer treated at St. Jude Children's Hospital (n = 2022; 48.3% female; median age, 31.5 years; median time since diagnosis, 23.6 years) completed neurocognitive testing and questionnaires. The presence, severity, resolution, and treatment history of seizures were abstracted from medical records. Adjusting for the age at diagnosis, sex, and prior cancer therapy, multivariable models examined the impact of seizures on neurocognitive and HRQOL outcomes. Mediation analyses were conducted for social outcomes.

RESULTS

Seizures were identified in 232 survivors (11.5%; 29.9% of survivors with central nervous system [CNS] tumors and 9.0% of those without CNS tumors). In CNS tumor survivors, seizures were associated with poorer executive function and processing speed (P < .02); in non-CNS tumor survivors, seizures were associated with worse function in every domain (P < .05). Among non-CNS survivors, seizure severity was associated with worse processing speed (P = .023), and resolution was associated with better executive function (P = .028) and attention (P = .044). In CNS survivors, seizure resolution was associated with improved attention (P = .047) and memory (P < .02). Mediation analysis revealed that the impact of seizures on social outcomes was mediated by neurocognitive function.

CONCLUSIONS

Seizures in cancer survivors adversely affect long-term functional and psychosocial outcomes independently of cancer therapy. The resolution of seizure occurrence is associated with better outcomes. Seizure severity is associated with poorer outcomes and should be a focus of clinical management and patient education.

Intellectual outcome after a cortical lesion with versus without epilepsy: A life span neurodevelopmental view

In patients with cortical lesions, the structure of intelligence has never been studied as a function of age at lesion onset and presence vs absence of lesional epilepsy over the life span.

METHOD

Two thousand one hundred eighty-six cases were assembled bearing unilateral cortical lesions occurring at all ages (1301 with seizures) with postlesion verbal intelligence quotient (IQ) (VIQ) and performance IQ (PIQ).

RESULTS

Global IQ significantly and constantly decreased as a function of age at lesion onset in the cases without epilepsy, and increased in the cases with epilepsy. Beyond the lesion onset age of 12 years, VIQ was significantly higher than PIQ in the cases without epilepsy, and lower in the cases with epilepsy. The VIQ/PIQ × lesion-side interaction indicative of hemispheric specialization increased significantly linearly with age at lesion onset in the patients without epilepsy but ceased to progress at the lesion-onset age of 30 years and beyond in the cases with epilepsy.

CONCLUSION

Postlesion global IQ, the difference between VIQ and PIQ, and the laterality index all vary significantly as a function of age at lesion onset. In addition, these changes over the life span are all quite different between cases with and without epilepsy.

Neurocognitive function in children after anterior temporal lobectomy with amygdalohippocampectomy

BACKGROUND

We assessed the postoperative neurocognitive function after temporal lobectomy in children with temporal lobe epilepsy.

METHODS

This was a retrospective analysis of the data of 20 patients with Engel's class I or II outcomes after anterior temporal lobectomy with amygdalohippocampectomy between 2005 and 2008. Twenty children underwent resection of either dominant (n = 8) or nondominant (n = 12) temporal lobes, and their median age at surgery was 12.8 ± 3.2 years. We serially assessed intelligence and memory function as measured by the Korean-Wechsler Scales of Intelligence and Rey-Kim Memory test both before and after surgery.

RESULTS

Intelligence quotient (IQ) and memory quotient scores remained stable during a 3.6-year median follow-up in these children after the surgery. There was no decrease of IQ or memory quotient scores in either the dominant or non-dominant hemisphere groups. Later onset of epilepsy, a shorter epilepsy duration, a smaller number of antiepileptic drugs, and postoperative seizure-free outcomes were significant good predictors of the postoperative IQ.

CONCLUSION

Temporal lobectomy in children did not provoke a significant decline in intelligence or memory function. Early surgical treatment in children with intractable seizures of temporal lobe origin may result in better neurocognitive outcomes.

Postnatal systemic inflammation exacerbates impairment of hippocampal synaptic plasticity in an animal seizure model

OBJECTIVE

To investigate the effects of systemic inflammation in the critical postnatal stages on neurophysiological actions of immune processes and neural plasticity in adult rats after kainic acid (KA)-induced seizures.

