A case of monozygotic twins with hereditary spastic paraplegia type 4 and epilepsy, of whom only one developed narcolepsy type 1.

We report a case of monozygotic twin sisters with hereditary spastic paraplegia type 4 (SPG4) and epilepsy, only one of whom had a diagnosis of narcolepsy type 1 (NT1). The older sister with NT1 exhibited excessive daytime sleepiness, cataplexy, sleep-onset rapid eye movement period in the multiple sleep latency test, and decreased orexin levels in cerebrospinal fluid. Both sisters had HLA-DRB1*15:01-DQB1*06:02 and were further identified to have a novel missense mutation (c.1156A > C, p.Asn386His) in the coding exon of the spastin (SPAST) gene. The novel missense mutation might be involved in the development of epilepsy. This case is characterised by a combined diagnosis of SPG4 and epilepsy, and it is the first report of NT1 combined with epilepsy and genetically confirmed SPG4. The fact that only one of the twins has NT1 suggests that acquired and environmental factors are important in the pathogenesis of NT1.

Atrophy of the hippocampal CA1 subfield relates to long-term forgetting in focal epilepsy.

OBJECTIVE: The mechanisms underlying accelerated long-term forgetting (ALF) in patients with epilepsy are still under investigation. We examined the contribution of hippocampal subfields and their morphology to long-term memory performance in patients with focal epilepsy. METHODS: We prospectively assessed long-term memory and performed magnetic resonance imaging in 80 patients with focal epilepsy (61 with temporal lobe epilepsy and 19 with extratemporal lobe epilepsy) and 30 healthy controls. The patients also underwent electroencephalography recording. Verbal and visuospatial memory was tested 30 s, 10 min, and 1 week after learning. We assessed the volumes of the whole hippocampus and seven subfields and deformation of the hippocampal shape. The contributions of the hippocampal volumes and shape deformation to long-term forgetting, controlling for confounding factors, including the presence of interictal epileptiform discharges, were assessed by multiple regression analyses. RESULTS: Patients with focal epilepsy had lower intelligence quotients and route recall scores at 10 min than controls. The focal epilepsy group had smaller volumes of both the right and left hippocampal tails than the control group, but there were no statistically significant group differences for the volumes of the whole hippocampus or other hippocampal subfields. Multiple regression analyses showed a significant association between the left CA1 volume and the 1-week story retention (ß = 7.76; Bonferroni-corrected p = 0.044), but this was not found for the whole hippocampus or other subfield volumes. Hippocampal shape analyses revealed that atrophy of the superior-lateral, superior-central, and inferior-medial regions of the left hippocampus, corresponding to CA1 and CA2/3, was associated with the verbal retention rate. SIGNIFICANCE: Our results suggest that atrophy of the hippocampal CA1 region and its associated structures disrupts long-term memory consolidation in focal epilepsy. Neuronal cell loss in specific hippocampal subfields could be a key underlying cause of ALF in patients with epilepsy.

Rapidly spreading seizures arise from large-scale functional brain networks in focal epilepsy.

