Neurodevelopmental outcomes after prenatal exposure to lamotrigine monotherapy in women with epilepsy: a systematic review and meta-analysis

BACKGROUND

Lamotrigine has become one of the most commonly prescribed antiseizure medications (ASM) in epileptic women during pregnancy and therefore requires regular updates regarding its safety. The aim of this study was to estimate the association between in utero exposure to lamotrigine monotherapy and the occurrence of neurodevelopmental outcomes.

METHODS

All comparative studies assessing the occurrence of neurodevelopmental outcomes after epilepsy-indicated lamotrigine monotherapy exposure during pregnancy were searched. First, references were identified through a snowballing approach, then, through electronic databases (Medline and Embase) from 2015 to June 2022. One investigator evaluated study eligibility and extracted data and a second independent investigator reviewed the meta-analysis (MA). A systematic review and random-effects model approach were performed using a collaborative WEB-based meta-analysis platform (metaPreg.org) with a registered protocol (osf.io/u4gva).

RESULTS

Overall, 18 studies were included. For outcomes reported by at least 4 studies, the pooled odds ratios and 95% confidence interval obtained with the number of exposed (N1) and unexposed children (N0) included were: neurodevelopmental disorders as a whole 0.84 [0.66;1.06] (N1 = 5,271; N0 = 22,230); language disorders or delay 1.16 [0.67;2.00] (N1 = 313; N0 = 506); diagnosis or risk of ASD 0.97 [0.61;1.53] (N1 = at least 5,262; N0 = 33,313); diagnosis or risk of ADHD 1.14 [0.75;1.72] (N1 = at least 113; N0 = 11,530) and psychomotor developmental disorders or delay 2.68 [1.29-5.56] (N1 = 163; N0 = 220). The MA of cognitive outcomes included less than 4 studies and retrieved a significant association for infants exposed to lamotrigine younger than 3 years old but not in the older age groups.

CONCLUSION

Prenatal exposure to lamotrigine monotherapy is not found to be statistically associated with neurodevelopmental disorders as a whole, language disorders or delay, diagnosis or risk of ASD and diagnosis or risk of ADHD. However, the MA found an increased risk of psychomotor developmental disorders or delay and cognitive developmental delay in less than 3 years old children. Nevertheless, these findings were based exclusively on observational studies presenting biases and on a limited number of included children. More studies should assess neurodevelopmental outcomes in children prenatally exposed to lamotrigine.

Early adolescent language development following intrathecal chemotherapy for acute lymphoblastic leukaemia

PURPOSE

Central nervous system (CNS) prophylaxis in the treatment of childhood acute lymphoblastic leukaemia (ALL) is routinely achieved through intrathecal chemotherapy (ITC). The presence of high level language deficits in older children who received CNS-directed ITC for ALL in early childhood is yet to be elucidated, with previous research suggesting that high level language deficits may appear later in ALL survivors' development at an age when these skills typically emerge.

METHOD

A test battery covering foundational language skills and higher-order language skills was administered to five participants (aged 10-15 years) with a history of ITC for ALL. Conversion of each child's language performance scores to z scores allowed for clinical interpretation of data across the language areas tested.

RESULT

Foundational language skills were, in general, of no clinical concern. Three of the five children presented with clinically impaired language skills in areas including resolving ambiguity, making inferences and composing novel sentences. Performance variation between the participants and within the individual participants was noted.

CONCLUSION

Given the importance of early adolescent language abilities to academic and social development in late primary and secondary schooling, these preliminary findings suggest further research into emerging adolescent language abilities following ITC for ALL is warranted.

[Reversible neuropsychological deterioration associated to zonisamide in a paediatric patient with tuberous sclerosis]

AIM

To document reversible cognitive deterioration associated to high doses of zonisamide, using the Reliable Change Index to control practice effects derived from repetitive neuropsychological assessments.

CASE REPORT

A 11 year-old boy with tuberous sclerosis complex and left frontal refractory epilepsy, evaluated within a paediatric epilepsy surgery program. The epileptogenic zone was found to be related with a tuber situated on the left inferior frontal gyrus. The effects of high doses of zonisamide simulate a disturbance of eloquent cortex within the epileptogenic zone and the impact of uncontrolled seizures on cognitive functioning over the language-dominant hemisphere. Drug withdrawal significantly improved total intelligence index, verbal comprehension intellectual index and specific language-sustained cognitive abilities, beyond practice effects.