METHODS

To determine changes in hippocampal synaptic plasticity after postnatal central nervous system inflammatory responses and seizure attacks, we performed intraperitoneal injections of lipopolysaccharide (LPS) in postnatal Sprague Dawley rats on day 14 (P14) to induce central nervous system inflammation. We then used a KA tail vein injection on P35 to induce seizure attacks. We compared the variability in synaptic plasticity in the hippocampal Schaffer collateral-CA1 region of seizure animals with or without LPS-induced inflammation preconditioning.

RESULTS

P14 injection of LPS increased susceptibility to seizures, while treatment with KA on P35 induced seizures. Long-term potentiation (LTP) of the Schaffer collateral-CA1 region was impaired in seizure animals, and this effect was more pronounced in the P14 LPS injection group. Fluoro-Jade staining revealed an increase in degenerated hippocampal CA1 pyramidal cells in the P14 LPS injection group. Cytokine expression in the hippocampus in the pre-, peri- and postictus periods was greater in P14 LPS rats than in saline-treated rats.

CONCLUSIONS

Intraperitoneal LPS injection on P14 induces higher cytokine secretion after KA-induced seizures, enhancing neuronal excitability, shortening seizure onset time and exacerbating neuronal degeneration and impairment of LTP formation in the hippocampal Schaffer collateral-CA1 region. Central nervous system inflammation during critical stages of childhood development could disrupt the balance needed for neurophysiological actions of immune processes, producing direct, pernicious effects on memory, neural plasticity and neurogenesis into adulthood.

Long-term intellectual outcome after temporal lobe surgery in childhood

OBJECTIVE

Temporal lobe resection is an established treatment for medication-resistant temporal lobe epilepsy, which in recent years has increasingly been performed in children. However, little is known about the long-term outcome in these children. The aim of this study was to characterize intellectual and psychosocial functioning of children after temporal lobe resection as they progress into late adolescence and adulthood.

METHODS

We report the long-term follow-up of 42 children who underwent temporal lobe surgery after an average postoperative period of 9 years. Longitudinal change in IQ was documented, psychosocial outcome including quality of life was assessed, and preoperative and postoperative T1-weighted MRI brain scans were evaluated quantitatively. A well-matched nonsurgical comparison group of 11 children with similar clinical characteristics was also assessed.

RESULTS

At follow-up, 86% of the surgical group were seizure-free, and 57% were no longer taking antiepileptic medication. A significant increase in IQ was found in the surgical group after an extended follow-up period of >5 years. This IQ change was not found in the nonsurgical comparison group. IQ increases were associated with cessation of antiepileptic medication and changes in MRI-derived gray matter volume. The surgical group also reported better psychosocial outcome including quality of life, which was more strongly associated with seizure freedom rather than surgery per se.

CONCLUSIONS

Surgery for temporal lobe epilepsy performed in childhood results in excellent long-term seizure control and favorable cognitive outcome along with positive effects on brain development.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that temporal lobectomy in children with temporal lobe epilepsy is associated with improved long-term intellectual outcomes compared with those undergoing standard medical treatment.

Cognitive changes following surgery in intractable hemispheric and sub-hemispheric pediatric epilepsy

OBJECTIVES

The objectives were to study the short and longitudinal changes in the cognitive skills of children with intractable epilepsy after hemispheric/sub-hemispheric epilepsy surgery.

METHODS

Sixteen patients underwent surgery from September 2005 until March 2009. They underwent detailed presurgical evaluation of their cognitive skills and were repeated annually for 3 years.

RESULTS

Their mean age was 6.6 years. Epilepsy was due to Rasmussen's encephalitis (n = 9), Infantile hemiplegia seizure syndrome (n = 2), hemimegalencephaly (n = 2), and Sturge Weber syndrome (n = 3). Fourteen (87.5%) patients underwent peri-insular hemispherotomy and two (12.5%) underwent peri-insular posterior quadrantectomy. The mental and social age, gross motor, fine motor, adaptive, and personal social skills showed a steady increase after surgery (p < 0.05). Language showed positive gains irrespective of the side and etiology of the lesion (p = 0.003). However, intelligence quotient (IQ) remained static on follow-up. Patients with acquired pathology gained more in their mental age, language, and conceptual thinking. Age of seizure onset and duration of seizures prior to surgery were predictive variables of postoperative cognitive skills.