It remains unclear whether epileptogenic networks in focal epilepsy develop on physiological networks. This work aimed to explore the association between the rapid spread of ictal fast activity (IFA), a proposed biomarker for epileptogenic networks, and the functional connectivity or networks of healthy subjects. We reviewed 45 patients with focal epilepsy who underwent electrocorticographic (ECoG) recordings to identify the patients showing the rapid spread of IFA. IFA power was quantified as normalized beta-gamma band power. Using published resting-state functional magnetic resonance imaging databases, we estimated resting-state functional connectivity of healthy subjects (RSFC-HS) and resting-state networks of healthy subjects (RSNs-HS) at the locations corresponding to the patients' electrodes. We predicted the IFA power of each electrode based on RSFC-HS between electrode locations (RSFC-HS-based prediction) using a recently developed method, termed activity flow mapping. RSNs-HS were identified using seed-based and atlas-based methods. We compared IFA power with RSFC-HS-based prediction or RSNs-HS using non-parametric correlation coefficients. RSFC and seed-based RSNs of each patient (RSFC-PT and seed-based RSNs-PT) were also estimated using interictal ECoG data and compared with IFA power in the same way as RSFC-HS and seed-based RSNs-HS. Spatial autocorrelation-preserving randomization tests were performed for significance testing. Nine patients met the inclusion criteria. None of the patients had reflex seizures. Six patients showed pathological evidence of a structural etiology. In total, we analyzed 49 seizures (2-13 seizures per patient). We observed significant correlations between IFA power and RSFC-HS-based prediction, seed-based RSNs-HS, or atlas-based RSNs-HS in 28 (57.1%), 21 (42.9%), and 28 (57.1%) seizures, respectively. Thirty-two (65.3%) seizures showed a significant correlation with either seed-based or atlas-based RSNs-HS, but this ratio varied across patients: 27 (93.1%) of 29 seizures in six patients correlated with either of them. Among atlas-based RSNs-HS, correlated RSNs-HS with IFA power included the default mode, control, dorsal attention, somatomotor, and temporal-parietal networks. We could not obtain RSFC-PT and RSNs-PT in one patient due to frequent interictal epileptiform discharges. In the remaining eight patients, most of the seizures showed significant correlations between IFA power and RSFC-PT-based prediction or seed-based RSNs-PT. Our study provides evidence that the rapid spread of IFA in focal epilepsy can arise from physiological RSNs. This finding suggests an overlap between epileptogenic and functional networks, which may explain why functional networks in patients with focal epilepsy frequently disrupt.

Characteristics of olfactory dysfunction in patients with temporal lobe epilepsy.

OBJECTIVE: To determine the characteristics of olfactory dysfunction in patients with temporal lobe epilepsy (TLE). METHODS: Odor identification was assessed using the odor stick identification test for Japanese (OSIT-J, full score 12 points) in 65 patients with TLE and in 74 controls. RESULTS: The mean OSIT-J score was significantly lower in patients with TLE (mean ±â€¯SD = 8.1 ±â€¯2.8; median = 9) than in the control subjects (mean ±â€¯SD = 10.6 ±â€¯1.1; median = 11) (P < 0.005). Olfactory dysfunction (hyposmia/anosmia) was associated with bilateral seizure foci and older age of onset in TLE. Patients who underwent temporal lobectomy for hippocampal sclerosis did not show significant decline after long-term recovery. The Indian ink part of OSIT-J was useful for the detection of olfactory deficits in patients with TLE (sensitivity = 47%, specificity = 93%). Patients with TLE tended to have preserved olfactory ability for stimulating odors and for familiar odors of daily life. SIGNIFICANCE: We observed characteristic odor identification deficits for individual odors used in OSIT-J. Our study findings provide deeper insight into the underlying mechanism of olfactory function in patients with TLE and may be beneficial in the clinical management of these patients.

Higher postictal parasympathetic activity following greater ictal heart rate increase in right- than left-sided seizures.

OBJECTIVES: The objectives of this study were to determine how hemispheric laterality of seizure activity influences periictal heart rate variability (HRV) and investigate the ability of HRV parameters to discriminate right- and left-sided seizures. METHODS: Long-term video electroencephalogram-electrocardiogram recordings of 54 focal seizures in 25 patients with focal epilepsy were reviewed. Using linear mixed models, we examined the effect of seizure laterality on linear (standard deviation of R-R intervals [SDNN], root mean square of successive differences [RMSSD], low frequency [LF] and high frequency [HF] power of HRV, and LF/HF) and nonlinear (standard deviation [SD]1, SD2, and SD2/SD1 derived from Poincaré plots) periictal HRV parameters, the magnitude of heart rate (HR) changes, and the onset time of increased HR. Receiver operating characteristics (ROC) were used to determine the ability of these parameters to discriminate between right- and left-sided seizures. RESULTS: Postictal SDNN, RMSSD, LF, HF, SD1, and SD2 were higher in right- than left-sided seizures. Root mean square of successive difference and HF were decreased after left- but not right-sided seizures. Standard deviation of R-R intervals, LF, and SD1 were increased after right- but not left-sided seizures. Increased ictal HR was earlier and larger in right- than left-sided seizures. Postictal HF showed the greatest area under the ROC curve (AUC) (0.87) for discriminating right- and left-sided seizures. CONCLUSIONS: Our data suggest that postictal parasympathetic activity is higher, whereas ictal HR increase is greater, in right- than left-sided seizures. Involvement of the right hemisphere may be associated with postictal autonomic instability. Postictal HRV parameters may provide useful information on hemispheric laterality of seizure activity.

