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.

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.

Caution to Poor Adherence With Immunosuppressant Medication That Causes Coma-Onset Autoimmune Encephalitis: A Case Report and Literature Review

Autoimmune encephalitis after liver transplantation (LT) is a rare disorder. This is because patients are usually in an immunosuppressed state after LT. Here, we report a rare case of autoantibody-negative autoimmune-encephalitis-induced coma after living-donor (LD) LT. A 45-year-old woman who underwent LDLT for primary biliary cholangitis (PBC) was brought to our hospital with the chief complaint of cognitive deficiency and an episode of memory loss. Physical examination, laboratory tests, and cerebrospinal fluid analysis revealed no significant findings. However, diffusion-weighted magnetic resonance imaging showed hyperintensity in the bilateral hippocampus. No autoantibodies associated with autoimmune encephalitis were detected. The diagnosis of antibody-negative autoimmune encephalitis was made on the basis of low immunosuppressive drug levels in the blood (indicative of poor adherence) and the presence of PBC as the autoimmune disease. The patient regained consciousness after intravenous methylprednisolone pulse therapy and plasma exchange. This case highlights that when examining patients with impaired consciousness after LDLT, it is important to consider autoimmune encephalitis as a potential diagnosis.

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.

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.

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 seconds, 10 minutes, 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 minutes 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 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 (β = 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.

Shadowboxing-induced reflex seizures in a patient with focal epilepsy

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We describe a focal epilepsy patient with shadowboxing-induced reflex seizures.

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We identified a precipitative motion within the shadowboxing by video-EEG.

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Avoiding the motion enabled him to continue boxing free from reflex seizures.

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.

Grand Total EEG Score Can Differentiate Parkinson's Disease From Parkinson-Related Disorders

Background: Semi-quantitative electroencephalogram (EEG) analysis is easy to perform and has been used to differentiate dementias, as well as idiopathic and vascular Parkinson's disease.

Purpose: To study whether a semi-quantitative EEG analysis can aid in distinguishing idiopathic Parkinson's disease (IPD) from atypical parkinsonian disorders (APDs), and furthermore, whether it can help to distinguish between APDs.

Materials and Methods: A comprehensive retrospective review of charts was performed to include patients with parkinsonian disorders who had at least one EEG recording available. A modified grand total EEG (GTE) score evaluating the posterior background activity, and diffuse and focal slow wave activities was used in further analyses.

Results: We analyzed data from 76 patients with a final diagnosis of either IPD, probable corticobasal degeneration (CBD), multiple system atrophy (MSA), or progressive supra-nuclear palsy (PSP). IPD patients had the lowest mean GTE score, followed those with CBD or MSA, while PSP patients scored the highest. However, none of these differences were statistically significant. A GTE score of ≤9 distinguished IPD patients from those with APD (p < 0.01) with a sensitivity of 100% and a specificity of 33.3%.

Conclusion: The modified GTE score can distinguish patients with IPD from those with CBD, PSP or MSA at a cut-off score of 9 with excellent sensitivity but poor specificity. However, this score is not able to distinguish a particular form of APD from other forms of the disorder.