Changes of P300 latency with age in childhood epilepsy

The P300 Event-Related Potential Component and Cognitive Impairment in Epilepsy: A Systematic Review and Meta-analysis

Background: Epilepsy is one of the most prevalent chronic brain diseases worldwide and is often accompanied by cognitive impairment. Event-related potentials (ERPs) are an objectively non-invasive approach for studying information processing and cognitive functions in the brain. The P300 is an important and extensively explored late component of ERPs that has been widely applied to assess cognitive function in epilepsy in previous studies. However, consistent conclusions have not yet been reached for various reasons.

Objective: We conducted a comprehensive systematic review and meta-analysis of P300-related studies to assess the latency and amplitude of the P300 in epileptic patients.

Methods: PubMed, EMBASE, and Cochrane Library databases were systematically searched for eligible studies. The standard mean difference (SMD) and the 95% confidence interval (CI) were calculated as the effect size of the P300 component.

Results: The main results of the present meta-analysis indicated that epileptic patients have a longer P300 latency and a lower P300 amplitude than controls. Subgroup analysis based on age group demonstrated that these differences can be observed in both children and adult patients compared with healthy controls. In addition, the P300 latency was longer in patients with the five main types of epileptic seizures than in controls.

Conclusion: This study revealed that epileptic patients have abnormalities in the P300 component, which may reflect deficits in cognitive function. Thus, the P300 may be a potential objective approach for evaluating cognitive function in epileptic patients.

P300 development from infancy to adolescence

This article provides an overview of P300 research from infancy through adolescence. First, a brief historical overview is provided highlighting seminal studies that began exploration of the P300 component in developmental groups. Overall, these studies suggest that the P300 can be detected in children and appears to reflect similar cognitive processes to those in adults; however, it is significantly delayed in its latency to peak. Second, two striking findings from developmental research are the lack of a clear P300 component in infancy and differential electrophysiological responses to novel, unexpected stimuli in children, adolescents, and adults. Third, contemporary questions are described, which include P300-like components in infancy, alteration of P300 in atypically developing groups, relations between P300 and behavior, individual differences of P300, and neural substrates of P300 across development. Finally, we conclude with comments regarding the power of a developmental perspective and suggestions for important issues that should be addressed in the next 50 years of P300 research.

Application of the P300 Event-Related Potential in the Diagnosis of Epilepsy Disorder: A Review

Epilepsy is one of the most serious chronical neurological disorders, affecting more than 50 million people worldwide. It can be defined as a spectrum disorder, and patients with epilepsy possess abnormalities in cognitive functions. A number of factors can cause cognitive dysfunctions in epileptic syndromes, including etiology, the age of onset, type of seizure and severity, duration, and antiepileptic drugs. Event-related potentials (ERPs) are very useful clinical and research instruments to evaluate cognitive function in patients with neuropsychiatry disorders. Event-related potentials directly reflect cortical neuronal activity and provide a particular level of temporal resolution. Among various ERP components, the P300 is the most important component for assessing cognitive processes such as attention, working memory, and concentration. Numerous studies have reported the abnormalities in amplitude or latency of P300 component of ERP in epileptic patients, and these abnormalities are indicative of cognitive dysfunction. Therefore, the purpose of this review is to consolidate the existing literature in connection with the use of P300 in epileptic patients.

Temporal lobe impairment in West syndrome: event-related potential evidence

Objective

This study investigates auditory processing in infants with West syndrome (WS) using event-related potentials (ERPs).

Methods

ERPs were measured in 25 infants with mainly symptomatic WS (age range = 3–10 months) and 26 healthy term infants (age range = 3–9 months) using an auditory novelty oddball paradigm. The ERP recordings were made during wakefulness and repeated in stage II sleep.

Results

The obligatory components (P150, N250, P350) and novelty response components (P300, Nc) were recordable during both sleep and wakefulness in patients and controls. All ERP latencies decreased with age in controls but not in the WS group (age × group interaction, F = 22.3, p < 0.0001). These ERP latency alterations were not affected by pharmacological treatment for WS.

