Multiorgan manifestations of COL4A1 and COL4A2 variants and proposal for a clinical management protocol.

COL4A1/2 variants are associated with highly variable multiorgan manifestations. Depicting the whole clinical spectrum of COL4A1/2-related manifestations is challenging, and there is no consensus on management and preventative strategies. Based on a systematic review of current evidence on COL4A1/2-related disease, we developed a clinical questionnaire that we administered to 43 individuals from 23 distinct families carrying pathogenic variants. In this cohort, we extended ophthalmological and cardiological examinations to asymptomatic individuals and those with only limited or mild, often nonspecific, clinical signs commonly occurring in the general population (i.e., oligosymptomatic). The most frequent clinical findings emerging from both the literature review and the questionnaire included stroke (203/685, 29.6%), seizures or epilepsy (199/685, 29.0%), intellectual disability or developmental delay (168/685, 24.5%), porencephaly/schizencephaly (168/685, 24.5%), motor impairment (162/685, 23.6%), cataract (124/685, 18.1%), hematuria (63/685, 9.2%), and retinal arterial tortuosity (58/685, 8.5%). In oligosymptomatic and asymptomatic carriers, ophthalmological investigations detected retinal vascular tortuosity (5/13, 38.5%), dysgenesis of the anterior segment (4/13, 30.8%), and cataract (2/13, 15.4%), while cardiological investigations were unremarkable except for mild ascending aortic ectasia in 1/8 (12.5%). Our multimodal approach confirms highly variable penetrance and expressivity in COL4A1/2-related conditions, even at the intrafamilial level with neurological involvement being the most frequent and severe finding in both children and adults. We propose a protocol for prevention and management based on individualized risk estimation and periodic multiorgan evaluations.

GABRA1-Related Disorders: From Genetic to Functional Pathways.

OBJECTIVE: Variants in GABRA1 have been associated with a broad epilepsy spectrum, ranging from genetic generalized epilepsies to developmental and epileptic encephalopathies. However, our understanding of what determines the phenotype severity and best treatment options remains inadequate. We therefore aimed to analyze the electroclinical features and the functional effects of GABRA1 variants to establish genotype-phenotype correlations. METHODS: Genetic and electroclinical data of 27 individuals (22 unrelated and 2 families) harboring 20 different GABRA1 variants were collected and accompanied by functional analysis of 19 variants. RESULTS: Individuals in this cohort could be assigned into different clinical subgroups based on the functional effect of their variant and its structural position within the GABRA1 subunit. A homogenous phenotype with mild cognitive impairment and infantile onset epilepsy (focal seizures, fever sensitivity, and electroencephalographic posterior epileptiform discharges) was described for variants in the extracellular domain and the small transmembrane loops. These variants displayed loss-of-function (LoF) effects, and the patients generally had a favorable outcome. A more severe phenotype was associated with variants in the pore-forming transmembrane helices. These variants displayed either gain-of-function (GoF) or LoF effects. GoF variants were associated with severe early onset neurodevelopmental disorders, including early infantile developmental and epileptic encephalopathy. INTERPRETATION: Our data expand the genetic and phenotypic spectrum of GABRA1 epilepsies and permit delineation of specific subphenotypes for LoF and GoF variants, through the heterogeneity of phenotypes and variants. Generally, variants in the transmembrane helices cause more severe phenotypes, in particular GoF variants. These findings establish the basis for a better understanding of the pathomechanism and a precision medicine approach in GABRA1-related disorders. Further studies in larger populations are needed to provide a conclusive genotype-phenotype correlation. ANN NEUROL 2023.

Quantitative EEG biomarkers for STXBP1-related disorders.

