bluuebunny/crossref_metadata_2025 huggingface dataset:
Trigeminal Somatosensory Evoked Potentials in Multiple Sclerosis: A Case Report
Authors: de Pablos C. , Agirre Z.
Published: February 2012

Somatosensory evoked potentials elicited by trigeminal nerve stimulation (TSEPs) allow the study of the trigeminal system, its peripheral to its central portion. As a routine clinical testing procedure, however, this method has not yet received greater attention and still has to wait to become a part of the diagnostic workup in multiple sclerosis (MS).

A patient diagnosed as MS was presented with selective involvement of the left trigeminal nerve. Neurophysiologically, the most prominent and persistent abnormalities were found in the TSEPs. The presumed diagnosis of MS was subsequently confirmed by MRI showing evidence of demyelinating disease.

There has been a scarcity of references on TSEP. Our study emphasizes its usefulness and a plea is being made for the inclusion of TSEP in protocols for the diagnostic workup in patients with MS.
EEG and the Variance of Motor Evoked Potential Amplitude
Authors: Zarkowski P. , Shin C.J. , Dang T. , Russo J. , Avery D.
Published: February 2012

The motor threshold is an important parameter in selecting the treatment intensity of patients undergoing transcranial magnetic stimulation. The large variance in magnitude of motor evoked responses has forced clinicians to perform many trials and average the results to find a repeatable value for motor threshold. Our objective is to investigate the source of the variance in amplitude.

Four clinically healthy adult males participated in an EEG and EMG during transcranial magnetic stimulation of the left motor cortex, 100% motor threshold, 0.1 Hz. Per our hypothesis, a significant negative correlation of .22 was found between the amplitude of the motor evoked potential and the power in the high alpha frequency band during the pre-stimulus period (p < .001). In addition, a significant positive correlation of. 17 was found between the motor evoked potential (MEP) amplitude and the gamma band (p < .001). The strongest correlation of .27 (p < .001) was found between the MEP amplitude and the ratio of the power in the low gamma to high alpha band. We conclude that the gamma to alpha power ratio may be a useful indicator of cortical excitability.
Memory Encoding and Retrieval in the Aging Brain
Authors: Friedman David , Nessler Doreen , Johnson Ray
Published: February 2012

Decline in episodic memory, the encoding and retrieval of autobiographical events, is a hallmark of normal cognitive aging. Although the primary causes of this decline remain elusive, event-related brain potential (ERP) studies have contributed to an understanding of age-related episodic memory failure. These data reveal that, although the retrieval-based episodic memory (EM) effect does not differ dramatically between young and older adults, the acquisition-related data suggest a decline in episodic encoding (i.e., semantic elaboration) with increasing age. We conclude that, at the current state of knowledge, encoding deficiencies are more important than retrieval deficits in understanding the causes of episodic memory decline in the older adult.
A Four-Step Approach for Developing Diagnostic Tests in Psychiatry
Authors: Boutros N. N. , Arfken C. L.
Published: February 2012

A four-step approach for developing diagnostic tests in psychiatry is proposed. Step 1, a biological variable is observed to be deviant from healthy controls in a particular patient population. The demonstration of test retest reliability of the finding using blinding procedures is an essential component of this early step. Step 2, is the demonstration of potential clinical usefulness of the specific finding. The two most important objectives at this step are demonstration of difference between the target patient population and appropriate control groups (these should be groups of patients with diagnoses that commonly appear on the differential diagnostic lists of the target disorder). Estimation of the effect size of the finding could be a reasonable guide to which findings should be considered good candidates for Step 3 studies. During Step 3 the performance characteristics of the test should be established. Specifically, the sensitivity, specificity, positive and negative predictive values of the biological marker should be examined. Step 4 defines the clinical application of the test and helps standardize the technique used in large and multicenter clinical trials. Multicenter trials should pave the road towards standardization of laboratory procedures used to conduct the test, as well as providing data regarding cost effectiveness and impact on both short-term and long-term clinical outcomes.
Rostral Anterior Cingulate Cortex Activity in the Theta Band Predicts Response to Antidepressive Medication
Authors: Mulert Christoph , Juckel Georg , Brunnmeier Michael , Karch Susanne , Leicht Gregor , Mergl Roland , Möller Hans-Jürgen , Hegerl Ulrich , Pogarell Oliver
Published: February 2012

During the last 10 years the knowledge about rostral anterior cingulate cortex (ACC) activity in major depression has substantially increased. Several groups have independently described a relationship between resting activity in this area and response to antidepressant treatment.

We have recently confirmed a relationship between resting activity of rostral ACC activity and response in a group of 20 patients with major depression using resting theta activity. In this earlier study regions of interest (ROI) were defined in order to establish regional specificity. Differences between responders and nonresponders were only found in the ACC-ROI, but not in the posterior cingulate region. We have now reanalyzed our data using a whole brain voxelwise approach, in order not to miss any other relevant functional differences. In addition to major differences between responders and nonresponders in the rostral ACC, we have identified a nearby region in the midline orbito-frontal region.
Reduced Axon Number in Juvenile Myoclonic Epilepsy Demonstrated by Motor Unit Number Estimation Analysis
Authors: Altindag Ebru , Baslo Baris , Baykan Betul , Bebek Nerses , Ertas Mustafa
Published: February 2012

Some conventional and quantitative EMG studies have already demonstrated a subclinical lower motor neuron involvement in juvenile myoclonic epilepsy (JME). Our aim was to investigate this subclinical involvement by using motor unit number estimation (MUNE) analysis with modified McComas' technique.