CONCLUSIONS

The differentiation between cognitive effects of drugs and functional deficits resulting from eloquent cortex involvement within the epileptogenic zone can be of crucial importance in the decision-making process for epilepsy surgery.

[Epilepsy and cognition: the role of antiepileptic drugs]

INTRODUCTION

Multiple factors underlie the cognitive changes associated with epilepsy, including the effect of antiepileptic drug (AED) therapy itself. The use of AEDs in the management of epilepsy requires an ongoing risk-benefit analysis that attempts to maximize seizure control while minimizing adverse cognitive side-effects.

AIM

This review focuses on the global and specific cognitive effects of the classic and the new AEDs.

DEVELOPMENT

All of the established AEDs can produce cognitive side effects, which are increased with polypharmacy and with increasing dosage and anticonvulsant blood levels. The main disorders are a diminished reaction and information processing time with alterations affecting memory, attention and language. Further, there is much debate concerning the existence and clinical importance of differential AED cognitive side effects and a large portion of the literature examining the comparative cognitive effects of AEDs is limited by inadequate study designs.

CONCLUSIONS

Cognitive side effects of antiepileptic drugs are common and can negatively affect tolerability, compliance, and long-term retention of the treatment. The role of cognitive side effects should be kept in proper perspective when choosing AED therapy. It is important to be able to recognize early these effects and to put them into perspective as to how they affect our patients.

Testicular-cancer survivors experience compromised language following chemotherapy: findings in a Swedish population-based study 3-26 years after treatment

BACKGROUND

Studies suggest an increased risk for compromised cognitive function among cancer survivors. It is unclear to what extent chemotherapy is the cause and how the dysfunction, when present, affects everyday life. The objective was to study self-reported behaviours that may depend on cognitive function, among testicular-cancer survivors who received various cycles of cisplatin-based chemotherapy by comparing them with those who did not.

MATERIAL AND METHODS

We identified 1173 eligible men diagnosed with non-seminomatous testicular cancer treated according to the national cancer-care programs SWENOTECA I-IV between 1981 and 2004. During an 18-month qualitative phase we constructed a study-specific questionnaire including questions about specific activities and behaviour in everyday life.

RESULTS

We obtained information from 960 of 1173 (82%) testicular-cancer survivors diagnosed on average 11 years previously. The prevalence of "saying similar but incorrect words" at least once a week was 5% among those having received no chemotherapy versus 16% among those having received five or more cycles, giving a prevalence ratio ("relative risk", RR) of 3.3 with a 95% confidence interval of 1.5 to 7.1. The corresponding figure for "saying words in the wrong order" was 3.1 (1.7-5.8), for "difficulties understanding what other people mean" 3.1 (1.3-7.7), for "saying words other than planned" 2.2 (1.1-4.5) and for "difficulties completing sentences" 2.0 (1.0-3.6). The relative risks for those with a low level of education ranged between 4.9 (1.6-14.9) and 15.3 (1.9-120.5).

CONCLUSION

Testicular-cancer survivors in Sweden who have received five or more cycles of cisplatin-based chemotherapy experience an increased incidence of long-term compromised language; the effect is primarily seen among men with a low level of education.

Donepezil treatment of topiramate-related cognitive dysfunction

Six migraine patients experienced significant topiramate-related cognitive and language dysfunction that improved with donepezil treatment and allowed uninterrupted topiramate use. These patients represent the first report of topiramate-related cognitive and language dysfunction that improved with a cholinesterase inhibitor. Although, the mechanism responsible for this effect is uncertain, cholinesterase inhibition resulting in cholinergic augmentation and enhanced cognition probably account for some if not most of the improvement.

Functional MRI reveals declined prefrontal cortex activation in patients with epilepsy on topiramate therapy

Functional magnetic resonance imaging of covert word generation was used to examine brain activation abnormalities associated with topiramate-induced cognitive language impairment in patients with epilepsy. Compared with a control epilepsy group, in the topiramate-treated group, there was significantly less activation in the language-mediating regions of the prefrontal cortex; the topiramate group also had significantly lower neuropsychological language scores. These findings suggest that topiramate has a critical effect on the cerebral neural systems that mediate expressive language.

