Epileptic encephalopathies and their relationship to developmental disorders: do spikes cause autism?

Epileptic encephalopathies are progressive clinical and electroencephalographic syndromes where deterioration is thought to be caused by frequent seizures and abundant EEG epileptiform activity. Seizures occur in approximately 10-15% of children with pervasive developmental disorders (PDD) and 8-10% have epileptiform EEG abnormalities without seizures. Thirty percent of children with PDD have regression of social behavior and language at 2-3 years of age. Some authors speculate that the regression is caused by epileptiform activity even in the absence of overt clinical seizures ("autism with epileptic regression") and suggest that elimination of the epileptiform activity, either medically or surgically, should lead to improvement in behavior. This review examines the data showing that interictal epileptiform discharges are associated with transient clinical dysfunction and discusses the implications of these observations for autistic behavioral abnormalities. The results of resective surgery, vagal nerve stimulation, and multiple subpial transaction on children with autism and epileptiform EEG abnormalities are also discussed. I conclude that there is no evidence that interictal discharges per se cause (or contribute to) the complex behavioral phenotype of autism. There is no justification to support the use of anticonvulsant medication or surgery in children with PDD without seizures; that is, there is no evidence that treatment to eliminate EEG spikes will have a therapeutic effect on the behavioral abnormalities of PDD and autism.     

Automatic detection of transient potentials in the EEG

A classifier based on the linear regression model was developed to automatically detect sharp transients in EEG, matching the definition of spikes and sharp waves accepted by IFSECN. Practical applications proved the accuracy of the method which succeeded in detecting 84% of sharp transients previously found by an experienced electronencephalographer. Computerized search for sharp transients in EEG records will be particularly useful in long term EEG records obtained from epileptic patients.     

A Review of Diagnostic Techniques in the Differential Diagnosis of Epileptic and Nonepileptic Seizures

The diagnosis of psychogenic nonepileptic seizures (PNES) is complex. Long-term electroencephalogram monitoring with video recording (video EEG) is the most common method of differential diagnosis of epilepsy and PNES. However, video EEG is complex, costly, and unavailable in some areas. Thus, alternative diagnostic techniques have been studied in the search for a diagnostic method that is as accurate as video EEG, but more cost effective, convenient, and readily available. This paper reviews the literature regarding possible diagnostic alternatives and organizes findings into 7 areas of study: demographic and medical history variables, seizure semiology, provocative testing, prolactin levels, single photon emission computed tomography, psychological testing, and neuropsychological testing. For each area, the literature is summarized, and conclusions about the accuracy of the technique as a diagnostic tool are drawn. Overall, it appears unlikely that any of the reviewed alternative techniques will replace video EEG monitoring; rather they may be more successful as complementary diagnostic tools. An important focus for further investigations involves combinations of diagnostic techniques for the differential diagnosis of epilepsy and PNES.     

Measurement of head movement during auditory localization

Head movement can have a significant effect on the ability to locate the direction of a sound source. A system has been designed to track the head movement in response to sound originating at different azimuth locations with respect to the head. A videotape record is made of a light approximating a point source carried on a lightweight “beanie” mounted on the listener’s head. Movement of the light is monitored by the video camera and recorded on tape, along with the sound stimulus and information concerning loudspeaker location and time. The horizontal and vertical coordinates of the light-spot image are determined in relation to the video synch pulses defining the field borders. Synch signals are available from a video monitor either in real-time or from tape replay to define each TV frame and horizontal scan line. The circuitry interfaces to a computer programmed to take the information, apply a calibration, and process the data into records of time-varying head position and velocity. Examples of both digital and graphic printouts of head movement are given. The system is capable of expansion to three-axis operation.     

Automatic recognition of sleep spindles using short-term spectral analysis

An approach tö recognize automatically sleep spindles by using short-term spectral analysis is described. The EEG signal is sampled and stored on a magnetic tape in digital form. The data is analyzed on a PDP-8 computer, and the result can be either displayed on an oscilloscope or stored on another magnetic tape for further analysis. The program is written in conversational form and provides the operator with the ability to change any parameter in the program quickly by a simple command on the Teletype keyboard.     