Altered neural synchronization to pure tone stimulation in patients with mesial temporal lobe epilepsy: An MEG study.

OBJECTIVE: Our previous study of monaural auditory evoked magnetic fields (AEFs) demonstrated that hippocampal sclerosis significantly modulated auditory processing in patients with mesial temporal lobe epilepsy (mTLE). However, the small sample size (n = 17) and focus on the M100 response were insufficient to elucidate the lateralization of the epileptic focus. Therefore, we increased the number of patients with mTLE (n = 39) to examine whether neural synchronization induced by monaural pure tone stimulation provides useful diagnostic information about epileptic foci in patients with unilateral mTLE. METHODS: Twenty-five patients with left mTLE, 14 patients with right mTLE, and 32 healthy controls (HCs) were recruited. Auditory stimuli of 500-Hz tone burst were monaurally presented to subjects. The AEF data were analyzed with source estimation of M100 responses in bilateral auditory cortices (ACs). Neural synchronization within ACs and between ACs was evaluated with phase-locking factor (PLF) and phase-locking value (PLV), respectively. Linear discriminant analysis was performed for diagnosis and lateralization of epileptic focus. RESULTS: The M100 amplitude revealed that patients with right mTLE exhibited smaller M100 amplitude than patients with left mTLE and HCs. Interestingly, PLF was able to differentiate the groups with mTLE, with decreased PLFs in the alpha band observed in patients with right mTLE compared with those (PLFs) in patients with left mTLE. Right hemispheric predominance was confirmed in both HCs and patients with left mTLE while patients with right mTLE showed a lack of right hemispheric predominance. Functional connectivity between bilateral ACs (PLV) was reduced in both patients with right and left mTLE compared with that of HCs. The accuracy of diagnosis and lateralization was 80%-90%. CONCLUSION: Auditory cortex subnormal function was more pronounced in patients with right mTLE compared with that in patients with left mTLE as well as HCs. Monaural AEFs can be used to reveal the pathophysiology of mTLE. Overall, our results indicate that altered neural synchronization may provide useful information about possible functional deterioration in patients with unilateral mTLE.

Neuromagnetic evidence for hippocampal modulation of auditory processing.

The hippocampus is well known to be involved in memory, as well as in perceptual processing. To date, the electrophysiological process by which unilateral hippocampal lesions, such as hippocampal sclerosis (HS), modulate the auditory processing remains unknown. Auditory-evoked magnetic fields (AEFs) are valuable for evaluating auditory functions, because M100, a major component of AEFs, originates from auditory areas. Therefore, AEFs of mesial temporal lobe epilepsy (mTLE, n=17) with unilateral HS were compared with those of healthy (HC, n=17) and disease controls (n=9), thereby determining whether AEFs were indicative of hippocampal influences on the auditory processing. Monaural tone-burst stimuli were presented for each side, followed by analysis of M100 and a previously less characterized exogenous component (M400: 300-500ms). The frequency of acceptable M100 dipoles was significantly decreased in the HS side. Beam-forming-based source localization analysis also showed decreased activity of the auditory area, which corresponded to the inadequately estimated dipoles. M400 was found to be related to the medial temporal structure on the HS side. Volumetric analysis was also performed, focusing on the auditory-related areas (planum temporale, Heschl's gyrus, and superior temporal gyrus), as well as the hippocampus. M100 amplitudes positively correlated with hippocampal and planum temporale volumes in the HC group, whereas they negatively correlated with Heschl's gyrus volume in the mTLE group. Interestingly, significantly enhanced M400 component was observed in the HS side of the mTLE patients. In addition, the M400 component positively correlated with Heschl's gyrus volume and tended to positively correlate with disease duration. M400 was markedly diminished after hippocampal resection. Although volumetric analysis showed decreased hippocampal volume in the HS side, the planum temporale and Heschl's gyrus, the two major sources of M100, were preserved. These results suggested that HS significantly influenced AEFs. Therefore, we concluded that the hippocampus modulates auditory processing differently under normal conditions and in HS.