We enrolled 75 consecutive JME patients and 26 normal controls. All subjects underwent motor and sensory nerve conduction studies, concentric needle EMG and MUNE analysis of the M. abductor pollicis brevis (APB) and M. tibialis anterior (TA). The clinical and EEG findings were evaluated to correlate with MUNE values.

MUNE values of the APB (54±25) and TA (35±17) muscles were significantly lower in the JME group (p<0.001) when compared to the normal controls (109±24 and 80±26 for APB and TA muscles, respectively). Our findings show that anterior horn cells were subclinically affected in some JME patients, suggesting a shared background for both JME phenotype and grey matter disorganization in spinal cord.
The Prognostic Significance of Interictal Epileptiform Activity in Postoperative EEGs of Patients with Mesial Temporal Lobe Epilepsy
Authors: Kipervasser Svetlana , Nagar Sari , Chistik Vladimir , Kramer Uri , Fried Itzhak , Neufeld Miri Y.
Published: February 2012

It has not been established whether electroencephalography (EEG) is a contributing factor in predicting the outcome of surgery for epilepsy. We conducted a prospective study on 26 patients (M/F 14/12, age: 33 ± 7.5 years, range 19–48) with mesial temporal lobe epilepsy (MTLE) who were followed for 2 years after surgery and who underwent routine EEG recordings 5.6 ± 3 months (range 3–12) postoperatively. Interictal epileptiform activity (IEA) on the EEG was compared in 17 seizure-free patients to 9 patients with recurrent seizures. The two groups were similar in gender, age, febrile convulsions, trauma, family history, seizure frequency prior to surgery, epilepsy duration and number of antiepileptic drugs.

Following surgery, 17 study patients (65%) became seizure free; 9 (35%) had seizure recurrence. Postoperative EEG recordings showed IEA in 8/26 study patients (31%), 3 of whom were from the seizure-free group (3/17, 18%); 5 had seizure recurrence (5/9, 56%) (p=0.078). IEAs in postoperative EEGs were less frequently demonstrated in patients who were seizure free, but the presence of postoperative IEAs does not preclude successful surgical outcome.
Scalp-Recorded Auditory P300 Event-Related Potentials in New-Onset Untreated Temporal Lobe Epilepsy
Authors: Chayasirisobhon Wuttichai V. , Chayasirisobhon Sirichai , Tin Sue Nwe , Leu Ngoc , Tehrani Keo , McGuckin Jeanne S.
Published: February 2012

We studied scalp-recorded auditory event-related potentials (ERPs) of 30 untreated patients with new-onset temporal lobe epilepsy and 30 age-and sex-matched normal controls. This study was designed to eliminate the effects of intractability of seizures and chronic use of antiepileptic drugs on P300 auditory ERPs. There were no statistically significant differences in both latency and amplitude of P300 between the two groups. Similar methods were also used to analyze component latencies and amplitudes of ERPs of 9 patients who had hippocampal sclerosis with comparison to control subjects. There were no statistically significant differences between these two groups as well. Our study evidently does not support temporal lobe sources of P300 scalp-recorded auditory ERPs. We also conclude that the scalp-recorded auditory ERPs procedure is not a useful tool to evaluate temporal lobe epilepsy.
EEG Infraslow Activity in Absence and Partial Seizures
Authors: Rodin E. , Constantino T. , van Orman C. , House P.
Published: February 2012

It is currently assumed that for recording of infraslow activity (ISA) DC-coupled amplifiers are required. This report will demonstrate that this may not be the case and presents some data about its potential clinical usefulness.

Archived EEGs of 29 seizures from 6 children with absence attacks, accompanied by 3 Hz classical spike-wave discharges (SW), were compared with 20 partial seizures from 10 adult patients. The data from the children were acquired on a Bio-logic system, those from the adults on a Grass-Telefactor instrument. In the children the original 30-minute routine EEG was used while in the adults stored videomonitored data were excerpted to provide 20-minute segments which included the preictal, ictal and postictal state. All data were analyzed with the BESA software package. The seizures were evaluated separately on conventional filter settings, full band of 0.01-to the upper limit of the instrument, and 0.01–0.1 Hz (infraslow activity, ISA).

Filter settings of 0.01–0.1 Hz provided a better assessment of ISA than when the full band was evaluated. Absence seizures showed bilateral essentially synchronous ISA with a negative positive sequence in the frontal areas and opposite polarity in the posterior head regions.