Gait analog tracings and computerized analysis through a PDP-11/45

Human gait movements are measured and simultaneously recorded on an eight-channel magnetic tape recorder. An electrogoniometer is used for monitoring lateral, vertical, and anteroposterior displacements of the dorsal spine. Independent potentiometers detect arm swings and a microswitch circuit identifies the steps. Bursts of audio signals triggered to a preset cadence by an electronic metronome are presented at discretion to the subject through headphones in order to guide his step rhythm. Analog data for each walk session are digitalized at the rate of 20 samples/sec and stored on mag tape and/or disk along with the corresponding codes. Analyses of movement data are carried out on a PDP-11/45 computer.     

Hemispheric Asymmetry and Regional Differences in Electroencephalographic Alpha Activity at the Wake-Sleep Transition

Electroencephalographic (EEG) alpha activity at the wake-sleep transition was studied in six right-handed adults in terms of hemispheric asymmetry and regional differences. Twelve-channel EEGs with linked mastoid references were recorded together with horizontal and vertical electro-oculograms (EOGs). Two types of alpha coefficient were obtained every 5.12 s by computing the relative proportion of right vs. left alpha band power and of anterior vs. posterior alpha band power. Four stages were scored using EEG sleep patterns (theta waves, vertex sharp waves, spindles, and K complex) and slow eye movement (SEM): stage W had neither EEG sleep patterns nor SEM; stage D1 had SEM and no EEG sleep patterns; stage D2 had theta waves or vertex sharp waves and SEM; stage S had spindles or K complex without SEM. It was found that the two types of alpha coefficient changed as a function of EEG-EOG stage and were correlated. Right-decreased and anterior-shifted alpha activities were manifest at stages D2 and S. Drowsiness was considered to be a heterogeneous state, exhibiting different spatial changes in alpha activity between stages D1 and D2.     

Clinical validation of a sleep assessment device

We have previously reported on the use of a sleep assessment device (SAD) with non-insomniac subjects. The SAD works by generating a brief, soft tone about every 10 min throughout the night and tape recording verbal responses to these cues. The sleep patterns reconstructed from the night's tape recordings proved highly concordant with EEG records. The present study tested the SAD against the EEG standard in 20 nights of monitoring chronic insomniacs. No significant differences were found between the SAD and EEG records with respect to sleep latency, duration of awakenings during the night, total sleep time and sleep efficiency percentage. The EEG detected many more very brief awakenings during the night than did the SAD due to the continuous monitoring by the former. The SAD proved to be a non-intrusive measure of sleep according to three independent measures. The usefulness of the SAD as a measure of sleep in the natural environment was discussed.     

The Observer Video-Pro: New software for the collection, management, and presentation of time-structured data from videotapes and digital media files

The Observer Video-Pro is a system for collecting, managing, analyzing, and presenting observational data. It integrates The Observer software with time code and multimedia hardware components. It extends the functionality of a conventional real-time event recording program in various ways. Observational data can be collected, reviewed, and edited with synchronized display of the corresponding video images. For optimal visual feedback during coding, one can display the video image in a window on the computer screen. Video playback from either a VCR or a digital media file can be controlled by the computer, allowing software-controlled jog, shuttle, and search functions. Besides a wide range of VCRs, The Observer Video-Pro supports all major digital video file formats. The software allows the user to summarize research findings in numerical, graphical, or multimedia format. One can create a time-event plot for a quick glance at the temporal structure of the observed process, or run specific analysis procedures and generate reports with statistics. An Event Summary function is available for exploratory and qualitative analysis. Video material can be summarized in a Video Play List, which allows on-screen summary presentations or the creation of highlight compilations on tape, CD, or other media. Video images can be captured and saved as disk files, for use as illustrations in documents, slides for presentations, and so forth. In this paper we describe the design and operation of the system, illustrated with a case study from research on Repetitive Strain Injury (RSI).     

