Seizure characterization and electroencephalographic features in Glut-1 deficiency syndrome

PURPOSE: To characterize seizure types and electroencephalographic features of glucose transporter type 1 deficiency syndrome (Glut-1 DS). METHODS: Twenty children with clinical and laboratory features of Glut-1 DS were evaluated. Age at seizure diagnosis, seizure classification, and response to treatment were determined by chart review. Thirty-two continuous 24-h EEG monitoring sessions and reports of 42 routine EEG studies were assessed. RESULTS: Age at seizure diagnosis was between 4 weeks and 18 months (mean, 5 months). Seizure types were generalized tonic or clonic (14), absence (10), partial (nine), myoclonic (six), or astatic (four). During 24-h EEGs, background activity showed generalized 2.5- to 4-Hz spike-wave discharges (41%), generalized slowing or attenuation (34%), no abnormalities (34%), focal epileptiform discharges (13%), or focal slowing or attenuation (9%). No seizures were captured during 69% of the studies; the remainder had absence (19%), myoclonic (9%), or partial seizures (3%). On evaluation of routine and 24-h EEG studies, focal epileptiform discharges (24%) and slowing (11%) were more frequent in ages 0-24 months. In older children (2-8 years), generalized epileptiform discharges (37.5%) and slowing (21%) were more common. CONCLUSIONS: In all ages, a normal interictal EEG was the most common EEG finding. When abnormalities occurred, focal slowing or epileptiform discharges were more prevalent in the infant. In older children (2 years or older), a generalized 2.5- to 4-Hz spike-wave pattern emerged. Seizure types observed included, absence, myoclonic, partial, and astatic.     

Clinical Electroencephalographic Biomarker for Impending Epilepsy in Asymptomatic Tuberous Sclerosis Complex Infants

BackgroundWe assessed the clinical utility of routine electroencephalography (EEG) in the prediction of epilepsy onset in asymptomatic infants with tuberous sclerosis complex.MethodsThis multicenter prospective observational study recruited infants younger than 7 months, seizure-free and on no antiepileptic drugs at enrollment, who all underwent serial physical examinations and video EEGs throughout the study. Parental education on seizure recognition was completed at the time of initial enrollment. Once seizure onset occurred, standard of care was applied, and subjects were followed up until 24 months.ResultsForty patients were enrolled, 28 older than 12 months with completed EEG evaluation at the time of this interim analysis. Of those, 19 (67.8%) developed seizures. Epileptic spasms occurred in 10 (52.6%), focal seizures in five (26.3%), generalized tonic-clonic seizure in one (5.3%), and a combination of epileptic spasms and focal seizures in three (15.7%). Fourteen infants (73.6%) had the first emergence of epileptiform abnormalities on EEG at an average age 4.2 months, preceding seizure onset by a median of 1.9 months. Hypsarrhythmia or modified hypsarrhythmia was not found in any infant before onset of epileptic spasms. All children with epileptiform discharges subsequently developed epilepsy (100% positive predictive value), and the negative predictive value for not developing epilepsy after a normal EEG was 64%.ConclusionsSerial routine EEGs in infants with tuberous sclerosis complex is a feasible strategy to identify individuals at high risk for epilepsy. The most frequent clinical presentation was epileptic spasms followed by focal seizures, and then a combination of both seizure types.     

Electroencephalogram confirmatory rate in neonatal seizures

The electroencephalogram (EEG) is confirmatory in 70% of children and adults with seizures, although gestation- and etiology-specific EEG confirmatory rates in neonates have not been well defined. All neonates treated for seizures and who underwent EEG were identified from 4,575 neonates admitted between 1985 and 1996 to a neonatal intensive care unit. The relationship between EEG findings (epileptiform discharges and background abnormalities) and gestation, mortality rate, and seizure etiology was examined using the Student t test. One hundred eighty-three neonates treated for seizures underwent a total of 352 EEGs: 144 of these neonates (79%) had an abnormal EEG (epileptiform discharges in 113 (60%) and nonepileptiform background abnormalities in 31). The EEG confirmatory rate increased with gestation (63% at 28 weeks vs 77% at term, P < 0.02). Etiology for seizures also influenced the EEG confirmatory rate: central nervous system (CNS) infection 95% (P < 0.05), hypoxic-ischemic encephalopathy 80% (P < 0.05), germinal matrix-intraventricular hemorrhage 65%, and CNS malformations 65%. The EEG confirmatory rate was predictive of neonatal mortality (19% vs 6%, P < 0.03). The EEG was directly confirmatory (epileptiform discharges) in 60% and supportive (nonepileptiform background abnormalities) in a further 17% of neonates with seizures. Gestation and etiology influence the EEG confirmatory rate in neonatal seizures.     