OBJECTIVE: EEG patterns and quantitative EEG (qEEG) features have been poorly explored in monogenic epilepsies. Herein, we investigate regional differences in EEG frequency composition in patients with STXBP1 developmental and epileptic encephalopathy (STXBP1-DEE). METHODS: We conducted a retrospective study collecting electroclinical data of patients with STXBP1-DEE and two control groups of patients with DEEs of different etiologies and typically developing individuals matched for age and sex. We performed a (1) visual EEG assessment, (b) qEEG analysis, and (c) electrical source imaging (ESI). We quantified the relative power (RP) of four frequency bands (α ß, θ, δ), in two electrode groups (anterior/posterior), and compared their averages and dynamics (standard deviation [SD] over time). The ESI was performed by applying the standard Distributed Source Modeling algorithm. RESULTS: We analyzed 42 EEG studies in 19 patients with STXBP1-DEE (10 female), with a median age at recordings of 9.6 years (range 9 months to 29 years). The δRP was higher in recordings of STXBP1-DEE (p < .001) compared to both control groups, suggesting the pathogenicity and STXBP1-specificity of these findings. In STXBP1-DEE, the δRP was significantly higher in the anterior electrode group compared to the posterior one (p = .003). There was no correlation between the anterior δRP and the epilepsy focus, age at recordings, and concomitant medications The ESI modeling of this activity showed a widespread involvement of the dorsomesial frontal cortex, suggesting a large corticosubcortical pathologic network. Finally, we identified two groups of recordings: cluster.1 with higher anterior δRP and low dynamics and cluster.2 with lower δRP and higher dynamics. Patients in cluster.1 had a more severe epilepsy and neurological phenotype compared to patients in cluster 2. SIGNIFICANCE: The qEEG analysis showed a predominant frontal slow activity as a specific STXBP1 feature that correlates with the severity of the phenotype and may represent a biomarker for prospective longitudinal studies of STXBP1-DEE.

Use, experience and perspectives of high-density EEG among Italian epilepsy centers: a national survey.

INTRODUCTION: High-density EEG (hdEEG) is a validated tool in presurgical evaluation of people with epilepsy. The aim of this national survey is to estimate diffusion and knowledge of hdEEG to develop a network among Italian epilepsy centers. METHODS: A survey of 16 items (and 15 additional items) was distributed nationwide by email to all members of the Italian League Against Epilepsy and the Italian Society of Clinical Neurophysiology. The data obtained were analyzed using descriptive statistics. RESULTS: A total of 104 respondents were collected from 85 centers, 82% from the Centre-North of Italy; 27% of the respondents had a hdEEG. The main applications were for epileptogenic focus characterization in the pre-surgical evaluation (35%), biomarker research (35%) and scientific activity (30%). The greatest obstacles to hdEEG were economic resources (35%), acquisition of dedicated personnel (30%) and finding expertise (17%). Dissemination was limited by difficulties in finding expertise and dedicated personnel (74%) more than buying devices (9%); 43% of the respondents have already published hdEEG data, and 91% of centers were available to participate in multicenter hdEEG studies, helping in both pre-processing and analysis. Eighty-nine percent of respondents would be interested in referring patients to centers with established experience for clinical and research purposes. CONCLUSIONS: In Italy, hdEEG is mainly used in third-level epilepsy centers for research and clinical purposes. HdEEG diffusion is limited not only by costs but also by lack of trained personnel. Italian centers demonstrated a high interest in educational initiatives on hdEEG as well as in clinical and research collaborations.

Encephalopathy related to status epilepticus during slow sleep (ESES). Pathophysiological insights and nosological considerations.