It is concluded that ISA can be recovered from conventional EEG recordings and may be helpful not only in determining the area(s) of seizure onset but can also differentiate truly focal seizures from those where an additional generalized seizure tendency is present. This is likely to be important when epilepsy surgery is performed in absence of a demonstrable structural lesion

In partial seizures when seizure onset was clearly lateralizeable from conventional frequency settings ISA corresponded to that hemisphere, but the electrode position could be displaced to a neighboring one from the one which was maximally involved on conventional settings. Topographic analysis showed two types of ISA: one with focal spread only and the other where there was in addition an element of synchrony especially in the frontal areas.
Ictal Scalp EEG Findings in Patients with Mesial Temporal Lobe Epilepsy
Authors: Dericioglu Nese , Saygi Serap
Published: February 2012

The syndrome of mesial temporal lobe epilepsy (MTLE) is a well-defined clinical entity that responds to surgical treatment in a considerable number of patients. Although it has been subjected to intensive clinical research, few investigators have published the ictal scalp EEG findings and looked for specific features that might predict postoperative outcome. This study was designed to examine ictal scalp EEG characteristics in detail, in a group of patients with pathologically confirmed hippocampal sclerosis (HS).

Patients who underwent long-term video-EEG monitoring at our center during a 3-year period and were diagnosed to have MTLE and pathologically proven HS were included in this retrospective study. All ictal scalp EEGs were investigated in a common reference montage, paying attention to the localization, morphology and frequency of ictal discharges that were accepted to represent a specific phase if the findings were sustained for at least 3 seconds. Any significant change in localization, morphology or frequency of discharges was said to represent a different phase. The ictal EEG patterns in different phases were later compared among seizures of different patients. In addition, the ictal EEG characteristics of the patients in Group I (Engel's classification) were compared with the ictal EEG findings in patients who were included in another group. All the patients have been followed for more than 5 years.

Seventy-one ictal EEGs were investigated in 25 adult patients (11 M, 14 F). Onset patterns were lateralized in 81.7% and localized in 76% of the seizures. Thirteen different patterns of onset were detected, the most common of which was the cessation of interictal discharges (35.2%). The most common ictal pattern following the initial changes was ipsilateral temporal rhythmic theta-delta activity (85.2%) that occurred on the average 13.4 seconds after onset. Nonlocalized/lateralized seizure onset of all the seizures or bilateral independent onset was present in 75% of the patients in Groups II-III, whereas this ratio was 14.3% in the patients in Group I (p=0.031).

In conclusion, ictal scalp EEG in MTLE allows correct lateralization and localization in most of the seizures. Onset patterns may vary considerably; however, a later significant pattern consisting of rhythmic ipsilateral temporal build-up develops in the majority of seizures. Some ictal EEG characteristics may be related to post-operative outcome.
Visual Gamma Oscillations in Schizophrenia: Implications for Understanding Neural Circuitry Abnormalities
Authors: Spencer Kevin M.
Published: February 2012

Gamma oscillations may play an important role in the representation of information in the brain by synchronizing the firing of neurons in local and distributed neural circuits. The Bleulerian conceptualization of schizophrenia as “disintegration of thought and personality” suggests that neural mechanisms responsible for the integration of neural activity, such as gamma oscillations, might be particularly disrupted in this disorder. Here we review studies of gamma oscillations in healthy and schizophrenic individuals performing visual perception tasks. The findings suggest that schizophrenia is associated with a variety of abnormalities of visual gamma oscillations, which appear to be linked to core symptoms and cognitive deficits of schizophrenia. The relationships between these abnormalities and neural circuitry abnormalities in schizophrenia are discussed.
Corollary Discharge Dysfunction in Schizophrenia: Evidence for an Elemental Deficit
Authors: Mathalon Daniel H. , Ford Judith M.
Published: February 2012

Evidence is accumulating that schizophrenia is characterized by dysfunction of efference copy/corollary discharge mechanisms that normally allow us to unconsciously recognize and disregard sensations resulting from our own actions. This dysfunction may give rise to subtle but pervasive sensory/perceptual aberrations in schizophrenic patients, altering their experience of their own overt and covert actions, as well as their interactions with the environment. It may also contribute to symptoms such as hallucinations and delusions, and may disrupt the motivation to engage with people and in activities.

We developed neurophysiological paradigms to study motor-sensory feed-forward processes, or efference copy/corollary discharge mechanisms, in the speech-auditory system, and showed these processes to be deficient in chronic schizophrenia. Specifically, we observed neural responses during talking that made evident the suppressive consequences of a successful corollary discharge mechanism. We also observed synchronous neural activity preceding talking that we believe reflects the efference copy in action. Recently, we extended this neurophysiological research to the somatosensory system, again finding evidence of deficient motor-sensory feed-forward processes in schizophrenia. If dysfunction of this elemental mechanism is reliable, valid, and not the result of antipsychotic medications, it might represent a major new class of electrophysiological measures sensitive to a fundamental and ubiquitous pathophysiological process in schizophrenia.
Prefrontal EEG Asymmetry as a Potential Biomarker of Antidepressant Treatment Response with Transcranial Magnetic Stimulation (TMS): A Case Series
Authors: Funk Agnes P. , George Mark S.
Published: February 2012