Interpretation

This study demonstrated a persistently altered ERP signature in patients with a recent history of infantile spasms. The prolongation of auditory obligatory and novelty ERPs in WS patients indicates a severe failure of temporal lobe maturation during infancy. It remains to be investigated whether this predicts long-term cognitive impairments characteristic for this epileptic encephalopathy.

Cognitive functions evaluated by P300 and visual and auditory number assays in children with childhood epilepsy with occipital paroxysms (CEOP)

PURPOSE

This study was planned to evaluate cognitive functions, especially attention and immediate recall, in children with childhood epilepsy with occipital paroxysms (CEOP), by using P300 and neuropsychological tests, which included visual and auditory number assays. Thirty patients with CEOP, ages ranging from 5 to 17 years were enrolled in the study. Twenty-five healthy children were taken as the control group.

METHODS

Oddball paradigm was used in P300 recordings. The latency and the amplitude of the P300 wave recorded from Cz were taken into consideration. The neuropsychological test battery included visual and auditory number assays.

RESULTS

P300 latency was significantly longer in the CEOP group (p=0.014). The results of the visual and auditory number assay test showed significant decline in the patient group when compared with the normal controls.

CONCLUSIONS

Attention and immediate recall deficits as well as prolonged P300 latencies in children with CEOP can be due to an ongoing epileptic activity either influencing the whole brain or only the occipital lobe which can also be involved in the neuropsychological organization of the human cortex. Therefore, children with CEOP should be evaluated with more detailed neuropsychological tests for possible cognitive deficits.

Sensitividade e especificidade do potencial de média latência

O Potencial Evocado Auditivo de Média Latência (PEAML) foi primeiramente descrito por Geisler, Frishkopf, Rosenblith em 1958.¹ É caracterizado por uma série de ondas/respostas neuroelétricas gravadas no cérebro através de eletrodos de superfície. Atualmente, tem sido visto como um dos testes eletrofisiológicos mais promissores para a avaliação das disfunções e/ou alterações do Sistema Nervoso Auditivo Central. Suas ondas aparecem no intervalo entre 10 e 80 milissegundos (ms) após o início do estímulo auditivo. A onda Pa é a mais estudada por ser a mais visível e robusta deste potencial. Esse teste ainda é pouco utilizado na prática clínica pelo fato de existir uma grande variabilidade nos resultados encontrados intersujeitos, o que torna difícil o estabelecimento de medidas de normalidade. OBJETIVO: O objetivo desse trabalho foi estabelecer a efetividade - sensitividade e especificidade do PEAML para que este potencial possa ser mais utilizado com maior fidedignidade. FORMA DE ESTUDO: Caso-controle. MATERIAL E MÉTODO: Fizeram parte desse estudo indivíduos com idade entre 15 e 55 anos, portadores de lesões de Sistema Nervoso Auditivo Central, comprovada através de diagnóstico por imagem ou que tenham sido submetidos a cirurgias crânio-encefálicas, indivíduos portadores de Transtornos do Processamento Auditivo (TPA) comprovadas através de avaliação comportamental e indivíduos normais (Grupo Controle). RESULTADOS: Os resultados mostram que o corte de 30% apresentou melhores resultados, tanto para o efeito de eletrodo quanto para o efeito de orelha. O efeito de orelha foi mais fidedigno para evidenciar Transtornos de Processamento Auditivo, enquanto o efeito de eletrodo foi mais efetivo para evidenciar lesão.

Benigne epilepsietypische Potentiale des Kindesalters (Rolando-Spikes) - neurobiologische und neuropsychologische Befunde und ihre klinische Bedeutung in der Kinder- und Jugendpsychiatrie