Encephalopathy related to Status Epilepticus during slow Sleep (ESES) is a childhood epilepsy syndrome characterized by the appearance of cognitive, behavioral, and motor disturbances in conjunction with a striking activation of EEG epileptic abnormalities during non-REM sleep. After more than 50 years since the first description, the pathophysiological mechanisms underlying the appearance of encephalopathy in association with a sleep-related enhancement of epileptic discharges are incompletely elucidated. Recent experimental data support the hypothesis that the development of the ESES encephalopathic picture depends on a spike-induced impairment of the synaptic homeostasis processes occurring during normal sleep and that is particularly pronounced during the developmental age. During sleep, synaptic homeostasis is promoted by synaptic weakening/elimination after the increment of synaptic strength that occurs during wakefulness. The EEG can display modifications in synaptic strength by changes in sleep slow wave activity (SWA). Recent studies during active ESES have failed to show changes in sleep SWA, while these changes occurred again after recovery from ESES, thus supporting a spike-related interference on the normal homeostatic processes of sleep. This impairment, during the developmental period, can lead to disruption of cortical wiring and brain plastic remodeling, which lead to the, often irreversible, neuropsychological compromise typical of ESES. From the nosographic point of view, these pathophysiological data lend support to the maintenance of the term ESES, i.e., "encephalopathy related to status epilepticus during sleep". Indeed, this term conveys the concept that the extreme activation of epileptic discharges during sleep is directly responsible for the encephalopathy, hence the importance of defining this condition as an encephalopathy related to the exaggerated activation of epileptic activity during sleep. In this respect, ESES represents a genuine example of a "pure" epileptic encephalopathy in which sleep-related epileptic activity "per se" has a crucial role in determining the encephalopathic picture. This paper was presented at the 8th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures held in September 2022.

Ictal semiology of gelastic seizures.

Gelastic seizures are rare epileptic manifestations characterized by laughter or a smile. The main etiology is represented by hypothalamic hamartoma, but also focal localization of the epileptogenic zone is described. We reviewed a group of patients with gelastic seizures to describe the semiology and to establish any difference related to diverse epilepsy etiologies. Thirty-five seizures from 16 patients (6 females) were reviewed. The study confirms that hypothalamic hamartoma is the more frequent etiology associated with gelastic seizures. Laughter represented the majority of gelastic ictal signs, while the ictal smile was less frequent. In 87.5% of patients, the manifestation of laughter or smile was the only ictal phenomenon, or the first and the most important clinical sign. Interestingly, it has been observed that patients with a lesion localized in the hypothalamic region had more frequently laughter with emotional involvement and that laughter was the only manifestation of the seizure. On the contrary, patients with lesions localized outside the hypothalamic region had more often seizures with laugh without emotional involvement, resembling a more mechanical action, and associated with other semeiological signs. It, therefore, seems possible to assume that the emotional involvement and the expression of mirth during the seizure, especially in children, are more frequently associated with hypothalamic hamartoma. On the contrary, when the semiology includes less conveyed emotion similar to a mechanical action and other symptoms, an extra hypothalamic localization should be considered.

Adaptive behaviour in adolescents and adults with Dravet syndrome.

AIM: To explore the feasibility of using an adaptive behaviour profile (ABP) assessment generated from a well-known measure-the Vineland Adaptive Behavior Scales, Second Edition (VABS-II)-as an instrument for outcome measures in adolescents and adults with Dravet syndrome. METHOD: We administered the VABS-II to 35 adolescents and adults with Dravet syndrome (15 males; mean age 24 years, SD 8 years, range: 12-46 years) and collected epilepsy history and neurological features at the time of assessment. We conducted a cross-sectional analysis of VABS-II raw scores and performed cluster analysis to identify different subgroups. We then explored possible relationships between clinical and epilepsy features, ABPs, and age. RESULTS: Most participants obtained the minimum standard scores in the various VABS-II subdomains, while the raw score analysis outlined interindividual and intraindividual differences among skills. We found two subpopulations: one with a 'lower' ABP and one with a 'higher' ABP, corresponding respectively to individuals in whom myoclonic seizures or generalized spike-and-wave activity were present ('complete phenotype') or absent ('incomplete phenotype') on electroencephalography. INTERPRETATION: This study further delineates the natural history of Dravet syndrome. The assessment of an ABP through the VABS-II raw score analysis provides a means by which to illustrate profiles of adaptive behaviour in adolescents and adults with Dravet syndrome but shows limitations related to poor sensitivity in measuring fine clinical details. There is a need for new and more specific tools to monitor patients with developmental and epileptic encephalopathies. WHAT THIS PAPER ADDS: Most adults with Dravet syndrome obtained the minimum standard scores in the Vineland Adaptive Behavior Scales, Second Edition (VABS-II) subdomains. The VABS-II raw score analysis showed interindividual and intraindividual variability. Individuals with myoclonic seizures and/or generalized spike-and-wave activity on electroencephalography showed a worse adaptive behaviour profile.

