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A 7-year-old right-handed girl presented to the pediatric neurology outpatient clinic after 5 episodes of headache over the previous 3 months. Her family history was positive for migraine in the mother and maternal grandmother and for febrile seizures in the older sister. The neurologic examination and cognitive profile were normal. Five seconds after the end of hyperventilation, video-EEG showed high-amplitude delta waves predominantly over the left hemisphere with concomitant acute aphasia and right-sided weakness. After the event, which self-resolved over 8 minutes, the girl showed intact recall. A second instance of hyperventilation evoked the appearance of pseudo-rhythmic slow activity localized to the right hemisphere, associated with left-sided weakness, 20 seconds after the end of the test. This event spontaneously resolved in 3 minutes and was followed by headache.An exaggerated physiologic response to hyperventilation, the possible epileptic nature of the events, and a migraine variant were all considered in the differential. Nonetheless, the EEG slowing is shorter in duration and generalized in physiologic and paraphysiological conditions. A clear ictal morphology and evolution of the EEG activity were lacking in this case, and migraine attacks induced by hyperpnea have not been reported to date. Instead, EEG alterations similar to that observed in our patient are described in association with vascular abnormalities. We report the clinical presentation and diagnostic workup of a rare cerebrovascular disorder, highlighting the key features in the differential. Our case emphasizes the clinical value of the EEG rebuild-up phenomenon, which can help the clinician in achieving a prompt diagnosis.

Background and Objectives: Pathogenic STXBP1 variants cause a severe early-onset developmental and epileptic encephalopathy (STXBP1-DEE). We aimed to investigate the natural history of STXBP1-DEE in adults focusing on seizure evolution, the presence of movement disorders, and the level of functional (in)dependence., Methods: In this observational study, patients with a minimum age of 18 years carrying a (likely) pathogenic STXBP1 variant were recruited through medical genetics departments and epilepsy centers. Treating clinicians completed clinical questionnaires and performed semistructured video examinations while performing tasks from the (modified) Unified Parkinson Disease Rating Scale when possible., Results: Thirty adult patients were included for summary statistics, with video recordings available for 19 patients. The median age at last follow-up was 24 years (range 18-58 years). All patients had epilepsy, with a median onset age of 3.5 months. At last follow-up, 80% of adults had treatment-resistant seizures despite long periods of seizure freedom in 37%. Tonic-clonic, focal, and tonic seizures were most frequent in adults. Epileptic spasms, an unusual feature beyond infancy, were present in 3 adults. All individuals had developmental impairment. Periods of regression were present in 59% and did not always correlate with flare-ups in seizure activity. Eighty-seven percent had severe or profound intellectual disability, 42% had autistic features, and 65% had significant behavioral problems. Video examinations showed gait disorders in all 12 patients able to walk, including postural abnormalities with external rotation of the feet, broad-based gait, and asymmetric posture/dystonia. Tremor, present in 56%, was predominantly of the intention/action type. Stereotypies were seen in 63%. Functional outcome concerning mobility was variable ranging from independent walking (50%) to wheelchair dependence (39%). Seventy-one percent of adults were nonverbal, and all were dependent on caregivers for most activities of daily living., Discussion: STXBP1-DEE warrants continuous monitoring for seizures in adult life. Periods of regression are more frequent than previously established and can occur into adulthood. Movement disorders are often present and involve multiple systems. Although functional mobility is variable in adulthood, STXBP1-DEE frequently leads to severe cognitive impairments and a high level of functional dependence. Understanding the natural history of STXBP1-DEE is important for prognostication and will inform future therapeutic trials., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

New-onset refractory status epilepticus (NORSE) is rare condition, and sharing knowledge is vital in its management, based on strict collaboration between multiple specialists, continuous EEG (c-EEG) monitoring, and prompt therapy modification. The coronavirus disease 2019 (COVID-19) pandemic challenged many of these established practices because of "social distancing" measures, making it necessary to work around physical restrictions. We report a case of a 10-year-old with NORSE admitted in a pediatric intensive-care unit and monitored with c-EEG and amplitude-integrated EEG. The monitoring interface was livestreamed using videoconference web-based platforms allowing remote viewing. Multiple daily web meetings took place between team members, where real-time therapy response was evaluated and confronted with medium-term trends in the epileptic activity, dictating further treatment and diagnostic steps. In addition to the known use of telemedicine in chronic conditions, we report how its use can be exploited to treat urgent conditions such as NORSE. By taking advantage of new tools and virtual environments, we were able to share treatment and diagnostic decisions and guarantee real-time therapy adjustments and a coherent course in treatment despite restrictions necessary for the COVID-19 pandemic. The constant specialist monitoring and the coherent and on-time communication of the patient's condition relieved the family stress, usually complained in these situations., (© 2020 American Academy of Neurology.)

Background: Benign familial neonatal convulsion (BFNC) is a rare autosomal dominant disorder caused by mutations in two genes, KCNQ2 and KCNQ3, encoding for potassium channel subunits underlying the M-current. This current limits neuronal hyperexcitability by causing spike-frequency adaptation., Methods: The authors describe a BFNC family with four affected members: two of them exhibit BFNC only while the other two, in addition to BFNC, present either with a severe epileptic encephalopathy or with focal seizures and mental retardation., Results: All affected members of this family carry a novel missense mutation in the KCNQ2 gene (K526N), disrupting the tri-dimensional conformation of a C-terminal region of the channel subunit involved in accessory protein binding. When heterologously expressed in CHO cells, potassium channels containing mutant subunits in homomeric or heteromeric configuration with wild-type KCNQ2 and KCNQ3 subunits exhibit an altered voltage-dependence of activation, without changes in intracellular trafficking and plasma membrane expression., Conclusion: The KCNQ2 K526N mutation may affect M-channel function by disrupting the complex biochemical signaling involving KCNQ2 C-terminus. Genetic rather than acquired factors may be involved in the pathophysiology of the phenotypic variability of the neurologic symptoms associated with BFNC in the described family.

Objective: To identify early manifestations of Rasmussen encephalitis (RE) that can prompt early and reasonably secure diagnosis, allowing medical or surgical therapies at an early stage when they may be more effective in slowing the disease., Methods: The authors studied 12 patients with clinical and neuropathologic diagnosis of RE, followed from disease onset, assessing clinical history, imaging, and EEG and focusing on early characteristics. Anti-GluR3 antibody assays were also considered in 11 patients., Results: By 4 months from first symptoms, all cases had 1) refractory focal seizures with a predominant motor component, 2) slow focal activity on EEG contralateral to the motor manifestations, and 3) focal contralateral white matter hyperintensity with insular cortical atrophy on neuroimaging. Less constant or later findings were epilepsia partialis continua, oligoclonal bands, and serum anti-GluR3 antibodies., Conclusions: The association of partial seizures with focal EEG and neuroimaging changes allows a tentative diagnosis of RE 4 to 6 months after first symptoms.

Benign familial nocturnal alternating hemiplegia of childhood refers to recurrent attacks of hemiplegia arising from sleep, described in young children without neurologic or mental impairment. It is probably migraine related. The authors report two unrelated patients with nocturnal attacks starting at 22 and 31 months, followed by daytime episodes in one. The authors confirm the benign course of this disorder. It is distinct from the classic malignant form of alternating hemiplegia of childhood.