The effects of sleep deprivation on the EEGs of epileptic children

Diagnostic yield of standard-wake and sleep EEG recordings

OBJECTIVE

To investigate whether Posterior Dominant Rhythm (PDR) can be reliably assessed in sleep-EEG recordings and to investigate the diagnostic yield of standard-wake and sleep-recordings.

METHODS

EEG recordings of 303 consecutive patients aged 18-88 years were analyzed. All patients had both standard-wake and sleep-recordings, including patients who had abnormal standard recordings. Melatonin was used in 6% of sleep EEGs, and sleep deprivation in 94%. The mean duration of sleep was 41 min. We measured the PDR frequency in standard and sleep-recordings, both before and after sleep. We compared the diagnostic yield of standard-wake and sleep EEG recordings.

RESULTS

Compared to standard EEG, sleep-recordings showed a significantly lower PDR frequency, both when measured before and after sleep (p < 0.001). One-hundred-fifty-six patients (51%) had normal standard recordings, and 35 of them (22%) had abnormal findings in the sleep-recording. One-hundred-forty-seven patients had abnormal standard recordings and in 16 of them (11%) these abnormalities were not present in sleep-recording.

CONCLUSIONS

PDR is significantly slower in the wake periods of sleep-recordings, compared to standard wake recordings.

SIGNIFICANCE

Sleep and standard wake recordings are complementary.

Feasibility of sleep-deprived EEG in children

BACKGROUND

Non-sedated EEG recording in children can be technically challenging, particularly when behavioral disorders are present. We aimed to assess the feasibility and the efficacy of non-sedated sleep-deprived EEG in children with behavioral disorders and in young children.

METHODS

We retrospectively reviewed the EEG recordings and computerized medical records of all pediatric inpatients at least 2-month-old that had a sleep-deprived EEG during a 5-year period between 2009 and 2014.

RESULTS

We present the data of 261 children, 142 (54%) boys, mean age 7.9 ± 4.9 years, 67 (26%) aged 0.5-4 years. Behavioral disorders were reported in 38 (15%) of the patients. Mean recording duration was 50.8 ± 12.5 min, and mean sleep duration- 31.8 ± 15.2 min. Thirty-seven (14%) patients slept less than 15 min during the EEG, including 19 (7%) patients with no sleep during the recording. Sleep duration and the presence of interictal epileptiform discharges did not significantly differ between children with/without behavioral disorders and in those younger/older than 4 years. Patients that did not fall asleep during the EEG did not differ from the others regarding presence of behavioral disorders or age.

CONCLUSIONS

These results suggest that non-sedated sleep-deprived EEG is feasible in young children and in those with behavioral disorders. Further studies are needed in order to better characterize the etiologies of sleepless pediatric sleep-deprived EEG recordings.

Usefulness of a simple sleep-deprived EEG protocol for epilepsy diagnosis in de novo subjects

OBJECTIVE

In case series concerning the role of EEG after sleep deprivation (SD-EEG) in epilepsy, patients' features and protocols vary dramatically from one report to another. In this study, we assessed the usefulness of a simple SD-EEG method in well characterized patients.

METHODS

Among the 963 adult subjects submitted to SD-EEG at our Center, in the period 2003-2010, we retrospectively selected for analysis only those: (1) evaluated for suspected epileptic seizures; (2) with a normal/non-specific baseline EEG; (3) still drug-free at the time of SD-EEG; (4) with an MRI analysis; (5) with at least 1 year follow-up. SD-EEG consisted in SD from 2:00 AM and laboratory EEG from 8:00 AM to 10:30 AM. We analyzed epileptic interictal abnormalities (IIAs) and their correlations with patients' features.

RESULTS

Epilepsy was confirmed in 131 patients. SD-EEG showed IIAs in 41.2% of all patients with epilepsy, and a 91.1% specificity for epilepsy diagnosis; IIAs types observed during SD-EEG are different in generalized versus focal epilepsies; for focal epilepsies, the IIAs yield in SD-EEG is higher than in second routine EEG.

CONCLUSIONS

This simple SD-EEG protocol is very useful in de novo patients with suspected seizures.

SIGNIFICANCE

This study sheds new light on the role of SD-EEG in specific epilepsy populations.

The complementary value of sleep-deprived EEG in childhood onset epilepsy

BACKGROUND

Although EEG is an important diagnostic tool in suspected childhood onset epilepsy, as many as 50% of wakefulness records remain normal. Sleep-deprived EEG has been reported in adults to serve as an activator of epileptic discharges but such effect is still not agreed upon in children reporting small series.