CONCLUSIONS

There are short- and long-term gains in the cognitive skills of children with intractable epilepsy after hemispherotomy and posterior quadrantectomy that was better in those patients with acquired diseases. Age of seizure onset and duration of seizures prior to surgery were independent variables that predicted the postoperative outcome.

The 2008 Judith Hoyer lecture: epilepsy in children: listening to mothers

The incidence of epilepsy is significantly higher in children than adults. When faced with the diagnosis of epilepsy, parents have many questions regarding cause, treatment, and prognosis. Although the majority of children with epilepsy have an excellent prognosis and respond well to therapy, some children are refractory to therapy and suffer from cognitive decline. Animal models are now providing insights into the mechanisms responsible for the high incidence of seizures during development and age-dependent seizure-induced damage. One of the causes of the increased susceptibility of the young brain to seizures is the depolarizing effects of GABA secondary to high intracellular concentrations of chloride in young neurons. Although cell loss is not a feature of seizures in the young brain, recurrent seizures do result in aberrant sprouting of mossy fibers, reduce neurogenesis, and alter excitatory and inhibitory neurotransmitter receptor structure and function. Behavioral consequences of early-life seizures include impaired spatial cognition, which now can be assessed using single-cell recordings from the hippocampus. Antiepileptic drugs have had a tremendous positive influence in epilepsy management, although there are now a number of studies demonstrating that antiepileptic drugs at therapeutic concentrations can impair cognition and result in increased apoptosis. While clinical judgment and experience are paramount when discussing the consequences of seizures and their treatment, awareness of studies from animals can provide the clinician with guidance in addressing these important issues with parents.

Early life seizures cause long-standing impairment of the hippocampal map

Children with seizures are at risk for long-term cognitive deficits. Similarly, recurrent seizures in developing rats are associated with deficits in spatial learning and memory. However, the pathophysiological bases for these deficits are not known. Hippocampal place cells, cells that are activated selectively when an animal moves through a particular location in space, provides the animal with a spatial map. We hypothesized that seizure-induced impairment in spatial learning is a consequence of the rat's inability to form accurate and stable hippocampal maps. To directly address the cellular concomitants of spatial memory impairment, we recorded the activity of place cells from hippocampal subfield CA1 in freely moving rats subjected to 100 brief flurothyl-induced seizures during the first weeks of life and then tested them in the Morris water maze and radial-arm water maze followed by place cell testing. Compared to controls, rats with recurrent seizures had marked impairment in Morris water maze and radial-arm water maze. In parallel, there were substantial deficits in action potential firing characteristics of place cells with two major defects: i) the coherence, information content, center firing rate, and field size were reduced compared to control cells; and ii) the fields were less stable than those in control place cells. These results show that recurrent seizures during early development are associated with significant impairment in spatial learning and that these deficits are paralleled by deficits in the hippocampal map. This study thus provides a cellular correlate for how recurrent seizures during early development lead to cognitive impairment.

Epilepsy surgery in the first 3 years of life: a Canadian survey

OBJECTIVE

To determine the clinical characteristics, surgical challenges, and outcome in children younger than 3 years of age undergoing epilepsy surgery in Canada.

METHODS

Retrospective data on patients younger than age 3 years who underwent epilepsy surgery at multiple centers across Canada from January 1987 to September 2005 were collected and analyzed.

RESULTS

There were 116 patients from eight centers. Seizure onset was in the first year of life in 82%, and mean age at first surgery was 15.8 months (1-35 months). Second surgeries were done in 27 patients, and a third surgery in 6. Etiologies were malformations of cortical development (57), tumor (22), Sturge-Weber syndrome (19), infarct (8), and other (10). Surgeries comprised 40 hemispheric operations, 33 cortical resections, 35 lesionectomies, 7 temporal lobectomies, and one callosotomy. There was one surgical mortality. The most common surgical complications (151 operations in 116 patients) were infection (17) and aseptic meningitis in 13. Of 107 patients with seizure outcome assessed more than one year postoperatively, 72 (67.3%) were seizure free (Engel I), 15(14%) had >90% improvement (Engel II), 12 had >50% improvement (Engel III), and 8 did not benefit from surgery (Engel IV). Development improved in 55.3% after surgery.

