Variations in Theta/Beta Ratio and Cognitive Performance in Subpopulations of Subjects with ADHD Symptoms: Towards Neuropsychological Profiling for Patient Subgrouping.

ADHD is a neurodevelopmental disorder appearing in childhood but remaining in many cases in adults. There are both pharmacological and non-pharmacological approaches to treating ADHD, but they do not have the same efficacy in all subjects. Better knowledge of the neurophysiological basis of this disorder will allow for the design of more effective treatments. Studies performing qEEG analysis in children suggest the existence of subgroups of ADHD patients with different neurophysiological traits. There are fewer studies in adults, who might have undergone plastic changes allowing them to cope with ADHD symptoms along with brain maturation. Herein, we study cognitive performance and the theta/beta ratio in young adults with ADHD symptoms. We found that subjects with ADHD symptoms and low working memory performance (n = 30) present higher theta/beta ratios than controls (n = 40) at O2 and T6 in the eyes-closed condition, as well as a tendency toward a higher theta/beta ratio at O1 and Cz. Subjects with ADHD and high working memory performance (n = 50) do not differ from the controls in their theta/beta ratios at any derivation. Our results suggest that neuropsychological profiling could be useful for patient subgrouping. Further research will allow for the distinction of neuropsychological profiles and their neurophysiological correlates, leading to a better classification of ADHD subtypes, thus improving treatment selection.

Analysis of Clinical Characteristics, Background, and Paroxysmal Activity in EEG of Patients with Juvenile Myoclonic Epilepsy.

Juvenile myoclonic epilepsy (JME) appears in adolescence with myoclonic, absence, and generalized tonic clonic (GTC) seizures with paroxysmal activity of polyspike and slow wave (PSW), or spike and wave (SW) complexes in EEG. Our aim was to analyze the clinical characteristics, background EEG activity, and paroxysmal events in 41 patients with JME. Background EEG activity was analyzed with visual, quantitative (QEEG), and neurometric parameters. Our JME patients started with absence seizures at 11.4 ± 1.5 years old, myoclonic seizures at 13.6 ± 2.5 years, and GTC seizures at 15.1 ± 0.8 years. The seizures presented in awakening at 7:39 h with sleep deprivation, alcoholic beverage intake, and stress as the most frequent precipitant factors. Paroxysmal activity was of PSW and fast SW complexes with 40.5 ± 62.6 events/hour and a duration of 1.7 s. Right asymmetric paroxysmal activity was present in 68.3% of patients. Background EEG activity was abnormal in 31.7% of patients with visual analysis. With QEEG beta AP (absolute power) increase and AP delta decrease were the most frequent abnormalities found. Spectral analysis showed that 48.7% of patients had normal results, and 26.83% and 24.4% had higher and lower frequencies than 10.156 Hz, respectively. We concluded that, with visual analysis, background EEG activity was abnormal in a few patients and the abnormalities increased when QEEG was used.

Analysis of auditory function using brainstem auditory evoked potentials and auditory steady state responses in infants with perinatal brain injury.

Approximately 2-4 % of newborns with perinatal risk factors present hearing loss. The aim of this study was to analyse the auditory function in infants with perinatal brain injury (PBI). Brainstem auditory evoked potentials (BAEPs), auditory steady state responses (ASSRs), and tympanometry studies were carried out in 294 infants with PBI (586 ears, two infants had unilateral microtia-atresia). BAEPs were abnormal in 158 (27%) ears, ASSRs in 227 (39%), and tympanometry anomalies were present in 131 (22%) ears. When ASSR thresholds were compared with BAEPs, the assessment yielded 92% sensitivity and 68% specificity. When ASSR thresholds were compared with tympanometry results as an indicator of middle-ear pathology, the assessment gave 96% sensitivity and 77% specificity. When BAEP thresholds were compared with tympanometry results, sensitivity was 35% and specificity 95%. In conclusion, BAEPs are useful test for neonatal auditory screening; they identify with more accuracy sensorineural hearing losses. ASSRs are more pertinent for identifying conductive hearing loss associated with middle-ear pathology. The consistency and accuracy of these results could be considered in additional studies.