Prediction of Surgical Outcome by Interictal Epileptiform Abnormalities During Intracranial EEG Monitoring in Patients with Extrahippocampal Seizures

PURPOSE: Ictal intracranial EEG recordings obtained during continuous preoperative monitoring are often used to localize the region of seizure onset for purposes of surgical resection in patients with extrahippocampal seizures. Whether interictal epileptiform abnormalities during long-term monitoring can predict surgical outcome in this group is not established. METHODS: Intracranial EEGs of patients who underwent extrahippocampal resective epilepsy surgery were reviewed for interictal epileptiform abnormalities before medication discontinuation or first seizure occurrence. Interictal abnormalities were categorized as within or beyond the confines of surgical resection. We correlated these findings with the region of seizure onset, the pathologic substrate, and surgical outcome (by using Engel criteria) at 1-year minimum follow-up. RESULTS: Of 13 patients with interictal epileptiform abnormalities, six patients had interictal epileptiform discharges extending beyond the confines of surgical resection. These patients all had poor surgical outcome even if the region of electrographic seizure onset was resected. Seven patients had focal interictal epileptiform discharges, the entire extent of which were resected. All had good outcomes. All patients with structural lesions had focal interictal epileptiform abnormalities and good surgical outcomes. The spatial extent of interictal epileptiform discharges varied among patients with nonstructural lesions. However, those whose regions of interictal epileptiform abnormality were included in surgical resection also had good surgical outcome. CONCLUSIONS: The presence of interictal epileptiform discharges extending beyond the area of resection correlates with poor surgical outcome in patients with extrahippocampal epilepsy. In contrast, patients with focal interictal epileptiform discharges included in surgical resection have good surgical outcomes.     

Corpus callosotomy: clinical and electroencephalographic effects

Six persons (five male, one female), 15-41 years of age (mean, 23 years), with medically intractable epilepsy for 7-35 years (mean, 15 years) underwent total corpus callosum section (anterior commissure to posterior commissure) for treatment of seizures resulting in falls and injuries. Preoperative EEGs demonstrated two or more morphologically distinct interictal discharges, at least one of which was generalized. Generalized ictal EEG discharges were documented in all cases to account for the clinical seizures resulting in injury. A comparison of generalized epileptiform discharges in comparable states of arousal pre- and postoperatively demonstrated a statistically significant (p less than 0.05) reduction of generalized discharges after surgery. Postoperative observation periods have ranged from 10 to 30 months (mean, 17.6 months) and have documented a statistically significant (p less than 0.05) decrease in the number of falling seizures (means: preoperative, 23.2 seizures/month; postoperative, 0.7 seizures/month). A statistically significant difference in pre- and postoperative total (generalized and focal) interictal discharges was not demonstrated. Long-term, clinically apparent complications of surgery did not occur in our patients. Thus, sectioning of the corpus callosum interrupts generalized epileptiform discharges (as documented by the postoperative EEG) and usually results in a significant decrease in generalized seizures.     

Visual seizures in children

Twenty-one children (11 boys, 10 girls) suffering from visual seizures were studied. The visual seizures manifested as loss of vision, flickering light, blurring or figurative hallucinations. Ictal EEGs during visual seizures were recorded in 4 cases; the ictal discharges all originated in the occipital area. Visual seizures appeared in association with two or more non-visual ictal signs. In 18 cases, interictal EEGs revealed epileptiform discharges in the occipital area. In 3 cases, all girls, interictal EEGs showed photoconvulsive responses and focal spikes outside the occipital areas. They experienced clinical seizures when watching television and were thought to have photosensitive partial seizures.     

Lateralization of interictal EEG findings.