Zusammenfassung: Einleitung: Die Rolando-Epilepsie ist das häufigste Epilepsie-Syndrom im Kindesalter. Sie ist elektroenzephalographisch charakterisiert durch das Auftreten von fokalen epilepsietypischen Potentialen, den sog. Rolando-Spikes (benigne epilepsietypische Potentiale des Kindesalters, BEPK). BEPK treten mit einer Häufigkeit von etwa 1,5 bis 2,4% bei Kindern auf; nur ein Zehntel erleidet epileptische Anfälle. Methoden: Diese Arbeit gibt einen Überblick über genetische, epidemiologische, radiologische, neurophysiologische, metabolische und neuropsychologische Befunde bei Kindern mit BEPK. Resultate: Der epileptologische Verlauf ist günstig, eventuell auftretende Anfälle sistieren spätestens mit der Pubertät; die epilepsietypischen Potentiale sind dann nicht mehr nachweisbar. Entgegen früherer Annahmen erstreckt sich das Symptomenspektrum über seltene Anfälle hinaus auf neuropsychologische Beeinträchtigungen und Verhaltensauffälligkeiten, auch bei Kindern ohne manifeste Anfälle. Der Einfluss der Rolando-Spikes auf die Entwicklung betroffener Kinder und ihr Verhalten ist unklar. Durch zwei Modelle wird versucht, den Zusammenhang von paroxysmaler EEG-Aktivität und neuropsychologischen Auffälligkeiten zu erklären. Das erste betrachtet die beobachtbaren Defizite als vorübergehende kognitive Beeinträchtigung infolge der epileptischen Aktivität; das zweite sieht als Ursache eine genetisch bedingte zerebrale Reifungsstörung mit enger Verwandtschaft zu Teilleistungsstörungen. Schlussfolgerung: Die Behandlungsnotwendigkeit neuropsychiatrischer Symptome bei Kindern mit BEPK ohne manifeste Anfälle wird derzeit kontrovers diskutiert.

Linguistic processing in idiopathic generalized epilepsy: an auditory event-related potential study

PURPOSE

Auditory processing of increasing acoustic and linguistic complexity was assessed in children with idiopathic generalized epilepsy (IGE) by using auditory event-related potentials (AERPs) as well as reaction time and performance accuracy.

METHODS

Twenty-four children with IGE [12 with generalized tonic-clonic seizures (GTCSs), and 12 with absence seizures (ASs)] with average intelligence and age-appropriate scholastic skills, uniformly medicated with valproic acid (VPA), and 20 healthy controls, performed oddball discrimination tasks that consisted of the following stimuli: (a) pure tones; (b) nonmeaningful monosyllables that differed by their phonetic features (i.e., phonetic stimuli); and (c) meaningful monosyllabic words from two semantic categories (i.e., semantic stimuli).

RESULTS

AERPs elicited by nonlinguistic stimuli were similar in healthy and epilepsy children, whereas those elicited by linguistic stimuli (i.e., phonetic and semantic) differed significantly in latency, amplitude, and scalp distribution. In children with GTCSs, phonetic and semantic processing were characterized by slower processing time, manifested by prolonged N2 and P3 latencies during phonetic processing, and prolongation of all AERPs latencies during semantic processing. In children with ASs, phonetic and semantic processing were characterized by increased allocation of attentional resources, manifested by enhanced N2 amplitudes. Semantic processing also was characterized by prolonged P3 latency. In both patient groups, processing of linguistic stimuli resulted in different patterns of brain-activity lateralization compared with that in healthy controls. Reaction time and performance accuracy did not differ among the study groups.

CONCLUSIONS

AERPs exposed linguistic-processing deficits related to seizure type in children with IGE. Neurologic follow-up should therefore include evaluation of linguistic functions, and remedial intervention should be provided, accordingly.

P300 (Latency) Event-Related Potential: An Accurate Predictor of Memory Impairment

To determine if P300 latency changes precede and correlate with memory and mental status, patients (N=1506 aged 20–100 years) who received medical and psychiatric diagnoses (from 1997 to 2002), were assessed for P300 (N=1496), WMS-III (N=694), and MMSE (N=456). Patient and control groups included, a) normal WMS-III on all 4 subscales (N=36), b) normal WMS-III and MMSE (N=189) with subjective memory/mental status complaints, and c) medical patients with normal WMS-III and no memory complaints (N=205), and d) P300 control group without medical, psychiatric or memory problems for ROC.

Patients with impaired/borderline memory had a prolonged P300 latency (P<0.02) compared to age matched non-impaired controls; in patients with normal WMS-III/MMSE, with subjective mild memory/mental status impairment, P300 latency was prolonged compared to controls (P=0.0004). The P300 latency increased by 0.72ms per year (P=7.9×10−65) and voltage decreased by 0.03dV per year (P=6.7×10−10), and both parameters were linearly correlated with the age of the subjects.