PURPOSE

Assess the complementary diagnostic value of sleep deprivation on the induction of epileptic discharges in childhood onset epilepsy having a normal awake record within a period of 5 years. EEG recording was performed during the awake, drowsiness and sleep states following sleep deprivation of 6h. BACKGROUND RESULTS: Fifty five children of whom the initial record failed to detect epileptiform discharges, were assessed at age 5-17 years (mean: 10+/-3.7), 27 boys and 28 girls. Sleep occurred in 51 (92.7%) after sleep deprivation and in only 1 (1.8%) during an awake record. Epileptic discharges were detected in 15 of 55 (27.2%) previous non-epileptic awake records during the sleep-deprived EEG either during wakefulness and more frequent during sleep. Eight abnormal records were detected in 18 (44%) children presenting with a focal seizure and 7 of 35 (20%) associated with generalized seizures. Epileptic discharges were recorded mainly and more frequent during sleep.

CONCLUSIONS

Our data suggests that sleep deprivation imposes an apparent activating impact uncovering epileptic discharges children corroborating with overt clinical seizures even beyond the sampling effect of repeat records.

The relationship between sleep and epilepsy

The occurrence of seizures in the sleep state is observed in nearly one third of patients. This is caused by an intimate relationship between the physiological state of sleep and the pathological process underlying epileptic seizures. Both sleep and sleep deprivation influence the frequency of epileptiform discharges on electroencephalograms as well as the occurrence of clinical seizures, typically during nonrapid eye movement sleep. The relationship of epileptiform activity to nonrapid eye movement sleep is vividly shown in the syndrome of continuous spikes in slow-wave sleep and the Landau-Kleffner syndrome. Seizure semiology can also be influenced by sleep and sleep deprivation. Sleep disorders may influence seizure control, and effective treatment of sleep disorders can improve seizure control. Seizures, antiepileptic drugs, ketogenic diet, and vagus nerve stimulation all influence sleep quality, daytime alertness, and neurocognitive function.

Increasing the yield of EEG

The EEG is the most common neurodiagnostic test performed to evaluate patients with suspected seizures. The majority of EEGs are requested in patients because of suspected seizures or for seizure management. It is unlikely that the patient's usual spell will be recorded during a routine EEG. Therefore, several activation techniques have been used in clinical EEG to help increase the occurrence of interictal epileptiform abnormalities, which are highly correlated with the diagnosis of a seizure disorder. EEG laboratories have long employed these techniques, which include hyperventilation, intermittent photic stimulation, sleep, and sleep deprivation. However, despite being utilized in routine clinical EEGs for decades, a number of differing views on the usefulness and indications for these procedures exist. This review will evaluate these procedures and review their history, technique, effectiveness, controversies, and unanswered questions.

Sleep and epilepsy: what we know, don't know, and need to know

Long-term video-EEG and, more recently, video-polysomnography, have provided the means to confirm and expand on the interconnections between sleep and epilepsy. Some of these relationships have become firmly established. When one of the authors (N.F.S.) presented part of this paper at a symposium on the Future of Sleep in Neurology at an American Clinical Neurophysiology Society annual meeting in 2004, the purpose was to summarize what we know, don't know, and need to know about the effects of sleep on epilepsy and epilepsy on sleep. Here we seek to summarize some of the more firmly established relationships between sleep and epilepsy and identify intriguing associations that require further elucidation.

Is the Sleep-deprivation EEG a Burden for Both Child and Parent?

BACKGROUND AND PURPOSE

Inducing sleep deprivation is supposed to increase interictal epileptic discharges on EEGs from children suspected of having epilepsy. Although it is supposed that depriving a child from sleep is a burden for both child and parent, this assumption has not been investigated in any study so far.

METHODS

To analyze the perception of the sleep deprivation procedure, we developed two questionnaires, one for the parent and one for the child over ten years of age at the time of the SDEEG. These questionnaires were sent to parents of all 179 patients and 47 children (older than ten) from which a SDEEG was obtained because of suspected epilepsy. A total of 103 questionnaires were returned by the parents and 18 by the children. The extent to which the SDEEG turned out to be inconvenient was assessed with regard to issues that covered the psychological and physical impact of the SDEEG.

RESULTS

Our results showed that the whole procedure of the SDEEG proved to be a burden for 18.6% of the parents and 23.5% of the children. 49.6% of the parents reported complaints including their child- like fatigue, illness and in 2 cases even an increase in seizure frequency. Overall, 47.1% of the children described having symptoms the next day. These consisted mainly of fatigue.

CONCLUSION

Our survey shows that the SDEEG places a notable burden on both parent and child. This should be taken into consideration before requesting an SDEEG.