Motor potentials by magnetic stimulation in periventricular leukomalacia.

Periventricular leukomalacia is characterized by damage to the brain's white matter and impairments in motor function. Motor-evoked potentials by transcranial magnetic stimulation evaluate corticospinal tract function. We analyzed alterations in motor-evoked potentials in newborns with periventricular leukomalacia. Thirty infants (aged 4.37 +/- 1.1 months mean +/- S.D.) were divided into three groups: 10 healthy, and 10 with focal and 10 with diffuse periventricular leukomalacia. Potentials recorded in the right abductor pollicis brevis of healthy infants indicated a total motor conduction time of 26.3 +/- 2.4 ms, central motor conduction time of 17.0 +/- 2.6 ms, and central motor conduction velocity of 12.3 +/- 2.2 m/s. In the tibialis anterior, total motor conduction time was 27.4 +/- 2.6 ms; central motor conduction time was 16.7 +/- 2.8 ms, and central motor conduction velocity was 25.2 +/- 3.4 m/s. In the focal periventricular leukomalacia and diffuse periventricular leukomalacia groups, an increase in central motor conduction time and a decrease in central motor conduction velocity (P < 0.05) were evident, without differences between the two groups. Motor-evoked potentials in periventricular leukomalacia revealed an increase in central motor conduction time and a decrease in central motor conduction velocity, without differences between diffuse and focal types.

Analysis of background EEG activity in patients with juvenile myoclonic epilepsy.

PURPOSE: To analyze background EEG activity of patients with juvenile myoclonic epilepsy (JME) with and without antiepileptic drugs. METHODS: We studied the background EEG activity in 18 patients with JME. The qEEG analysis included absolute power (AP), relative power (RP) and mean frequency (MF) of delta, theta, alpha and beta bands. The Z scores were calculated by comparison with population parameters based on the age-dependent regression function. Seven patients were unmedicated (UM) and eleven medicated (M). RESULTS: The UM group presented 69 (4.32%) abnormal Z scores and 227 (9.05%) in the M group (P<0.001). In the UM group, AP delta abnormal Z scores were identified in frontotemporal and occipital leads. In AP alpha and beta bands an increase in Z scores was encountered in frontoparietal leads in three patients. In addition, in three patients, the AP theta Z scores were below -1.96 and distributed in all regions. In the M group, AP beta Z scores were above 1.96 in frontoparietal leads in 7 of 11 patients. The AP delta increased above 1.96 in frontotemporal and occipital leads in 6 patients of 11. The AP alpha showed an abnormal decrease in Z scores in 5 of 11 patients, whereas other 5 patients presented normal scores. The AP theta presented 7 normal Z scores out of 11; this band exhibited the lowest number of abnormalities of the 4. CONCLUSION: Patients with JME have an increase in AP delta, alpha and beta bands, which is more evident in frontoparietal regions.

Repetitive transcranial magnetic stimulation decreases the number of seizures in patients with focal neocortical epilepsy.

PURPOSE: To evaluate the number of seizures and interictal epileptiform discharges (IEDs) in patients with focal neocortical epilepsy before, during and after rTMS. METHODS: Twelve patients (seven men and five women, mean age 29.3+/-15.8 years) were studied. An open-label study with baseline (4 weeks), intervention (2 weeks) and follow-up (8 weeks) periods was carried out. Repetitive transcranial magnetic stimulation (rTMS) with 900 pulses, intensity of 120% motor resting threshold and 0.5Hz frequency was used. A 120 channel EEG was recorded; an electrical source analysis of IEDs with Variable Resolution Electromagnetic Tomography (VARETA) was performed. The number of seizures per week and IEDs per minute were measured and compared in the three periods. RESULTS: During the basal period the mean seizure frequency was 2.25 per week; in the intervention period it decreased to 0.66 per week (F=2.825; p=0.0036) which corresponds to a 71% reduction. In the follow-up period the mean frequency was 1.14 seizures per week, that is, a 50% reduction in the number of seizures. In the visual EEG analysis, the baseline IED frequency was 11.9+/-8.3events/min; it decreased to 9.3+/-7.9 during 2 weeks of rTMS with a further reduction to 8.2+/-6.6 in the follow-up period. These differences however were not significant (p=0.190). CONCLUSION: We conclude that 2 weeks of rTMS at 0.5Hz with a figure-of-eight coil placed over the epileptic focus, determined with VARETA, decreases the number of seizures in patients with focal epilepsy, without reduction in IEDs.