Male subjects had an average voltage of 6.1dV and female 6.8dV(P=0.00009). Statistically, prolonged latency began at age range 41–50 (P=0.0002); reduced P300 voltage began at age range 51–60 (P=0.003). WMS-III memory decline for all measures began in females at age range 61–70 (P value at least=0.02) and for males at age range 61–80 (P=0.02). Prolonged P300 latency (P≤0.0001) and memory impairment (at least <0.02) were greater for females than males. MMSE memory decline, male and female, began at age range 81–90 (P value of at least 0.00007).

In our logistic regression model P300 latency was more predictive of WMS-III impairment than MMSE >24. In patients whose WMS-III score is impaired ≤69, or borderline ≤79 (P at least =0.004), a P300 latency more prolonged than the norm (≥300 + 30 + Age) identifies these patients, whereas a MMSE >24 failed. With the ROC curve, we confirmed that P300 latency could accurately identify borderline/impaired memory.

Staggered spondaic word test in epileptic patients

CONTEXT

Auditory processing during childhood may be altered if there is any predisposing factor during the course of development. Neurological disorders are among the risk factors for auditory processing impairment. From this perspective, epileptic children present such a risk factor and could present auditory processing dysfunction.

OBJECTIVE

To evaluate central auditory processing in epileptic patients using the Staggered Spondaic Word Test (SSW) in order to verify whether these patients presented auditory disorders and whether the type of crisis partial or generalized played a role in the occurrence and type of disorder.

SETTING

Tertiary care hospital.

SAMPLE

Thirty-eight children and adolescents, ranging from 7 to 16 years old, with a diagnosis of epilepsy divided into two groups: 23 patients with partial crisis and 15 patients with generalized crisis.

MAIN MEASUREMENTS

Performance in the Staggered Spondaic Word Test versus epileptic crisis type (partial or generalized).

RESULTS

The majority of epileptic patients showed central auditory processing disorders. There were no differences in relation to crisis type. Both groups showed similar performance, although the results observed for these patients differ from what is obtained with normal populations. With regard to response bias, there were also no differences in performance between subjects with partial or generalized seizures. All possible disorders were found in both groups, without the prevalence of one specific disorder over the other.

CONCLUSIONS

This study revealed a high prevalence of disorders among epileptic patients in relation to processing partially overlapped verbal sounds in a dichotic paradigm.

Seizure frequency affects event-related potentials (P300) in epilepsy

To analyse the effect of epilepsy an P300 event-related potentials we studied 27 patients with idiopathic generalized epilepsy (IGE), 13 patients with temporal lobe epilepsy (TLE) and 60 normal controls. The prolongation of P300 latencies was highly cor related with increasing age in controls but not epileptic patients. The age-corrected P300 latency used in this study was actual P300 latency-predicted P300 latency (predicted P300 (msec)=306.20+0.79 age, P=0.001, R2=0.32). By using ANOVA analysis, the age-corrected latencies of P300 were significantly longer in TLE patients (19.72+/-47.82 msec, mean+/-SD) than in IGE patients (10.97+/-36.97 msec) and controls (0.23+/-20.28 msec). Likewise, significantly prolonged P300 latencies were seen in the epileptic patients with a seizure frequency more than 400 times (37.21+/-47.50 msec). The multivariate-adjusted odds ratio for those who had TLE was 10.97 (95% CI=3.99 - 30.14 ) in the prolonged latencies of P300 compared with that of IGE patients. The odds ratio of longer latencies of P300 was 7.43 (95% CI=2.75 - 20.08) among those who had a high seizure frequency (> or =400 times) compared with those who had a low seizure frequency. No interaction between TLE and high frequency of attacks was found. The age at onset of seizure and duration of illness was not associated with P300 latency prolongation. From the above results, we might infer that the seizure type of TLE and a high frequency of seizure are two major independent precipitate factors for abnormal latencies of P300 in the epileptic patients.