Simple instructions for partial sleep deprivation prior to pediatric EEG reduces the need for sedation

OBJECTIVE

To study the effects of providing simple instructions for partial sleep deprivation on the necessity for sedation in children and adolescents undergoing electroencephalography (EEG).

METHODS

Children and adolescents below 18 years undergoing non-urgent routine EEG were studied for the need for sedation during the EEG test. Two consecutive 3-year periods were reviewed. During the first 3 years no instructions for sleep deprivation were given, and during the second 3-year period, simple instructions were given to the patient or parents of young children to have less sleep prior to the EEG test. This was achieved by using the same sleep deprivation schedule irrespective of the age of the patient.

RESULTS

In the first 3-year period between January 1996 and December 1998, 785 non-urgent routine EEG recordings were performed in which only 146 (19%) pediatric patients managed to fall asleep without the need for any sedation within 30 min of being ready for the sleep recording. When partial sleep deprivation was implemented in the 3-year period between January 2000 and December 2002, 449 (55%) out of 821 patients undergoing the test fell asleep in the laboratory without sedation, an overall increase of 36%. Analyzing the different age-specific groups, the maximal increase in the success for natural sleep following partial sleep deprivation was 44% for pediatric patients aged above 10 years.

CONCLUSIONS

Simple instructions for partial sleep deprivation prior to the EEG reduced the need for sedation in children and adolescents undergoing the test.

The relationship between sleep and epilepsy

Seizures occur extensively during sleep or on awakening in a substantial proportion of patients with epilepsy. Interictal epileptiform discharges are also influenced by sleep and sleep deprivation. Continuous spike-waves in slow-wave sleep are the hallmark of Landau-Kleffner syndrome and ESES (Electrical Status in Slow Sleep). Sleep deprivation is known to influence not only the occurrence but also the symptomatology of epileptic seizures. Sleep architecture and daytime alertness are influenced by seizures and antiepileptic medications. This review examines the clinical and basic science aspects of this relationship between sleep and epilepsy.

Interactions between sleep and epilepsy

Sleep is one of the best-documented factors influencing the expression of seizures and interictal discharges. Janz studied the relation between seizures and the sleep/wake cycle and divided the epilepsies into three categories: nocturnal, awakening, and diffuse. Since then, the effect of sleep on the ictal and interictal manifestations of epilepsy has been studied extensively. Many seizures are activated by sleep or arousal from sleep. Interictal discharges are also seen more commonly during sleep, with the greatest activation seen during nonrapid eye movement sleep. Sleep not only increases the frequency of epileptiform abnormalities, but also may alter their morphology and distribution. Sleep deprivation also facilitates both epileptiform abnormalities and seizures. Seizures, on the other hand, also impact sleep. Epileptic patients demonstrate multiple sleep abnormalities, including an increased sleep latency, fragmented sleep, increased awakenings and stage shifts, and an increase in stages 1 and 2 of nonrapid eye movement sleep. These disturbances may in turn be modulated by antiepileptic treatment. This review summarizes the interactions between sleep and epilepsy, including the timing of seizures during the sleep/wake cycle, the influence of sleep on various seizure disorders, the effects of sleep deprivation, and the changes in sleep patterns caused by seizures and their treatment.

Sleep and sleep deprivation as EEG activating methods

OBJECTIVES

We examined retrospectively 19 patients with a history of clinical seizures, but normal activity or unclear epileptiform abnormalities in wake EEG recordings and obtained preliminary data for a controlled cohort study to evaluate the effects of sleep deprivation (SD) on interictal epileptic activity.

METHODS

Nineteen patients referred to our EEG department for diagnostic or follow-up purposes were divided in two groups on the basis of the different EEG protocols applied. The first group (n=5) underwent two laboratory polysomnographies during afternoon naps, after SD, but the patients failed to fall asleep in one of the two occasions. The second group (n=14) was submitted to two polysomnographies, the first without SD and the second after SD.

RESULTS

The first group of patients demonstrated focal epileptic discharges in 4 patients in which wake after SD appeared to be less activated that sleep after SD. In the second group the results obtained from the waking part of the recordings suggest a lack of activating effect due to SD.

CONCLUSIONS

SD does not seem to offer greater activation than sleep alone. However, a mild SD may be a convenient activating method for inducing sleep and drowsiness without using any drug.