PRRT2 benign familial infantile seizures (BFIS) with atypical evolution to encephalopathy related to status epilepticus during sleep (ESES).

PURPOSE: Heterozygous variants in PRRT2 are mostly associated with benign phenotypes, being the major genetic cause of benign familial infantile seizures (BFIS), as well as in paroxysmal disorders. We report two children from unrelated families with BFIS that evolved to encephalopathy related to status epilepticus during sleep (ESES). METHODS AND RESULTS: Two probands presented with focal motor seizures at 3 months of age, with a limited course. Both children presented, at around 5 years of age, with centro-temporal interictal epileptiform discharges with a source in the frontal operculum, markedly activated by sleep, and associated with stagnation on neuropsychological development. Whole-exome sequencing and co-segregation analysis revealed a frameshift mutation c.649dupC in the proline-rich transmembrane protein 2 (PRRT2) in both probands and all affected family members. CONCLUSION: The mechanism leading to epilepsy and the phenotypic variability of PRRT2 variants remain poorly understood. However, its wide cortical and subcortical expression, in particular in the thalamus, could partially explain both the focal EEG pattern and the evolution to ESES. No variants in the PRRT2 gene have been previously reported in patients with ESES. Due to the rarity of this phenotype, other possible causative cofactors are likely contributing to the more severe course of BFIS in our probands.

Expanding the genetic and phenotypic spectrum of CHD2-related disease: From early neurodevelopmental disorders to adult-onset epilepsy.

CHD2 encodes the chromodomain helicase DNA-binding protein 2, an ATP-dependent enzyme that acts as a chromatin remodeler. CHD2 pathogenic variants have been associated with various early onset phenotypes including developmental and epileptic encephalopathy, self-limiting or pharmacoresponsive epilepsies and neurodevelopmental disorders without epilepsy. We reviewed 84 previously reported patients carrying 76 different CHD2 pathogenic or likely pathogenic variants and describe 18 unreported patients carrying 12 novel pathogenic or likely pathogenic variants, two recurrent likely pathogenic variants (in two patients each), three previously reported pathogenic variants, one gross deletion. We also describe a novel phenotype of adult-onset pharmacoresistant epilepsy, associated with a novel CHD2 missense likely pathogenic variant, located in an interdomain region. A combined review of previously published and our own observations indicates that although most patients (72.5%) carry truncating CHD2 pathogenic variants, CHD2-related phenotypes encompass a wide spectrum of conditions with developmental delay/intellectual disability (ID), including prominent language impairment, attention deficit hyperactivity disorder and autistic spectrum disorder. Epilepsy is present in 92% of patients with a median age at seizure onset of 2 years and 6 months. Generalized epilepsy types are prevalent and account for 75.5% of all epilepsies, with photosensitivity being a common feature and adult-onset nonsyndromic epilepsy a rare presentation. No clear genotype-phenotype correlation has emerged.

Agrypnia excitata as the main feature in anti-leucine-rich glioma-inactivated 1 encephalitis: a detailed clinical and polysomnographic semiological analysis.

