Pallidal deep brain stimulation for patients with myoclonus-dystonia without SGCE mutations.

BACKGROUND: Pallidal deep brain stimulation (GPi-DBS) is effective for treating myoclonus and dystonia caused by SGCE mutations (DYT-SGCE, DYT11). However, it is unknown whether GPi-DBS is effective for the treatment of myoclonus-dystonia which is not associated with the SGCE gene mutations. In this study, we investigated the efficacy of GPi-DBS in treating myoclonus-dystonia in SGCE mutation-negative cases. METHODS: Three patients with myoclonus-dystonia without SGCE mutations who underwent GPi-DBS were evaluated preoperatively and 6 months postoperatively using the Unified Myoclonus Rating Scale (UMRS) and Fahn-Marsden Dystonia Rating Scale (FMDRS) for myoclonus and dystonia, respectively. In two of the three patients, myoclonus was more evident during action. Myoclonus was predominant at rest in the other patient, and he was unaware of his dystonia symptoms. The results were compared with those of the four DYT-SGCE cases. RESULTS: The mean UMRS score in patients with myoclonus-dystonia without SGCE mutations improved from 61.7 to 33.7 pre- and postoperatively, respectively, and the mean FMDRS score improved from 7.2 to 4.5. However, the degree of improvement in myoclonus-dystonia in patients without SGCE mutations was inferior to that in patients with DYT-SGCE (the UMRS score improved by 45% and 69%, respectively). CONCLUSIONS: GPi-DBS is effective for treating myoclonus-dystonia in patients with and without SGCE mutations. GPi-DBS should be considered as a treatment option for myoclonus-dystonia without SGCE mutations.

Specific consistency score for rational selection of epilepsy resection surgery candidates.

OBJECTIVE: Degree of indication for epilepsy surgery is determined by taking multiple factors into account. This study aimed to investigate the usefulness of the Specific Consistency Score (SCS), a proposed score for focal epilepsy to rate the indication for epilepsy focal resection. METHODS: This retrospective cohort study included patients considered for resective epilepsy surgery in Kyoto University Hospital from 2011 to 2022. Plausible epileptic focus was tentatively defined. Cardinal findings were scored based on specificity and consistency with the estimated laterality and lobe. The total points represented SCS. The association between SCS and the following clinical parameters was assessed by univariate and multivariate analysis: (1) probability of undergoing resective epilepsy surgery, (2) good postoperative seizure outcome (Engel I and II or Engel I only), and (3) lobar concordance between the noninvasively estimated focus and intracranial electroencephalographic (EEG) recordings. RESULTS: A total of 131 patients were evaluated. Univariate analysis revealed higher SCS in the (1) epilepsy surgery group (8.4 [95% confidence interval (CI) = 7.8-8.9] vs. 4.9 [95% CI = 4.3-5.5] points; p < .001), (2) good postoperative seizure outcome group (Engel I and II; 8.7 [95% CI = 8.2-9.3] vs. 6.4 [95% CI = 4.5-8.3] points; p = .008), and (3) patients whose focus defined by intracranial EEG matched the noninvasively estimated focus (8.3 [95% CI = 7.3-9.2] vs. 5.4 [95% CI = 3.5-7.3] points; p = .004). Multivariate analysis revealed areas under the curve of .843, .825, and .881 for Parameters 1, 2, and 3, respectively. SIGNIFICANCE: SCS provides a reliable index of good indication for resective epilepsy surgery and can be easily available in many institutions not necessarily specializing in epilepsy.

Periodic discharges plus fast activity on electroencephalogram predict worse outcomes in poststroke epilepsy.

