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Background Data defining the utility of the system for improving and measuring procedural learning (SIMPL) in surgical education is limited. The aim of this pilot study is to describe the impact of SIMPL on resident and faculty perspectives regarding operative feedback. Methods Residents and faculty were surveyed prior to and 6 months after SIMPL implementation. Associations were analyzed using [Formula: see text] for categorical and Student’s t-test for continuous variables. Statistical significance was defined as P-value < .05. Results The proportion of residents receiving intraoperative feedback at least once/day increased significantly (35% to 73%, P = .025); there was a trend toward increased postoperative feedback (15% to 33%, P = .201). Faculty reported an increase in intraoperative (55% to 91%, P = .041) and postoperative feedback (21% to 64%, P = .020). Satisfaction with intraoperative feedback improved from a score of 3.50 ± 1.05 to 3.93 ± .62, although not statistically significant ( P = .181). Satisfaction with postoperative feedback improved significantly from 2.85 ± .93 to 3.50 ± .65 ( P = .032). The proportion of faculty who felt they were providing effective feedback increased (53% to 91%, P = .032). The proportion of residents who perceived that feedback enhanced their surgical skill increased as well (65% to 93%, P = .048). Discussion Despite a modest increase in frequency of postoperative feedback, perceived quality of feedback improved substantially after implementation of SIMPL. Introduction of SIMPL also increased the amount of feedback provided by faculty intraoperatively. SIMPL, via direct and indirect effects, has a positive impact on the resident operative learning environment. Further work is necessary to examine the influence this may have on resident operative skill and patient outcomes.

Pediatric bariatric surgery is increasingly recognized as a safe and effective option for the management of obesity and obesity-related conditions. However, insurance coverage is a key barrier to accessing these procedures. Criteria are variable and often not evidence-based. In an effort to characterize common patterns in insurance coverage, we report coverage criteria for adolescents relative to adults. We surveyed medical policies of the 50 highest market share health insurance providers in the USA. Private insurer coverage criteria included age, Tanner staging, skeletal maturity, body mass index, procedures covered, medical weight management requirements, co-morbidities, and multidisciplinary team criteria. These were then compared to the American Society for Metabolic and Bariatric Surgery (ASMBS) guidelines. Two thirds (n = 33, 66%) of companies provided inclusion criteria for adolescents. All policies covered RYGB (n = 33), most covered sleeve gastrectomy (n = 32, 97.0%). Obstructive sleep apnea (OSA) (n = 32, 97%), hypertension (HTN) (n = 27, 81.8%), and gastroesophageal reflux disease (GERD) (n = 11, 33.3%) were the three most commonly cited co-morbidities used as inclusion criteria. Tanner staging or skeletal maturity were most commonly used (n = 10, 30.3%). Similarly, twenty (60.6%) insurers required medical weight management programs. Multi-disciplinary teams were required by 81.8% of adolescent policies (n = 27) as described by the ASMBS. Seventeen (51.5%) policies defined providers for these teams, and 10 (30.3%) provided other defined criteria. Contrary to ASMBS guidelines, companies commonly require Tanner staging and/or skeletal maturity criteria as well as participation in medical weight management programs. Also, multi-disciplinary team are frequently required but not well defined.

Electronic information is a vital resource used by fellowship applicants. This study aimed to assess the completeness of colon and rectal surgery (CRS) fellowship program online information. Program information on the Association of Program Directors for Colon and Rectal Surgery (APDCRS) website as well as each institutional website was evaluated based on templated criteria. Sixty-eight accredited fellowship programs were identified. Six (9%) programs had complete profiles on the APDCRS platform, with an average of 3.5 details completed per program. Sixty-two (91%) websites were easily accessible. None of these contained all 28 criteria assessed and 47 (69%) contained less than half of assessed content. The most common data point was fellowship program description (96%), while board pass rate (1%) was the least common. Most CRS fellowship websites were grossly incomplete. Electronically available information is vital to fellowship applicants, and programs should try to provide easily accessible information about their program.

