Mesial Frontal Lobe Epilepsy Research Articles

Ictal barking in frontal lobe epilepsy

Abstract Nonspeech vocalizations are usually seen in temporal or frontal lobe epileptic focus, especially in the dominant side of the brain. There can be screaming, hooting, barking, humming grunting, etc., Barking is most characteristic, which is commonly seen in mesial frontal lobe epilepsy. In this report, we describe a unique case of ictal barking with onset at 18 years of age mistaken for unspecified psychotic disorder, which was subsequently diagnosed as complex partial seizure following electroencephalogram findings and was maintained on valproate 1500 mg/day, and levetiracetam 1500 mg/day was added along with clobazam 10 mg/day. Ictal barking is mostly focal, similar to our case; however, there has been sparse evidence of ictal barking in generalized seizures as well.

6. Frontopolar sharp potentials

Sudden appearance of totally unexpected bisynchronous frontal-polar dominant unexpected potential initially embedded in eye blink with progressive recruitment and phase change. At times, it reaches up to 2.5 Hz, with awake background, and virtually minimal or limited spread to fronto-temporal or posterior frontal area on encephalogram. After very close examination and accepting wide variety of opinions, patient is being considered for epilepsy monitoring unit (EMU), so as same potential can be reproduced and evaluated for any fronto-polar epilepsies. Download : Download high-res image (572KB) Download : Download full-size image There are few unexpected potentials appears at fronto-polar region in EEG laboratory recording and must not escape, even though the patient has no additional oculographic leads. Potential described here, presented while ambulatory monitoring. The ocular potentials are mostly quite impressive and almost always give rise to marked eye movement artifacts in fronto-polar and anterior temporal leads. The use of polygraphic documentation makes the task much easier, as patient is being considered for EMU. When an REM phase occurs directly at sleep onset, the transition from drowsiness to REM is not very pronounced in the EEG, whereas the change from deep NREM sleep to REM is a very dramatic one ( Matsuo, 1981 ). During photic stimulation, light from the flash stimulus may produce artifact in the fronto-polar leads (Fp1/Fp2). This artifact can be mistaken for photic driving due to the synchrony with the stimuli. The source maybe the retina (ERG) or from a nonphysiologic source such as a frontopolar electrode with high impedance creating a photo-cell. Covering the eye with a towel will block the input to the retina (ERG) and this should not be confused with the photo-electric effect ( Tyner et al., 1983 ). The alpha rhythm may occasionally extend slightly into the superior frontal leads (F3, F4). Extension into the fronto-polar region (Fp1, Fp2) is practically unheard of. Apparent alpha rhythm in the fronto-polar leads may be very prominent in referential (unipolar) montages if the referential ear electrode picks up the posterior alpha rhythm. This is particularly com-mon when the mastoid region is used instead of the ear lobe (the mastoid being a preferred place with paste technique) ( Niedermeyer’s Electroencephalography ). Fronto-polar or orbito-frontal onset of seizures may be recorded from fronto-polar electrodes, and better resolved by supera-orbital or infra-orbital electrodes, sometimes it’s been referenced to midline electrodes like electrode on nose/chin, Fz, Cz or Pz. It is not uncommon for bilateral synchrony to occur in frontal lobe epilepsy ( Atlas of EEG, 2013 ). Subtle lateralization may be present with bilateral synchronous activity, mainly during sleep. This lateralization could be misleading. Absence of any ictal or immediate post ictal slowing has been reported in patient with mesial frontal lobe epilepsy ( Bautista et al., 1998 ). Behavioral manifestations with normal interictal EEG encountered in frontal lobe epilepsy may be misdiagnosed as psychogenic nonepileptic seizures. It emphasizes the need for early video-EEG monitoring in ambiguous cases before starting or modifying AED treatment.

Spindle frequency activity may provide lateralizing information in drug-resistant nocturnal mesial frontal lobe epilepsy: A pilot study on the contribution of sleep recordings

PurposeNocturnal frontal lobe epilepsy (NFLE) is characterized by sleep-related paroxysmal motor attacks occurring almost exclusively during non-REM sleep. Surgical treatment may relieve symptoms in drug-resistant patients. However, the identification of the epileptogenic zone, the region to be resected, is frequently challenging because of the absence of lateralizing and localizing information and the lack of informative EEG correlates. The aim of this study was to find asymmetries in the ictal activity that could provide information on the lateralization of the epileptogenic zone. MethodWe retrospectively analyzed the sleep EEG of four patients recorded prior to surgical intervention. The epileptogenic zone was known, as these patients had subsequently undergone successful surgery after bilateral intracerebral stereo-EEG investigation. Sleep EEG during the ictal phase was compared with sleep EEG during the pre-ictal phase. ResultsIn all patients, electrical sources of sigma activity (12–16Hz) exhibited increased activity during the ictal phase which was higher in the epileptogenic hemisphere. Conversely, increased delta activity (1–4Hz) was predominant contralateral to the epileptogenic focus in three of four patients. ConclusionSigma activity may have a predictive role in the lateralization of the epileptogenic zone and be useful during the pre-surgical evaluation of patients with NFLE.