OBJECTIVE: Postseizure functional decline is a concern in poststroke epilepsy (PSE). However, data on electroencephalogram (EEG) markers associated with functional decline are scarce. Thus, we investigated whether periodic discharges (PDs) and their specific characteristics are associated with functional decline in patients with PSE. METHODS: In this observational study, patients admitted with seizures of PSE and who had scalp EEGs were included. The association between the presence or absence of PDs and postseizure short-term functional decline lasting 7 days after admission was investigated. In patients with PD, EEG markers were explored for risk stratification of short-term functional decline, according to the American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology. The association between EEG markers and imaging findings and long-term functional decline at discharge and 6 months after discharge, defined as an increase in the modified Rankin Scale score compared with the baseline, was evaluated. RESULTS: In this study, 307 patients with PSE (median age = 75 years, range = 35-97 years, 64% males; hemorrhagic stroke, 47%) were enrolled. Compared with 247 patients without PDs, 60 patients with PDs were more likely to have short-term functional decline (12 [20%] vs. 8 [3.2%], p < .001), with an adjusted odds ratio (OR) of 4.26 (95% confidence interval [CI] = 1.44-12.6, p = .009). Patients with superimposed fast-activity PDs (PDs+F) had significantly more localized (rather than widespread) lesions (87% vs. 58%, p = .003), prolonged hyperperfusion (100% vs. 62%, p = .023), and a significantly higher risk of short-term functional decline than those with PDs without fast activity (adjusted OR = 22.0, 95% CI = 1.87-259.4, p = .014). Six months after discharge, PDs+F were significantly associated with long-term functional decline (adjusted OR = 4.21, 95% CI = 1.27-13.88, p = .018). SIGNIFICANCE: In PSE, PDs+F are associated with sustained neuronal excitation and hyperperfusion, which may be a predictor of postseizure short- and long-term functional decline.

Focal tonic seizures with asymmetrical posturing could allow voluntary movements: A lesson to not be misled for a non-epileptic event.

This report documents the clinical features of supplementary motor area seizures with voluntary movements in two patients. The first case describes a 13-year-old boy with a 2-year history of nocturnal seizures, characterized by an asymmetrical brief tonic posture followed by bilateral rapid hand shaking, but without impaired awareness. Magnetic resonance imaging revealed no abnormalities. Video electroencephalogram indicated interictal focal spikes and ictal activity 2 s before clinical onset in the frontal midline area. The patient stated that he purposely shook his hands to lessen the seizure-induced upper limb stiffness. The second case describes a 43-year-old man with a 33-year history of nocturnal seizures, characterized by an asymmetric brief tonic posture, with the right hand grabbing to hold this posture, but without impaired awareness. Video electroencephalogram indicated that he voluntarily moved his right hand during the latter part of the seizures; however, no clear ictal electroencephalogram change was noted. Magnetic resonance imaging revealed a mass lesion in the right medial superior frontal gyrus. Fluorodeoxyglucose-positron emission tomography and ictal single-photon emission computed tomography indicated ictal focus in the mesial frontal area, as confirmed by invasive electroencephalogram and seizure freedom after surgery. Both patients had typical supplementary motor area seizures, except they could perform voluntary movements in the body parts. The co-occurrence of supplementary motor area seizures and voluntary movements is clinically useful, as it may help avoid the inaccurate and misleading diagnosis of non-epileptic events such as psychogenic non-epileptic seizures.

Interictal epileptiform discharges as a predictive biomarker for recurrence of poststroke epilepsy.

Poststroke epilepsy is a major ischaemic/haemorrhagic stroke complication. Seizure recurrence risk estimation and early therapeutic intervention are critical, given the association of poststroke epilepsy with worse functional outcomes, quality of life and greater mortality. Several studies have reported risk factors for seizure recurrence; however, in poststroke epilepsy, the role of EEG in predicting the risk of seizures remains unclear. This multicentre observational study aimed to clarify whether EEG findings constitute a risk factor for seizure recurrence in patients with poststroke epilepsy. Patients with poststroke epilepsy were recruited from the PROgnosis of POst-Stroke Epilepsy study, an observational multicentre cohort study. The enrolled patients with poststroke epilepsy were those admitted at selected hospitals between November 2014 and June 2017. All patients underwent EEG during the interictal period during admission to each hospital and were monitored for seizure recurrence over 1 year. Board-certified neurologists or epileptologists evaluated all EEG findings. We investigated the relationship between EEG findings and seizure recurrence. Among 187 patients with poststroke epilepsy (65 were women with a median age of 75 years) admitted to the lead hospital, 48 (25.7%) had interictal epileptiform discharges on EEG. During the follow-up period (median, 397 days; interquartile range, 337-450 days), interictal epileptiform discharges were positively correlated with seizure recurrence (hazard ratio, 3.82; 95% confidence interval, 2.09-6.97; P < 0.01). The correlation remained significant even after adjusting for age, sex, severity of stroke, type of stroke and generation of antiseizure medications. We detected periodic discharges in 39 patients (20.9%), and spiky/sharp periodic discharges were marginally associated with seizure recurrence (hazard ratio, 1.85; 95% confidence interval, 0.93-3.69; P = 0.08). Analysis of a validation cohort comprising 187 patients with poststroke epilepsy from seven other hospitals corroborated the association between interictal epileptiform discharges and seizure recurrence. We verified that interictal epileptiform discharges are a risk factor for seizure recurrence in patients with poststroke epilepsy. Routine EEG may facilitate the estimation of seizure recurrence risk and the development of therapeutic regimens for poststroke epilepsy.