We review studies that have used EEG as a response biomarker in depression, and then present preliminary EEG change data from an ongoing TMS depression treatment trial. These data in 4 depressed subjects over 3 weeks of treatment suggest but do not prove that there may be asymmetry changes that occur both within a daily TMS session and over the course of several weeks that may be associated with antidepressant response. EEG shows potential as a biomarker of response for depression treatments, particularly the brain stimulation devices, which, unlike medications, can focally interact with neural tissue in specific frequency patterns.
Cortical Functional Anatomy of Voluntary Saccades in Parkinson Disease
Authors: Rieger Jochem W. , Kim Aleander , Argyelan Miklos , Farber Mark , Glazman Sofya , Liebeskind Marc , Meyer Thomas , Bodis-Wollner Ivan
Published: February 2012

In Parkinson Disease (PD) several aspects of saccades are affected. The saccade-generating brainstem neurons are spared, however, the signals they receive may be flawed. In particular voluntary saccades suffer, but the functional anatomy of the impairment of saccade-related cortical control is unknown.

We measured blood-oxygenation-level-dependent (BOLD) activation with functional Magnetic Resonance Imaging (fMRI) while healthy participants and patients with PD performed horizontal voluntary saccades between peripheral visual targets or fixated centrally. We compared saccade-related BOLD-activity vs. fixation in patients with PD and in healthy controls and correlated perisaccadic BOLD-activity in PD patients with saccade kinetics (multistep saccades). Saccade related BOLD-activation was found in both PD and healthy participants in the superior parietal cortex (PEF) and the occipital cortex. Our results suggest remarkable hypoactivity of the frontal and supplementary eye fields (FEF and SEF) in PD patients. On the other hand, PD patients showed a statistically more reliable BOLD modulation than healthy participants in the posterior cingulate gyrus, the parahippocampal gyrus, inferior parietal lobule, precuneus and in the middle temporal gyrus.

Given abnormal frontal and normal PEF responses, our results suggest that in PD a frontal cortical circuitry, known to be associated with saccade planning, selection, and predicting a metric error of the saccade, is deficient.
Changes in Brain Function during Administration of Venlafaxine or Placebo to Normal Subjects
Authors: Leuchter Andrew F. , Cook Ian A. , DeBrota David J. , Hunter Aimee M. , Potter William Z. , McGrouther Caroline C. , Morgan Melinda L. , Abrams Michelle , Siegman Barbara
Published: February 2012

Previous research has demonstrated neurophysiologic effects of antidepressants in depressed subjects. We evaluated neurophysiologic effects of venlafaxine in normal subjects.

Healthy adults (n=32) received a 1-week placebo lead-in followed by 4 weeks randomized double-blind treatment with venlafaxine IR 150 mg. (n = 17) or placebo (n = 15). Brain function was examined using quantitative electroencephalographic (QEEG) power and theta cordance.

Normal subjects receiving venlafaxine showed a decrease in theta-band cordance in the midline-and-right-frontal (MRF) region at 48 hours and at 1 week after randomization. Decreases in relative power also were seen in the MRF region; there were no significant changes in absolute power. These changes were significantly different from those in subjects receiving placebo. Changes in MRF cordance accurately identified treatment condition at 48 hours in 81.3% of subjects, and relative power from this region identified 60.7% of subjects.

In conclusion, cordance may detect the pharmacological effects of antidepressant medication in normal subjects. Future studies should examine other classes of medication, as well as antidepressants with other mechanisms of action, to determine if cordance detects antidepressant medication effects in general in normal subjects.
Is the Decreased Longevity among Left-Handers Related to an Increase in Heart Disease?
Authors: Hughes John R. , Dorner Elizabeth , Wind Michele
Published: February 2012

Many studies report that left-handers have a shorter longevity than right-handers, and the present study may provide a possible explanation for that finding. In a Cardiac Rehabilitation Unit for the elderly with a mean age of 75.2 years the prevalence of left-handers was 16.7%. This latter value was significantly different (p = 0.0028) from the 6.7% in controls of similar age. These data suggest that heart disease may be one reason for a reduced longevity among lefthanders. Left-handers use the right hemisphere for movement, and unilateral activation of that hemisphere in the form of EEG desynchronization and deactivation in the form of EEG slow waves are both related to cardiac abnormalities.
Hippocampic Theta Rhythm
Authors: Niedermeyer E.
Published: February 2012

A prominent theta rhythm dominates the EEG of rodents such as rabbits, rats and mice. This rhythmical activity is preponderant in the hippocampus and may become quite widespread; it is usually arousal-related and generated by cholinergic mechanisms. This pattern has been intensively studied by experimental neuroscientists but is rather little known in circles of clinical electroencephalographers.