Mesial Frontal Lobe Epilepsy

Mesial frontal lobe epilepsies can be divided into epilepsies arising from the anterior cingulate gyrus and those of the supplementary sensorimotor area. They provide diagnostic challenges because they often lack lateralizing or localizing features on clinical semiology and interictal and ictal scalp electroencephalographic (EEG) recordings. A number of unique semiologic features have been described over the last decade in patients with mesial frontal lobe epilepsy (FLE). There are few reports of applying advanced neurophysiologic techniques such as electrical source imaging, magnetoencephalography, EEG/functional magnetic resonance imaging, or analysis of high-frequency oscillations in patients with mesial FLE. Despite these diagnostic challenges, it seems that patients with mesial FLE benefit from epilepsy surgery to the same extent or even better than patients with FLE do, as a whole.

Early ictal face wiping in frontal lobe epilepsy

We describe two patients with medication-resistant nonlesional mesial frontal lobe epilepsy and seizures that manifested with early face wiping prior to other motor phenomena. Ictal scalp monitoring either was nonlocalizing or involved the central regions. Intracranial monitoring demonstrated anterior mesial frontal ictal low-voltage gamma activity during the face wiping activity in both patients. Habitual seizures with the same clinical characteristics were induced during extraoperative functional mapping with stimulation of the same region. Ictal activation of mesial frontal regions can elicit early ictal face wiping activity, and this clinical sign may play a role in presurgical evaluation.

Mesial Frontal Epilepsy and Ictal Body Turning Along the Horizontal Body Axis

To evaluate the clinical utility of mesial frontal semiology. Retrospective case series. Tertiary epilepsy referral center. Part 1 of the study involved 152 patients who underwent frontal lobe surgery. Part 2 involved 253 patients who underwent non-frontal lobe surgery. Inclusion criteria for both parts of the study were seizure localization by analysis of resection margins (mesial frontal, lateral frontal, orbitofrontal, nonfrontal) or intracranial exploration and an Engel class I outcome. In part 1, 84 patients had their habitual seizures analyzed by video encephalography using a semiology checklist of 47 items during the early phase (electrographic onset to 10 seconds) and late phase (rest of episode). Localization semiology was analyzed by chi(2) test with Bonferroni correction and cluster analysis when occurrence exceeded 10% in at least 1 region. In part 2, 144 patients had their habitual seizures screened with mesial frontal semiology from the first part of study during the early phase only. In part 1 of the study, the statistically significant localizing semiology for the mesial frontal region in the early phase was ictal body turning along the horizontal axis (57% of patients), crawling (57% of patients), restlessness (64.3% of patients), facial expressions of anxiety (42.9% of patients) and fear (35.7% of patients), grimacing produced by bilateral facial contraction (42.9% of patients), barking (32.1% of patients), head shaking (25% of patients), and pelvic raising (25% of patients) (all P< .001). In the late phase, recurrent utterance (21.4% of patients) was the additional statistically significant item (P< .002). In part 2 of the study, ictal body turning along the horizontal axis gave a 55.2% positive predictive value, which improved to 85.7% when clustered with restlessness, facial expressions of anxiety and fear, and barking. Ictal body turning along the horizontal body axis and semiology with physiological movement are not only prevalent semiology items of mesial frontal lobe epilepsy but they distinguish mesial frontal from lateral frontal and orbitofrontal seizures.

The localizing value of ictal EEG in focal epilepsy.

To investigate the lateralization and localization of ictal EEG in focal epilepsy. A total of 486 ictal EEG of 72 patients with focal epilepsy arising from the mesial temporal, neocortical temporal, mesial frontal, dorsolateral frontal, parietal, and occipital regions were analyzed. Surface ictal EEG was adequately localized in 72% of cases, more often in temporal than extratemporal epilepsy. Localized ictal onsets were seen in 57% of seizures and were most common in mesial temporal lobe epilepsy (MTLE), lateral frontal lobe epilepsy (LFLE), and parietal lobe epilepsy, whereas lateralized onsets predominated in neocortical temporal lobe epilepsy and generalized onsets in mesial frontal lobe epilepsy (MFLE) and occipital lobe epilepsy. Approximately two-thirds of seizures were localized, 22% generalized, 4% lateralized, and 6% mislocalized/lateralized. False localization/lateralization occurred in 28% of occipital and 16% of parietal seizures. Rhythmic temporal theta at ictal onset was seen exclusively in temporal lobe seizures, whereas localized repetitive epileptiform activity was highly predictive of LFLE. Seizures arising from the lateral convexity and mesial regions were differentiated by a high incidence of repetitive epileptiform activity at ictal onset in the former and rhythmic theta activity in the latter. With the exception of mesial frontal lobe epilepsy, ictal recordings are very useful in the localization/lateralization of focal seizures. Some patterns are highly accurate in localizing the epileptogenic lobe. One limitation of ictal EEG is the potential for false localization/lateralization in occipital and parietal lobe epilepsies.