CONCLUSION

Epilepsy surgery in children younger than 3 years of age is relatively safe and is effective in controlling seizures. Very young age is not a contraindication to surgery in children with refractory epilepsy, and early surgery may impact development positively.

Evaluation of quality of life and clinical status of children operated on for intractable epilepsy

AIM

The aim of the study was evaluation of surgical treatment of epilepsy measured by changes in quality of life (QOL) and in seizure frequency and severity.

MATERIALS AND METHODS

Examined group consists of 24 boys and 9 girls. We performed corpus callosotomy, lesionectomy, vagal nerve stimulation, temporal lobectomy and multiple subpial transections. Age at surgery ranged from 5 months to 19 years, with mean follow-up of 11.9 months. QOL was evaluated on the basis of the questionnaire created by us, in which parents were asked to assess the following variables before and after the surgical procedure: communication, socialization, daily living skills, movement abilities and behavioural problems. The seizure frequency was assessed with the Engel's scale, the modified Engel's scale and the Seizure Scoring System. Clinical state of all the patients was evaluated as well.

RESULTS

There were no patients with stable and worsening QOL status. In the whole group treated with callosotomy, the considerable improvement in QOL concerned 36.4% of cases. In more than 95% of cases, the reduction in seizures frequency is greater than 75%. In more than 43% of patients, there are no seizures after surgery.

CONCLUSIONS

Surgical treatment of intractable epilepsy is an effective method in terms of both seizure control and QOL improvement. Our results indicate the improvement in QOL of all operated patients. The improvement in QOL was accompanied by decrease in frequency and 'positive' changes in morphology of seizures. Improvement in QOL, as equivalent to seizure reduction rate, may influence further differentiation of qualification methods and surgical procedures of epilepsy.

Cognitive effects of seizures

We aimed to review recent prospective and cross-sectional studies regarding the gradual and chronic effects of (cumulative) seizures on cognition. In contrast with the increasing evidence of structural changes in the brain associated with repeated seizures, its functional repercussions remain unclear. Methodological difficulties of cross-sectional and prospective studies are addressed. It appears that all but one of the prospective studies available on children are limited to measures of intelligence. Most studies revealed no significant adverse effects, although there appears to be a subgroup of about 10-25% of children that shows a clinically significant intellectual decline. Children with generalized symptomatic epilepsies, frequent seizures, high antiepileptic drug use, and early onset of epilepsy appear at risk, although psychosocial factors may also play an important role. Five of the six prospective studies on adults report evidence of a mild decline in cognition in patients with a (longstanding) history of pharmacoresistant epilepsy. The adverse effect on cognitive abilities, memory in particular, seems somewhat more robust than that on measures of intelligence. A significant association between cognitive decline and seizure related variables is rarely substantiated in prospective research and cross-sectional studies show contradicting results. Taken together, the data suggest a mild but measurable decline of intellectual performance in children and adults. Decline of specific cognitive abilities in children is impossible to evaluate given the very little data available. In adults, memory appears to be the most vulnerable cognitive function. Due to many confounding variables, the effect of seizures per se is difficult to estimate, but appears limited.

Impact of epilepsy surgery on developing minds: how do we weigh the consequences?

Cognitive Function in Preschool Children after Epilepsy Surgery: Rationale for Early Intervention

Freitag H, Tuxhorn I

Epilepsia 2005;46(4):561–567

Purpose

The detrimental effect of frequent early seizures on the cognitive potential of children is a significant clinical issue. Epilepsy surgery in childhood offers a good prognosis for seizure control and improved developmental outcome. We studied the postoperative outcome and the developmental velocity after surgery and analyzed risk factors for developmental delay in 50 consecutive preschool children treated surgically for severe epilepsy at ages 3 to 7 years.

Methods

Pre- and postoperative developmental quotients (DQs) were analyzed with analysis of variance; step-wise linear regressions were performed on preoperative DQs and on a difference score between post- and preoperative DQs to determine risk factors for preoperative development and factors influencing postoperative development.