Background Minimally Invasive Surgery (MIS) is one of the more recently established surgical fellowships, with many candidates applying due to a perception of inadequate exposure to advanced MIS during residency. The desire for advanced training should be reflected in increased competitiveness for fellowship positions. The aim of this study is to determine the desirability of MIS fellowships over time through review of national application data. Methods We reviewed the fellowship match statistics obtained from The Fellowship Council, the organizing body behind the MIS fellowship match. Data from January 1, 2008 - December 31, 2019 were included. We compared match rates to other specialties using the National Resident Matching Program, a nonprofit organization established for US residency and some fellowship programs. Results In the period of 2008 to 2019, the number of certified MIS fellowship programs increased from 124 to 141. While this program expansion was associated with a 19% increase in available positions, the number of applications increased 36%. As a result, the number of positions filled increased from 83% to 97%, but the match rate among US applicants fell from 82% to 71% during this interval. In comparison, the match rates for pediatric surgery, surgical oncology, vascular surgery, and surgical critical care fellowships remained largely unchanged, most recently 50%, 56%, 99%, and 100% respectively. Conclusion Over the last decade, US residents have shown an increased interest in pursuing MIS fellowship positions. As a consequence, the match process for MIS fellowships is becoming increasingly competitive.

Various quantitative descriptors for EEG data will be compared taking sleep as an example. In this contribution, Hjorth's mobility and complexity measures will be used to classify sleep stages. The results will be compared with those of a dimensionality analysis. Several authors have shown that the correlation exponent can describe the complexity of sleep EEG data and is able--with the exception of REM sleep--to distinguish significantly between sleep stages. The discriminative power of a bivariate global frequency analysis appears to be superior to that of the correlation exponent. Furthermore a very high statistical correlation between the estimator of fractal dimension and Hjorth's mobility was obtained.

According to our experiences (parietal) sleep spindles often show a periodical appearance. Successive sleep spindles in series have a distance of about four seconds. In 95% the duration of such series of sleep spindles is not longer than 40 s, so that there appears no more than ten successive periodical sleep spindles. In the present study ten subjects aged between 57 and 77 years were given Placebo and 7.5 mg Zopiclone. Under the effect of verum we found a doubling of sleep spindle series. However, the distance between the periodical spindles and the length of the spindle series remained unchanged. The variance in the ability to generate sleep spindle series was very high across subjects. One subject for example produced only one sleep spindle series in the Placebo-night (three under verum) and another subject on the other hand 95 (under verum 130). The results of the present study well corresponding to the results of a former investigation comparing Placebo, Pentobarbital, Methaqualon, Carbromal, Flunitrazepam, Triazolam and Lormetazepam.

The evaluation of EEG-patterns is usually accomplished by visual analysis. Nowadays however, even personal computers are fast enough for an efficient pattern recognition of EEG signals. Using sleep spindles and K-complexes as examples, our aim was to demonstrate how patterns can be detected in an EEG signal with a high degree of accuracy. Furthermore, recognition of K-complexes has been improved by applying an additional "adaptive algorithm" allowing individual adjustments to the signal's form and amplitude.