Effects of Dark Chocolate Intake on Brain Electrical Oscillations in Healthy People.

Dark chocolate is rich in flavonoids that can have effects on body composition and cognitive performance. The aim of this study was to analyze the effects of acute and subchronic chocolate intake on electrical brain oscillations. A study with 20 healthy subjects (mean age of 24.15 years) and a control group with five subjects (mean age of 23.2 years) was carried out. In the acute effect study, the subjects' intake was dark chocolate (103.72 mg/kg of body weight) rich in flavonoids and low in calories as in fasting. In the control group, the subjects intake was only low-calorie milk. For the subchronic effect, a daily dose of dark chocolate was given for eight days. The baseline electroencephalogram (EEG) was recorded before dark chocolate intake; at 30 min, the second EEG was carried out; on the eighth day, the third and fourth EEGs were performed before and after the last intake. In acute and subchronic intake, Delta Absolute Power (AP) decrease was observed in most brain regions (p < 0.05), except in the right fronto-centro-temporal regions. In the Theta band, there was a generalized decrease of the AP of predominance in the left fronto-centro-temporal regions. In contrast, an increase in AP was observed in the temporo-occipital regions in the Alpha band, and in the right temporal and parieto-occipital regions in the Beta band. The control group did not have significant changes in brain oscillations (p > 0.05). We concluded that acute and subchronic chocolate intake decreased the Delta and Theta AP and increased Alpha and Beta AP in most brain regions.

Development of Emotional Face Processing in Premature and Full-Term Infants.

The rate of premature births has increased in the past 2 decades. Ten percent of premature birth survivors develop motor impairment, but almost half exhibit later sensorial, cognitive, and emotional disabilities attributed to white matter injury and decreased volume of neuronal structures. The aim of this study was to test the hypothesis that premature and full-term infants differ in their development of emotional face processing. A comparative longitudinal study was conducted in premature and full-term infants at 4 and 8 months of age. The absolute power of the electroencephalogram was analyzed in both groups during 5 conditions of an emotional face processing task: positive, negative, neutral faces, non-face, and rest. Differences between the conditions of the task at 4 months were limited to rest versus non-rest comparisons in both groups. Eight-month-old term infants had increases ( P ≤ .05) in absolute power in the left occipital region at the frequency of 10.1 Hz and in the right occipital region at 3.5, 12.8, and 16.0 Hz when shown a positive face in comparison with a neutral face. They also showed increases in absolute power in the left occipital region at 1.9 Hz and in the right occipital region at 2.3 and 3.5 Hz with positive compared to non-face stimuli. In contrast, positive, negative, and neutral faces elicited the same responses in premature infants. In conclusion, our study provides electrophysiological evidence that emotional face processing develops differently in premature than in full-term infants, suggesting that premature birth alters mechanisms of brain development, such as the myelination process, and consequently affects complex cognitive functions.

Interictal regional cerebral blood flow and electrical source analysis in patients with complex partial seizures.