Non-degenerative mild cognitive impairment in elderly people and use of anticholinergic drugs: longitudinal cohort study

OBJECTIVE

To assess the potential of anticholinergic drugs as a cause of non-degenerative mild cognitive impairment in elderly people.

DESIGN

Longitudinal cohort study.

SETTING

63 randomly selected general practices in the Montpellier region of southern France.

PARTICIPANTS

372 people aged > 60 years without dementia at recruitment.

MAIN OUTCOME MEASURES

Anticholinergic burden from drug use, cognitive examination, and neurological assessment.

RESULTS

9.2% of subjects continuously used anticholinergic drugs during the year before cognitive assessment. Compared with non-users, they had poorer performance on reaction time, attention, delayed non-verbal memory, narrative recall, visuospatial construction, and language tasks but not on tasks of reasoning, immediate and delayed recall of wordlists, and implicit memory. Eighty per cent of the continuous users were classified as having mild cognitive impairment compared with 35% of non-users, and anticholinergic drug use was a strong predictor of mild cognitive impairment (odds ratio 5.12, P = 0.001). No difference was found between users and non-users in risk of developing dementia at follow-up after eight years.

CONCLUSIONS

Elderly people taking anticholinergic drugs had significant deficits in cognitive functioning and were highly likely to be classified as mildly cognitively impaired, although not at increased risk for dementia. Doctors should assess current use of anticholinergic drugs in elderly people with mild cognitive impairment before considering administration of acetylcholinesterase inhibitors.

Volumetric Neuroimaging and Low-Dose Early-Life Exposures: Loose Coupling of Pathogenesis-Brain-Behavior Links

The interface of developmental neuroimaging with developmental neurotoxicology can, broadly speaking, address two complementary concerns. The first is to study the impact of specific exposures on brain development. The second is to study known neurobehavioral disorders with an eye to discerning toxicological contributions to pathogenesis. Pathogenesis targets brain based upon physical properties (receptors, growth factors, etc.) while behavior is modulated by regional and neural systems alterations. The distribution of pathogenesis-brain relationships overlaps only partially with that of brain-behavior relationships. The goal of this paper is to highlight methodological issues involved in designing and interpreting volumetric neuroimaging studies in the light of this loose coupling.

Associative recognition in a patient with selective hippocampal lesions and relatively normal item recognition

Previous work (Mayes et al., Hippocampus 12:325-340, 2002) found that patient YR, who suffered a selective bilateral lesion to the hippocampus in 1986, showed relatively preserved verbal and visual item recognition memory in the face of clearly impaired verbal and visual recall. In this study, we found that YR's Yes/No as well as forced-choice recognition of both intra-item associations and associations between items of the same kind was as well preserved as her item recognition memory. In contrast, YR was clearly impaired, and more so than she was on the above kinds of recognition, at recognition of associations between different kinds of information. Thus, her recognition memory for associations between objects and their locations, words and their temporal positions, abstract visual items or words and their temporal order, animal pictures and names of professions, faces and voices, faces and spoken names, words and definitions, and pictures and sounds, was clearly impaired. Several of the different information associative recognition tests at which YR was impaired could be compared with related item or inter-item association recognition tests of similar difficulty that she performed relatively normally around the same time. It is suggested that YR's familiarity memory for items, intra-item associations, and associations between items of the same kind was mediated by her intact medial temporal lobe cortices and was preserved, whereas her hippocampally mediated recall/recollection of these kinds of information was impaired. It is also suggested that the components of associations between different kinds of information are represented in distinct neocortical regions and that initially they only converge for memory processing within the hippocampus. No familiarity memory may exist in normal subjects for such associations, and, if so, YR's often chance recognition occurred because of her severe recall/recollection deficit. Conflicting data and views are discussed, and the way in which recall as well as item and associative recognition need to be systematically explored in patients with apparently selective hippocampal lesions, in order to resolve existing conflicts, is outlined.

Beyond the K-hole: a 3-year longitudinal investigation of the cognitive and subjective effects of ketamine in recreational users who have substantially reduced their use of the drug

RATIONALE

Ketamine is a dissociative anaesthetic that is also a drug of abuse. Previous studies have demonstrated persisting episodic and semantic memory impairments in recreational ketamine users 3 days after taking ketamine. However, the degree to which these deficits might be reversible upon reduction or cessation of ketamine use was not known.