Neuromagnetic detection of the laryngeal area: Sensory-evoked fields to air-puff stimulation.

The sensory projections from the oral cavity, pharynx, and larynx are crucial in assuring safe deglutition, coughing, breathing, and voice production/speaking. Although several studies using neuroimaging techniques have demonstrated cortical activation related to pharyngeal and laryngeal functions, little is known regarding sensory projections from the laryngeal area to the somatosensory cortex. The purpose of this study was to establish the cortical activity evoked by somatic air-puff stimulation at the laryngeal mucosa using magnetoencephalography. Twelve healthy volunteers were trained to inhibit swallowing in response to air stimuli delivered to the larynx. Minimum norm estimates was performed on the laryngeal somatosensory evoked fields (LSEFs) to best differentiate the target activations from non-task-related activations. Evoked magnetic fields were recorded with acceptable reproducibility in the left hemisphere, with a peak latency of approximately 100ms in 10 subjects. Peak activation was estimated at the caudolateral region of the primary somatosensory area (S1). These results establish the ability to detect LSEFs with an acceptable reproducibility within a single subject and among subjects. These results also suggest the existence of laryngeal somatic afferent input to the caudolateral region of S1 in human. Our findings indicate that further investigation in this area is needed, and should focus on laryngeal lateralization, swallowing, and speech processing.

ILAE focal cortical dysplasia type IIIc in the ictal onset zone in epileptic patients with solitary meningioangiomatosis.

"Solitary" meningioangiomatosis (MA) is a rare, benign, hamartomatous lesion of the cerebral cortex and frequently leads to epilepsy. However, the source of the epileptogenicity in meningioangiomatosis remains controversial. We report two surgically-treated meningioangiomatosis cases with medically intractable epilepsy. In both cases, chronic subdural electrocorticogram (ECoG) recordings identified the ictal onset zone on apparently normal cortex, adjacent to and/or above the meningioangiomatosis lesion, not on the meningioangiomatosis lesion itself. The ictal onset zone was resected, along with the MA lesion, and good seizure outcome was achieved. Histological examination of the ictal onset zone revealed the presence of ILAE focal cortical dysplasia (FCD) type IIIc. Our case studies suggest that in the surgical management of epilepsy with meningioangiomatosis, it is important to identify undetected, but epileptogenic, ILAE FCD Type IIIc, using preoperative multimodal examinations, including chronic ECoG recordings.

[Patients with intractable epilepsy who achieved good seizure control after craniotomy instead of vagal nerve stimulation].

Vagal nerve stimulation(VNS)is an effective adjunctive therapy for medically intractable epilepsy. However, VNS is a palliative therapy, and craniotomy should preferably be performed when complete seizure remission can be expected after craniotomy. We report here three patients who were referred for VNS therapy, but underwent craniotomy instead of VNS based on the results of a comprehensive preoperative evaluation, and achieved good seizure control. Case 1 was a 48-year-old woman with left temporal lobe epilepsy and amygdalar enlargement. Even though no left hippocampal sclerosis was observed on magnetic resonance imaging, she underwent left anterior temporal lobectomy and hippocampectomy. Case 2 was a 36-year-old woman with multiple bilateral subependymal nodular heterotopias, who underwent resection of the left medial temporal lobe including subependymal nodular heterotopias adjacent to the left inferior horn. Case 3 was a 25-year-old man with posttraumatic epilepsy. As the right hemisphere was most affected, multiple subpial transections were performed on the left frontal convexity. These three patients were referred to us for VNS therapy because there was a dissociation between the interictal electroencephalogram and magnetic resonance imaging findings, or because they had multiple or extensive epileptogenic lesions. Comprehensive preoperative evaluation including ictal electroencephalography can help to identify patients who are suitable candidates for craniotomy.

[Electroencephalography for patient with epilepsy].