BACKGROUND: Recently, new methods of EEG source analysis have been developed. Dipole modeling and brain distributed source analysis localize in three-dimensions the origin of the electrical source of spikes registered in EEG. With single photon emission computed tomography (SPECT), it is possible to detect hypo- and hyperperfusion zones. Our aim in this study is to compare the regions where the electrical sources are detected, with the hypoperfusion regions in patients with complex partial seizures (CPS). METHODS: The concordance of localization with dipole analysis, brain distributed source analysis and regional cerebral flow blood in patients with CPS was studied. The hypoperfusion zones detected with interictal SPECT were compared with electrical sources localized with brain electric source analysis (BESA) and brain distributed source analysis with variable resolution electromagnetic tomography (VARETA). RESULTS: Hypoperfusion zones were found to localize with the origin of dipoles in 18 cases (90%), between lobes in 17 (85%) and between mesial or lateral regions in the temporal lobe in 12 cases (60%). With VARETA, agreement between side of hypoperfusion and electrical current source localization was found in 18/20 cases (90%), with lobes in 17 (85%) and with mesial or lateral regions of the temporal lobe only in 2 cases (10%). CONCLUSIONS: Hypoperfusion zones in interictal SPECT of patients with CPS are in agreement with the origin of dipoles in 85% of the cases, but in specifics zones of temporal lobe the agreement falls to 60%. The concordance of hypoperfusion zones was better with dipole analysis than with VARETA.

Effects of two different cycles of vagus nerve stimulation on interictal epileptiform discharges.

PURPOSE: To evaluate the effects of two cycles of vagus nerve stimulation (VNS), 30 s/5 min and 7 s/18 s on the interictal epileptiform discharges (IEDs). METHODS: Twenty patients were studied, 12 with generalized and 8 with partial seizures. An EEG of 120 channels was performed during 3 different conditions, each one lasting 30 min: basal state (BS), 30 s/5 min and 7 s/18 s VNS cycles. The number and duration of IEDs, time of IEDs in 1 min (TIEDM), IEDs/NIEDs index and the spike-free period (SFP) were determined. RESULTS: In 16 patients (80%), IED decreased during 30 s/5 min cycle (Group 1) and increased in 4 (Group 2). In Group 1, during the 30 s/5 min cycle the following variables showed a decrease: TIEDM, from 12.64 s to 9.62 s (p=0.001); IED/NIED index, from 0.53 to 0.31 (p=0.021), and IED duration, from 1.57 s to 1.05 s (p=0.015); whereas SFP duration increased from 20.06 s to 37.73 s (p=0.008). The decrease in IED was 41% and the increase in SFP 88%. In the 7s/18s cycle, only SFP had an increase, 72% (p<0.043). In Group 2, an increase in IED during both cycles was found. In the 30 s/5 min cycle, TIEDM increased 56% (p=0.042) and IED/NIED index 259% (p=0.040). CONCLUSION: VNS modifies IED in an acute form, in 80% of patients the 30 s/5 min cycle decreases the epileptiform activity and it is not modified by 7 s/18 s cycle. In 20% of patients, both cycles increase the epileptiform activity.

Auditory steady-state responses in infants with perinatal brain injury.

Infants with perinatal brain injury present impairments in motor, visual, auditory, and cognitive functions. The most useful methods for detecting auditory alterations are auditory brainstem responses and otoacoustic emissions. Auditory steady-state responses have been reported as a reliable and objective technique for evaluating the hearing threshold. Auditory brainstem responses and auditory steady-state responses were carried out in 53 infants with perinatal brain injury and abnormal neurologic findings. With auditory brainstem responses, 33 (62.26%) infants presented normal and 20 abnormal results; 8 (15.09%) exhibited mild alterations, 8 (15.09%) moderate, and 4 (7.54%) severe alterations. With auditory steady-state responses, 17 (32.0%) infants were normal and 36 (67.9%) had abnormal results. When auditory steady-state responses were compared with auditory brainstem responses gold standard, the assessment gave 100% sensitivity, 51.51% specificity, 55.55% positive predictive value, and 100% negative predictive value. Abnormalities were mild in 21 (39.6%) infants, moderate in 10 (18.9%), and 5 (9.4%) exhibited severe hearing loss. We conclude that hearing loss is a frequent abnormality in infants with perinatal brain injury, and auditory steady-state responses have a high sensitivity for detecting hearing impairment, which is more evident in mild hearing loss for specific frequencies.

Quantitative electroencephalography analysis in university students with hazardous alcohol consumption, but not alcohol dependence.

