The usefulness of sleep and sleep deprivation as activating methods in electroencephalographic recording: contribution to a long-standing discussion

Yield of Sleep Deprivation EEG in Suspected Epilepsy. A Retrospective Study

Background. Sleep is an activation procedure and is considered the most potent and best-documented modulator of seizures and interictal epileptiform discharges (IEDs) on electroencephalogram (EEG). The precise role of sleep deprivation in the diagnostic process of epilepsy has not been fully clarified after more than 50 years of use. Sleep deprivation is a procedure that is accompanied by discomfort for patients and their families. Therefore, an accurate indication according to each patient-specific characteristic is needed. This study aims to assess the effectiveness of sleep deprivation EEG in the diagnostic process of patients with suspected epilepsy in our center. Methods. We included patients with a first unprovoked seizure and patients with paroxysmal events suspecting seizures who underwent a sleep deprivation EEG (sdEEG) or routine EEG (rEEG). All patients were subsequently classified with confirmed epilepsy or not. Results. We included 460 patients. The group with sdEEG consisted of 115 patients, while the group with rEEG comprised 345 patients. In the sdEEG group, 19 patients (17%) were confirmed with epilepsy, of which 17 presented interictal epileptiform discharges (IEDs). For the rEEG group, 66 patients (19%) were confirmed with epilepsy, of which 63 presented IEDs. The difference was not statistically significant. Conclusion. Our study failed to find a difference in the yield of sleep deprivation versus routine EEG in patients with epilepsy, but there are many significant confounders/sample biases that limit the generalizability of the findings, particularly to the majority of adult practices.

Melatonin Versus Chloral Hydrate for Sleep Electroencephalography Recording in Children: A Comparative Study Using Bispectral Index Monitoring Scores and Electroencephalographic Sleep Stages

PURPOSE

To compare the effects of chloral hydrate and melatonin on sleep EEG recordings in children by using standard EEG sleep stages and the bispectral index scores (BIS).

METHODS

A total of 86 children were randomly assigned to two groups: (1) melatonin group (n = 43) and (2) chloral hydrate group (n = 43). BIS monitoring scores and sleep EEGs were recorded simultaneously. The effect of two drugs on sleep EEG recording was evaluated with sleep stages of EEG and BIS.

RESULTS

There was no statistically significant difference between the groups with regard to time to sleep onset and the need for a second drug ( P = 0.432; P = 1.000). Eight patients (18.6%) in chloral hydrate group reported side effects while there were no reported side effects in the melatonin group ( P = 0.006). Mean BIS values during EEG recordings were similar in both groups (59.72 ± 18.69 minutes and 66.17 ± 18.44 minutes, respectively, P = 1.000). The average time to achieve N2 sleep was 32.38 minutes in the chloral hydrate group and 43.25 minutes in the melatonin group ( P < 0.001). Both "time spent in wakefulness" and "N1 sleep" were found to be significantly higher in the melatonin group ( P < 0.001 and P = 0.005). BIS scores higher than 75 were found to be suggestive for wakefulness; 75 to 66 for N1, 65 to 46 for N2, and values lower than 46 were found to be indicative for N3 sleep with a good strength of agreement in weighted Kappa analysis (95% confidence interval; weighted Kappa = 0.67).

CONCLUSIONS

Melatonin is reliable and at least as effective as chloral hydrate for sleep EEG acquisition in children.

When should we obtain a routine EEG while managing people with epilepsy?

More than eight decades after its discovery, routine electroencephalogram (EEG) remains a safe, noninvasive, inexpensive, bedside test of neurological function. Knowing when a routine EEG should be obtained while managing people with epilepsy is a critical aspect of optimal care. Despite advances in neuroimaging techniques that aid diagnosis of structural lesions in the central nervous system, EEG continues to provide critical diagnostic evidence with implications on treatment. A routine EEG performed after a first unprovoked seizure can support a clinical diagnosis of epilepsy and differentiate those without epilepsy, classify an epilepsy syndrome to impart prognosis, and characterize seizures for antiseizure management. Despite a current viral pandemic, EEG services continue, and the value of routine EEG is unchanged.