The role of the intracarotid amobarbital procedure in evaluation of patients for epilepsy surgery.

To examine the role of the intracarotid amobarbital procedure (IAP) in the presurgical evaluation of patients with medically refractory localization-related epilepsy. We retrospectively studied 111 patients who underwent cortical resective surgery at our center between 1991 and 1996. In patients with mesial temporal lobe epilepsy (mTLE), a presurgical determination of the epileptogenic zone was compared with localization based on IAP memory asymmetry scores, and with ultimate localization after resective surgery. In patients with neocortical or mesial frontal epilepsy, the IAP was evaluated for evidence of unilateral or bilateral poor memory performance. Of 68 patients with mTLE localized by noninvasive tests, 60 had concordant lateralized memory deficits on IAP. Eight patients had lateralized memory deficits on IAP that were discordant with noninvasive tests and with localization as determined by surgical outcome. All 11 mTLE patients requiring invasive EEG monitoring were correctly lateralized by IAP, including one patient in whom the noninvasive evaluation otherwise provided false lateralization. Of 32 patients with neocortical or mesial frontal lobe epilepsy, 21 displayed memory deficits on IAP. Of 10 patients with bilateral deficits, five had mesial frontal lobe epilepsy. In 13 patients with lateralized memory deficits, seven underwent electrode implantation in the mesial temporal lobe, and four ultimately underwent resection of an epileptogenic mesial temporal lobe in addition to a neocortical resection. In patients with mTLE, lateralized memory deficits on IAP usually confirm localization provided by noninvasive tests. However, in mTLE not well lateralized by the noninvasive evaluation, and in neocortical or mesial frontal epilepsy, the IAP may provide information regarding localization that ultimately alters surgical management.

Intracranial Ictal Recordings in Mesial Frontal Lobe Epilepsy

Localization of ictal onset in patients with medically refractory frontal lobe epilepsy is challenging even with intracranial monitoring. We present a series of nine patients with presumed mesial frontal lobe epilepsy in whom successful localization of ictal onset was achieved in most cases. Intracranial electrodes were placed over cingulate and supplementary motor cortex bilaterally, with additional electrodes placed over lateral and inferior frontal lobes as part of an evaluation for epilepsy surgery. Localization of the ictal onset was clearly defined in seven of nine patients and was characterized by a pattern of lower amplitude beta/gamma range frequencies noted in one to four adjacent electrodes arising from cingulate cortex or supplementary motor cortex in six patients. In the remaining patient, ictal onset was characterized by periodic high amplitude spike and slow-wave discharges evolving into a higher voltage faster rhythm. Electrographic onset occurred coincident with or preceded clinical findings. Ictal pattern also did not demonstrate a widespread propagation pattern in most of the recordings in which ictal onset was well localized. Precise localization of ictal onset within the mesial frontal lobe is possible. Rapid propagation to regions within and outside the frontal lobe does not always occur.

Usefulness of PET scan in a child with mesial frontal lobe epilepsy

Positron emission tomography (PET) scan with 18F-fluorodeoxyglucose (18F-FDG) was performed in a 14-year-old boy who had seizures suspected to have originated in mesial frontal lobe. The seizures occurred in clusters and were characterised by a change in the facial expression at seizure onset and complex motor manifestations consisting of kicking, swaying and screaming. Ictal EEG showed rhythmic alpha-waves in the left frontal area association with the ictus. Cerebral CT, MRI and SPECT revealed nothing of significance, but the PET brain scans showed frontal and parietal hypometabolism, which was most prominent in the left mesial frontal lobe. The present case suggests that FDG-PET scanning may be useful for the diagnosis of the mesial frontal epilepsy, when other imaging studies fail to show abnormalities.

Mesial frontal lobe epilepsy: A clinical entity not sufficiently described

Mesial frontal lobe epilepsy provokes a complex clinical syndrome characterized by mainly nocturnal occurrence of seizures with stereotyped patterns of repetitive rhythmic movements and diffuse or lateralized postures. Because the EEG is sometimes normal, this syndrome is not always recognized, and these patients risk misdiagnosis and mismanagement. To define guidelines for diagnosis, we describe eight patients with mesial frontal lobe epilepsy and compare them with similar cases reported as mesial frontal lobe epilepsy or given other diagnostic labels, including hysteria and parasomnia.