BACKGROUND AND PURPOSE: The core manifestations of leucine-rich glioma-inactivated 1 (LGI1) autoantibody-mediated encephalitis are limbic encephalitis and faciobrachial dystonic seizures. Agrypnia excitata (AE) is a rare syndrome characterized by sleep-wake cycle disruption, autonomic hyperactivation and episodes of oneiric stupor. Only a few diseases are known to present with AE. An autoimmune etiology must be considered when accompanied by neuromyotonia. A case of anti-LGI1 encephalitis presenting with AE is reported. METHODS: Detailed clinical, video-polysomnographic, laboratory, radiological and long-term follow-up assessments were performed. RESULTS: A previously healthy 58-year-old man was referred for a rapidly progressive change in mental status, characterized by persistent drowsiness and confusion, accompanied by frequent episodes of unconscious gestures ranging from simple stereotyped movements to more complex actions mimicking various daily activities. Other symptoms included tachycardia, hyperhidrosis, mild hyponatremia, rare faciobrachial dystonic seizures, and a single generalized tonic-clonic seizure, but no neuromyotonia. Prolonged video-polysomnography excluded epileptic activity and showed continuous monomorphic slowing of background activity not consistent with a regular wakefulness or sleep state. A brain magnetic resonance imaging scan was unremarkable. Brain fluorodeoxyglucose positron emission tomography revealed hypermetabolism of the hippocampi, amygdala and basal ganglia. Anti-LGI1 antibodies were detected in the cerebrospinal fluid. The sleep disorder resolved progressively after starting immunotherapy. CONCLUSIONS: Agrypnia excitata can be a dominant, treatable manifestation of anti-LGI1 encephalitis. Oneiric stupor episodes are a useful clinical feature for establishing diagnostic suspicion and could provide a window to understanding the mechanisms behind some movement disorders in autoimmune encephalitis.

SYNGAP1-related developmental and epileptic encephalopathy: The impact on daily life.

SYNGAP1-developmental and epileptic encephalopathy (SYNGAP1-DEE) has been recently featured as a distinct genetic disease characterized by global psychomotor delay mainly involving language, moderate-to-severe cognitive impairment, autism spectrum disorder, and a generalized epilepsy with spontaneous and reflex seizures. The severity and variability of function impairment and the impact on patients' and caregivers' daily life are still poorly acknowledged. The SYNGAP1 Italian Family Association developed a survey, shared online with caregivers, exploring several issues, including: epilepsy outcome, comorbidities, daily-living skills, hospitalizations, rehabilitation treatments, economic burden, and COVID-19 pandemic impact. Caregivers of 13 children and adolescents participated in the survey. They most often show a fine and gross-motor impairment and a drug-resistant epilepsy with possibility to experience pluridaily absence seizures that may lead to periods of psychomotor regressions. Eating and sleep problems are reported in the majority. Most parents are concerned about language impairment, behavioral issues and lack of autonomy in daily-living activities. Specific neuropsychological evaluations for autism should be early considered in order to identify intervention strategies involving alternative communication strategies, which can positively affect behavior and quality of life. Rehabilitation treatment should aim to the acquisition and consolidation of personal autonomy.

Spinal cord involvement and paroxysmal events in "Infantile Onset Transient Hypomyelination" due to TMEM63A mutation.

Monoallelic mutations on TMEM63A have been recently reported as cause of a previously unrecognized disorder named "infantile-onset transient hypomyelination". Clinical and neuroradiological presentation is described as highly similar to Pelizaeus-Merzbacher Disease but evolution over time was surprisingly benign with a progressive spontaneous improving course. We report on a new TMEM63A-mutated girl. The clinical picture was similar to the one already described except for the presence of recurrent episodes of unilateral eyelid twitching, and for the evidence of spinal cord involvement on MRI. These are interesting findings helping in distinguishing this condition from classic PMD since early disease stages. However, additional observations are needed to confirm if these are common features of this condition.

Epilepsy and movement disorders in CDG: Report on the oldest-known MOGS-CDG patient.

Congenital glycosylation disorders (CDG) are inherited metabolic diseases due to defective glycoprotein and glycolipid glycan assembly and attachment. MOGS-CDG is a rare disorder with seven patients from five families reported worldwide. We report on a 19-year-old girl with MOGS-CDG. At birth she presented facial dysmorphism, marked hypotonia, and drug-resistant tonic seizures. In the following months, her motility was strongly limited by dystonia, with forced posture of the head and of both hands. She showed a peculiar hyperkinetic movement disorder with a rhythmic and repetitive pattern repeatedly documented on EEG-polygraphy recordings. Brain MRI showed progressive cortical and subcortical atrophy. Epileptic spasms appeared in first months and ceased by the age of 7 years, while tonic seizures were still present at last assessment (19 years). We report the oldest-known MOGS-CDG patient and broaden the neurological phenotype of this CDG.