Several reports indicate that interictal epileptiform discharges (IED) may be more likely to occur over the left cerebral hemisphere than over the right. The objective of our study was to determine the frequency and type of IED on routine and multihour EEGs in a tertiary epilepsy center to estimate the frequency of left-sided versus right-sided IED and to determine interictal spike distribution pattern differences between adult and pediatric epilepsy patients. The current study retrospectively reviewed 31,207 EEGs (25,793 routine EEGs and 5414 multihour EEGs) recorded on 24,003 patients during the period from 1993 to 2003. All EEGs were read according to a systematic EEG classification system. Every patient was considered only once by including the first abnormal EEG. Regional unilateral or bilateral IEDs were recorded in 1707 patients (7%). Regional unilateral or bilateral slow was recorded in 2297 patients (9.6%). Left-sided regional IED were seen in 828 patients and accounted for 58% of all unilateral IED. Left-sided slow was seen in 1389 patients and accounted for 65% of all unilateral slow. Lateralization of slow was due to intermittent slow, whereas continuous slow involved both hemispheres equally. There was no lateralization difference in benign focal epileptiform discharges of childhood. Lateralization shows a tendency toward greater left-sided lateralization of interictal findings with aging. Benign focal epileptiform discharges were only seen under the age of 20 years old. Regional IEDs were seen in approximately 7% of patients and slowing occurs in 10% of patients. Both abnormalities were seen more frequently in the left hemisphere. Age adjusted analysis of the data revealed that this left-sided predominance was mildly increased in adults as compared with pediatric patients.     

Interictal, unifocal spikes in refractory extratemporal epilepsy predict ictal origin and postsurgical outcome.

OBJECTIVES: To evaluate the significance of exclusively unifocal, unilateral, interictal epileptiform patterns on scalp electroencephalography (EEG) in surgical candidates with medically intractable extratemporal epilepsy. METHODS: We reviewed 126 patients with refractory extratemporal partial seizures who underwent epilepsy surgery at our center. All were followed for at least 2 years after resections. Surgery was based on ictal EEG recordings. We examined ictal onsets and surgical outcome in subjects whose preoperative, interictal scalp EEGs during long-term monitoring (LTM) demonstrated only unilateral, well-defined focal discharges, and outcome in patients whose interictal EEGs during LTM showed bilateral, non-localized, or multifocal epileptiform patterns. RESULTS: We found that 26 subjects exhibited only unilateral, unifocal, interictal epileptiform patterns. In all 26 cases (100%) clinical seizures arose from the regions expected by the interictal findings (P<0.0001, Sign test). At last follow-up 77% (20/26) of these patients were seizure-free, while 23% (6/26) had >75% reduction in seizures. This compares to the remaining patients, of whom 34% (34/100) were seizure-free, 41% (41/100) had >75% reduction in seizures, and 25% (25/100) had <75% reduction in seizures (P=0.0001, Fisher's Exact test). CONCLUSIONS: Strictly unifocal, interictal epileptiform patterns on scalp EEG, though seen in a minority of subjects, may be an important, independent factor in evaluating subjects with intractable extratemporal, localization-related epilepsy for surgical therapy. This finding is highly predictive of both ictal onsets and successful postsurgical outcome.     

EEG of partial seizures.

EEG remains the primary technique in the diagnosis, characterization, and localization of partial seizures. This review examines the significance and character of interictal epileptiform abnormalities, periodic lateralized epileptiform discharges, and ictal patterns in patients with partial epilepsy. Interictal epileptiform discharges are common and assist in the diagnosis and localization of partial seizures. Fortunately, true "false positive" EEGs with focal epileptiform abnormalities are distinctly rare. Periodic lateralized discharges have characteristics of both interictal and ictal activity and are an area of controversy as to their clinical significance. Ictal patterns in partial seizures are variable, with the most distinctive features seen in seizures from a mesial temporal lobe origin. The unifying EEG feature of a partial seizure is in its evolution. A partial seizure begins with a clear delineation of the onset of activity that is distinct from the preceding background, followed by an evolution of this activity in both frequency and amplitude and terminating with an identifiable cessation of the rhythmic pattern that merges again into the background activity.     