Developing an Asymmetry Method for Detecting Postictal Hyperperfusion in Poststroke Epilepsy.

Using dual single-photon emission computed tomography (SPECT) scanning, we recently found the postictal-interictal (P-I) subtraction method frequently detects prolonged postictal hyperperfusion in poststroke epilepsy (PSE) and thus may be valuable for auxiliary diagnosis. This study aimed to determine if the asymmetry method can localize hyperperfusion to reflect epileptic activity in PSE using a single postictal SPECT scan. Sixty-four patients with PSE who had undergone perfusion SPECT two times (postictal and interictal) were enrolled. We formulated a novel asymmetry method (subtraction analysis of reversed postictal SPECT from postictal SPECT, co-registered to magnetic resonance imaging) to identify paradoxical asymmetric increase, defined as a higher perfusion area adjacent to stroke lesions compared to the contralateral side. The postictal hyperperfusion area and detection rates were determined by the asymmetry and P-I subtraction methods independently. We subsequently calculated the sensitivity and specificity of the asymmetry method, compared to the gold standard P-I subtraction method. We also evaluated lateralization concordance between the asymmetry method and other clinical findings. Among 64 patients (median age, 75 years), prolonged postictal hyperperfusion was detected in 43 (67%) by the asymmetry, and 54 (84%) the P-I, method. The asymmetry method had high sensitivity (80%) and specificity (100%) in detecting postictal hyperperfusion, showing high lateralization concordance with seizure semiology (97%) and epileptiform electroencephalography findings (interictal/ictal epileptiform discharges or periodic discharges) (100%). The present study demonstrated the advantages of the objective asymmetry method for detecting prolonged hyperperfusion through using one postictal SPECT scan in PSE.

Clinical and imaging features of nonmotor onset seizure in poststroke epilepsy.

OBJECTIVE: Motivated by the challenges raised by diagnosing poststroke epilepsy (PSE), especially in nonmotor onset seizure (non-MOS), we aimed to investigate the features of non-MOS, including seizure sequences, patient characteristics, and electrophysiological and imaging findings in PSE. METHODS: This observational cohort study enrolled patients with PSE whose seizure onset was witnessed. According to the International League Against Epilepsy (ILAE) 2017 seizure classification, we classified seizure-onset symptoms into the non-MOS and MOS groups. We compared the different clinical characteristics between the two groups. RESULTS: Between 2011 and 2018, we enrolled 225 patients with PSE (median age, 75 years), consisting of 97 (43%) with non-MOS and 128 (57%) with MOS. Overall, 65 (67%) of the patients without MOS had no subsequent convulsions. Multivariable logistic regression analysis showed significant associations of non-MOS with absence of poststroke hemiparesis (adjusted odds ratio [OR], 1.88; 95% confidence interval [CI], 1.03-3.42), frontal stroke lobe lesions (OR, 2.11; 95% CI, 1.14-3.91), and putaminal stroke lesions (OR, 2.51; 95% CI, 1.22-5.18) as negative indicators. Postictal single-photon emission computed tomography (SPECT) detected prolonged hyperperfusion in the temporal lobe more frequently in the non-MOS than in the MOS group (48% vs 31%; p = .02). The detection rate was higher than spikes/sharp waves in scalp electroencephalography, both in the non-MOS group (72% vs 33%; p < .001) and the MOS group (68% vs 29%; p < .001). SIGNIFICANCE: This study provides the clinical features of non-MOS in patients with PSE. Compared with the patients with MOS, patients with non-MOS showed less likely subsequent convulsive seizures, highlighting the clinical challenges. Postictal perfusion imaging and negative indicators of the non-MOS type may help diagnose and stratify PSE.