The value of partial sleep deprivation as a routine measure in pediatric electroencephalography

For more than 50 years it has been known that in patients with epilepsy, sleep markedly increases the diagnostic yield of the electroencephalogram (EEG). Sleep deprivation could have an additional activating role. Many laboratories do not use these methods routinely but reserve them for a second EEG if equivocal or negative findings are present in the initial EEG. We studied a regime of routine partial sleep deprivation without the use of hypnotic agents in 396 children younger than age 17 years who were referred for EEG with a diagnosis of epilepsy or suspected epilepsy. Sleep was achieved for the EEG in 77% (96% in the 1 month to 2 year age group, 78% in the 2 to 8 year age group, and in 64% of those more than 8 years old). In a comparison group of 72 children who had not been sleep-deprived, sleep was achieved in 44% (69% of those less than 2 years old, 27% of those between 2 and 8 years of age, and 33% of those older than 8 years). The differences were highly significant. The regime was well tolerated. Routine partial sleep deprivation is a practical and effective method of obtaining sleep and thus maximizing the information obtained from a single EEG.

EEG in epilepsy: current perspectives

The electroencephalogram (EEG) plays an important diagnostic role in epilepsy and provides supporting evidence of a seizure disorder as well as assisting with classification of seizures and epilepsy syndromes. Emerging evidence suggests that the EEG may also provide useful prognostic information regarding seizure recurrence after a single unprovoked attack and following antiepileptic drug withdrawal. Continuous EEG video telemetry monitoring has an established role in the diagnosis of non-epileptic pseudo-seizures and in localizing the seizure focus for epilepsy surgery. Newer tools such as EEG mapping and magneto-encephalogram, although still investigational, appear potentially useful for defining the seizure focus in epilepsy. This review examines the traditional concepts of clinical EEG in the light of newly available data.

Sleep deprivation activates epileptiform discharges independent of the activating effects of sleep

An electroencephalogram (EEG) recorded after sleep deprivation (SDEEG) in epilepsy patients often discloses epileptiform discharges (ED) when routine EEG (REEG) does not, but since sleep alone activates ED, activation during SDEEG may result merely from the induction of sleep. We retrospectively investigated whether SDEEG is useful when REEG containing wakefulness and sleep fails to show ED. Subjects were patients with definite or highly probable epilepsy whose REEG lacked ED and who later underwent SDEEG. All had wakefulness and at least stage II sleep during both REEG and SDEEG. Patients with ED on REEG were specifically excluded to avoid including patients with activation due merely to the occurrence of sleep. Patient and EEG characteristics were studied, including duration of wakefulness and each sleep stage and timing and characteristics of ED. Fifteen of 29 patients (52%) had activation on SDEEG; exclusively during wakefulness in 1, exclusively during sleep in 6 and in both wakefulness and sleep in 8. Activation rates were not significantly different between wakefulness (9, 60%), stage I (11, 74%) and stage II (11, 74%). EEG characteristics were similar for REEG and SDEEG, except that total EEG duration and stage II sleep were longer in SDEEG than in REEG, which did not influence activation by a logistic regression model (p > 0.05). We conclude that sleep deprivation activates ED independent of the activating effects of sleep and therefore is useful in evaluation of suspected epilepsy even when REEG contains sleep.

The diagnostic yield of a second EEG after partial sleep deprivation: a prospective study in children with newly diagnosed seizures

PURPOSE

To assess the diagnostic yield of a repeated EEG (REPEEG) after partial sleep deprivation (SD) in children and adolescents with one or more seizures who previously had had a standard EEG (STDEEG) without epileptiform abnormalities (EAs). In the literature, 32-75% of such REPEEGs after SD were reported to show EA.

METHODS

In a prospective, multicentred study, we selected children aged 1 month to 16 years with one or more idiopathic or remote symptomatic newly diagnosed seizures. A REPEEG was recorded in children without EAs in their STDEEG.

RESULTS

Of 552 children and adolescents who entered the study, 243 (44%) had a STDEEG without EAs. In 177 (73% of eligible children), REPEEGs were recorded after SD. We found EAs in 61 (34.5%) REPEEGs and new nonepileptiform abnormalities in five (1%). In 552 children in the total cohort, the REPEEG thus added 11% with EAs to the 56% with EAs in the STDEEG. Of REPEEGs, 81% included sleep compared with 20% of STDEEGs. In about half the REPEEGs, EAs occurred during sleep only. One child had tonic-clonic seizures probably related to the SD.

CONCLUSIONS

One third of REPEEGs yielded new diagnostic information. Partial, age-dependent SD was highly effective in inducing sleep, which is important because in many cases EAs were found only during EEG recording in sleep. The procedure was safe and convenient.