Autozygosity-driven genetic diagnosis in consanguineous families from Italy and the Greater Middle East.

Autozygosity-driven exome analysis has been shown effective for identification of genes underlying recessive diseases especially in countries of the so-called Greater Middle East (GME), where high consanguinity unravels the phenotypic effects of recessive alleles and large family sizes facilitate homozygosity mapping. In Italy, as in most European countries, consanguinity is estimated low. Nonetheless, consanguineous Italian families are not uncommon in publications of genetic findings and are often key to new associations of genes with rare diseases. We collected 52 patients from 47 consanguineous families with suspected recessive diseases, 29 originated in GME countries and 18 of Italian descent. We performed autozygosity-driven exome analysis by detecting long runs of homozygosity (ROHs > 1.5 Mb) and by prioritizing candidate clinical variants within. We identified a pathogenic synonymous variant that had been previously missed in NARS2 and we increased an initial high diagnostic rate (47%) to 55% by matchmaking our candidate genes and including in the analysis shorter ROHs that may also happen to be autozygous. GME and Italian families contributed to diagnostic yield comparably. We found no significant difference either in the extension of the autozygous genome, or in the distribution of candidate clinical variants between GME and Italian families, while we showed that the average autozygous genome was larger and the mean number of candidate clinical variants was significantly higher (p = 0.003) in mutation-positive than in mutation-negative individuals, suggesting that these features influence the likelihood that the disease is autozygosity-related. We highlight the utility of autozygosity-driven genomic analysis also in countries and/or communities, where consanguinity is not widespread cultural tradition.

Epileptic seizures of suspected autoimmune origin: a multicentre retrospective study.

OBJECTIVE: To analyse autoantibody status in a well-defined European multicentre cohort of patients with epilepsy of unknown aetiology and to validate the recently proposed Antibody Prevalence in Epilepsy (APE2) and Response to ImmunoTherapy in Epilepsy (RITE2) scores. METHODS: We retrospectively collected clinical and paraclinical data of 92 patients referred to the Neurology Units of Verona and Salzburg between January 2014 and July 2019 with new-onset epilepsy, status epilepticus or chronic epilepsy of unknown aetiology. Fixed and live cell-based assays, tissue-based assays, immunoblot, and live rat hippocampal cell cultures were performed in paired serum/cerebrospinal fluid (CSF) to detect antineuronal and antiglial antibodies. The APE2 and RITE2 scores were then calculated and compared with clinical and laboratory data. RESULTS: Autoantibodies were detected in 29/92 patients (31.5%), with multiple positivity observed in 6/29 cases. The APE2 score (median 5, range 1-15) significantly correlated with antibody positivity (p=0.014), especially for the presence of neuropsychiatric symptoms (p<0.01), movement disorders (p<0.01), dysautonomia (p=0.03), faciobrachial dyskinesias (p=0.03) and cancer history (p<0.01). Status epilepticus was significantly more frequent in antibody-negative patients (p<0.01). Among the items of the RITE2 score, early initiation of immunotherapy correlated with a good treatment response (p=0.001), whereas a cancer history was significantly more common among non-responders (p<0.01). Persistence of neuropsychiatric symptoms and seizures correlated with antiepileptic maintenance after at least 1 year. CONCLUSIONS: This is the first study that independently validates the APE2 and RITE2 scores and includes the largest cohort of patients whose paired serum and CSF samples have been tested for autoantibodies possibly associated with autoimmune epilepsy.

The spectrum of REM sleep-related episodes in children with type 1 narcolepsy.