[Assessment through P300 of epileptic and non-epileptic children and school performance]

Learning disability is common in epileptic children. Epilepsy has been associated with disorders of intelligence. Cognitive potential (P300) is considered to be a clinical aid in the neurophysiological measurement of the cognitive process. Ninety-nine children between the ages of 10 years and 11 years and 11 months formed our sample, with good and poor school performance. Group I, non-epileptic, had 64 children of whom 32 had good and 32 poor school performance. Group II, epileptic, had 35 children, of whom 21 had good and 15 poor school performance. No significant difference in P300 latency was found between Groups I and II. When groups were stratified based on school performance, Group I children with good school performance had P300 latency of 336 ms, while the ones with poor school performance had latency of 382 ms. Group II children with good school performance had P300 latency of 363, while the ones with poor school performance had latency of 400 ms. There was a statistically significant difference between the non-epileptic children with good school performance and the children with poor school performance, epileptic or not.

Limbic P300s in temporal lobe epilepsy with and without Ammon's horn sclerosis

Limbic P300 potentials can be recorded within the mesial temporal lobes of patients with temporal lobe epilepsy (TLE). To delineate possible mechanisms of their generation and pathological alteration, we analysed limbic P300s in 55 TLE patients with and 29 without Ammon's horn sclerosis (AHS) and correlated their amplitudes with neuronal cell counts in 30 histopathological specimens. Limbic P300 amplitudes were reduced on the side of the epileptogenic focus only in patients with AHS. Moreover, in AHS patients, limbic P300 latencies were prolonged bilaterally; and in patients with left-sided AHS, amplitudes were reduced bilaterally. Both findings suggest bilateral functional deficits in TLE with unilateral AHS. Limbic P300 areas correlated significantly with neuronal densities of dentate gyrus granule cells but not hippocampal pyramidal cells in the CA1-4 (cornu ammonis) subfields. This finding points to a potential mechanism for the bilateral effects of unilateral AHS as both dentate gyri exhibit strong reciprocal contralateral connectivity.

Epileptic seizures and event-related potentials (P300) in childhood partial epilepsies

To clarify the relationship between cognitive function and clinical seizures, auditory event-related potentials (P300) were examined in 72 patients (185 trials) with partial epilepsy. Twenty-six patients (67 trials) had idiopathic partial epilepsies (IPE), and 46 (118 trials) symptomatic or cryptogenic partial epilepsies (SPE). In this study, to rule out the effects of epileptogenesis and other factors, we only examined patients with partial epilepsies undergoing carbamazepine (CBZ) monotherapy at doses of less than 16 mg/kg/day. The results were: 1) the mean age-corrected P300 latency in the patients with SPE (394 +/- 38 msec) was significantly prolonged compared with that in the patients with IPE (378 +/- 28). 2) The prolongation of the P300 latency had no relationship to the seizure frequency, seizure type or seizure duration. 3) In both epileptic groups, there was no significant correlation between the seizure-free period and the age-corrected P300 latency. Our results suggest that the effect of clinical seizures on the cognitive function may be relatively little, and that the cognitive dysfunction in partial epilepsies may mainly originate from epileptogenesis or other factors.

Event-related potentials (P300) and EEG activity in childhood partial epilepsy

To clarify the relationship between the cognitive function and EEG activity, auditory event-related potentials (P300) were examined in 72 patients with partial epilepsy. Twenty-six patients (67 trials) had idiopathic partial epilepsies (IPE), and 46 (118 trials) symptomatic or cryptogenic partial epilepsies (SPE). For this study, patients undergoing carbamazepine monotherapy with a dose of less than 16 mg/kg/day were selected to rule out the effects of anti-epileptic drugs. The results were as follows: (1) The P300 latency tended to be prolonged in association with the EEG slowing in both epileptic groups. (2) There was no clear relationship between the frequency of paroxysmal discharges and the P300 latency. (3) The P300 latency was slightly prolonged in the patients with temporal foci compared with that in ones with extra-temporal foci. (4) There was no significant relationship between the generalization of focal paroxysmal discharges and the P300 latency. These results suggested that the influence of EEG abnormalities (particularly paroxysmal discharges) on the P300 latency is relatively little, and the cognitive dysfunction in partial epilepsies mainly originates from other factors such as the epileptogenic lesion itself.