On the genetics of complex partial seizures: waking and sleep EEGs in siblings

Waking and sleep EEGs were recorded in 29 siblings of 19 patients with complex partial seizures. At least 1 sibling with epileptic activity (EA) was found for 36.8% of the patients. Taking the 29 siblings as a basis, in 7 EA was recorded. Most EA was seen during sleep in stage C (29%). More EA was recorded in female siblings (28%: 18%) and in siblings of female patients (56%: 20%). All EA was seen in the age range 5-14 years. Siblings with occipital theta-delta activity with a generalization tendency showed more EA (59%) than those without this pattern (8%). Of the siblings of patients with generalized EA 50% showed EA, but only 25% of those of patients with localized EEG patterns.

Effect of sleep deprivation on the EEG of learning-impaired children with absence seizures

Learning-impaired children can present with a clinical history suggesting additional problems, including attention deficit disorder and absence seizures. Physicians use clinical judgment in diagnosing the former, but rely heavily on the electroencephalogram (EEG) to diagnose the latter. Most clinicians are reluctant to treat patients with anticonvulsants without seeing 3 Hz spike-and-wave discharges in an EEG. We studied 21 learning-impaired and 7 control children, ages 5 through 12 years, with normal baseline EEGs. All had an additional EEG recorded after 24 hour sleep deprivation. Nine learning-impaired children had a history compatible with absence seizures; 8 of them showed spike-and-wave discharges after sleep deprivation. Of the 12 learning-impaired children with no history of absence seizures, 2 showed spike-and-wave discharges after sleep deprivation. These results are significant (p less than 0.001). Of the 7 controls, none had epileptiform activity following sleep deprivation. Our results show that routine EEGs may be falsely negative in patients with absence seizures, and that sleep deprivation is a potent activator.

A contribution to the genetics of febrile seizures: waking and sleep EEG in siblings

Waking and sleep EEGs were recorded in 67 siblings of 52 patients with febrile seizures (FS). Epileptic activity was noted in at least 1 sibling for 28 of the 52 patients (53.8%). Epileptic discharges were noted in 33 (49.2%) of the 67 siblings. Thirty-two siblings had 3-4 Hz spike wave complexes, and 1 sibling had independent centrotemporal spike foci (rolandic foci). Epileptic activity was noted exclusively in the waking state in only 3%, in waking and sleep in 31.3%, and only in sleep in 14.9%. The greatest number of epileptic discharges occurred in waking during hyperventatilation (32.8%) and during stage C sleep (38.8%). In 5 photosensitive siblings, additional epileptic discharges were noted in sleep in 1 and in waking and sleep in 4. At least 1 sibling in 5 (55.6%) of 9 patients with complicated febrile seizures, in 23 (53.5%) of 43 patients with simple FS, and in 4 of 9 patients (44.4%) with later onset epileptic seizures had seizure discharges. At least 1 sibling in 24 of 43 patients (55.8%) with exclusively FS in 13 of 30 (43.3%) male patients and in 15 of 22 (68.2%) female patients had seizure discharges. Siblings aged 6-10 years had (66.7%) the highest rates of activation. Epileptic discharges were noted in 83.3% of siblings with seizures, but in only 45.9% of siblings without seizures. Seizure activity was recorded in 68.2% of siblings who had occipital 3-4-Hz theta-delta-activity but in only 13.0% of siblings without this pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Absence epilepsy and the level of vigilance in rats of the WAG/Rij strain

In man, a relationship exists between sleep-wake states and absence epilepsy. During wakefulness, spike-wave discharges predominantly occur when the level of vigilance is not high, while during sleep they have a preference to occur during slow-wave sleep. During this latter type of sleep, spike-wave discharges prevail in periods where slow-wave sleep is light. In a series of experiments, the WAG/Rij rat model for absence epilepsy was characterized with respect to the relationships between the level of vigilance, sleep-wake states and the occurrence of spike-wave discharges. In the first experiment, continuous recordings were made for a period of 48 h and a clear circadian rhythm was established for the number of spike-wave discharges. A maximum appeared during the middle of the dark period of the rat, whereas a minimum was detected directly after the onset of the light period, the time period during which deep slow-wave sleep predominates. The relationship of spike-wave discharges with states of vigilance was elaborated in a second study. Spike-wave discharges were mainly found during light slow-wave sleep, during passive wakefulness and in transition phases from sleep to wakefulness. During REM sleep no spike-wave discharges were found. In the last three experiments, the level of alertness was enhanced by various procedures as photostimulation, a learning task and deprivation of REM sleep. In all cases, an increase of alertness decreased the amount of epilepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Some genetic aspects of idiopathic and symptomatic absence seizures: waking and sleep EEGs in siblings