All night sleep deprivation prior to an EEG registration causes some inconvenience not only to the organization of the EEG department but presents a burden on the patients as well as their family members, and for these reasons is not suitable to be frequently employed as a routine procedure. As an alternative, we performed short-term sleep recordings in the early afternoon following a partial sleep deprivation of the patients during the preceding night. This method was well accepted by the patients and their family. Our only goal was to shorten the total time of night sleep using the following guideline: for very small children 22.00-06.00; for 4-14-year-old patients 24.00-06.00; and for patients older than that 01.00-06.00. 79.9%, out of 719 patients (573) who had been given the above instructions subsequently showed sleep patterns in their EEG. Additionally we had to administer an oral dose of promazine to only 67 patients. However, for the most part, patients showed only light sleep stages: 114 patients only reached sleep stage 1; 323 patients sleep stage 2; 88 patients sleep stage 3; and 48 patients sleep stage 4. As expected, REM sleep was never recorded. Nonetheless, in 32 out of 146 patients who were tired but unable to fall asleep, epileptic patterns could be provoked. In 636 patients, the EEG-recording after sleep reduction was ordered because of a suspected seizure disorder; in the remaining patients it was initiated solely because of sharp components in the routine-EEG. In 341 (53.6%) of the patients with suspected epilepsy, electroencephalographic activity indicative of a seizure disorder was activated. Such epileptic patterns were recorded almost exclusively in stages of waking, 1 and 2. Only in one out of the 124 patients who reached sleep stages 3 and 4 epileptic patterns were not seen until deep sleep was entered. We observed 2/s, 3/s and 6/s spike-and-wave complexes, sharp waves, spikes, polyspikes, groups containing remarkably sharp components and so called sharp vertex grapho-elements. Patients with suspected seizure disorders frequently show grapho-elements which can be interpreted as the expression of a disposition for epilepsy. These sharp vertex elements were evident in 54 out of 719 short term sleep recordings, more often in children than in adults. 49 times they coincided with typical epileptic discharges such as sharp waves, spikes or spike-and-waves in the same recording.

We observed the α-sleep pattern in 6 out of 44 subjects who offered neither somatic nor psychological complaints. All of the 6 subjects demonstrated the pattern consistently over a period of several y

"Equipotential" doses of lormetazepam, triazolam and flunitrazepam were tested regarding their influence on K-complexes, sleep spindles and rapid eye movements. The receptor affinity was used to determine the equipotency. In this respect triazolam, lormetazepam and flunitrazepam show a relationship of 1:2:4. Lormetazepam, however, showed only slight changes of the three neurophysiological parameters even when given as double dosage. Triazolam and flunitrazepam reduce K-complexes considerably, increase sleep spindles enormously and reduce REM activity markedly; both substances suppress the first REM period, flunitrazepam even the second one. All three of the benzodiazepines have the same effect on the dissociation of K-complexes and sleep spindles; epochs with K-complexes or sleep spindles are favored compared to epochs with K-complexes and sleep spindles. The general reduction of K-complexes and the increase in sleep spindles can be interpreted as a sleep protective function. When deciding on the dosage, however, REM-suppression should be used as a guide since it has the strongest effect on the cyclic structure of sleep which nowadays is considered to be the safest evidence of well balanced sleep behavior.

Both pentazocine and buprenorphine are hypnoanalgetics of the agonistic-antagonist group. They suppress the inhibitory effect of fentanyl upon the central nervous system. They show also secondary their own inhibitory properties (fig. 8). The agonistic-antagonists can be further divided in excitants (like pentazocine) and non-excitants (buprenorphine).