Hazardous alcohol consumption is a pattern of consumption that leads to a higher risk of harmful consequences either for the user or for others. This pattern of alcohol consumption has been linked to risky behaviors, accidents, and injuries. Individuals with hazardous alcohol consumption do not necessarily present alcohol dependence; thus, a study of particular neurophysiological correlates of this alcohol consumption pattern needs to be carried out in nondependent individuals. Here, we carried out a quantitative electroencephalography analysis in health sciences university students with hazardous alcohol consumption, but not alcohol dependence (HAC), and control participants without hazardous alcohol consumption or alcohol dependence (NHAC). We analyzed Absolute Power (AP), Relative Power (RP), and Mean Frequency (MF) for beta and theta frequency bands under both eyes closed and eyes open conditions. We found that participants in the HAC group presented higher beta AP at centroparietal region, as well as lower beta MF at frontal and centroparietal regions in the eyes closed condition. Interestingly, participants did not present any change in theta activity (AP, RP, or MF), whereas previous reports indicate an increase in theta AP in alcohol-dependent individuals. Our results partially resemble those found in alcohol-dependent individuals, although are not completely identical, suggesting a possible difference in the underlying neuronal mechanism behind alcohol dependence and hazardous alcohol consumption. Similarities could be explained considering that both hazardous alcohol consumption and alcohol dependence are manifestations of behavioral disinhibition.

Sources of EEG activity in learning disabled children.

The sources of different EEG frequencies were studied in 25 normal children and 46 learning disabled (not otherwise specified) children between 7 and 11 years old. The EEG sources were computed using Frequency-domain Variable Resolution Electromagnetic Tomography which produces a three dimensional picture of the currents at each EEG frequency. Significant differences between groups were observed. LD children showed more theta activity (3.5 to 7.02 Hz) in the frontal lobes and control children more alpha (9.75 to 12.87 Hz) in occipital areas. These results may support the maturational lag hypothesis, as the neurobiological cause of learning deficiencies not otherwise specified.

EEG source localization of interictal epileptiform activity in patients with partial complex epilepsy: comparison between dipole modeling and brain distributed source models.

The precision between dipole Brain Electric Source Analysis (BESA) and brain distributed Variable Resolution Electromagnetic Tomography (VARETA) models for the localization of brain sources of interictal epileptiform discharges in patients with partial complex epilepsy was compared. The localization of brain sources calculated with dipole analysis and variable resolution electromagnetic tomography in 20 interictal recordings was analyzed. The origin of the dipoles was temporal in 18 cases, frontal in 1 and occipital in another. One dipole was enough in 7 cases, whereas two dipoles were necessary in 13 cases. The localization of paroxysmal activity was the same with BESA and VARETA in 17 patients. BESA and VARETA are useful methods for EEG sources analysis; BESA has more precision for the localization of punctate epileptogenic regions, and VARETA provides more information concerning the extension of the epileptic zone.

Source analysis of polyspike and wave complexes in juvenile myoclonic epilepsy.

We applied dipole modeling and brain distributed source analysis to find current sources comprising spikes and slow waves of polyspike and wave complexes (PSWC) in patients with juvenile myoclonic epilepsy (JME). The dipoles were localized in frontal, parietal and temporal lobes. The frontal dipoles were clustered in the frontal medial gyrus and fronto-orbital region. A midsagittal frontal current source was observed using brain distributed source analysis in all patients. When the slow wave was analyzed, multiple sources in different cortical regions were detected using dipole modeling and brain distributed analysis. These results show pre-frontal medial current sources corresponding to spikes and many diffuse sources in cortical regions corresponding to wave components of PSWC in patients with JME.

[Risk factors for therapeutic noncompliance of patients with epilepsies]. / Factores de riesgo para incumplimiento terapéutico en pacientes con epilepsias.