Indications for epilepsy monitoring in pediatric and adolescent health care

Seizures present in childhood with infinite diversity. History alone may suffice for diagnosis in some cases; more often additional evidence is needed to clarify events of concern. Electroencephalography (EEG) is a primary methodology used for seizure identification and management. Pediatric and adolescent health care providers are increasingly asked to make decisions about when and how to refer patients for eventual monitoring and must then be able to confidently interpret any resulting report(s). Comprehensive literature review was undertaken to provide a succinct and up-to-date overview aimed at general and subspecialty non-neurologist pediatric and adolescent health care providers to not only convey a solid general understanding of EEG and what it entails for patients and their families, but also foster a deeper understanding of the indications for monitoring-and how to interpret documented findings. In plain language this resultant guide reviews EEG basics, provides a crash course in the various types of EEG available, discusses broad indications for epilepsy monitoring, guides counseling and management for patients and their families both before and after EEG, and ultimately aids in the interpretation of both findings and prognosis. This review should allow both primary and subspecialty non-neurologic pediatric and adolescent health care providers to better identify when and how to best utilize EEG as part of a larger comprehensive clinical approach, distinguishing and managing both epileptic and nonepileptic disorders of concern while fostering communication across providers to facilitate and coordinate better holistic long-term care of pediatric and adolescent patients.

Can absence seizures be predicted by vigilance states?: Advanced analysis of sleep-wake states and spike-wave discharges' occurrence in rats

Spike-wave discharges (SWDs) are the main manifestation of absence epilepsy. Their occurrence is dependent on the behavioral state, and they preferentially occur during unstable vigilance periods. The present study investigated whether the occurrence of SWDs can be predicted by the preceding behavioral state and whether this relationship is different between the light and the dark phases of the 24-h day. Twenty-four-hour (12:12 light/dark phases) electroencephalographic (EEG) recordings of 12 Wistar Albino Glaxo, originally bred in Rijswijk (WAG/Rij) rats, a well-known genetic model of absence epilepsy, were analyzed and transformed into sequences of 2-s length intervals of the following 6 possible states: active wakefulness (AW), passive wakefulness (PW), deep slow-wave sleep (DSWS), light slow-wave sleep (LSWS), rapid eye movement (REM) sleep, and SWDs, given discrete series of categorical data. Probabilities of all transitions between states and Shannon entropy of transitions were calculated for the light and dark phases separately and statistically analyzed. Common differences between the light and the dark phases were found regarding the time spent in AW, LSWS, DSWS, and SWDs. The most probable transitions were that AW was preceded and followed by PW and vice versa regardless of the phase of the photoperiod. A similar relationship was found for light and deep slow-wave sleep. The most probable transitions to and from SWDs were AW and LSWS, respectively, with these transition likelihoods being consistent across both circadian phases. The second most probable transitions around SWDs appeared more variable between light and dark. During the light phase, SWDs occurred around PW and participated exclusively in sleep initiation; in the dark phase, SWDs were seen on both, ascending and descending steps towards and from sleep. Conditional Shannon entropy showed that AW and DSWS are the most predictable events, while the possible prediction horizon of SWDs is not larger than 4 s and despite the higher occurrence of SWDs in the dark phase, did not differ between phases. It can be concluded that although SWDs show a stable, strong circadian rhythm with a peak in number during the dark phase, their occurrence cannot be reliably predicted by the preceding behavioral state, except at a very short time base.

Sleep deprivation and melatonin for inducing sleep in paediatric electroencephalography: a prospective multicentre service evaluation

AIM

To compare the efficacy of the main methodologies in attaining sleep and electroencephalography (EEG) abnormalities in children with a view to producing recommendations on best practice.