Type 1 narcolepsy is a central hypersomnia due to the loss of hypocretin-producing neurons and characterized by cataplexy, excessive daytime sleepiness, sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. In children, close to the disease onset, type 1 narcolepsy has peculiar clinical features with severe cataplexy and a complex admixture of movement disorders occurring while awake. Motor dyscontrol during sleep has never been systematically investigated. Suspecting that abnormal motor control might affect also sleep, we systematically analysed motor events recorded by means of video polysomnography in 40 children with type 1 narcolepsy (20 females; mean age 11.8 ± 2.6 years) and compared these data with those recorded in 22 age- and sex-matched healthy controls. Motor events were classified as elementary movements, if brief and non-purposeful and complex behaviours, if simulating purposeful behaviours. Complex behaviours occurring during REM sleep were further classified as 'classically-defined' and 'pantomime-like' REM sleep behaviour disorder episodes, based on their duration and on their pattern (i.e. brief and vivid-energetic in the first case, longer and with subcontinuous gesturing mimicking daily life activity in the second case). Elementary movements emerging either from non-REM or REM sleep were present in both groups, even if those emerging from REM sleep were more numerous in the group of patients. Conversely, complex behaviours could be detected only in children with type 1 narcolepsy and were observed in 13 patients, with six having 'classically-defined' REM sleep behaviour disorder episodes and seven having 'pantomime-like' REM sleep behaviour disorder episodes. Complex behaviours during REM sleep tended to recur in a stereotyped fashion for several times during the night, up to be almost continuous. Patients displaying a more severe motor dyscontrol during REM sleep had also more severe motor disorder during daytime (i.e. status cataplecticus) and more complaints of disrupted nocturnal sleep and of excessive daytime sleepiness. The neurophysiological hallmark of this severe motor dyscontrol during REM sleep was a decreased atonia index. The present study reports for the first time the occurrence of a severe and peculiar motor disorder during REM sleep in paediatric type 1 narcolepsy and confirms the presence of a severe motor dyscontrol in these patients, emerging not only from wakefulness (i.e. status cataplecticus), but also from sleep (i.e. complex behaviours during REM sleep). This is probably related to the acute imbalance of the hypocretinergic system, which physiologically acts by promoting movements during wakefulness and suppressing them during sleep.

Photosensitive epilepsy is associated with reduced inhibition of alpha rhythm generating networks.

See Hamandi (doi:10.1093/awx049) for a scientific commentary on this article.Photosensitivity is a condition in which lights induce epileptiform activities. This abnormal electroencephalographic response has been associated with hyperexcitability of the visuo-motor system. Here, we evaluate if intrinsic dysfunction of this network is present in brain activity at rest, independently of any stimulus and of any paroxysmal electroencephalographic activity. To address this issue, we investigated the haemodynamic correlates of the spontaneous alpha rhythm, which is considered the hallmark of the brain resting state, in photosensitive patients and in people without photosensitivity. Second, we evaluated the whole-brain functional connectivity of the visual thalamic nuclei in the various populations of subjects under investigation. Forty-four patients with epilepsy and 16 healthy control subjects underwent an electroencephalography-correlated functional magnetic resonance imaging study, during an eyes-closed condition. The following patient groups were included: (i) genetic generalized epilepsy with photosensitivity, 16 subjects (mean age 25 ± 10 years); (ii) genetic generalized epilepsy without photosensitivity, 13 patients (mean age 25 ± 11 years); (iii) focal epilepsy, 15 patients (mean age 25 ± 9 years). For each subject, the posterior alpha power variations were convolved with the standard haemodynamic response function and used as a regressor. Within- and between-groups second level analyses were performed. Whole brain functional connectivity was evaluated for two thalamic regions of interest, based on the haemodynamic findings, which included the posterior thalamus (pulvinar) and the medio-dorsal thalamic nuclei. Genetic generalized epilepsy with photosensitivity demonstrated significantly greater mean alpha-power with respect to controls and other epilepsy groups. In photosensitive epilepsy, alpha-related blood oxygen level-dependent signal changes demonstrated lower decreases relative to all other groups in the occipital, sensory-motor, anterior cingulate and supplementary motor cortices. Coherently, the same brain regions demonstrated abnormal connectivity with the visual thalamus only in epilepsy patients with photosensitivity. As predicted, our findings indicate that the cortical-subcortical network generating the alpha oscillation at rest is different in people with epilepsy and visual sensitivity. This difference consists of a decreased alpha-related inhibition of the visual cortex and sensory-motor networks at rest. These findings represent the substrate of the clinical manifestations (i.e. myoclonus) of the photoparoxysmal response. Moreover, our results provide the first evidence of the existence of a functional link between the circuits that trigger the visual sensitivity phenomenon and those that generate the posterior alpha rhythm.