Electroencephalography (EEG) is the primary means by which epileptic activity in the brain is measured. The frequency of epileptic discharges is influenced by vigilance and biological rhythms. When checking for epileptic activity using EEG, measurements must be repeated and recordings made during sleep are recommended if epileptic discharges do not readily appear. Epileptic discharges must be classified as generalized or focal discharges, and discriminated from non-epileptic discharges such as vertex sharp transients, positive occipital sharp transients, 14 & 6 positive spike discharge, and artifacts. Attention should be paid to small sharp spikes, 6Hz spike and slow wave, focal slow waves, and generalized rhythmic slow waves, which should all be considered variants of epileptic activity. EEG provides information regarding focal and generalized brain dysfunction in addition to epileptic activity. Because the misreading of EEG may negatively affect the lives of patients, reading the EEG correctly is quite important.

Progressive myoclonic epilepsy as an expanding phenotype of NGLY1-associated congenital deglycosylation disorder: A case report and review of the literature.

INTRODUCTION: NGLY1-associated congenital disorder of deglycosylation (CDDG1: OMIM #615273) is a rare autosomal recessive disorder caused by a functional impairment of endoplasmic reticulum in degradation of glycoproteins. Neurocognitive dysfunctions have been documented in patients with CDDG1; however, deteriorating phenotypes of affected individuals remain elusive. CASE PRESENTATION: A Japanese boy with delayed psychomotor development showed ataxic movements from age 5 years and myoclonic seizures from age 12 years. Appetite loss, motor and cognitive decline became evident at age 12 years. Electrophysiological studies identified paroxysmal discharges on myoclonic seizure and a giant somatosensory evoked potential. Perampanel was effective for controlling myoclonic seizures. Exome sequencing revealed that the patient carried compound heterozygous variants in NGLY1, NM_018297.4: c.857G > A and c.-17_12del, which were inherited from mother and father, respectively. A literature review confirmed that myoclonic seizures were observed in 28.5% of patients with epilepsy. No other patients had progressive myoclonic epilepsy or cognitive decline in association with loss-of-function variations in NGLY1. CONCLUSION: Our data provides evidence that a group of patients with CDDG1 manifest slowly progressive myoclonic epilepsy and cognitive decline during the long-term clinical course.

Reflection of the Ictal Electrocorticographic Discharges Confined to the Medial Temporal Lobe to the Scalp-Recorded Electroencephalogram.

Objective: Previous reports on the simultaneous recording of electroencephalography (EEG) and electrocorticography (ECoG) have demonstrated that, in patients with temporal lobe epilepsy (TLE), ictal ECoG discharges with an amplitude as high as 1000 µV originating from the medial temporal lobe could not be recorded on EEG. In contrast, ictal EEG discharges were recorded after ictal ECoG discharges propagated to the lateral temporal lobe. Here, we report a case of TLE in which the ictal EEG discharges, corresponding to ictal ECoG discharges confined to the medial temporal lobe, were recorded. Case report: In the present case, ictal EEG discharges were hardly recognized when the amplitude of the ECoG discharges was less than 1500 µV. During the evolution and burst suppression phase, corresponding to highly synchronized ECoG discharges with amplitudes greater than 1500 to 2000 µV, rhythmic negative waves with the same frequency were clearly recorded both on the lateral temporal lobe and scalp. The amplitude of the lateral temporal ECoG was approximately one-tenth of that of the medial temporal ECoG. The amplitude of the scalp EEG was approximately one-tenth of that of the lateral temporal ECoG. Conclusions: Highly synchronized ictal ECoG discharges with high amplitude of greater than 1500 to 2000 µV in the medial temporal lobe could be recorded on the scalp as ictal EEG discharges via volume conduction.

Mandibular and chin electrodes as a supplemental recording for detection of epileptiform discharges in mesial temporal lobe epilepsy.