Is Generalized and Segmental Dystonia Accompanied by Impairments in the Dopaminergic System?

Background: The pathogenesis of dystonia is remarkably diverse. Some types of dystonia, such as DYT5 (DYT-GCH1) and tardive dystonia, are related to dysfunction of the dopaminergic system. Furthermore, on pathological examination, cell loss in the substantia nigra (SN) of patients with dystonia has been reported, suggesting that impaired dopamine production may be involved in DYT5 and in other types of dystonia. Objectives: To investigate functional dopaminergic impairments, we compared patients with dystonia and those with Parkinson's disease (PD) with normal controls using neuromelanin-sensitive magnetic resonance imaging (NM-MRI) and dopamine transporter single photon emission computed tomography (DAT SPECT). Methods: A total of 18, 18, and 27 patients with generalized or segmental dystonia, patients with PD, and healthy controls, respectively, were examined using NM-MRI. The mean area corresponding to NM in the SN (NM-SN) was blindly quantified. DAT SPECT was performed on 17 and eight patients with dystonia and PD, respectively. The imaging data of DAT SPECT were harmonized with the Japanese database using striatum phantom calibration. These imaging data were compared between patients with dystonia or PD and controls from the Japanese database in 256 healthy volunteers using the calibrated specific binding ratio (cSBR). The symptoms of dystonia were evaluated using the Fahn-Marsden Dystonia Rating Scale (FMDRS), and the correlation between the results of imaging data and FMDRS was examined. Results: The mean areas corresponding to NM in the SN (NM-SN) were 31 ± 4.2, 28 ± 3.8, and 43 ± 3.8 pixels in patients with dystonia, PD, and in healthy controls, respectively. The mean cSBRs were 5 ± 0.2, 2.8 ± 0.2, 9.2 (predictive) in patients with dystonia, PD, and in healthy controls, respectively. The NM-SN area (r = -0.49, p < 0.05) and the cSBR (r = -0.54, p < 0.05) were inversely correlated with the FMDRS. There was no significant difference between the dystonia and PD groups regarding NM-SN (p = 0.28). In contrast, the cSBR was lower in patients with PD than in those with dystonia (p < 0.5 × 10-6). Conclusions: Impairments of the dopaminergic system may be involved in developing generalized and segmental dystonia. SN abnormalities in patients with dystonia were supposed to be different from degeneration in PD.

A Biomarker for Benign Adult Familial Myoclonus Epilepsy: High-Frequency Activities in Giant Somatosensory Evoked Potentials.

BACKGROUND: Benign adult familial myoclonus epilepsy (BAFME) is one of the diseases that cause cortical myoclonus (CM) with giant somatosensory evoked potentials (SEPs). There are no useful diagnostic biomarkers differentiating BAFME from other CM diseases. OBJECTIVE: To establish reliable biomarkers including high-frequency oscillations (HFOs) with giant SEPs for the diagnosis of BAFME. METHODS: This retrospective case study included 49 consecutive CM patients (16 BAFME and 33 other CM patients) who exhibited giant P25 or N35 SEPs. SEPs were processed by a band-pass filter of 400-1000 Hz to analyze HFOs. Clinical and SEP findings were compared between (1) BAFME and other CM groups and (2) patients with presence and absence of P25-HFOs (HFOs superimposed on giant P25). The diagnostic power of each factor for BAFME was calculated. RESULTS: All 16 BAFME patients showed SEP P25-HFOs with significantly higher occurrence (P < 0.0001) compared with that of other CM groups. The presence of P25-HFOs significantly correlated with a BAFME diagnosis (P < 0.0001) and high SEP P25 and N35 amplitudes (P = 0.01 and P < 0.0001, respectively). BAFME was reliably diagnosed using P25-HFOs with high sensitivity (100%), specificity (87.9%), positive predictive value (80%), and negative predictive value (100%), demonstrating its superiority as a diagnostic factor compared to other factors. CONCLUSIONS: P25-HFOs with giant SEPs is a potential biomarker for BAFME diagnosis. P25-HFOs may reflect cortical hyperexcitability partly due to paroxysmal depolarizing shifts in epileptic neuronal activities and higher degrees of rhythmic tremulousness than those in ordinary CM. © 2021 International Parkinson and Movement Disorder Society.

