Spatial distribution of abnormal EEG activity in Creutzfeldt-Jakob disease.

OBJECTIVES: Electroencephalogram (EEG) pattern in Creutzfeldt-Jakob disease (CJD) is characterized by diffuse abnormal activity, although lateralization to one hemisphere has been described in the first stages of the disease. This study aimed to determine whether abnormal EEG activity predominantly occurs in anterior versus posterior brain regions. METHODS: As part of a prospective study, the demographics, clinical features and MRI findings of genetic E200K CJD patients were collected. EEG was performed and the recordings reviewed for the typical periodic sharp wave complex (PSWC) and non-specific slow activity. Data were analyzed using the qEEG tool, and the activity in anterior and posterior regions of the brain compared. RESULTS: Eleven genetic E200K CJD patients were included in the study (67% women). The average age was 59.1 ±â€¯8.4 SD years and the average disease duration was 2.4 ±â€¯2.1 months. EEG showed the classic PSWC pattern in 5/11 (45%) of the patients, and slow activity was seen in 9/11 (82%). EEG was normal in 2 patients. PSWC activity was diffuse in 2/5 patients and unilateral in 3/5 patients; slow activity was diffuse in 9 patients. Quantitative analysis of PSWC and slow activity showed no significant difference between anterior and posterior distribution. CONCLUSION: The abnormal EEG activity in CJD is diffuse with no clear spatial predominance in anterior or posterior brain regions.

The association of quantitative EEG and MRI in Creutzfeldt-Jakob Disease.

INTRODUCTION: Previous studies showed concordance between the typical Periodic Sharp Wave Complex (PSWC) activity in EEG of Creutzfeldt-Jakob Disease (CJD) patients and the MRI findings, while the concordance with slow activity in EEG is less established. The aim of this study was to better characterize the association between MRI findings and EEG changes using quantitative EEG (qEEG) analysis. METHODS: The demographics, clinical features, and the MRI findings of 12 familial E200K patients with CJD were gathered. EEG test was done and reviewed for the typical PSWC and for the non-specific slow activity. A possible association between the MRI findings and the EEG activity was examined. Then, EEG was analyzed using qEEG tool, and the association between the qEEG finding and the MRI was examined. RESULTS: Twelve patients were included in the study (67% women). Cortical MRI lesions finding were seen in 6/12 (50%) of the patients, and deep gray mater lesions were seen in 8/12 patients (67%). EEG showed the classic PSWC in 6/12 (50%) of the patients where slow activity was seen in 10/12 (83%). Slow activity and cortical MRI findings were associated in only 2/6 (33%) where deep gray matter findings and the slow activity had concordance of 4/8 (50%). qEEG analysis improved this concordance between slow activity and cortical findings to 3/6 (50%) and with the deep gray matter findings to 5/8 (63%). CONCLUSIONS: Quantitative EEG analysis modesty but not significantly, improves the association of EEG slow activity in familial E200K CJD patients with MRI findings.

Do Prenatal Corticosteroids Affect Brain Maturation of the Premature Infant? An Electroencephalography Study.

OBJECTIVE: To assess whether prenatal treatment with betamethasone has a significant influence on cerebral maturation indices as measured by electroencephalographic (EEG) indices. STUDY DESIGN: Infants born less than 35 weeks postmenstrual age (PMA) were prospectively enrolled if their mother received a full course of bethametasone prior to delivery (study group) or not (control group); infants with major intracranial abnormalities were excluded as well as those who were sedated or needed assisted ventilation. EEG was recorded during the first 10 days of life. Interburst intervals and maximal amplitudes of theta and delta bandwidths were calculated by a signal processing software. A multivariate general linear model was used to analyze the relationship between the 2 groups and the different electrophysiologic parameters, adjusting for PMA and mode of delivery. RESULTS: Thirty-eight infants were included in the study group and 36 in the control group. Univariate analysis demonstrated a negative correlation between PMA at test and EEG indices (interburst interval and delta and theta frequencies). Multivariate analysis demonstrated a less robust correlation of PMA and EEG indices and a positive correlation of prenatal betamethasone treatment with Theta frequencies. Repeating the data analysis separately for each study group, the above results remained significant mainly in the study group. CONCLUSIONS: Our findings suggest a possible stabilization effect of corticosteroids on the central nervous system and a possible delay of the maturation of cerebral activity related to prenatal corticosteroids use. These findings may relate to a better neurodevelopmental outcome of infants treated prenatally with corticosteroids.

Comparison of Amplitude-Integrated EEG and Conventional EEG in a Cohort of Premature Infants.

OBJECTIVE: To compare amplitude-integrated EEG (aEEG) and conventional EEG (EEG) activity in premature neonates. METHODS: Biweekly aEEG and EEG were simultaneously recorded in a cohort of infants born less than 34 weeks gestation. aEEG recordings were visually assessed for lower and upper border amplitude and bandwidth. EEG recordings were compressed for visual evaluation of continuity and assessed using a signal processing software for interburst intervals (IBI) and frequencies' amplitude. Ten-minute segments of aEEG and EEG indices were compared using regression analysis. RESULTS: A total of 189 recordings from 67 infants were made, from which 1697 aEEG/EEG pairs of 10-minute segments were assessed. Good concordance was found for visual assessment of continuity between the 2 methods. EEG IBI, alpha and theta frequencies' amplitudes were negatively correlated to the aEEG lower border while conceptional age (CA) was positively correlated to aEEG lower border ( P < .001). IBI and all frequencies' amplitude were positively correlated to the upper aEEG border ( P ≤ .001). CA was negatively correlated to aEEG span while IBI, alpha, beta, and theta frequencies' amplitude were positively correlated to the aEEG span. CONCLUSIONS: Important information is retained and integrated in the transformation of premature neonatal EEG to aEEG. SIGNIFICANCE: aEEG recordings in high-risk premature neonates reflect reliably EEG background information related to continuity and amplitude.