OBJECTIVE

To follow-up a population of ketamine users tested 3 years previously and examine whether impairments observed 3 days after drug use are enduring or reversible.

METHODS

Eighteen ketamine users and 10 polydrug controls from studies conducted between 3 and 4 years earlier were re-tested on the same battery of cognitive tasks and subjective measures. These tapped episodic, semantic and working memory and executive and attentional functioning. Subjective schizotypal, dissociative, mood and bodily symptoms were also examined and a drug use history recorded.

RESULTS

The ketamine users had reduced their frequency of use of ketamine by an average of 88.3%. Performance of ketamine users on tasks tapping semantic memory had improved and this improvement was correlated with their reduction in ketamine use. On tasks tapping episodic memory and attentional functioning, ketamine users still showed deficits compared to polydrug controls. Higher levels of schizotypal symptoms and perceptual distortions were exhibited by the ketamine group, although dissociative symptoms were similar to controls.

CONCLUSIONS

These findings indicate that semantic memory impairments associated with recreational ketamine are reversible upon marked reduction of use; however, impairments to episodic memory and possibly attentional functioning appear long-lasting. In addition, schizotypal symptoms and perceptual distortions may persist after cessation of ketamine use. Ketamine users, or potential users, should be aware of the enduring effects of this drug on aspects of memory and subjective experience.

Thimerosal exposure in infants and developmental disorders: a retrospective cohort study in the United kingdom does not support a causal association

OBJECTIVE

After concerns about the possible toxicity of thimerosal-containing vaccines in the United States, this study was designed to investigate whether there is a relationship between the amount of thimerosal that an infant receives via diphtheria-tetanus-whole-cell pertussis (DTP) or diphtheria-tetanus (DT) vaccination at a young age and subsequent neurodevelopmental disorders.

METHODS

A retrospective cohort study was performed using 109 863 children who were born from 1988 to 1997 and were registered in general practices in the United Kingdom that contributed to a research database. The disorders investigated were general developmental disorders, language or speech delay, tics, attention-deficit disorder, autism, unspecified developmental delays, behavior problems, encopresis, and enuresis. Exposure was defined according to the number of DTP/DT doses received by 3 and 4 months of age and also the cumulative age-specific DTP/DT exposure by 6 months. Each DTP/DT dose of vaccine contains 50 microg of thimerosal (25 microg of ethyl mercury). Hazard ratios (HRs) for the disorders were calculated per dose of DTP/DT vaccine or per unit of cumulative DTP/DT exposure.

RESULTS

Only in 1 analysis for tics was there some evidence of a higher risk with increasing doses (Cox's HR: 1.50 per dose at 4 months; 95% confidence interval [CI]: 1.02-2.20). Statistically significant negative associations with increasing doses at 4 months were found for general developmental disorders (HR: 0.87; 95% CI: 0.81-0.93), unspecified developmental delay (HR: 0.80; 95% CI: 0.69-0.92), and attention-deficit disorder (HR: 0.79; 95% CI: 0.64-0.98). For the other disorders, there was no evidence of an association with thimerosal exposure.

CONCLUSIONS

With the possible exception of tics, there was no evidence that thimerosal exposure via DTP/DT vaccines causes neurodevelopmental disorders.

Reversible language regression as an adverse effect of topiramate treatment in children

Profound language regression developed in three children with epilepsy 4 to 28 weeks after beginning topiramate (TPM). TPM was administered as an adjunctive antiepileptic drug at doses of 2.5 to 6.0 mg/kg/day. Language functions recovered while TPM was being reduced in dose or stopped.

[Environmental epidemiology research leads to a decrease of the exposure limit for mercury]

The central nervous system is particularly vulnerable to prenatal exposure to methylmercury. Due to the widespread exposure to methylmercury from fish, several prospective environmental epidemiology studies have been initiated, in which the maternal exposure during the pregnancy is related to the neurobehavioural development of the children. We have studied a Faroese birth cohort prenatally exposed to methylmercury from maternal intake of contaminated pilot whale meat. At seven years of age, clear dose-response relationships were observed for deficits in attention, language, and memory. An increase in blood pressure was also associated with the prenatal exposure level. The exposure limit for mercury has therefore been decreased.