Hippocampic theta rhythm is also found in canines and felines but at a clearly lesser degree and is practically absent in monkeys and humans. An olfactory memory of the macrosmatic rodents helps us understand “the world in which they live,” their EEG patterns being an objective sign of their neuropsychology.
EEG Findings in an Eleven-Year-Old Girl with Mercury Intoxication
Authors: Setz J. M. , van der Linde A. A. A. , Gerrits G. P. J. M. , Meulstee J.
Published: February 2012

An 11-year-old female was seen at our outpatient clinic with a broad variety of symptoms that were due to elemental mercury intoxication. Electromyography and sequential electroencephalography findings obtained at days 2, 36, 88 and 148 are described. The patient was treated with chelation therapy during which she clinically improved considerably. A profound decrease in urinary mercury concentration occurred as well as normalization of the electroencephalogram.
Substance Use Underlying Behavior: Investigation of Theta and High Frequency Oscillations in Emotionally Relevant Situations
Authors: Knyazev G.G. , Slobodskoy-Plusnin J.Y.
Published: February 2012

High sensitivity of the Behavioral Approach System (BAS) was shown to be one of the strongest predictors of substance use (SU). It was hypothesized that individuals with high BAS sensitivity would experience higher emotional arousal in the reward expectancy situation and lower in the punishment expectancy situation than individuals with low BAS activity. The level of emotional arousal indicated by theta spectral power, and general cortical excitability indicated by high frequency oscillations (HFO), were measured in a sample of young people who filled out Carver and White's Behavioral Inhibition System/Behavioral Approach System (BIS/BAS) scales. Frontal theta and HFO increased in high BAS scorers during expectation of reward and decreased during expectation of punishment. In low BAS scorers spectral powers of theta and HFO increased, contrary to those for the punishment cue, and decreased for reward cue. Theta-gamma coupling increased in high Drive scorers (those above the median) in reward and in low Drive scorers (those who appeared to be below the median split on this scale) in punishment situation.
QEEG Guided Neurofeedback Therapy in Personality Disorders: 13 Case Studies
Authors: Surmeli Tanju , Ertem Ayben
Published: February 2012

According to DSM-IV, personality disorder constitutes a class only when personality traits are inflexible and maladaptive and cause either significant functional impairment or subjective distress. Classical treatment of choice for personality disorders has been psychotherapy and/or psychopharmacotherapy. Our study is to determine if subjects with antisocial personality disorders will benefit from quantitative EEG (qEEG) guided neurofeedback treatment.

Thirteen subjects (9 male, 4 female) ranged in age from 19 to 48 years. All the subjects were free of medications and illicit drugs. We excluded subjects with other mental disorders by clinical assessment. Psychotherapy or psychopharmacotherapy or any other treatment model was not introduced to any of the subjects during or after neurofeedback treatment. For the subject who did not respond to neurofeedback, training was applied with 38 sessions of LORETA neurofeedback training without success. Evaluation measures included qEEG analysis with Nx Link data base, MMPI, T.O.V.A tests and SA-45 questionaries at baseline, and at the end of neurofeedback treatment. Lexicor qEEG signals were sampled at 128 Hz with 30 minutes-neurofeedback sessions completed between 80–120 sessions depending on the case, by Biolex neurofeedback system. At baseline and after every 20 sessions, patients were recorded with webcam during the interview.

Twelve out of 13 subjects who received 80–120 sessions of neurofeedback training showed significant improvement based on SA-45 questionaries, MMPI, T.O.V.A. and qEEG/Nx Link data base (Neurometric analysis) results, and interviewing by parent/family members. Neurofeedback can change the view of psychiatrists and psychologists in the future regarding the treatment of personality disorders. This study provides the first evidence for positive effects of neurofeedback treatment in antisocial personality disorders. Further study with controls is warranted.
Design and Validation of an Improved Nonferrous Smoking Device for Self-Administration of Smoked Drugs with Concurrent fMRI Neuroimaging
Authors: Lindsey K.P. , Lukas S.E. , MacLean R.R. , Ryan E.T. , Reed K.R. , de Frederick B.B.
Published: February 2012

Several popularly abused drugs, such as nicotine (tobacco) and THC (Δ9-tetrahydrocannabinol) (marihuana) are commonly selfadministered by the smoked route. Although the neuronal substrates mediating the effect of smoked drugs are of interest, studies of their acute actions in living human brain has been difficult due to the unique constraints imposed by neuroimaging equipment and scanning environments. We have previously reported a device for the self-administration of smoked drugs with concurrent blood oxygen level dependent (BOLD) fMRI imaging. Here we report improvements to the device which result in improved drug delivery to the smoker. Gas chromatography/mass spectrometry (GCMS) analysis of nicotine recovered from filter extracts revealed that the amount of nicotine delivered to subjects smoking with our original device was reduced by approximately 44% compared to nicotine delivered by cigarettes smoked normally. Improvements were made to the smoke delivery component of our apparatus in an attempt to improve drug delivery, while not interfering with collection of MRI data.