Background: We previously demonstrated the usefulness of periorbital electrodes in supplemental recording to detect epileptiform discharges in patients with mesial temporal lobe epilepsy (MTLE). However, eye movement may disturb periorbital electrode recording. To overcome this, we developed mandibular (MA) and chin (CH) electrodes and examined whether these electrodes could detect hippocampal epileptiform discharges. Methods: This study included a patient with MTLE, who underwent insertion of bilateral hippocampal depth electrodes and video-electroencephalographic (EEG) monitoring with simultaneous recordings of extra- and intracranial EEG as part of a presurgical evaluation. We examined 100 consecutive interictal epileptiform discharges (IEDs) recorded from the hippocampus and two ictal discharges. We compared these IEDs from intracranial electrodes with those from extracranial electrodes such as MA and CH electrodes in addition to F7/8 and A1/2 of international EEG 10-20 system, T1/2 of Silverman, and periorbital electrodes. We analyzed the number, rate of laterality concordance, and mean amplitude of IEDs detected in extracranial EEG monitoring and characteristics of IEDs on the MA and CH electrodes. Results: The MA and CH electrodes had nearly the same detection rate of hippocampal IEDs from other extracranial electrodes without contamination by eye movement. Three IEDs, not detected by A1/2 and T1/2, could be detected using the MA and CH electrodes. In two ictal events, the MA and CH electrodes detected the ictal discharges from the hippocampal onset as well as other extracranial electrodes. Conclusion: The MA and CH electrodes could detect hippocampal epileptiform discharges as well as A1/A2, T1/T2, and peri-orbital electrodes. These electrodes could serve as supplementary recording tools for detecting epileptiform discharges in MTLE.

High-echoic line tracing of transthoracic echocardiography accurately assesses right ventricular enlargement in adult patients with atrial septal defect.

Accurate measurement of right ventricular (RV) size using transthoracic echocardiography (TTE) is important for evaluating the severity of congenital heart diseases. The RV end-diastolic area index (RVEDAi) determined using TTE is used to assess RV dilatation; however, the tracing line of the RVEDAi has not been clearly defined by the guidelines. This study aimed to determine the exact tracing method for RVEDAi using TTE. We retrospectively studied 107 patients with atrial septal defects who underwent cardiac magnetic resonance imaging (CMR) and TTE. We measured the RVEDAi according to isoechoic and high-echoic lines, and compared it with the RVEDAi measured using CMR. The isoechoic line was defined as the isoechoic endocardial border of the RV free wall, whereas the high-echoic line was defined as the high-echoic endocardial border of the RV free wall more outside than the isoechoic line. RVEDAi measured using high-echoic line (high-RVEDAi) was more accurately related to RVEDAi measured using CMR than that measured using isoechoic line (iso-RVEDAi). The difference in the high-RVEDAi was 0.3 cm2/m2, and the limit of agreement (LOA) was - 3.7 to 4.3 cm2/m2. With regard to inter-observer variability, high-RVEDAi was superior to iso-RVEDAi. High-RVEDAi had greater agreement with CMR-RVEDAi than with iso-RVEDAi. High-RVEDAi can become the standard measurement of RV size using two-dimensional TTE.

Detection of ictal and periictal hyperperfusion with subtraction of ictal-interictal 1.5-Tesla pulsed arterial spin labeling images co-registered to conventional magnetic resonance images (SIACOM).

Background: Our recent report showed that 1.5-T pulsed arterial spin labeling (ASL) magnetic resonance (MR) perfusion imaging (1.5-T Pulsed ASL [PASL]), which is widely available in the field of neuroemergency, is useful for detecting ictal hyperperfusion. However, the visualization of intravascular ASL signals, namely, arterial transit artifact (ATA), is more remarkable than that of 3-T pseudocontinuous ASL and is easily confused with focal hyperperfusion. To eliminate ATA and enhance the detectability of (peri) ictal hyperperfusion, we developed the subtraction of ictal-interictal 1.5-T PASL images co-registered to conventional MR images (SIACOM). Methods: We retrospectively analyzed the SIACOM findings in four patients who underwent ASL during both (peri) ictal and interictal states and examined the detectability for (peri) ictal hyperperfusion. Results: In all patients, the ATA of the major arteries was almost eliminated from the subtraction image of the ictal-interictal ASL. In patients 1 and 2 with focal epilepsy, SIACOM revealed a tight anatomical relationship between the epileptogenic lesion and the hyperperfusion area compared with the original ASL image. In patient 3 with situation-related seizures, SIACOM detected minute hyperperfusion at the site coinciding with the abnormal electroencephalogram area. SIACOM of patient 4 with generalized epilepsy diagnosed ATA of the right middle cerebral artery, which was initially thought to be focal hyperperfusion on the original ASL image. Conclusion: Although it is necessary to examine several patients, SIACOM can eliminate most of the depiction of ATA and clearly demonstrate the pathophysiology of each epileptic seizure.