Inadequate compliance is a major contributor to unsuccessful treatment in epilepsies. To establish risk factors associated with therapeutic non-compliance in patients with epilepsy, we carried out a case-control study, nested into a cohort, with thirteen factors possibly implicated in therapeutic non-compliance. The patient's general characteristics, the illness, and patient-practitioner relationship were studied. Patients were followed during 6 months; during this time, serum levels and pill counts were registered. Of 150 patients, 66 were non-compliers and 84 were compliers. Seven of thirteen factors were statistically different with an odds ratio greater than 3 (p < 0.05). However, after log-lineal regression analysis, only the total number of pills per day and the subject's intellectual level were significant. These two factors increase 3.66 times the risk of non-compliance. We conclude that epileptic patients with a low intellectual level and more than three prescribed pills per day have a 3.66 times greater risk of non-compliance to anti epileptic treatment.

Visual Evoked Potentials in Infants With Diffuse Periventricular Leukomalacia.

Periventricular leukomalacia (PVL) is characterized by necrosis of the cerebral white matter in the dorsolateral portions of the lateral ventricles. PVL causes motor, sensory, and cognitive deficits. The aim of this study was to analyze the conduction characteristics of the visual pathway in infants with diffuse PVL using visual evoked potentials (VEPs). We studied 11 healthy infants (mean age 3.3 ± 1.3 months) and 17 with diffuse PVL (mean age 2.9 ± 0.8 months and mean gestational age 31.9 ± 3.1 weeks). The N75, P100, and N135 wave latencies; the interwave N75-P100 and P100-N135 latencies; and the N75-P100 and P100-N135 amplitudes were measured in the occipital leads. VEPs were recorded during binocular stimulation at an angle of 120' from the Fz-Oz lead. Healthy children had mean N75, P100, and N135 wave latencies of 84.4 ± 5.8, 143.4 ± 30.6 and 222.9 ± 40.4 ms, respectively. The mean interwave N75-P100 and P100-N135 latencies were 59.0 ± 28.6 and 79.5 ± 13.6 ms, respectively. Compared with the healthy group, infants with PVL had longer N75 and N135 latencies at 92.3 ± 15.3 (P = .05) and 265.0 ms ± 60.3 (P = .05), respectively. The interwave latency P100-N135 (105.5 ± 29.1 ms; P = .017) was longer in children with PVL than in healthy infants. Infants with diffuse PVL had mild alterations in their N75, P100 and, particularly, their N135 latencies. These increases in P100-N135 interwave latencies could be because of damage to the geniculocortical pathways and V2-V3 networks.

El consumo de riesgo de alcohol y el riesgo de dependencia al alcohol presentan correlatos neurofisiológicos diferentes / Hazardous alcohol consumption and risk of alcohol dependence present different neurophysiological correlates

Introducción. El consumo de riesgo de alcohol (CRA) es un patrón de consumo que puede resultar dañino para el usuario o para los demás. Investigaciones previas sugieren que el CRA y la dependencia al alcohol comparten algunas características neurofisiológicas, pero difieren en otras. Objetivo. Determinar si el CRA y la dependencia al alcohol presentan correlatos neurofisiológicos diferentes. Sujetos y métodos. Doscientos sujetos realizaron la prueba de detección de CRA y riesgo de dependencia al alcohol (DEP). Se realizó un estudio de electroencefalografía cuantitativa para determinar la potencia absoluta, la potencia relativa y la frecuencia media de las bandas delta, theta, alfa y beta en sujetos con CRA, con DEP y controles. Resultados. Un total de 114 sujetos cumplió los criterios de inclusión. El grupo con CRA presentó mayor potencia absoluta, mayor potencia relativa y menor frecuencia media de la banda beta en comparación con los controles, mientras que el grupo con DEP presentó menor potencia absoluta de la banda delta que los controles. Conclusiones. El DEP y el CRA presentan diferentes correlatos neurofisiológicos. Hay un efecto importante de la gravedad de la dependencia al alcohol sobre sus correlatos neurofisiológicos. Nuestros resultados apoyan la existencia de dos tipos distintos de desinhibición conductual