METHOD

Fifty-one UK centres participated. Methods for sleep induction (sleep deprivation, melatonin, and combined sleep deprivation/melatonin) were compared. Data pertaining to demographics, achievement of stage II sleep, and recording characteristics (duration of study, presence of epileptiform activity in awake/sleep states) were prospectively collected for consecutive patients in November and December 2013.

RESULTS

Five hundred and sixty-five patients were included. Age range was 1 years to 17 years (mean 7y 10mo), 27.7 per cent had an underlying neurobehavioural condition. Stage II sleep was achieved in 69 per cent of sleep deprived studies, 77 per cent of melatonin studies, and 90 per cent of combined intervention studies (p<0.001, χ² ). In children who slept, there was no difference between the three interventions in eliciting epileptiform discharges. In children who did not sleep, epileptiform abnormalities were seen more often than after sleep deprivation alone (p=0.02, χ² ). Seizures were rare.

INTERPRETATION

Combined sleep deprivation/melatonin is more effective than either method alone in achieving sleep. The occurrence of epileptiform activity during sleep is broadly similar across the three groups. We recommend the combined intervention to induce sleep for paediatric EEG.

WHAT THIS PAPER ADDS

Combined sleep deprivation/melatonin is more effective in achieving sleep than either sleep deprivation or melatonin alone. Sleep latency is shorter with combined sleep deprivation/melatonin. When children do sleep, there is no difference in the occurrence of epileptiform abnormalities between different induction methods. Seizures are rare in sleep electroencephalography recordings.

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.

Evaluation of the "non-epileptic" patient in a tertiary center epilepsy clinic

PURPOSE

The epilepsy clinic at the Montreal Neurological Institute receives a high volume of referrals. Despite most patients assessed in the clinic eventually being diagnosed with epilepsy, other disorders causing alteration of consciousness or paroxystic symptoms that could be misdiagnosed as seizures are seen frequently. The incidence and clinical characteristics of such patients have not yet been determined. We aimed to determine the proportion and clinical characteristics of patients referred to our epilepsy clinic who had a final diagnosis other than epilepsy.

METHODS

We performed a retrospective chart analysis of consecutive patient referrals to the epilepsy clinic from January 2013 to January 2015, inclusively.

RESULTS

Four hundred four patient referrals were evaluated, 106 (or 26%) had a final diagnosis other than epilepsy. Referrals came primarily from general practitioners and nonneurology specialists. Although most patients had a normal routine electroencephalography (EEG) prior to the clinic visit, sleep-deprived EEG and cardiac investigations were rarely performed. Patients received a final diagnosis other than epilepsy after 1 to 2 visits in 92% of cases and with minimal paraclinical investigations. Prolonged video-EEG recording was required in 27% of patients. The most common diagnoses were syncope (33%), psychiatric symptoms (20%), followed by migraine (10%), and psychogenic nonepileptic seizures (9%).

CONCLUSIONS

A significant proportion of patients seen in our tertiary care epilepsy clinic is in fact, not patients with epilepsy. Enhanced knowledge of these differential diagnosis and important anamnesis components to rule out seizures will help improve guidelines for referral to Epilepsy clinic and cost-effectively optimize the use of paraclinical investigations.

IPS Interest in the EEG of Patients after a Single Epileptic Seizure

Objective. This study aims to evaluate the incidence of pathological cerebral activity responses to intermittent rhythmic photic stimulation (IPS) after a single epileptic seizure. Patients and Methods. One hundred and thirty-seven EEGs were performed at the Neurophysiology Department of Mohamed V Teaching Military Hospital in Rabat. Clinical and EEG data was collected. Results. 9.5% of our patients had photoparoxysmal discharges (PPD). Incidence was higher in males than in females, but p value was not significant (p = 0.34), and it was higher in children compared to adults with significant p value (p = 0.08). The most epileptogenic frequencies were within the range 15-20 Hz. 63 patients had an EEG after 72 hours; among them 11 were photosensitive (p = 0.001). The frequency of the PPR was significantly higher in patients with generalized abnormalities than in focal abnormalities (p = 0.001). EEG confirmed a genetic generalized epilepsy in 8 cases among 13 photosensitive patients. Conclusion. PPR is age related. The frequencies within the range 15-20 Hz should inevitably be included in EEG protocols. The presence of PPR after a first seizure is probably more in favor of generalized seizure rather than the other type of seizure. PPR seems independent from the delay Seizure-EEG. Our study did not show an association between sex and photosensitivity.