Epileptic activity was recorded in the waking and sleep EEG of 62.5% of 80 siblings of 38 patients with absence seizures. Epileptic discharges were noted in waking only in 8.7%, in waking as well as sleep in 28.8%, and in sleep only in 25%. Generalized, partly irregular, and slow spike-wave complexes were found, twice with lateral emphasis. Spike-wave complexes were recorded in 72% of 50 siblings of patients with idiopathic absence and in 46.7% of 30 siblings of patients with symptomatic absence. One epileptic discharge was observed every 108.6 s on the average, without striking differences between siblings of patients with idiopathic (99.7 s) and symptomatic absence (119.3 s). Without any differences between siblings of children with idiopathic and symptomatic absence, the most epileptic discharges were activated in sleep stages C and D, followed by stages A and B. The highest activation rate was observed in the 7-14-year-old group (73.5%) and to a somewhat lesser degree in the group between 15 and 20 years of age (66.7%); fewer epileptic discharges were recorded in younger (25%) and older patients (28.6%). The higher activation rates in the male sex were significant only in siblings of patients with idiopathic absence. Although only five patients (13.2%) were photosensitive, a photosensitivity was found in 24% of siblings of children with idiopathic absence and in 20% of siblings of patients with symptomatic absence. Three siblings of patients with idiopathic absence also had absence seizures; in one of them a febrile seizure occurred at an earlier age. All of them showed generalized spike wave discharges in waking as well as sleep. Occipital theta delta activity with generalization was observed more frequently in siblings of patients with idiopathic absence (82.2%) than in those of patients with symptomatic absence (63.6%). Our waking and sleep EEG recordings prove that concerning etiology-genetic factors play a striking role in idiopathic absence, but are also of considerable significance in the symptomatic types.

Some genetic aspects of rolandic epilepsy: waking and sleep EEGs in siblings

Epileptic activity was recorded electroencephalographically in at least one sibling in 22 (51.16%) of 43 patients with rolandic epilepsy and/or centrotemporal spikes. In 26 of 69 (37.68%) siblings, epileptic discharges were observed. These were recorded only in waking in 1 subject (1.5%), in waking and sleep in 13 (18.8%), and in sleep only in 12 (17.4%). The greatest number of epileptic discharges was noted in waking during hyperventilation (52.4%) and in sleep stage C (88%). Foci were recorded in only 4 (5.8%) of the 26 cases with epileptic discharges, and generalized spike-wave complexes were recorded in 22 (31.9%). In one sibling, the sharp-wave focus was located in the right centrotemporal area, in a second in the left occipital, and in a third in the left frontal region with spreading to the centrotemporal; in the fourth, two independent foci were observed in the left and right centrotemporal area. One epileptic discharge was observed every 74.9 s in waking and every 150.9 s in sleep. Epileptic activity was greatest in the group between 5 and 12 years of age (54.3%). The same activation rates were noted in siblings of patients with (47.2%) and without seizures (42.9%), and no differences were noted in siblings with (40%) or without (37.5%) seizures. Family history and sex of the siblings of patient did not play a role in the rate of activation. An autosomal dominant inheritance is assumed, but further investigations are necessary.

Absence epilepsy in rats is reduced by deprivation of REM sleep

Effects of deprivation of REM sleep on spontaneous occurring spike wave complexes in the WAG/Rij rat strain were studied by means of the pendulum and platform technique. During the deprivation period, which lasted three days, variable results were obtained. While a suppression of the total duration of epileptic activity was found for the pendulum deprived animals, no such evident effect was detected in the platform deprived rats. Probably, instrumental effects are responsible for these differential results. On the other hand, subsequent to deprivation, a prolonged reduction of the total duration of spike wave activity was seen in both deprived groups. While it is known that under normal circumstances absences only occur during low levels of arousal and because there is evidence that deprivation of REM sleep has arousal increasing properties, it is suggested that the reduction in epilepsy is caused by an increase of arousal. This result also implies that, at least in the case of absence epilepsy, REM sleep deprivation is not the crucial factor for the epilepsy provoking effect of total sleep deprivation.

The effect of sleep deprivation on the rate of focal interictal epileptiform discharges

Eight men with complex partial seizures who had frequent focal interictal epileptiform discharges (FIEDs) during routine EEGs were selected for all-night EEG recording before, and after 36 h of sleep deprivation. After sleep deprivation 6 of 8 patients showed increased FIEDs. The pooled mean number of FIEDs was greatest during light non-REM stages of sleep, especially stage II. Thus sleep deprivation is an effective activation method in medicated patients with complex partial seizures. However, a significant activation requires recording stage II sleep after sleep deprivation.