Five-Year Outcome After Epilepsy Surgery in Nonmonitored and Monitored Surgical Candidates

Summary: Purpose : We wished to compare outcome 5 years after temporal lobectomy in 28 patients selected for surgery on the basis of interictal EEG patterns with that in 46 patients who underwent EEG-video monitoring studies as part of their preoperative evaluation during the same era.
Methods : The 28 nonmonitored patients had interictal EEG patterns that demonstrated a consistent, unilateral, anterior-midtemporal epileptiform focus, without discordant findings from other studies. Outcomes were assessed for years 4 and 5 after operation.
Results : Twenty-six of 28 (92.9%) nonmonitored patients were seizure-free or had at least 75% reduction in seizures. Twenty-nine of 46 (63.0%) monitored patients were seizure-free or had at least 75% reduction in seizures. Preoperative interictal EEGs of 29 of these patients showed independently localized bitemporal, ex-tratemporal, midposterior temporal, or diffuse epileptiform patterns. The remaining 17 monitored patients had preoperative strictly unilateral anterior-midtemporal interictal discharges, and their outcome was comparable to the nonmonitored group, with 15 (88.8%) seizure-free or with at least 75% reduction in seizures.
Conclusions : A proportion of candidates for epilepsy surgery can be selected without ictal recordings provided that interictal EEGs demonstrate consistent unilateral anterior-midtemporal epileptiform discharges and that other data are not discordant.     

Peri-ictal EEG in infants with PRRT2-related self-limited infantile epilepsy

Objective

Pathogenic PRRT2 variants cause self-limited (familial) infantile epilepsy (SeLIE), which is responsive to sodium channel blocking antiseizure medications. The interictal EEG is typically normal. We describe a cohort of infants with PRRT2-related SeLIE with striking peri-ictal EEG abnormalities.

Methods

We included all infants diagnosed with PRRT2-related SeLIE during July 2020 to November 2021 at the Royal Children's Hospital, Melbourne. Clinical features and results of aetiologic investigations were collected from electronic medical records. All EEGs were reviewed independently by two epileptologists.

Results

Ten infants presented with focal seizures at a median age of 5 months (range: 3–6 months). Eight had a family history of epilepsy, paroxysmal kinesigenic dyskinesia (PKD) or hemiplegic migraine. Seven of the eight infants with an EEG performed within 24 h of the most recent seizure had epileptiform discharges. Their EEGs showed focal sharp waves, spikes, polyspikes or fast activity independently over the left and right temporo-occipital regions. Conversely, the two infants with last known seizure greater than 24 h prior to their EEG had no epileptiform discharges. Oxcarbazepine was commenced in two infants and was effective. Eight infants were initially treated with levetiracetam, and all were subsequently switched to oxcarbazepine due to ongoing seizures or side effects.

Significance

Posterior polymorphic focal epileptiform discharges on a peri-ictal EEG recording are a feature of PRRT2-related SeLIE. This finding, particularly in the presence of a family history of infantile epilepsy, PKD or hemiplegic migraine, suggests a diagnosis of PRRT2-related SeLIE and has important treatment implications.     

Treatment and outcome in patients with febrile convulsion associated with epileptiform discharges on electroencephalography

The aim of this study is to determine the efficacy of prophylactic treatment for patients with febrile convulsions (FCs) in whom electroencephalograms (EEGs) revealed epileptiform discharges. We retrospectively investigated 43 patients who met the following criteria: (a) at least one FC during the study period; (b) epileptiform discharges were first recognized; (c) no unevoked seizures before epileptiform discharges were first seen; (d) normal psychomotor development and no neurological abnormality; and (e) follow-up >3 years. The clinical characteristics, treatment, and a later occurrence of FCs or unevoked seizures were studied. EEGs revealed focal epileptiform discharges in 25 patients and generalized ones in 18. There was no significant difference in the rate of recurrence of FC or occurrence of unevoked seizures between those with focal and generalized epileptiform discharges. No prophylaxis was performed in ten patients, 14 patients being treated with intermittent diazepam and 19 with a daily anticonvulsant. The rate of recurrence of FC was not significantly different between patients with and without prophylaxis. Unevoked seizures were only observed in two patients undergoing daily treatment. Intermittent or daily anticonvulsant therapy will not reduce the risk of recurrence of FCs or later development of unevoked seizures in patients with FC with epileptiform discharges.     