Melanopsin retinal ganglion cell loss in Alzheimer disease.

OBJECTIVE: Melanopsin retinal ganglion cells (mRGCs) are photoreceptors driving circadian photoentrainment, and circadian dysfunction characterizes Alzheimer disease (AD). We investigated mRGCs in AD, hypothesizing that they contribute to circadian dysfunction. METHODS: We assessed retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT) in 21 mild-moderate AD patients, and in a subgroup of 16 we evaluated rest-activity circadian rhythm by actigraphy. We studied postmortem mRGCs by immunohistochemistry in retinas, and axons in optic nerve cross-sections of 14 neuropathologically confirmed AD patients. We coimmunostained for retinal amyloid ß (Aß) deposition and melanopsin to locate mRGCs. All AD cohorts were compared with age-matched controls. RESULTS: We demonstrated an age-related optic neuropathy in AD by OCT, with a significant reduction of RNFL thickness (p = 0.038), more evident in the superior quadrant (p = 0.006). Axonal loss was confirmed in postmortem AD optic nerves. Abnormal circadian function characterized only a subgroup of AD patients. Sleep efficiency was significantly reduced in AD patients (p = 0.001). We also found a significant loss of mRGCs in postmortem AD retinal specimens (p = 0.003) across all ages and abnormal mRGC dendritic morphology and size (p = 0.003). In flat-mounted AD retinas, Aß accumulation was remarkably evident inside and around mRGCs. INTERPRETATION: We show variable degrees of rest-activity circadian dysfunction in AD patients. We also demonstrate age-related loss of optic nerve axons and specifically mRGC loss and pathology in postmortem AD retinal specimens, associated with Aß deposition. These results all support the concept that mRGC degeneration is a contributor to circadian rhythm dysfunction in AD.

Sleep disordered breathing in a cohort of children with achondroplasia: correlation between clinical and instrumental findings.

BACKGROUND: The aim of the present study was to show the results of an overnight polysomnography in a cohort of 9 children (7 females and 2 males) with achondroplasia, aged between 1 and 12 years (5.56±4.7 years). All of the children carried the Gly380Arg (G380R) mutation on the FGFR3 gene. METHODS: All the young patients underwent nocturnal polysomnography without sleep deprivation. Sleep staging was noted according to the guidelines of the American Academy of Sleep Medicine. At the time of registration, the parents answered to a Sleep Control Test questionnaire regarding medical history and diurnal and nocturnal symptoms of their children. RESULTS: Respiratory sleep disorder was present in 78% of cases, and was generally mild. In 67% of the children there was respiratory effort for more than 30% of the total sleep time. The sample was divided into two age categories: 5 children under the age of 3 years and 4 children over 10 years old. A higher incidence of sleep disorder was found in the first few years of life, where the obstructive pattern predominates. Regarding sleep architecture, we did not find macroscopic alterations of sleep architecture and its phasic manifestations in our paediatric group. However, parents have not been referred daytime sleepiness, attention deficiency, hyperactivity and nocturnal enuresis. Only one had referred recurrent respiratory infections. CONCLUSIONS: Polysomnography is a very useful tool in the evaluation of sleep-disordered breathing in children with achondroplasia.