The diagnostic value of the sleep EEG with and without sleep deprivation in patients with atypical absences

Hitherto it has not been known whether or not the sleep EEG after sleep deprivation is more effective than the simple or drug-induced sleep EEG. To investigate this, we recorded for 32 patients both sleep EEGs without sleep deprivation and, on the following day, sleep EEGs after 24 h of sleep deprivation. All the patients had atypical absences which were almost exclusively combined with generalized seizures or some other seizure types. All patients were receiving antiepileptic therapy. Sleep without sleep deprivation was induced by oral administration of 2 mg/kg body weight Protactyl (promazine hydrochloride). In patients showing no epileptic activity in the routine EEG, epileptic discharges could be provoked in 78% without sleep deprivation and in 72% after sleep deprivation. Epileptic activity was already seen in 28.1% of the cases in the awake EEG without sleep deprivation, recorded immediately before the sleep EEG, and in 50% of the cases in the awake EEG after sleep deprivation. It is unlikely that promazine hydrochloride in the dose used here has an additional inherent provocative effect. Generalized spike-and-wave complexes or sharp slow wave complexes which were combined twice with foci and runs of rapid spikes were recorded. In the sleep EEG without sleep deprivation, epileptic discharges were seen in the somewhat shallower stages (C leads to A leads to B leads to D) and, in the sleep EEG after sleep deprivation, in the somewhat deeper stages (D leads to C leads to B leads to A). Fewer epileptic discharges were elicited in patients who were older at the time of their first seizure. The illness was mild in patients whose sleep EEGs showed no epileptic activity. It is concluded that, as a rule, it is not necessary to record an EEG after sleep deprivation in patients with atypical absences whose routine EEGs show no epileptic activity; the drug-induced sleep EEG shows the same provocative effect.

The effect of sleep deprivation on the EEG in epilepsy

Many published studies report an increased incidence of epileptiform EEG activity following sleep deprivation in persons with epilepsy in whom a previous routine EEG was normal or inconclusive. Few such studies, however, permit a clear distinction to be made between the effects of sleep deprivation per se, sleep induction following deprivation, or simply repeated EEG recording. Sixty-nine patients have been investigated in whom a routine waking record, a secobarbital-induced sleep recording and an EEG following 24 h sleep deprivation were obtained in random order irrespective of whether or not the initial EEG contained epileptiform activity. For each record the incidence of epileptiform activity if any, was quantified in terms of discharges per minute for wake, drowsiness and each sleep stage. The findings confirmed the marked activating effect of light sleep on the EEG but there was no evidence of an overall increase in discharge rate after sleep deprivation either in the waking state or in the various sleep stages when these were compared with secobarbital-induced or spontaneous sleep. There was a significant increase of generalized discharges in the waking state only, after sleep deprivation, but a decrease in incidence of focal epileptiform activity. It is concluded that although specific indications may exist for the use of sleep deprivation, as a general method of EEG activation in epilepsy it has no advantages over barbiturate-induced sleep to offset the greater inconvenience to patients.

Comparative evaluation of sleep deprivation and sedated sleep EEGs as diagnostic aids in epilepsy

The comparative value of sedated sleep and sleep deprivation EEGs was investigated in a consecutive series of 43 patients who had received both types of activation study for diagnostic purposes. Patients were referred because of persisting doubt concerning either the diagnosis of epilepsy, or the type of epilepsy present in those with definite seizures. Forty-one had had routine waking EEGs, all of which were normal or only mildly abnormal. EEGs were rated without access to previous reports or clinical data, and epileptiform discharges (ED) were semiquantified during wakefulness and sleep. De novo precipitation of ED, increase in abundance of ED and discovery of a new independent focus or a new type of ED were taken as the yield of useful information. 44% of sleep deprivation records provided useful information compared to 14% of sedated sleep recordings (P less than 0.005). In addition, sleep deprivation was significantly superior to sedated sleep in differentiating those with a final clinical diagnosis of epilepsy from those with doubtful or no epilepsy (P less than 0.001). It is suggested that the usefulness of the interictal EEG in patients with uncertain epilepsy or epilepsy of unknown type is increased by performance of a diagnostic series to include routine waking, sedated sleep and sleep deprivation recordings.