Nicotine plasma levels in 9 subjects smoking both with and without the improved smoking device in the laboratory were not significantly different. Similarly, the device produced no significant difference in either ratings of the subjective effects of nicotine, or changes in cardiovascular parameters in this experiment. The improved device does not interfere with typical drug effects produced by normal smoking. Phantom scans revealed that BOLD signal was not found to be altered by the (inbore) installation and operation of the improved device. Preliminary data analysis of smoking induced changes in the BOLD response to visual stimulation suggest that this response is not affected by the improved device, the act of smoking, air puffing, nicotine, or other components of cigarette smoke. The improved device does not interfere with the collection of MRI neuroimaging data. Use of this device will facilitate investigations of the acute neuronal effects of smoked drugs.
The Influence of Substance Use on Adolescent Brain Development
Authors: Squeglia L.M. , Jacobus J. , Tapert S.F.
Published: February 2012

Adolescence is a unique period in neurodevelopment. Alcohol and marijuana use are common. Recent research has indicated that adolescent substance users show abnormalities on measures of brain functioning, which is linked to changes in neurocognition over time. Abnormalities have been seen in brain structure volume, white matter quality, and activation to cognitive tasks, even in youth with as little as 1–2 years of heavy drinking and consumption levels of 20 drinks per month, especially if >4–5 drinks are consumed on a single occasion. Heavy marijuana users show some subtle anomalies too, but generally not the same degree of divergence from demographically similar non-using adolescents. This article reviews the extant literature on neurocognition, brain structure, and brain function in adolescent substance users with an emphasis on the most commonly used substances, and in the context of ongoing neuromaturational processes. Methodological and treatment implications are provided.
EEG and Cerebral Blood Flow Velocity Abnormalities in Chronic Cocaine Users
Authors: Copersino Marc L. , Herning Ronald I. , Better Warren , Cadet Jean-Lud , Gorelick David A.
Published: February 2012

EEG and cerebral blood flow abnormalities have been documented in chronic cocaine abusers. To identify possible relationships between EEG and blood flow changes and their relationship to the intensity of cocaine use, we recorded the resting eyes-closed EEG and anterior (ACA) and middle (MCA) cerebral artery blood flow velocity during systole (VS) and diastole (VD) by transcranial Doppler (TCD) sonography of 99 (76 male, 23 female; mean [SD] age 34.3 [5.2] years, 8.6 [5.5] years of cocaine use, 17.8 [7.7] days of cocaine use in month prior to screening) cocaine users within 5 days of admission to a closed research unit. Forty-two non-drug-using, age-matched control subjects (22 male, 20 female) were tested as outpatients. A 3-minute period of resting EEG was recorded from 16 standard scalp electrodes. Artifact-free EEG was converted to six frequency bands (delta, theta, alpha1, alpha2, beta1 and beta2) using a Fast Fourier Transform. Pulsatility index (PI) was calculated as a measure of small vessel resistance.

Cocaine users had decreased VD and increased PI in the MCA, with no difference in VS, and reduced EEG theta, beta1 and beta2 absolute power in posterior brain regions. Recent cocaine use was positively associated with MCA PI (r = 0.27, p < 0.001) and negatively associated with low frequency EEG power (delta power: r = −0.25, p < 0.002; theta power: r = −0.29, p< 0.001). EEG beta1 (r = −0.211, p < 0.05) and beta2 (r = −0.176, p < 0.05) power measures were correlated with PI. These observations suggest that EEG and TCD changes reflect related physiological processes during early cocaine abstinence.
QEEG Studies in the Assessment and Treatment of Childhood Disorders
Authors: Cantor David S. , Chabot Robert
Published: February 2012

Quantifying EEG measures across age allows the ability to establish parameters of normalcy at any age which can be used as a reference when children exhibit developmental delays in their abilities and/or other atypical and maladaptive behaviors. A review of the current literature on the utilization of QEEG methods to serve as an aid for identifying these children as distinctively different from normal, and in some cases as distinctive from other clinical considerations has been shown to provide a sufficient sensitivity and specificity worthy of consideration as a diagnostic aid in evaluating clinical deviations in development. Furthermore, these same QEEG measures can provide a means of establishing treatment efficacy for the evident brain dysfunctions underlying these childhood disorders.
Evidence-Based Evaluation of Diagnostic Accuracy of Resting EEG in Dementia and Mild Cognitive Impairment
Authors: Jelic Vesna , Kowalski Jan
Published: February 2012

Cognitive impairment is the most frequent chronic condition in the elderly, and dementia is the most disabling form of cognitive impairment in elderly. In the absence of specific and reliable markers of etiologically different dementia syndromes and their preclinical stages, diagnosis in living patients is probabilistic and based on standardized clinical diagnostic criteria. There is still not enough information on the validity of the EEG method in dementia work-up, and an updated evidence-based consensus on appropriateness of this method in the initial evaluation of patients with suspected cognitive disorder and dementia is missing.

Using an evidence-based technique we searched for articles on diagnostic accuracy of spontaneous EEG in dementia disorders published from 1980 until June 2008. Inclusion criteria were: original article published in English with 10 or more subjects per diagnostic group, diagnosed according to the established consensus clinical diagnostic criteria used as a “gold standard.” In addition, it should have been possible to calculate from the reported results indexes of diagnostic test accuracy: sensitivity, specificity, likelihood ratios and diagnostic odds ratios.