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.

Screening electroencephalograms are feasible in the emergency department

We investigated the feasibility and quality of a wireless, four-channel screening electroencephalogram (EEG) device on patients presenting to the emergency department (ED) with a possible seizure disorder. A convenience sample was used of ED patients presenting with a preliminary diagnosis of syncope, potential partial-complex or generalized seizure disorder, head injury with prolonged symptoms or acute undiagnosed altered mental status. Study patients had a screening EEG in the ED, but the emergency physician and patient were blinded to the results of the EEG so that neither patient care nor disposition were affected by inclusion in the study. A total of 227 patients were enrolled, with a mean age of 56 years. EEG quality was acceptable, i.e. a screening interpretation was able to be provided, in 208 of 227 cases (92%). The EEG interpretation was normal in 65%, identified generalized or focal slowing in 24% and identified sub-clinical epileptiform activity in 12% of patients. Screening EEGs performed in the ED are feasible, can be acquired with acceptable quality, and may identify sub-clinical seizure activity in a significant number of patients.

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.

Influence of sleep and sleep deprivation on ictal and interictal epileptiform activity

Sleep is probably one of the most important physiological factors implicated both in epileptic seizures and interictal epileptiform discharges. The neurophysiology concerning the relationship between sleep and epilepsy is well described in the literature; however, the pathological events that culminate in the seizures are poorly explored. The present paper intends to make a rigorous approach to the main mechanisms involved in this reciprocal relation. Knowledge of sleep and sleep deprivation effects in epilepsy stands as crucial in the understanding of how seizures are produced, their possible lines of treatment, and future research.

Controversial issues on EEG after sleep deprivation for the diagnosis of epilepsy

EEG after sleep deprivation (SD-EEG) is widely used in many epilepsy centers as an important tool in the epilepsy diagnosis process. However, after more than 40 years of use, there are a number of issues which still need to be clarified concerning its features and role. In particular, the many scientific papers addressing its role in epilepsy diagnosis often differ remarkably from each other in terms of the type of patients assessed, their description and study design. Furthermore, also the length and the type of EEG performed after SD, as well as the length of SD itself, vary dramatically from one study to another. In this paper we shortly underscore the abovementioned differences among the different reports, as well as some interpretations of the findings obtained in the different studies. This analysis emphasizes, if needed, how SD-EEG still represents a crucial step in epilepsy diagnosis, and how additional, controlled studies might further shape its precise diagnostic/prognostic role.

When should a sleep-deprived EEG be performed following a presumed first seizure in adults?

OBJECTIVES

To evaluate the effect of the interval between the seizure and the EEG recording on the yield of early sleep-deprived EEG (SD-EEG) in patients admitted following a presumed first seizure.

MATERIALS AND METHODS

We retrospectively reviewed the EEG recordings and medical records of patients admitted to the Neurology Department in Assaf Harofeh Medical Center because of a presumed first seizure during a 3-year period between 2006 and 2009 and who had a SD-EEG following a first routine EEG without epileptiform discharges (EDs).

RESULTS

The study group included 78 patients aged 18-78 years (mean 35 ± 17). Previous seizures were recognized through repeated history in 32 (41%) patients. EDs were recorded in the SD-EEG in 16 (21%) patients: 13/46 (28%) with a SD-EEG performed within 3 days following the seizure and 3/32 (9%) with a later SD-EEG (P = 0.042) and in 10/32 (31%) patients in whom previous seizures were recognized and 6/46 (13%) with a first seizure (P = 0.05).

CONCLUSIONS

EDs in the SD-EEG following a first diagnosed seizure occur more commonly when the test is performed within 3 days following a first seizure or when previous seizures are recognized.

