Ismet Karacan

EEG sleep stage scoring by an automatic hybrid system

Abstract The present paper reports the first systematic application of a hybrid sleep EEG scoring system and compares performance of that system with human scoring techniques. The automatic analysis technique can be used on line or 32 times real time, allowing for the scoring of an 8 h sleep EEG record in 15 min. Therefore, the system has obvious potential for reducing the cost and increasing the efficiency of scoring EEG sleep records. Generally, the system has proven to be both accurate and reliable, giving satisfactory levels of agreement upon repeated scoring of the same record or upon scoring different records. The present study indicates further that frequency spectrum analysis is not practical in sleep staging, since the amplitude of delta activity and spindles changes throughout a given night. The incorporation of detectors of phenomena such as K complexes into the sleep-analyzing hybrid computer system will further increase its accuracy and reliability. However, linear analog filters, such as were used for spindle detection, are too sensitive to amplitude variations in the EEG. We have recently developed a non-linear spindle filter, which is not subject to this criticism. This filter will be the subject of a future communication.

Automatic Detection of the K-Complex in Sleep Electroencephalograms

The development and application of an electronic system which is capable of automatically detecting the K-complexes, aperiodic waveforms found in sleep electroencephalograms, is described. The system can be used either on- or off-line.

Ontogeny of delta activity during human sleep.

The study describes the ontogenetic and time-related changes in peak amplitude, frequency, and incidence of delta waves of twenty-five normal subjects between the ages of 3 and 79 years of age. All slow waves greater then 5 muV in magnitude and between 0.5 and 3.0 c/sec were analyzed for the first 6 h of the nights sleep. In this study increasing age was accompanied by decreases in average peak amplitude of delta waves over 5 muV, slowing of delta frequencies, and decreases in incidence of waves greater than 20 muV. Across 2-h epochs of the night there were tendencies for the average peak amplitude of delta waves to decrease, for the average frequency for a given amplitude range to decrease, and for the incidence of low-amplitude delta waves to increase and high-amplitude waves to decrease. The incidence of waves greater than 5 muV remained constant across ages and epochs. Frontal channel delta waves exhibited an age-group difference whereas no such difference was apparent for central channel delta activity, suggesting that the frontal channel may possess advantages over the central because of greater sensitivity to age related changes.

A simple and inexpensive transducer for quantitative measurements of penile erection during sleep

The construction of a mercury strain-gauge transducer for measuring penile erection and scoring rules for tumescence episodes are described. The gauge device has been found to be cheap, reliable, and easy to construct. It is capable of transducing changes in circumference in the penis of adults and infants, the clitoris of congenital adrenal hyperplasia patients, and the nipples of adult females.

Some characteristics of nocturnal penile tumescence in early middle-aged males

Abstract This report describes in detail the characteristics of nocturnal penile tumescence in a group of 30–39 year old males, and suggests that the neural activity characteristic of REM sleep is not a necessary condition for nocturnal tumescence, and that tumescence probably serves more than one function for the organism. (The functions suggested are of a highly speculative nature at the moment, but continuing research is expected to give us a clearer picture.)

Nocturnal Penile Tumescence and Sleep of Convicted Rapists and Other Prisoners

Nocturnal penile tumescence, sleep EEG, and eye movement patterns were monitored for three consecutive nights among 12 convicted rapists, 12 prison controls, and 12 normal controls. Both prison groups exhibited significantly greater frequencies and amounts of non-REM semitumescence; shorter periods in bed, shorter sleep periods, and shorter total sleep times; lower sleep efficiency indexes; greater percentages of awake time; and shorter latencies to the first awakening after sleep onset than normal controls. Rapists experienced less slow-wave sleep than prison controls, and prison controls showed a greater number of awakenings and a smaller percentage of stage 2 sleep than normal controls. There were no significant nocturnal penile tumescence differences between prison groups. MMPI profiles of the two prison groups did not differ significantly, but both indicated significant psychopathology on several scales. Quick Test IQ scores of rapists were slightly, but significantly, lower than those of prison controls.

A multichannel hybrid system for rapid eye movement detection (REM detection)

Abstract The design, development, and application of a multichannel hybrid system capable of accurate automatic detection of rapid eye movements (REMs) in electrooculograms (EOGs) recorded from sleeping subjects is described. A definition of a rapid eye movement as it appears as a waveform in recorded EOGs is given and used to develop a REM model. This model serves as a basis for the development of the detection system. The interface between the system circuitry and system software is discussed. In addition, comparative results of the application of the system to automated rapid eye movement analysis are presented.

Sleep characteristics and endocrine response in progeria

T ~ I E P R O O ~ R I A of Hutchinson-Gi l ford is a car ica ture of normal senescence tha t begins in the first year of life wi th fai lure to ga in weight, loss of subcutaneous fat, ba lding, a t rophy of the skin, and wizened facies and ends in dea th from atheroscterosis before age 20; menta t ion is un impai red . A recent extensive metabol ic invest igat ion of 2 pat ients ind ica ted a lack of g rowth hormone response to insul ininduced hypoglycemia and relat ive insulin resis tance? Growth hormone unresponsiveness to insul ininduced hypoglycemia has been described in ano ther report , 2 bu t the pa t i en t was la ter repor ted to have g rowth hormone response to the infusion of a rg in ine? T h e present study was under taken to extend previous endocr ine observations, to eva lua te growth hormone release as a funct ion of sleep stage, and to determine whe ther

Automated sleep EEG analysis applied to the evaluation of drugs: illustration by study of clorazepate dipotassium.

An automated sleep EEG analysis system was used to evaluate the effects of clorazepate dipotassium in normal subjects. Ten young-adult men slept 18 consecutive nights in the laboratory. On days 8-15 clorazepate (7.5 mg) was administered three times daily; on days 5-7 and 16-18 a placebo was administered in a similar fashion. The drug reduced amounts of alpha and delta activity and increased the amount of beta activity and the number of spindles. These effects generally persisted through the 3 day placebo recovery period. Our results suggest that sleep EEG waveform descriptors are sensitive indicators of drug activity and that beta activity in particular may be useful in the detailed description of various drug effects.