Forty-six articles were retrieved that satisfied eligibility criteria. Thirty-four (74%) studies employed case-control design where study population was recruited from consecutive patients at specialist clinic settings, 12 (26%) were prospective in terms of reported clinical follow-up of study population. Four (9%) studies used population-based samples and 5 (11%) studies stated in methods the recruitment procedures for patients and healthy subjects. Number of patients included in diagnostic groups and healthy subjects varied in included studies between 10 and 180 and 10 and 171, respectively. Figures on sensitivity and specificity across the studies varied widely. Positive likelihood ratio in studies reporting classification accuracies between Alzheimer's disease and controls ranged between 2.3 and 38.5, and diagnostic odds ratios consequently showed large variations between 7 and 219.

In conclusion, despite the wealth of published research and reported high indexes of diagnostic accuracy of EEG, and qEEG in particular, in individual studies, evidence of diagnostic utility of resting EEG in dementia and mild cognitive impairment (MCI) is still not sufficient to establish this method for the initial evaluation of subjects with cognitive impairment in the routine clinical practice. Joint effort of preferably multicenter studies using uniform standards should develop optimized methods, investigate added diagnostic value of EEG in clinically established dementia diagnosis and predictive utility of EEG in MCI and questionable dementia.
Meta-Analysis of EEG Biofeedback in Treating Epilepsy
Authors: Tan Gabriel , Thornby John , Hammond D. Corydon , Strehl Ute , Canady Brittany , Arnemann Kelly , Kaiser David A.
Published: February 2012

About one third of patients with epilepsy do not benefit from medical treatment. For these patients electroencephalographic (EEG) biofeedback is a viable alternative. EEG biofeedback, or neurofeedback, normalizes or enhances EEG activity by means of operant conditioning. While dozens of scientific reports have been published on neurofeedback for seizure disorder, most have been case series with too few subjects to establish efficacy. The purpose of this paper is to meta-analyze existing research on neurofeedback and epilepsy.

We analyzed every EEG biofeedback study indexed in MedLine, PsychInfo, and PsychLit databases between 1970 and 2005 on epilepsy that provided seizure frequency change in response to feedback. Sixty-three studies have been published, 10 of which provided enough outcome information to be included in a meta-analysis. All studies consisted of patients whose seizures were not controlled by medical therapies, which is a very important factor to keep in mind when interpreting the results. Nine of 10 studies reinforced sensorimotor rhythms (SMR) while 1 study trained slow cortical potentials (SCP). All studies reported an overall mean decreased seizure incidence following treatment and 64 out of 87 patients (74%) reported fewer weekly seizures in response to EEG biofeedback. Treatment effect was mean log (post/pre) where pre and post represent number of seizures per week prior to treatment and at final evaluation, respectively. Due to prevalence of small groups, Hedges's g was computed for effect size. As sample heterogeneity was possible (Q test, p=.18), random effects were assumed and the effect of intervention was −0.233, SE= 0.057, z [Formula: see text] −4.11, p<.001.

Based on this meta-analysis, EEG operant conditioning was found to produce a significant reduction on seizure frequency. This finding is especially noteworthy given the patient group, individuals who had been unable to control their seizures with medical treatment.
Changes in Midlatency Auditory Evoked Potentials following Two Yoga-Based Relaxation Techniques
Authors: Subramanya Pailoor , Telles Shirley
Published: February 2012

Practicing meditation while focusing on a sound or a symbol influenced midlatency auditory evoked potentials (MLAEPs). Cyclic meditation (CM) is a technique combining yoga postures with meditation while supine, which has influenced the P300 event-related potential. The effects of CM on MLAEPs have not been previously studied.

The MLAEPs were studied before and after the practice of CM compared to an equal duration of supine rest (SR) in 47 male volunteers (group mean age 26.5 ± 4.4 years), recorded from the vertex referenced to linked earlobes. The sessions were one day apart and subjects were randomly assigned to each session.

The Pa wave peak latency and Nb wave peak latency significantly increased following CM compared to before CM (repeated measures ANOVA, post-hoc analysis with least significant difference, p<0.05). There was a significant increase in the peak amplitude of the Nb wave ( p<0.05) compared to before CM. Post SR there was a significant increase in the peak latency of the Na wave ( p<0.05) compared to before SR.

In conclusion following CM the latencies of neural generators corresponding to cortical areas is prolonged, whereas following SR a similar change occurs at mesencephalic-diencephalic levels.
Benign Childhood Epilepsy with Centrotemporal Spikes: An Ictal EEG
Authors: Tedrus G.M.A.S. , Fonseca L.C. , Castilho D.P. , Bossoni A.S.
Published: February 2012

Benign childhood epilepsy with centrotemporal spikes (BECTS) is common during childhood, but there are few reports in the literature recording the EEG during a seizure.