A long existing hypothesis, i.e. that the EEG effects, in lead O2A2, of typical psychotropic drugs are substance class specific, when given as single oral dosages to healthy volunteers, is discussed. Using the technique of pharmacoelectroencephalograhpy, five typical representatives of neuroleptics, anxiolytics, antidepressives, psychostimulants (Fig. 2) as well as placebo were investigated in 75 volunteers, each receiving one representative of each substance class in a double blind 5-fach change over latin square design (Fig. 3). A five minute EEG record for lead O2A2 was obtained pre, 1 h and 3 hrs post drug intake unter RR (Relaxed Recording) conditions. Typical samples of th EEG records are shown in Figs. 4--7. Parametrisation was done using power spectrum analysis. Then 3 x 7 target variables were formed--six relative power values in predetermined frequency bands and the total power between 1.5 and 30.0 Hz for 3 occasions of measurement (Fig. 4--7). Using a (five-group) linear discriminant analysis the substance effects on the EEG were transformed into 5 probability measures for the five substance classes (Fig. 4--7). The present paper should provide a demonstration of some typical examples, using single subjects, of the projection of substance effects onto an electrophysiological level using a vector of 21 components (7 target variables for 3 occasions of measurement) as can be seen from Table 1. Furthermore, the transformation into probability measures of the five substance classes are shown in Table 2. Table 3 shows five examples of projections of substance effects, which do not fit into the classifications to which they belong. An attempt is made to explain, whether single target variables from the power spectrum can contribute differently to the discrimination between single substances of different substance classes. Within the accepted system of 4 psychotropic drug classes, the following variables seem to be of importance: a) The benzodiazepine anxiolytics show a marked increase in beta F1 (12.0--18.0 Hz) power and activity and, related to sedation, an increase in delta F-power and a decrease in alpha-power; b) The psychostimulants of the amphetamine type show an increase in total power and alpha-power, an increase in the power of the frequency ranges near to the alpha-band (slow beta, fast theta) and a decrease in delta F (1.5--5.5 Hz)-power, when delta F-power is high in the pre-values, indicating a stabilization in vigilance; c) The neuroleptics show a marked increase in theta F (5.5--8.5 Hz)-power, some increase in the delta F--and a decrease in the beta F1-and beta F3-power; d) Tricyclic antidepressants show an interaction between delta F-theta F-, alpha- and beta-power, in the sense of a dissociative shift in vigilance.

Equipotent analgesic doses of sulfentanil and fentanyl showed similar effects in 281 cases of clinical neuroleptanalgesia. In rabbits equimolecular doses of sulfentanil induced a deeper narcotic effect (burst suppression) than fentanyl. This supports the thesis of a coincidental increase of analgesic potency and narcotic effect in agonistic opioids. In equipotent doses the conventional EEG and the amplitude-frequency-spectra are equal. Quantificated analyses and statistical calculations show essentially similar changes in animal: - Fentanyl as well as sulfentanil changes only the dominant frequency in the theta-bands. - The percentage value increases only in the sigma-band, doesn't change in the alpha- and beta1-band and decreases in the theta-band, beta2--and beta3-band. - The power of sigma rises by a potency of ten in both substances; the change in the other frequencies shows similar sizes. Fentanyl and sulfentanil do not coure differences in the EEG.

The rules by Rechtschaffen and Kales present numerous problems; they sometimes even contradict physiological facts. This is due on the one hand to the manual being limited to central leads only, and on the other hand to rules which are partly too narrow, partly too broad and partly too complex. Furthermore, there are situations and physiological facts for which the manual does not have any rules. The exclusive evaluation of central leads has to result in a different scoring for numerous epoches of stages than an evaluation of leads from all hemisphere electrodes. In addition, frontal or occipital graphoelements such as mitten-pattern and sleep lambda are not even included. It is often difficult to make a distinction between an "alpha-sleep type" and pre-arousals (micro-arousals); the latter also applies to alpha groups in REM sleep. In particular however, if frontal, parietal and occipital leads are included, then the stage 2, above all however stages 3 and 4 will be represented more frequently, as sigma spindles, K-complexes and delta-waves are frequently found in a recognizable form only in the non-central leads. Further difficulties result from different paper speeds of 15 or 10 mm/s and from the rule concerning the allocation from stage 1 to stages 2 or REM.

Pentazocine dependencies are rare. In a period of 5 years, 60 were notified. The majority of these were not dependent. Of 46 utilizable notifications, 38 were false, 5 had taken pentazocine only temporarily or not at all. 19 received it for chronic or recurrent pains, 13 were polytoxicomaniacs, and 1 patient could not be classified. Only 8 cases could be referred to as pentazocine-dependent. The dose for addicts and polytoxicomaniacs was 11 ampoules daily on the average, almost three times as high as that for patients with painful diseases. Pentazocine dependencies are considerably less of a problem than those of opiates used up to now: withdrawal symptoms are slight, neglect and social dangers need scarely be considered. "Users" generally only turn to pentazocine when a painful disease supervenes. Dependency practically never occurs with oral administration.