Antiepileptic drugs and atypical evolution of idiopathic partial epilepsy

Six patients with classic benign epilepsy of childhood with centrotemporal spikes, treated with carbamazepine (four patients) or sodium valproate (two patients) evolved atypically because the epileptic disorder, diffusion of the electroencephalographic (EEG) discharges during wakefulness, and continuous spike-and-wave during slow sleep associated with severe neuropsychologic abnormalities worsened. These features appeared after a seizure-free interval varying for 2 weeks to 1 year 6 months after initiating therapy and remitted when the previous anticonvulsant drug was discontinued and either substituted with another drug or the patient was left without any treatment. Once the initial antiepileptic drug was discontinued and after a period roughly proportional to the duration of the clinical-EEG complication, the evolution of the patients' seizures was not unusual for this type of epilepsy, with patients eventually becoming free of both seizures and medication and reaching normal school achievement. The clinical complications cannot be attributed solely to the drugs. It must also be related to the underlying substract (i.e., the specific epileptic syndrome involved) that in some patients becomes susceptible to atypical evolution when either product is administered.

A male with fetal valproate syndrome and autism

Fetal valproate syndrome (FVS) is characterized by minor craniofacial anomalies, major organ malformations, and developmental delay. We report on a patient who has a clinical phenotype compatible with both FVS and autism. The presence of an autistic disorder in a previously reported case of FVS and similar findings in our patient suggest that a relation between this known teratogen and autism may exist.

Semantic, phonological, and perceptual changes following left and right intracarotid injection (Wada) with a low amytal dosage

Intracarotid injection of a low dosage of amobarbital (75 mg, 5% solution) was studied in 30 temporal lobectomy candidates while naming achromatic, incongruously, and congruously colored pictorial objects and reading real, nonsense, and embedded words. Semantic errors and phonological alexia followed the left injection, while the right injection induced visuoperceptual errors. When the contralateral hemisphere was anesthetized, the left brain formulated supraordinate categories for words and objects, while the right brain applied concrete labels. The basic language proficiency of patients influenced recovery and outcome; left temporal patients who were interictally anomic performed especially poorly after both injections. Codifying phonological and perceptual changes during the intracarotid amobarbital procedure can improve interpretations about language laterality and organization.

Neurocognitive effects of aluminum

The neurocognitive effects of aluminum (Al) were studied in 35 hemodialysis patients. Higher Al levels were associated with a decline in visual memory. As Al levels increased, patients with lower vocabulary scores (a measure of premorbid intelligence) showed a decline in attention/concentration, frontal lobe functions, and on several neurocognitive measures, while those with higher vocabulary scores revealed no Al-related decline. These results suggest that individuals with lower verbal intelligence may possess less well-developed compensatory strategies to overcome the neurocognitive effects associated with Al. These data also indicate that Al is neurotoxic and, therefore, potential sources of environmental Al should be identified and eliminated.

Behavioral toxicology: evaluating cognitive functions

Behavioral toxicology is concerned with the identification of adverse effects on neural and behavioral functions resulting from exposure to a neurotoxicant. Many substances are known to have effects on cognitive functions such as memory, attention and perception. This paper reviews some of the issues that must be addressed when trying to assess these neurotoxic effects on cognition, and identifies a variety of paradigms that have been explored for use in behavioral toxicology.

Language and speech behaviors of children with undue lead absorption: a review of the literature

This article reviews the effects of chronic undue or low lead absorption on the speech and language behavior of children. While the effects of high-level lead poisoning have been documented, the effects of chronic low-lead absorption remain controversial. It is concluded that the evidence supports the presence of speech and language problems in some low-lead level children. The severity, duration, and specific nature of the problems, however, are not clear. Pertinent research issues are addressed.

Nonaphasic misnaming and other neurobehavioral features of an unusual toxic encephalopathy: case study

A patient with propranolol-induced mental status changes was studied during and after the period of propranolol intoxication. While intoxicated he manifested the syndrome of "non-aphasic misnaming," did poorly on the nonverbal portions of the WAIS, and exhibited perseveration and variability of performance. Our observations clarify the nature of the neurobehavioral disturbances in toxic-metabolic encephalopathies.