Shadowboxing-induced reflex seizures in a patient with focal epilepsy.

Exercise-induced reflex seizures are a rare form of reflex seizures that are exclusively induced by a specific type of exercise. Many patients with exercise-induced reflex seizures exhibit drug-resistance, and are therefore advised to avoid the triggering exercise. Here, we describe a focal epilepsy patient with shadowboxing-induced reflex seizures. His semiology included focal aware seizures with speech and behavioral arrest that evolved to head version to the right, preceded by cephalic aura. We identified a specific motion that induced these seizures during shadowboxing using video-electroencephalographic recording, and the patient was able to continue boxing by avoiding this motion. We speculate that a broad brain network may be the pathological substrate of his exercise-induced reflex seizures. Identification of the specific motion that induces exercise-induced reflex seizures is useful for not only understanding the underlying pathophysiology, but also for minimizing the therapeutic restriction of the exercise.

The effect of interictal epileptic discharges and following spindles on motor sequence learning in epilepsy patients.

Purpose: Interictal epileptic discharges (IEDs) are known to affect cognitive function in patients with epilepsy, but the mechanism has not been elucidated. Sleep spindles appearing in synchronization with IEDs were recently demonstrated to impair memory consolidation in rat, but this has not been investigated in humans. On the other hand, the increase of sleep spindles at night after learning is positively correlated with amplified learning effects during sleep for motor sequence learning. In this study, we examined the effects of IEDs and IED-coupled spindles on motor sequence learning in patients with epilepsy, and clarified their pathological significance. Materials and methods: Patients undergoing long-term video-electroencephalography (LT-VEEG) at our hospital from June 2019 to November 2021 and age-matched healthy subjects were recruited. Motor sequence learning consisting of a finger-tapping task was performed before bedtime and the next morning, and the improvement rate of performance was defined as the sleep-dependent learning effect. We searched for factors associated with the changes in learning effect observed between the periods of when antiseizure medications (ASMs) were withdrawn for LT-VEEG and when they were returned to usual doses after LT-VEEG. Results: Excluding six patients who had epileptic seizures at night after learning, nine patients and 11 healthy subjects were included in the study. In the patient group, there was no significant learning effect when ASMs were withdrawn. The changes in learning effect of the patient group during ASM withdrawal were not correlated with changes in sleep duration or IED density; however, they were significantly negatively correlated with changes in IED-coupled spindle density. Conclusion: We found that the increase of IED-coupled spindles correlated with the decrease of sleep-dependent learning effects of procedural memory. Pathological IED-coupled sleep spindles could hinder memory consolidation, that is dependent on physiological sleep spindles, resulting in cognitive dysfunction in patients with epilepsy.

Postoperative striatal degeneration: a hitherto unrecognized impact of frontal disconnection surgery for drug-resistant epilepsy. Illustrative cases.

BACKGROUND: Frontal disconnection surgery is a useful surgical option for patients with frontal epilepsy whose seizure onset zones are exceedingly large and thus are not amenable to conventional resective surgery. While it has the advantage of avoiding sequelae stemming from a large resection cavity, the impact of radical anatomofunctional disconnection of such a vast frontal region is not fully understood. OBSERVATIONS: The authors have identified secondary degeneration in the striatum ipsilateral to the frontal disconnection surgery in two adult patients who had otherwise favorable postoperative outcomes following the surgery. On serial postoperative magnetic resonance imaging, the striatum showed transient restricted diffusion in the caudate head and rostral putamen around several weeks postoperatively and subsequent atrophy in the caudate head. The affected striatal regions (i.e., the anterior portion of the striatum) were congruent with the known fronto-striatal connectivity corresponding to the disconnected frontal regions anterior to the primary and supplementary motor areas. Both patients achieved 1-year seizure freedom without apparent disability related to the surgery. LESSONS: The benign postoperative course despite the marked degenerative changes in the ipsilateral striatum supports the feasibility of the frontal disconnection surgery in otherwise inoperable patients with broad frontal epileptogenicity.