Polysomnograms were recorded of twelve patients with acquired immune deficiency syndrome (AIDS) during different stages in an open design. During the first night no hypnotics were administered, during the second night 30 mg flurazepam per os were given. Flurazepam affected mainly the NREM parameters. The times "awake" during the night were reduced, sleep stage 2 showed an increase, and the effective sleep time was also increased. The increase in sleep spindle density was remarkable, however, delta sleep and generation of K-complexes were not affected. Flurazepam did not affect REM sleep at all. The amount of REM sleep showed a slight increase. REM distribution during the night did not show the "bell shaped" increase and the decrease in the morning; the degree of the illness correlated with a flattening of REM distribution.

Somnopolygraphic recordings were registered from 29 patients with AIDS, their age ranged from 20 to 55 years (mean: 40.9; median: 44). The patients represent the full range of cerebral disintegration representing the picture of a progressing destruction of physiological sleep organization. Some disturbances begin quite early and progress successively, such as the reduction of REM- and delta-sleep as well as the reduction of sleep spindle- and K-complex-densities. Other changes are not manifest until intellectual capabilities break down; they occur massively such as the shortening of real sleep time and the reduction of sleep stage 2 with a simultaneous increase in waking time. It is remarkable that despite the enormous REM reduction there is no suppression of REM periods corresponding to "REM sine REM". REM periods become very short at an early stage; this is not only because the patients awake more frequently and earlier from their dream periods.

Here we investigated the applicability of a computer-aided video-tracking as a method for evaluating potential deficits of neural information processing in patients with AIDS and those showing only positive HIV-seroreactivity. Video-tracking was accompanied with a simultaneous recording of EEG. Eight HIV-positive asymptomatic volunteers and eight AIDS-patients with cerebral manifestation of the disease participated in the pilot study. Two groups of eight normals each served as a control. Video-tracking performance of the HIV-positive volunteers and AIDS-patients significantly differed (p less than 0.05) from those of the healthy volunteers. Although the AIDS-patients' performance tended to be worse than that of the HIV-group, this difference was not significant. Power spectrum analysis of the EEG-data indicated that the diminished performance of the two test groups (AIDS and HIV-positives), accompanied by an increased spectral power across the entire frequency range measured in the study, could be an expression of an enhanced synchronization in cortical neuronal networks. The synchronization in turn could be a sign of possible organic brain damage resulting from HIV-infection. In conclusion, we suppose that video-tracking measures parameters which may indicate early deficits of information processing in CNS.

15 male AIDS-patients from 26 to 55 years (mean 41.8 +/- 8.5) with various cerebral manifestations had a whole-night-sleep-EEG registration. As control the recordings of 15 age-matched volunteers (26-55 years, mean 41.8 +/- 9.8) were examined. Spectral characteristics of elementary EEG-epochs of 40 s length were computed, and sleep staging was performed visually for these intervals. The spectral power density of eight EEG-derivations (left and right frontopolar, frontal, central and occipital electrodes, reference montage to the ipsilateral Cb) were measured (sampling rate 64(-1) s, spectral resolution .25 Hz, frequency range from .25 to 24 Hz). Interhemispherical coherences of the frontal and occipital derivation pairs, and intrahemispherical fronto-occipital coherences of the left and right hemisphere, were computed. In the patients the frontal power density of NREM sleep showed lower values in the frequency range of 10 to 14 Hz. In central and in occipital derivations the power density between 12.5 and 15 Hz was lower in the patients, but the difference was less accentuated. The spectral power density of REM sleep showed similar characteristics in both groups. The interhemispherical frontal coherence of the whole frequency range below 13 Hz was markedly lower in the patient group. This was true for the NREM sleep, and, slightly less, for the REM sleep, too. The interoccipital spectral coherence was generally slightly lower in the patient group; the difference was most clearly in the 12.5 to 15 Hz range of NREM sleep.