Introduction. Hazardous alcohol consumption (HAC) is a pattern of alcohol use that may result in harm for the user and/or for those around them. Prior research has suggested that HAC and alcohol dependence share some neurophysiological features but differ in others. Aim. To determine whether HAC and alcohol dependence presented different neurophysiological correlates. Subjects and methods. Two hundred subjects were screened for HAC or alcohol dependence. A quantitative electroencephalographic analysis of delta, theta, alpha and beta absolute power, relative power and mean frequency in subjects with HAC but not alcohol dependence, subjects with risk of alcohol dependence and controls was performed. Results. One hundred and fourteen subjects met inclusion criteria. The HAC group presented with higher beta absolute power and relative power, as well as a lower beta mean frequency than the control group, while the group with risk of alcohol dependence presented lower delta absolute power than controls. Conclusions. HAC and risk of alcohol dependence present different neurophysiological correlates. There is an important effect of the severity of alcohol dependence on neurophysiological correlates of this condition. Our results support the existence of two different types of behavioral disinhibition

Visuospatial working memory in toddlers with a history of periventricular Leukomalacia: an EEG narrow-band power analysis.

BACKGROUND: Periventricular Leukomalacia (PVL) affects white matter, but grey matter injuries have also been reported, particularly in the dorsomedial nucleus and the cortex. Both structures have been related to working memory (WM) processes. The aim of this study was to compare behavioral performances and EEG power spectra during a visuospatial working memory task (VSWMT) of toddlers with a history of PVL and healthy toddlers. METHODOLOGY/PRINCIPAL FINDINGS: A prospective, comparative study of WM was conducted in toddlers with a history of PVL and healthy toddlers. The task responses and the EEG narrow-band power spectra during a VSWMT were compared in both groups. The EEG absolute power was analyzed during the following three conditions: baseline, attention and WM retention. The number of correct responses was higher in the healthy group (20.5 ± 5.0) compared to the PVL group (16.1 ± 3.9) (p = 0.04). The healthy group had absolute power EEG increases (p ≤ 0.05) during WM compared to the attention condition in the bilateral frontal and right temporal, parietal and occipital regions in frequencies ranging from 1.17 to 2.34 Hz and in the right temporal, parietal and occipital regions in frequencies ranging from 14.06 to 15.23 Hz. In contrast, the PVL group had absolute power increases (p ≤ 0.05) in the bilateral fronto-parietal, left central and occipital regions in frequencies that ranged from 1.17 to 3.52 Hz and in the bilateral frontal and right temporal regions in frequencies ranging from 9.37 to 19.14 Hz. CONCLUSIONS/SIGNIFICANCE: This study provides evidence that PVL toddlers have visuospatial WM deficits and a very different pattern of absolute power increases compared to a healthy group of toddlers, with greater absolute power in the low frequency range and widespread neuronal networks in the WM retention phase.

Effect of hearing aids on auditory function in infants with perinatal brain injury and severe hearing loss.

BACKGROUND: Approximately 2-4% of newborns with perinatal risk factors present with hearing loss. Our aim was to analyze the effect of hearing aid use on auditory function evaluated based on otoacoustic emissions (OAEs), auditory brain responses (ABRs) and auditory steady state responses (ASSRs) in infants with perinatal brain injury and profound hearing loss. METHODOLOGY/PRINCIPAL FINDINGS: A prospective, longitudinal study of auditory function in infants with profound hearing loss. Right side hearing before and after hearing aid use was compared with left side hearing (not stimulated and used as control). All infants were subjected to OAE, ABR and ASSR evaluations before and after hearing aid use. The average ABR threshold decreased from 90.0 to 80.0 dB (p = 0.003) after six months of hearing aid use. In the left ear, which was used as a control, the ABR threshold decreased from 94.6 to 87.6 dB, which was not significant (p>0.05). In addition, the ASSR threshold in the 4000-Hz frequency decreased from 89 dB to 72 dB (p = 0.013) after six months of right ear hearing aid use; the other frequencies in the right ear and all frequencies in the left ear did not show significant differences in any of the measured parameters (p>0.05). OAEs were absent in the baseline test and showed no changes after hearing aid use in the right ear (p>0.05). CONCLUSIONS/SIGNIFICANCE: This study provides evidence that early hearing aid use decreases the hearing threshold in ABR and ASSR assessments with no functional modifications in the auditory receptor, as evaluated by OAEs.