Low-dose perampanel improves refractory cortical myoclonus by the dispersed and suppressed paroxysmal depolarization shifts in the sensorimotor cortex.

OBJECTIVE: To elucidate the effects of perampanel (PER) on refractory cortical myoclonus for dose, etiology and somatosensory-evoked potential (SEP) findings. METHODS: We examined 18 epilepsy patients with seizure and cortical myoclonus. Based on data accumulated before and after PER treatment, correlations among clinical scores in myoclonus and activities of daily life (ADL); early cortical components of SEP; and PER blood concentration, were analyzed. RESULTS: PER (mean dose: 3.2 ±â€¯2.1 mg/day) significantly improved seizures, myoclonus and ADL and significantly decreased the amplitude of and prolonged latency of giant SEP components. The degree of P25 and N33 prolongations (23.8 ±â€¯1.6 to 24.7 ±â€¯1.7 ms and 32.1 ±â€¯4.0 to 33.7 ±â€¯3.4 ms) were significantly correlated with improved ADL score (p = 0.019 and p = 0.025) and blood PER concentration (p = 0.011 and p = 0.025), respectively. CONCLUSIONS: Low-dose PER markedly improved myoclonus and ADL in patients with refractory cortical myoclonus. Our results suggest that SEP, particularly P25 latency, can be used as a potential biomarker for assessing the objective effects of PER on intractable cortical myoclonus. SIGNIFICANCE: In this study, PER lessened the degree of synchronized discharges in the postsynaptic neurons in the primary motor cortex.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy with a Novel NOTCH3 Cys323Trp Mutation Presenting Border-Zone Infarcts: A Case Report and Literature Review.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary and progressive small-vessel disease caused by NOTCH3 mutations, pathologically characterized by the degeneration of vascular mural cells, white matter changes, and ischemic strokes. Recently, dysautoregulation has received increasing attention regarding the pathogenesis of stroke in CADASIL. Here, we report a CADASIL case with a novel Cys323Trp mutation in the NOTCH3 gene, which suggests a close relationship between hemodynamic factors and clustering of cerebral infarctions in CADASIL. A 47-year-old male patient presented with internal border-zone infarcts in the bilateral hemispheres and was diagnosed with CADASIL by the presence of granular osmiophilic material and the accumulation of the Notch3 extracellular domain around small vessels. A literature review revealed 7 reports of similar CADASIL cases with clustering of cerebral infarctions related to blood pressure fluctuations. Not only large-artery stenosis but also small-vessel pathologies potentiate watershed infarctions, which might be triggered by hemodynamic fluctuation due to cerebral dysautoregulation.

[Two cases of acute onset of focal cortical reflex myoclonus following acute aseptic meningoencephalitis with positive anti-glutamate receptor autoantibody].

Patient 1 was a 40-year-old man, who suffered from right leg myoclonus 1 week after an episode of fever and headache. Myoclonus disappeared 4 months after administration of clonazepam. Patient 2 was a 42-year-old man, who suffered from right leg myoclonus, attacks of speech arrest and a generalized tonic-clonic seizure. His symptoms disappeared after steroid-pulse therapy, but right leg myoclonus and episodic impairment of consciousness recurred within a month. He underwent another steroid-pulse therapy and his symptoms disappeared. In both patients, cerebrospinal fluid (CSF) study showed pleocytosis and elevated protein level, electrophysiological study showed cortical reflex by stimulation of the right tibial nerve, and brain MRI showed the high intensity area in the left parietal lobe. In addition, on electroencephalogram (EEG) spikes at vertex preceded myoclonic jerk of the right tibialis anterior muscle in both patients. These findings indicate that focal cortical reflex myoclonus was accompanied by acute central nervous system (CNS) infection. Furthermore, in both patients, autoantibody against glutamate receptor subunits ε2 was detected both in serum and CSF, which also suggest that autoimmune mechanism contributed in the pathophysiology of acute development of focal cortical reflex myoclonus.