Neurophysiology of Rett syndrome

Neurophysiological evaluations have been widely applied in the study of Rett syndrome (RS) to provide information concerning the developmental aspects of RS; the character and extent of involvement of the central, peripheral, and autonomic nervous system pathways; and evaluation of the clinical symptomatology of RS. The electroencephalogram (EEG) is invariably abnormal and shows characteristic, though not diagnostic, changes: loss of expected developmental features; the appearance of focal, multifocal, and generalized epileptiform abnormalities; and the occurrence of rhythmic slow (theta) activity primarily in the frontal-central regions. Epileptic seizures are reported to occur frequently in RS, and partial and generalized seizures may be experienced by RS girls. However, many events presumed to be seizures have no EEG correlate during video-EEG monitoring, suggesting the possibility of a nonepileptic mechanism. Such monitoring may be necessary to determine appropriate use of antiepileptic drugs. Evoked potentials typically demonstrate intact peripheral auditory and visual pathways and suggest dysfunction of central or "higher" cortical pathways. Somatosensory-evoked potentials may be characterized by "giant" responses, suggesting cortical hyperexcitability. An increased incidence of long QT intervals during electrocardiographic recordings and diminished heart-rate variability, suggesting impairment of the autonomic nervous system, are described in RS. With the discovery of the genetic basis of RS, neurophysiological studies will provide parameters for phenotype-genotype correlations and characterization of animal models.     

Computer Technology Audio tape storage of experimental data: An application to tachistoscopic research with children

An inexpensive portable system is described for storing digital data on audio tape for later computer processing. The technique involves the use of integrated circuits and an ordinary stereo tape recorder. Each datum is converted to a binary-coded voltage level that, through a sampling device, controls the phase of a square-wave signal. Depending on whether the bit being coded is \ld0\rd or \ld1,\rd the signal recorded on one tape track is either in phase or 180 deg out of phase with a reference signal recorded on the other track. Later, the recorded tape may be played back into a computer for data analysis. An application of this technique for tachistoscopic research is described.     

An economical system for collecting and reducing heart-rate data,using someone else’s small computer

Hardware and program are described for a heart-rate data collection and reduction system that uses a small computer at a time removed from the actual data collection. The system is portable and inexpensive; exclusive of the computer, it can cost under $1,500. It uses an ordinary tape recorder to record discrete signals upon each occurrence of a heart beat, and it returns edited second-by-second averages of interheart-beat intervals.     

A method for analyzing the motion of an object on a VTR screen with an Apple II computer

To detect position on a video tape recorder (VTR) monitor screen, two different types of apparatus were developed. One was a light pen, and the other was an instrument similar to an X-Y tracker. These were designed to work with the Apple II computer. Their circuit diagrams are presented.     

An automatic recording system of the positional behavior of mice for experimental analysis

A device for automatic recording of a mouse positional behavior within a circular corridor-like cage is described. The animal’s position is successfully monitored by capacitor detection and its time spent at each position measured; the results are punched on the paper tape as binary coded numbers, and the data are processed off-line by a general-purpose computer.     

Summarization of videos by analyzing affective state of the user through crowdsource

Video summarization is one of the key techniques to access and manage a huge chunk of videos. Video summarization is used to extract the effective contents of a video sequence to generate a concise representation of its content. The involvement of crowdsourcing models in recent years is effectively used by researchers in E-commerce domain to increase the quality of the data contents. In this paper, we present a video summarization framework based on users emotion while they watch videos by analyzing cerebral activities through Electroencephalogram (EEG) signals. Three emotions, namely happy, sad and neutral have been extracted from the EEG signals. Video frames have been synchronized with EEG signals and tagged with various emotions. Finally, a crowdsourcing model has been used for effective summarization of the videos. The qualitative assessment of video summarization has been conducted with the help of user ratings using online Google Forms application. EEG signals of 28 users have been recorded while video streams of different emotions. An average accuracy of 83.93% has been recorded in emotion classification using crowdsourcing. Output summarized videos include dynamic video skims and the corresponding audio stream for better understanding.     

A computer-oriented system for high-speed recording of operant behavior

A method is described by which large quantities of data, generated at high and variable rates from a large number of test boxes, are recorded on a single eight-channel punched paper tape. The data, which include a record of the occurrence time of each event in 1/10-sec units, are in a compact form, suitable for conversion to standard Hollerith punched card codes and for decoding and summarizing by a large digital computer. Experience with the system has demonstrated a high degree of accuracy and reliability, and low operating cost.