A comparative study of the diagnosis value of drug-induced sleep EEGs and sleep EEGs following sleep deprivation in patients with complex partial seizures

The purpose of the study was to investigate whether the sleep EEG after sleep deprivation has a stronger provocative effect than the drug-induced sleep EEG. For this purpose a sleep EEG, induced by 2 mg/kg body weight of promazine hydrochloride, was recorded. On the following day a sleep EEG of the same patient was recorded after sleep deprivation of 24--26 h. If only patients whose wake EEGs were free from epileptic activity are considered, the rate of provocation was 58%. As epileptic activity could be recorded even in the sleep EEG without sleep deprivation in 45%, the advantage gained by recording a sleep EEG after sleep deprivation (52%) is only relatively small. The occurrence of epileptic activity was shown to be significantly more frequent amongst women and those who developed epilepsy at a younger age. For practical purposes it is recommended that for those patients whose wake EEGs are free from epileptic activity, a sleep EEG--possibly drug-induced--should be recorded. Only in instances where epileptic activity can not then be recorded should a wake EEG after sleep deprivation be carried out, and followed immediately, if necessary, by a sleep EEG.

A study of the diagnostic value of waking and sleep EEGs after sleep deprivation in epileptic patients on anticonvulsive therapy

One hundred and twenty-seven waking and sleep EEGs were recorded from 102 epileptic patients on anticonvulsant therapy, after sleep deprivation. Epileptiform activity was found in 63% of the patients, or 57% of the records. Since in previously recorded waking EEGs epileptic discharges had been registered in 19%, or 17% respectively, the rate of increase was considerable. The rate of activation was 51% in patients without epileptic activity in their waking EEGS. Two-thirds of the epileptiform activity were already recorded in the waking EEGS, after sleep deprivation, One-third was recorded only during sleep. Epileptic discharges in the different sleep stages ranged from 25% (E) to 48% (C). On the other hand, approximately the same frequency was recorded in the separate sleep stages in patients whose waking EEGS after sleep deprivation showed epileptiform activity. The EEG changes were correlated with the different clinical parameters (type of seizure, frequency and duration of seizures, age at the first seizure and the time of examination, neurological findings, and personality changes).

A review of the biological effects of total sleep deprivation in man

This biologically oriented review attempts to complement earlier and more psychological performance based reviews of total sleep deprivation. Also, the effects of total sleep deprivation are interpreted, here, from a function of human sleep perspective, rather than from the more usual stress viewpoint. It would appear that total sleep deprivation does not produce any major changes in biochemical and physiological measures of somatic functioning. Such a conclusion would not seem to support an hypothesis that human sleep is for body restitution. Although there are equivocal results amongst several of the more psychophysiological measures, EEG does show a pronounced change. This latter finding, together with many reports of psychological performance detriment, would appear to sustain a CNS or cerebral restitutional role for human sleep. However, before definitive conclusions can be drawn from the biochemical and physiological findings of total sleep deprivation, the following qualifications of experimental methodology are made: (1) Apart from sleep loss, many studies have provided unnatural regimes which may have ameliorated possible effects of total sleep deprivation. (2) Most studies are of relatively short duration and may not have been sufficiently long for effects to develop. (3) Measures are often limited in range and depth of analysis. (4) Subjects are mostly fit, young adult, intelligent males and there is little constitutional variability. (5) Reported changes of statistical significance may be of no physiological significance and changes of possible physiological significance may be obscured by statistical procedures. (6) Intervening behavioural variables, such as novelty and anticipation of the sleep deprivation situation, may confound real effects.

Selective deprivation of sleep in pycnoleptic children. Effects of deprivation of slow-wave and REM sleep on the frequency and duration of petit mal attacks

1. Selective deprivation of slow-wave and paradoxical sleep was performed in 10 children with pycnoleptic attacks (8 of them before anticonvulsive treatment, 2 of them while under medication). The frequency and duration of petit mal attacks were intraindividually compared during night sleep and after waking for a 5-h period. 2. After deprivation of slow-wave sleep with reduction of EEG stages 3 and 4 to about one-third of the baseline but normal duration of sleep, petit mal attacks are more frequent and long-lasting than after normal sleep or selective deprivation of REM sleep. 3. Although total sleep time is significantly diminished after selective deprivation of paradoxical sleep the frequency of attacks during the waking state was lower than after normal sleep and deprivation of slow wave sleep. This observation shows a clear i nfluence of the quality of sleep on the frequency of epileptic attacks. 4. During sleep petit mal seizures were mainly found during stages 2 and paradoxical sleep. Single spike and irregular spike were discharges, however, occurred more frequently during slow-wave sleep. Their frequency was not significantly different in the deprivation conditions. 5. In contrast to experimental data in animals, REM deprivation is less provoking to epileptic attacks outside sleep than deprivation of stages 3 and 4 sleep. Therefore a sufficient amount of slow-wave should be preserved for pycnoleptic children.