In order to determine whether the clinically used frequency bands of the EEG can also be obtained by a mathematical system we did a factor analysis with 480 EEG recordings, 5 minutes each, in 60 healthy male volunteers. A power spectrum analysis was done and 57 frequency bands between 1.5 and 30.0 Hz in a half Hz steps were calculated. The factor structure obtained made the following frequency bands (Hz) reasonable: deltaF = 1.5 - 6.0, thetaF = 6.0 - 8.5, alpha1F = 8.5 - 10.5, alpha2F = 10.5 - 12.5, beta1F = 12.5 - 18.5, beta2F = 18.2 - 21.0, beta3F = 21.0 - 30.0. Except for alpha1F all other 6 frequency bands were represented by one general factor with the complexity 1. The variance of the alpha1F band is explained by several of the 6 factors. The clinically known and the by factor analysis obtained frequency bands in the beta-range are similar. The clinically alpha-band is subdivided into two frequency bands alpha1F and alpha2F by the factor analysis. The clinically known border line between delta- and theta-band of 3.5 Hz cannot be found by factor analysis.

Many persons show two different types of delta-activity during synchronized sleep; these can already be differentiated visually as follows: one is located over the anterior brain areas, has a high frequency and is monomorph, the other one is located over the posterior brain areas, has a low frequency and is polymorph. However, both rhythms overlap considerably regarding their cortical distribution. The high high frequency delta-activity usually ranges from 1.5-2.9 Hz with a maximum at 2Hz; the one with low frequency ranges from 0.1-1.4 Hz with a maximum at 0.9 Hz. The interhemispheric coherence of the delta-activities is high with 0.7-0.9; for the anterior regions it is slightly higher than for the posterior ones. The intrahemispheric coherence is low, as was to be expected, and it is less than 0.3.

The amount of sleep spindles and K-complexes shows a great interindividual variety of combinations, such as many or few sleep spindles and K-complexes respectively. There seems to be no direct correlation between the amount of sleep spindles and K-complexes intraindividually. In our unselected population - age range between 18 and 77 years - the mean sleep spindle density is at 2.59 +/- 1.85/min and the mean K-complex density at 1.96 +/- .96/min stage 2. The diffuse individual distribution, however, does not reflect the age factor involved. The sleep spindle and K-complex density were practically half the amount for the age group above 50 years as compared to the age group of less than 30 years.

The influence of narcotics on the duration of the ultradian NREM/REM cycle can be clearly recognized only when the first, particularly instable cycle is also included in the evaluation. A study with Lopirazepame and Flurazepame showed that compared to placebo Lopirazepame prolonged the first cycle particularly. In contrast with Flurazepame the first, but mainly the second cycle was shortened, and not until the third NREM/REM cycle the duration was compatible with that of placebo and Lopirazepame. The result is, that in nights of the same length Flurazepame shows a half or one cycle more compared to Lopirazepame.

Patients with suspected seizure disorders frequently show graphoelements which can be interpreted as the expression of a disposition for epilepsy. These sharp vertex elements were evident in 54 out of 719 short term sleep recordings, more often in children than in adults. 49 times they coincided with typical epileptic discharges such as sharp waves, spikes or spike waves in the same recording.

We 941, a Triazolodiazepine, has satisfying hypnotic properties. The optimum dosage lies nearly at 0.3 mg. In this dosage the sleep-begin is shortened, the number of nightly wakeness is decreased and the total sleep-time is extended, while the sleep-profile remains unchanged. A normal cycling can be taken as a sign of qualitative good sleep. The REM-percentage is diminished insignificantly and increases again under the continuated therapy. The percentage of deep sleep increases by 0.3 mg. The subjective presentations confirm the melioration of sleep. In higher dosages troubles occur as decrease of deep-sleep stage and deteriorations of feeling. Remarkable is the withdrawal effect after 1.0 mg with an initial and a dissociated REM. However, such strong disturbances couldn't be observed in the carried on therapy with 0.3 mg.