Generalized onset seizures with focal evolution (GOFE) — A unique seizure type in the setting of generalized epilepsy

PurposeWe report clinical and electrographic features of generalized onset seizures with focal evolution (GOFE) and present arguments for the inclusion of this seizure type in the seizure classification.MethodsThe adult and pediatric Epilepsy Monitoring Unit databases at Vanderbilt Medical Center and Children's Hospital were screened to identify generalized onset seizures with focal evolution. We reviewed medical records for epilepsy characteristics, epilepsy risk factors, MRI abnormalities, neurologic examination, antiepileptic medications before and after diagnosis, and response to medications. We also reviewed ictal and interictal EEG tracings, as well as video-recorded semiology.ResultsTen patients were identified, 7 males and 3 females. All of the patients developed generalized epilepsy in childhood or adolescence (ages 3–15 years). Generalized onset seizures with focal evolution developed years after onset in 9 patients, with a semiology concerning for focal seizures or nonepileptic events. Ictal discharges had a generalized onset on EEG, described as either generalized spike-and-wave and/or polyspike-and-wave discharges, or generalized fast activity. This electrographic activity then evolved to focal rhythmic activity most commonly localized to one temporal or frontal region; five patients had multiple seizures evolving to focal activity in different regions of both hemispheres. The predominant interictal epileptiform activity included generalized spike-and-wave and/or polyspike-and-wave discharges in all patients. Taking into consideration all clinical and EEG data, six patients were classified with genetic (idiopathic) generalized epilepsy, and four were classified with structural/metabolic (symptomatic) generalized epilepsy. All of the patients had modifications to their medications following discharge, with three becoming seizure-free and five responding with > 50% reduction in seizure frequency.ConclusionGeneralized onset seizures may occasionally have focal evolution with semiology suggestive of focal seizures, leading to a misdiagnosis of focal onset. This unique seizure type may occur with genetic as well as structural/metabolic forms of epilepsy. The identification of this seizure type may help clinicians choose appropriate medications, avoiding narrow spectrum agents known to aggravate generalized onset seizures.     

Interictal EEG in temporal lobe epilepsy in childhood.

The authors clarified the value of interictal discharges and verified which extratemporal regions may also show epileptiform activity in temporal lobe epilepsy (TLE) in childhood. Thirty consecutive patients aged 3 to 18 years (mean age = 12.16 years; 16 male) with TLE associated with hippocampal atrophy were studied. Each patient had 1 to 15 interictal EEG recordings (mean: 5.6; total = 192 EEGs). Video-EEG monitoring was performed in 20 patients. All patients had MRI. The findings were compared with a control group of 53 consecutive TLE adult outpatients with hippocampal atrophy. Each adult patient underwent 3 to 21 routine EEGs (mean: 10.67; total = 566). Interictal EEGs of children with TLE showed extratemporal epileptiform discharges more frequently than EEGs of adults with TLE. Frontal, parietal, and occipital discharges were more frequently seen in children (P < 0.05). These results suggest a close interaction between temporal and other cerebral regions in children with epilepsy and provide further evidence of the existence of neural networks.     

Interictal EEG prediction of response to antiepileptic drug monotherapy

Forty-eight patients had sleep-deprived EEGs prior to antiepileptic drug monotherapy. The majority were seizure-free after one year, or had more than 50% reduction in seizure frequency. Among those with normal EEGs 50% were seizure-free, while 75% with diffuse slowing, 44% with focal abnormality, and 83% with generalized epileptiform discharges were fully controlled. Freedom from seizures was achieved in 13% taking phenobarbital, 50% taking phenytoin, 63% taking carbamazepine, and 100% taking valproate. The sleep-deprived interictal EEG should be an integral part of initial assessment and drug selection in patients with clinical histories of convulsive seizure.     

Transitory effect of spike and spike-and-wave discharges on EEG power in children

Background: Spikes and spike-and-wave discharges on the EEG of children are a strong biomarker of epilepsy. There is increasing evidence that these EEG abnormalities also impair brain function and result in transitory cognitive impairment. Studies in animal models have shown that EEG spikes alters single cell firing and that such impairment in firing may extend beyond the duration of the spike-and-wave discharge. Whether interictal epileptiform discharges have lasting effects on EEG activity in humans is not known. Methods and Results: The EEGs of 60 consecutive children with focal or interictal spike-and-wave discharges were evaluated using power spectral analysis to determine if there were any changes in power spectra from before to after the interictal abnormalities. Neither focal spike-and-wave nor generalized spike-and-wave discharges had any effect on the EEG frequency or spectral power following the discharge. Conclusion: While interictal EEG discharges temporarily alter neural activity during the duration of the spike-and-wave discharge, there is no evidence that alterations of spectral power continue beyond the duration of the interictal discharge. The effects of interictal activity on EEG rhythms therefore appear to be quite transient and confined to the duration of the interictal discharge.     