We studied an 8-year-old boy with oropharyngeal seizures during wakefulness and sleep. Both his neuropsychomotor development and neurological examination were normal. While awake, the subjects's electroencephalogram (EEG) showed normal background activity and epileptiform activity characterized by spikes in the temporal regions (mid and anterior), central region of the right cerebral hemisphere and in the median central and parietal regions. During sleep, his EEG recorded an epileptic seizure that lasted 46 seconds. In the initial phase, the EEG showed an increase in the number of spikes with higher potential in the median central and parietal regions, followed by slow waves associated with the increase in slow waves in the right hemisphere. This was followed by a brief decrease in amplitude of the background activity, and then by rhythmic, diffuse discharges predominantly in the right centrotemporal region, of sharp waves at 12–13 Hz, with increasing potential. Slow waves of high amplitude then occurred for 5 seconds, and finally very high potential spikes reappeared in the central and temporal regions of the right cerebral hemisphere with normalization of the background activity. During these critical phases of the EEG, clonic lip movements and pouting could be observed with the mouth locked shut, associated with “throat noises,” but there were no other motor manifestations. The child did not wake up during the seizure and there were no postictal signs or symptoms. Although there are some aspects in common in recordings of BECTS seizures, such as a reduction in amplitude followed by rhythmic discharges of increasing amplitude, differences exist that possibly correspond to the diverse characteristics of the electrical generators.
Wavelet-Synchronization Methodology: A New Approach for EEG-Based Diagnosis of ADHD
Authors: Ahmadlou Mehran , Adeli Hojjat
Published: February 2012

A multi-paradigm methodology is presented for electroencephalogram (EEG) based diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD) through adroit integration of nonlinear science; wavelets, a signal processing technique; and neural networks, a pattern recognition technique. The selected nonlinear features are generalized synchronizations known as synchronization likelihoods (SL), both among all electrodes and among electrode pairs. The methodology consists of three parts: first detecting the more synchronized loci (group 1) and loci with more discriminative deficit connections (group 2). Using SLs among all electrodes, discriminative SLs in certain sub-bands are extracted. In part two, SLs are computed, not among all electrodes, but between loci of group 1 and loci of group 2 in all sub-bands and the band-limited EEG. This part leads to more accurate detection of deficit connections, and not just deficit areas, but more discriminative SLs in sub-bands with finer resolutions. In part three, a classification technique, radial basis function neural network, is used to distinguish ADHD from normal subjects. The methodology was applied to EEG data obtained from 47 ADHD and 7 control individuals with eyes closed. The Radial Basis Function (RBF) neural network classifier yielded a high accuracy of 95.6% for diagnosis of the ADHD in the feature space discovered in this research with a variance of 0.7%.
Nonconvulsive Status Epilepticus Presenting with Throat Clearing as Part of Clinical Seizure Semiology
Authors: Sethi Nitin K. , Torgovnick Josh , Sethi Prahlad K. , Arsura Edward
Published: February 2012

Oro-alimentary automatisms such as chewing movements, lip-smacking, repeated snuffling, swallowing and retching have been reported with seizures usually of temporal lobe origin. Throat clearing, usually along with other vegetative signs, has been reported in patients with temporal and rarely extra-temporal lobe epilepsy.

We report a case of a 93-year-old woman admitted with acute right temporo-occipital stroke. Repeated throat clearing episodes raised suspicion for complex partial seizures. Video-EEG recording confirmed frequent right hemispheric focal seizures originating from the right posterior temporal area concordant with her cortical stroke. The value of throat clearing as a sign of complex partial seizures of temporal lobe origin and its lateralizing and localizing value is discussed.
Online Removal of Muscle Artifact from Electroencephalogram Signals Based on Canonical Correlation Analysis
Authors: Gao Junfeng , Zheng Chongxun , Wang Pei
Published: February 2012

The electroencephalogram (EEG) is often contaminated by electromyography (EMG). In this paper, a novel and robust technique is presented to eliminate EMG artifacts from EEG signals in real-time. First, the canonical correlation analysis (CCA) method is applied on the simulated EEG data contaminated by EMG and electrooculography (EOG) artifacts for separating EMG artifacts from EEG signals. The components responsible for EMG artifacts are distinguished from those responsible for brain activity based on the relative low autocorrelation. We demonstrate that the CCA method is more suitable to reconstruct the EMG-free EEG data than independent component analysis (ICA) methods. In addition, by applying CCA to analyze a number of EEG data contaminated by EMG artifacts, a correlation threshold is determined using an unbiased procedure. Hence, CCA can be used to remove EMG artifacts automatically. Finally, an example is given to verify that, after EMG artifacts were removed successfully from the EEG data contaminated by EMG and EOG simultaneously, not only the underlying brain activity signals but the EOG artifacts are preserved with little distortion.
Current Aspects of Cognitive Neurophysiology of Parkinson Disease: An Introduction
Authors: Bodis-Wollner Ivan
Published: February 2012

Parkinson Disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. With increased longevity and improved health care, our society is experiencing an unprece-dented challenge posed by neurodegenerative disorders. Alzheimer's disease alone is now the third most expensive disease to treat in the U.S., costing close to $100 billion annually. While treatment of the motor manifestations of PD has advanced much, the treatment of its non-motor features, in particular mental dysfunction remain as unresolved problems in PD. Electrophysiological and imaging studies in this issue are providing new information on the roles of the frontal cortex, pedunculopontine nucleus, dopaminergic mesolimbic system and thalamocortical circuits on cognitive and mental dysfunction in PD.