The results of EEG investigations after Spiller-Frazier's operation for trigeminal neuralgia in 112 patients are reported. Follow-up EEGs were recorded within 1-8 years after surgery; two to three follow-up tracings were available in 53 patients. Two distinct phases of EEG alterations were noted: 1) The immediate postoperative phase characterized by bilateral delta waves of maximal distribution in the frontal-precentral area and in the temporal area on the side of surgery. Such alterations are supposedly due to postoperative edema or associated metabolic disturbances. 2) Several months after surgery focal abnormalities of the temporal lobe develop, which consist of high amplitude alpha-, beta- or theta-waves, sharp waves, spikes and occasional stypical spike-and-wave complexes. These abnormalities are reflected on the contralateral side in approximately one third of the case. Repeated EEGs confirmed the consistency of degree and location of these findings with the exception of a less constant incidence of spikes and sharp waves. Severity of EEG abnormalities and incidence of potentially epileptogenic discharges increases with age. In spite of the precarious location of such focal abnormalities in the temporal lobe only 3 of 112 patients (2.7%) reported seizures with temporal lobe features. The age of the three patients was below the average age of 59.1 years. Seizures occurred sporadically beginning approximately 2 years after surgery. The low incidence of seizures may in our opinion be due to the advanced age of most patients.

The visual evaluation of 370 clinical EEGs of 125 patients in different stages of the HIV-infection as well as 42 HIV-seronegative volunteers of the same high risk population (male homosexuals) proved the increasing appearance of CNS dysfunction with progression of the disease. An especially established hyperventilation-index for a semiquantitative evaluation of hyperventilation response showed an increase of slow-wave activity in the course of the infection. The appearance of slow-waves as well as a significant slowing of background activity in advanced stages of the HIV-infection can be regarded as unspecific signs of a beginning diffuse functional CNS disorder caused by a direct affection of the CNS through the Human Immunodeficiency Virus (HIV). The EEG changes in early stages are not specific as to their causative agent and do not allow the distinction between primary and secondary CNS involvement. The changes may precede clinical-neurological alterations.

Das Elektroenzephalogramm ist ein so unmittelbarer Ausdruck der Vigilanz, das die Aufdeckung der Beziehung zwischen Schlaftiefe und bestimmten Schlafmustern schon in die Pionierzeit der EEG-Forschung fiel. Die Grundlagen der elektroenzephalographischen Schlaftiefenbestimmung verdanken wir der Arbeitsgruppe um Loomis [39–41], die damit bereits in den dreisiger Jahren die moderne Schlafforschung einleitete, ohne deren Methodik unser heutiger Wissensstand undenkbar ware. Bis dahin veranderten die Schlaftiefenbestimmungen durch Weckreize den Schlafablauf jeweils so entscheidend, das vor der EEG-Aera von einer effektiven Schlafforschung nicht gesprochen werden konnte.

Stable EEG-characteristics of a normal healthy person can be subdivided into posterior basic rhythms and normal variants. Posterior basic rhythms are: alpha type, theta type, occipital beta type and diffuse beta type. Normal variants--accessory characteristics without pathological significance--are: occipital theta variant, mu waves, beta bursts over the frontal areas, lambda and sleep lambda waves as well as subvigil beta bursts. It has been proven that posterior basic rhythms as well as normal variants--the latter only to some extent Both types of posterior beta rhythm show a high correlation with low voltage and are inherited in a simple autosomal dominant mode. Both types of frontal beta bursts are rare normal variants, and show characteristics which can be easily distinguished from each other. Type 1 is inherited in a simple autosomal dominant mode whereas type 2 is inherited in a simple dominant mode. Subvigil beta bursts are found in 10% of the population as a stable characteristic during light NREM and during REM sleep. A sleep dominant mode of inheritance--although quite likely--has not yet been proven even though this characteristic shows a marked individual stability.