In and ex utero maturation of premature infants electroencephalographic indices.

OBJECTIVES: To assess the effect of extra uterine life on continuity and amplitude of premature infants' cerebral activity at different gestational age as compared to soon after birth. METHODS: Stable infants less than 34weeks gestation were prospectively recruited and EEG was recorded bi-weekly. Interburst interval and different wavelength amplitudes were digitally measured during the most discontinuous and most continuous (periods with longest and shortest interburst intervals, respectively) parts of the tracings. Linear regression was used to assess conceptional age prediction of interburst interval and wavelength amplitudes. Significant regression results were compared to the group of babies recorded close to delivery (newborn group). RESULTS: 144 EEG tracings from 59 infants were analyzed. Interburst intervals were significantly predicted by conceptional age in the newborn group only (p⩽0.002). Delta and theta amplitudes were significantly predicted by conceptional age in the newborn group and most of the other conceptional age groups (p<0.004). No significant differences were detected between the different groups. CONCLUSIONS: Our data reiterates the normal maturation of cerebral activity in the premature infant and support the concept of similar in and ex-utero maturation of cerebral activity in stable premature infants. SIGNIFICANCE: The effect of ex-utero maturation on the brain of stable premature infant is not readily discernible when using specific neonatal EEG indices.

Electroencephalographic activity in response to procedural pain in preterm infants born at 28 and 33 weeks gestational age.

OBJECTIVES: Preterm infants undergo frequent painful procedures in the neonatal intensive care unit. Electroencephalography (EEG) changes in reaction to invasive procedures have been reported in preterm and full-term neonates. Frontal EEG asymmetry as an index of emotion during tactile stimulation shows inconsistent findings in full-term infants, and has not been examined in the context of pain in preterm infants. Our aim was to examine whether heel lance for blood collection induces changes in right-left frontal asymmetry, suggesting negative emotional response, in preterm neonates at different gestational age (GA) at birth and different duration of stay in the neonatal intensive care unit. MATERIALS AND METHODS: Three groups of preterm infants were compared: set 1: group 1 (n=24), born and tested at 28 weeks GA; group 2 (n=22), born at 28 weeks GA and tested at 33 weeks; set 2: group 3 (n=25), born and tested at 33 weeks GA. EEG power was calculated for 30-second artifact-free periods, in standard frequency bandwidths, in 3 phases (baseline, up to 5 min after heel lance, 10 min after heel lance). RESULTS: No significant differences were found in right-left frontal asymmetry, or in ipsilateral or contralateral somatosensory response, across phases. In contrast, the Behavioral Indicators of Infant Pain scores changed across phase (P<0.0001). Infants in group 1 showed lower Behavioral Indicators of Infant Pain scores (P=0.039). DISCUSSION: There are technical challenges in recording EEG during procedures, as pain induces motor movements. More research is needed to determine the most sensitive approach to measure EEG signals within the context of pain in infancy.

Auditory conflict processing: behavioral and electrophysiologic manifestations of the stroop effect.

BACKGROUND: One of the most extensively studied phenomena in cognitive neuroscience is the Stroop effect. In an enormous corpus of literature, the Stroop task has been used to study conflict processing in the visual modality; however, scarce data exist in the auditory modality. PURPOSE: The main goal of the present study was to investigate auditory conflict processing by means of behavioral and electrophysiologic measures elicited during standard and reversed Stroop tasks. A secondary goal was to examine practice-related effects. RESEARCH DESIGN: Event-related potentials (ERPs) were recorded from 16 adults during tasks requiring classification of word meaning or speaker's gender while ignoring the irrelevant (congruent or incongruent) speaker's gender or word meaning, respectively. The behavioral measures, reaction time and performance accuracy, were simultaneously obtained. RESULTS: Results indicated (1) a significant behavioral Stroop effect manifested by prolonged reaction time and reduced performance accuracy. In contrast, ERP latencies were unaffected by the processing of incongruent versus congruent stimuli, supporting postperceptual conflict processing associated with response selection and execution; (2) reduced N1 amplitude while processing incongruent versus congruent stimuli; (3) similar behavioral Stroop effects in both tasks together with nonsignificant task by stimulus type (incongruent, congruent) interactions for N1 and N4; (4) significantly prolonged N4 and reaction time together with reduced N1 amplitude in the speaker's gender task (to both congruent and incongruent stimuli) compared to those found in the word meaning task; and (5) practice-related improvement in processing efficacy based on enhanced N1 amplitude, as well as shorter N4 and reaction time. CONCLUSIONS: Auditory conflict processing was predominantly postperceptual and was located at the response selection and execution stages. Alterations in the N1 component, however, provided support for an auditory conflict-processing "signature" at the initial stages of the arrival of information to the auditory cortex. The current data indicate that speaker's gender and word meaning intruded on one another in a similar fashion, supporting symmetry between standard and reversed auditory Stroop effects. Nonetheless, improved processing efficacy was evident while classifying word meaning. Utilization of the present methodology may prove advantageous for studying clinical populations exhibiting auditory and/or linguistic processing deficits.