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.

Use of routine MEG in the primary diagnostic process of epilepsy

At present, in epilepsy, magnetoencephalography (MEG) is mostly used for presurgical evaluations. It has proven to be robust for detecting and localizing interictal epileptiform discharges. Whether this is also true for first-line investigation in the diagnosis of epilepsy has not been investigated yet. We present our data on the usefulness of MEG in the earliest phase of diagnosing epilepsy. We examined 51 patients with suspicion of neocortical epilepsy and an inconclusive routine EEG. A method to integrate MEG in daily routine was developed. Results of visually assessed MEG recordings were compared, retrospectively, with clinical data and with the results of EEG after sleep deprivation. After a finding of inconclusive, routine MEG generated a gain in diagnostic value of 63% when compared with "final" clinical diagnosis. This is comparable with the added value of EEG after sleep deprivation recorded previously in the same patients. However, MEG is less of a burden for patient and hospital and has no association with risk of increase in seizure frequency. The routine MEG with visual assessment only is a reliable diagnostic tool in the routine diagnosis of epilepsy and may replace or precede EEG after sleep deprivation in daily clinical practice. Furthermore, MEG together with MRI enables magnetic source imaging and, thus, may provide additional information on the cortical localization of the epilepsy of a patient.

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.

Seizure versus syncope

One of the most common but difficult management problems in medicine is that of patients who present with a paroxysmal loss of consciousness. All too often the underlying diagnosis remains elusive. This has a cost both in terms of mortality and ongoing morbidity and in terms of the financial burden associated with hospitalisation and repeated investigations. We describe a practical approach to this clinical dilemma, which is rooted in adherence to basic principles of history taking and examination, formulation of a reasonable differential diagnosis, followed by an intelligent use of specific investigations and selection of an appropriate treatment. We also discuss the effect of sudden unexpected death in epilepsy and sudden cardiac death. Despite a careful and thorough approach to the patient with a "seizure versus syncope" problem, many will require repeated assessment before a diagnosis is made.

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.

The effect of sleep deprivation on median nerve somatosensory evoked potentials

The purpose of the study was to determine the effect of one night's sleep deprivation on the early and middle-latency median nerve (MN) somatosensory evoked potentials (SEPs). In 20 healthy volunteers, SEPs in response to electrical stimulation of the MN at the wrist were recorded for the 100-ms post-stimulus period, before and after one night of sleep deprivation. The P14 latency was significantly prolonged after sleep deprivation. We found significant increases in the amplitudes of the early parietal (N20-P24) and the frontal middle-latency (P45-N60) components following sleep deprivation. Our results indicate that somatosensory processing is altered after sleep deprivation.

Comparison of clonidine to sleep deprivation in the potential to induce spike or sharp-wave activity

OBJECTIVE

This study aimed to investigate previously observed side effects, i.e. increased epileptic activity during clonidine medication. The safety and effectiveness of clonidine as spike inducing agent compared to sleep deprivation were tested.

METHODS

Patients suffering from drug-resistant localization related epilepsy took part in 3 magnetoencephalography (MEG) sessions. One session was recorded without any activating measures. The other two sessions were either performed after sleep deprivation or after medication with clonidine. Target parameter was the number of spikes or sharp-waves during a 30 min recording period.

RESULTS

About 67% of the patients showed increased spike activity after clonidine, whereas sleep deprivation increased the number of spikes in 33%, and 29% of the patients did not show any activation at all. Clonidine was most effective in temporal lobe epilepsy, when the focus was located in the right hemisphere, and when clonidine serum concentrations were ranging between 0.6 and 1.0 ng/ml.

CONCLUSIONS

This study showed for the first time that clonidine can be considered an effective spike or sharp-wave inducing drug that is superior to the potency of sleep deprivation.

SIGNIFICANCE

The administration of clonidine increases the probability of recording ictal and interictal epileptic activity during limited acquisition time.

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.