EEG Abnormalities in Children with a First Unprovoked Seizure

Summary: We examined EEG findings from an ongoing study of 347 children with a first unprovoked seizure. EEGs were available in 321 (93%), and 135 (42%) had an abnormal EEG. EEG abnormalities included focal spikes (n = 77), generalized spike and wave discharges (n = 28), slowing (n = 43), and nonspecific abnormalities (n = 7). Abnormal EEGs were more common in children with remote symptomatic seizures (60%) than in those with idiopathic seizures (38%) (p < 0.003), more common in partial seizures (56%) than in generalized seizures (35%) (p < 0.001), and more common in children age >3 years (52%) than in younger children (12%) (p < 0.001). Records including both awake and sleep tracings were available in 148 (46%) cases. For 122 (38%) only awake tracings and for 51 (16%) only sleep tracings were available. Fifty-nine (40%) of the 148 patients with both an awake and asleep tracing had abnormal EEGs. Of 50 such EEGs with epileptiform abnormalities, 15 (30%) demonstrated the abnormality either only while awake (n = 8) or only while asleep (n = 7). Of 17 patients with EEG slowing, 8 showed slowing only in the awake tracing and 9 showed slowing in both the awake and asleep tracing. Children with even a single unprovoked seizure have a high incidence of EEG abnormalities. Obtaining a combined awake and sleep EEG significantly increases the yield of EEG abnormalities. In children with an idiopathic first seizure, EEG abnormalities are associated with an increased risk of seizure recurrence.     

Sleep and sleep deprived EEG in partial and generalized epilepsy

Sleep and sleep deprivation are often used for EEG activation in epilepsy. We compared postprandial naps and day-long sleep deprived EEGs in 36 patients with generalized seizures, 57 complex partial seizure patients, and 7 individuals with mixed seizure disorders. Ten of 36 generalized seizure patients had normal sleep and sleep deprived EEGs, while both were normal in 16 of 57 partial seizure patients. Both were abnormal in 18 of 36 generalized and 22 of 57 partial epileptics. Seven generalized seizure patients had epileptiform discharges or seizures during afternoon naps but normal sleep deprived EEGs. No partial seizure patients had normal sleep deprived EEGs and abnormal nap, but 29 of 57 had abnormalities or seizures only with sleep deprivation. All 7 mixed seizure patients had abnormal sleep and sleep deprived studies, and 6 had seizures, 4 on both studies. Natural sleep may facilitate the appearance of generalized seizures or epilepti-form discharges, while sleep deprivation may accentuate the yield of EEG abnormality in partial epilepsy. Either is likely to be abnormal in patients with mixed seizures and encephalopathy. Natural sleep and sleep deprived EEGs are an appropriate combination in the evaluation of refractory seizures.     

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.     

Tactile‐evoked Rolandic Discharges: A Benign Finding?

PURPOSE: This retrospective study was undertaken to determine if patients having tactile-evoked rolandic discharges were a more "benign" patient population than those with spontaneously occurring nontactile rolandic discharges and to determine whether the presence of tactile-evoked rolandic discharges was a marker for the future development of epilepsy, as previously reported. METHODS: During this 8-year study, 304 patients were seen with rolandic discharges. These patients all had tactile stimulation of their hands and/or feet. They formed two groups: patients with spontaneous rolandic discharges that could not be evoked by tactile stimulation (NT) and patients with spontaneous rolandic discharges that could be enhanced with tactile stimulation (TE). Over a 14-month period, every patient had tactile stimulation of both hands and both feet, resulting in a third group of patients having rolandic discharges seen only with tapping (TO). RESULTS: Tactile-enhanced discharges constituted 38.2% of all rolandic discharges. Patients with TE and TO discharges had a higher incidence of normal development and intelligence, normal neurologic examinations, and a lower incidence of seizures and focal or generalized background abnormalities on their EEGs. Only one patient with normal background and no coexisting epileptiform abnormalities had partial motor seizures with corresponding contralateral central discharges. Only two patients who had no seizures at the time of their first EEG subsequently went on to develop seizures. Neither fit the pattern of the seizure disorder described in the literature. CONCLUSIONS: It is hypothesized that tactile-evoked rolandic discharges are a benign, age-related phenomenon, which do not represent a marker for the future development of epilepsy and are not the interictal electrographic correlate to an already existing seizure disorder.