EEG Characteristics to Hyperventilation by Age and Sex in Patients With Various Neurological Disorders.

Introduction: Hyperventilation provocation test(s) (HPT) concomitant to electroencephalography (EEG) may detect hidden disorders of the nervous system (CNS). There are various types of abnormal EEG in responses to HPT that provoke different interpretations. However, it is not evident how the onset time of pathological EEG responses to hyperventilation (PERH) reveals dysfunction of the CNS in humans. It is also not clear if age and biological sex affect EEG characteristics in response to HPT. Our previous studies have revealed three types of PERH (disorganization of basic rhythm, paroxysmal discharges, epileptiform activity) concerning the manifestation time of first, second, and third minutes. The current work aims to classify the PERH with regards to age (3-6, 7-12, 13-18, 19-30, 31-50, 50 > year) and the biological sex of the patients. Methods: This study examined the EEG of 985 outpatients with various functional disorders of the CNS. The patients were assigned to one of three experimental groups based on the time occurrence of PERH in response to the HPT. Results: The disorganized basic EEG rhythm in the first, second, third minute of HPT was observed across all age and sex groups. All three types of PERH in the first minute were comparable for both sexes. However, some discrepancies between females compared to males were observed in the second and third minutes. All three types of PERH in the first and the second minutes were found only in women. The second type of PERH has revealed at the second minute of PHT in 13-18-year-old five girls. Conclusion: The three main types of PERH were detected at the first minute in all age groups and sex in patients with various CNS dysfunctions. It is diagnostically informative should be used as a marker during the monitoring of treatment. The specific activity of the brain's response to HPT depends on time, age, sex. The data indicate that taking into account sex differences and age during HPT leads to better results. The sensitivity and severity of the NS reaction toward hypocapnia, stress, and emotion increase in women. Therefore, in such cases should not be recommended to expand functional loads.

Atypical Processing of Novel Distracters in a Visual Oddball Task in Autism Spectrum Disorder.

Several studies have shown that children with autism spectrum disorder (ASD) show abnormalities in P3b to targets in standard oddball tasks. The present study employed a three-stimulus visual oddball task with novel distracters that analyzed event-related potentials (ERP) to both target and non-target items at frontal and parietal sites. The task tested the hypothesis that children with autism are abnormally orienting attention to distracters probably due to impaired habituation to novelty. We predicted a lower selectivity in early ERPs to target, frequent non-target, and rare distracters. We also expected delayed late ERPs in autism. The study enrolled 32 ASD and 24 typically developing (TD) children. Reaction time (RT) and accuracy were analyzed as behavioral measures, while ERPs were recorded with a dense-array EEG system. Children with ASD showed higher error rate without normative post-error RT slowing and had lower error-related negativity. Parietal P1, frontal N1, as well as P3a and P3b components were higher to novels in ASD. Augmented exogenous ERPs suggest low selectivity in pre-processing of stimuli resulting in their excessive processing at later stages. The results suggest an impaired habituation to unattended stimuli that incurs a high load at the later stages of perceptual and cognitive processing and response selection when novel distracter stimuli are differentiated from targets.

The investigation of EEG specificity in epileptic children during Depakine therapy.

BACKGROUND: Antiepileptic drug (AED) therapy in epileptic children can be optimized via an anticipation of AED efficacy during early stages of therapy. We hypothesize that the comprehensive electroencephalography (EEG) evaluation can determine AED efficacy in epileptic children. Thus, this study aimed to investigate the alteration of characteristics of interictal EEG during the AED therapy. METHODS: Forty-three children aged 3-9 were investigated. EEGs were recorded three times: prior to valproic acid-Depakine (Dep) monotherapy and twice under the Dep therapy (at three and six/eight months). Baseline EEG was analyzed for quantitative characteristics of interictal EEG, such as absolute values of the power (AVP) spectra and EEG topography/brain mapping. The study involved epileptiform EEG and clinical condition assessments. RESULTS: Dep decreased AVP spectra in a low-frequency range, suppressed spontaneous epileptic discharge, and spike-wave complex 3/s. Dep partially decreased spikes-polyspikes, sharp waves, and generalized paroxysmal bursts during functional trials. Dep did not diminish rhythmic monomorphic theta-waves (RMT) of tempo-parietal localization observed by brain mapping. The presence of RMT correlated with the reocurrence of seizures if Dep was withdrawn. CONCLUSIONS: The findings of this study suggest that the presence of RMT with tempo-parietal localization on the interictal EEG can anticipate reocurrence of seizures if Dep dose will be reduced or withdrawn. The efficacy of the AED therapy can be revealed via reduction of low-frequency waves and suppression of epileptiform EEG elements parallel to clinical improvement. Thus, optimal treatment strategies can be tailored based on the evaluation of background EEG characteristics using spectral analysis, EEG mapping, and the quantitative EEG approach.

The investigation of EEG specificity in epileptic children during Depakine therapy.

BACKGROUND: Antiepileptic drug (AED) therapy in epileptic children can be optimized via an anticipation of AED efficacy during early stages of therapy. We hypothesize that the comprehensive EEG evaluation can determine AED efficacy in epileptic children. Thus, this study aimed to investigate the alteration of characteristics of interictal EEG during AED therapy. METHODS: Forty-three children aged 3-9 were investigated. EEGs were recorded three times: prior to Valproic Acid-Depakin (Dep) monotherapy and twice under Dep therapy (at three and six/eight months). Baseline EEG was analyzed for quantitative characteristics of interictal EEG such as absolute values of the power (AVP) spectra and EEG topography/Brain Mapping. The study involved epileptiform EEG and clinical condition assessments. RESULTS: Dep decreased AVP spectra in a low-frequency range, suppressed spontaneous epileptic discharge, and spike-wave complex 3/s. Dep partially decreased spikes-polyspikes, sharp waves, and generalized paroxysmal bursts during functional trials. Dep did not diminish rhythmic monomorphic theta-waves (RMT) of tempo-parietal localization observed by Brain Mapping. The presence of RMT correlated with the reocurrence of seizures if Dep was withdrawn. CONCLUSIONS: The findings of this study suggest that the presence of RMT with tempo-parietal localization on the interictal EEG can anticipate reocurrence of seizures if Dep dose will be reduced or withdrawn. The efficacy of AED-therapy can be revealed via reduction of low-frequency waves and suppression of epileptiform EEG elements parallel to clinical improvement. Thus, optimal treatment strategies can be tailored based on the evaluation of background EEG characteristics using spectral analysis, EEG mapping and the quantitative EEG approach.