Results

Of the 50 patients, 70% were retarded, with IQ <70; 16% were of average intelligence, with IQ ranging from 85 to 115. Age at seizure onset and extent of lesion were predictive variables for preoperative cognitive development. Six to 12 months after surgery (early postoperative phase), 66% were seizure free (Engel outcome class I), 26% had substantial to worthwhile seizure reduction (classes II and III), and 8% were unchanged (class IV). Forty-one (82%) children showed stable velocity of development; three children showed gains of 15 IQ points; three had developmental decline (loss of 10 IQ points), which was transient in two children; and three children moved from not assessable to assessable. At last follow-up (6 months to 10 years after surgery), 11 children showed IQ/DQ gains of 15 IQ points. Gains in IQ were observed only in seizure-free children and were stable over time. Shorter duration of epilepsy was significantly associated with a postoperative increase in DQ.

Conclusions

(a) Substantial global mental delay is common in young children treated for epilepsy with surgery; (b) in most patients, postoperative development proceeded at a stable velocity; (c) catch-up development may occur but only in seizure-free patients; (d) substantial cognitive losses were noted in only one child; and (e) early seizure control stabilized developmental velocity in this patient cohort.

Two-year follow-up of intelligence after pediatric epilepsy surgery

Research findings concerning cognitive effects of pediatric epilepsy surgery form an important basis for decisions about surgery. However, most follow-up studies have been of limited duration. In this study, a 2-year follow-up of intelligence was undertaken. Risk factors were analyzed. Included were 38 patients aged 3 to 17 years. Surgery was left in 19 patients and right in 19 patients. Types of surgery included temporal lobe resection (n = 23), extratemporal or multilobar resection (n = 8), and hemispherectomy (n = 7). The Wechsler Scales of Intelligence were administered presurgically, 6 months postsurgically, and 2 years postsurgically. No significant change in verbal or performance intelligence quotient (IQ) was demonstrated on a group level. Lateralization, type of surgery, age at surgery, sex, and presurgical IQ did not affect outcome. Across assessments, IQ scores of left-hemisphere patients were lower than those of right-hemisphere patients. Scores of patients in the hemispherectomy group were lower than those of the extratemporal or multilobar resection group, which were lower than the temporal lobe resection group. Scores improved significantly in six patients and deteriorated in seven. In conclusion, epilepsy surgery in children and adolescents does not, in general, have a significant impact on cognitive development in a 2-year perspective. In individual patients, poor seizure control and extensive surgery for Rasmussen's encephalitis were related to a deterioration of IQ.

Cognitive Function in Preschool Children after Epilepsy Surgery: Rationale for Early Intervention

PURPOSE

The detrimental effect of frequent early seizures on the cognitive potential of children is a significant clinical issue. Epilepsy surgery in childhood offers a good prognosis for seizure control and improved developmental outcome. We studied the postoperative outcome and the developmental velocity after surgery and analyzed risk factors for developmental delay in 50 consecutive preschool children treated surgically for severe epilepsy at ages 3 to 7 years.

METHODS

Pre- and postoperative developmental quotients (DQs) were analyzed with analysis of variance; stepwise linear regressions were performed on preoperative DQs and on a difference score between post- and preoperative DQs to determine risk factors for preoperative development and factors influencing postoperative development.

RESULTS

Of the 50 patients, 70% were retarded, with IQ < 70; 16% were of average intelligence, with IQ ranging from 85 to 115. Age at seizure onset and extent of lesion were predictive variables for preoperative cognitive development. Six to 12 months after surgery (early postoperative phase), 66% were seizure free (Engel outcome class I), 26% had substantial to worthwhile seizure reduction (classes II and III), and 8% were unchanged (class IV). Forty-one (82%) children showed stable velocity of development; three children showed gains of >/=15 IQ points; three had developmental decline (loss of >/=10 IQ points), which was transient in two children; and three children moved from not assessable to assessable. At last follow-up (6 months to 10 years after surgery), 11 children showed IQ/DQ gains of >/=15 IQ points. Gains in IQ were observed only in seizure-free children and were stable over time. Shorter duration of epilepsy was significantly associated with a postoperative increase in DQ.

CONCLUSIONS

(a) Substantial global mental delay is common in young children treated for epilepsy with surgery; (b) In most patients, postoperative development proceeded at a stable velocity; (c) Catch-up development may occur but only in seizure-free patients; (d) Substantial cognitive losses were noted in only one child. and (e) Early seizure control stabilized developmental velocity in this patient cohort.