Hyperekplexia is a rare, but potentially fatal, neuromotor disorder characterized by exaggerated startle reflexes and hypertonia in response to sudden, unexpected auditory or tactile stimuli. This disorder is primarily caused by inherited mutations in the genes encoding the glycine receptor (GlyR) ␣1 subunit (GLRA1) and the presynaptic glycine transporter GlyT2 (SLC6A5). In this study, systematic DNA sequencing of GLRA1 in 88 new unrelated human hyperekplexia patients revealed 19 sequence variants in 30 index cases, of which 21 cases were inherited in recessive or compound heterozygote modes. This indicates that recessive hyperekplexia is far more prevalent than previous estimates. From the 19 GLRA1 sequence variants, we have investigated the functional effects of 11 novel and 2 recurrent mutations. The expression levels and functional properties of these hyperekplexia mutants were analyzed using a high-content imaging system and patch-clamp electrophysiology. When expressed in HEK293 cells, either as homomeric ␣1 or heteromeric ␣1␤ GlyRs, subcellular localization defects were the major mechanism underlying recessive mutations. However, mutants without trafficking defects typically showed alterations in the glycine sensitivity suggestive of disrupted receptor function. This study also reports the first hyperekplexia mutation associated with a GlyR leak conductance, suggesting tonic channel opening as a new mechanism in neuronal ligand-gated ion channels.

Summary:Purpose: Our aim is to outline the clinical and electroencephalographic (EEG) features of patients with hot water epilepsy (HWE), a rare and unique form of reflex epilepsy.Methods: Twenty-one patients with HWE, seen in our clinic until 1999, were studied. Male outnumbered female subjects in a ratio of 3:1. The age at the onset of seizures ranged from 19 months to 27 years (mean age at onset, 12 years).Results: The main factors precipitating seizures were bathing with hot water and/or pouring water over the head. Six patients reported self-induction, either by increasing the heat or the amount of water and/or recalling earlier bathing experiences. Nine patients expressed feeling pleasure during the seizures. Twenty patients had partial seizures, eight of whom also had secondarily generalized seizures. One patient had apparent generalized seizures only. Spontaneous seizures were present in 62% of the cases. Interictal epileptogenic abnormalities were documented in the EEGs of eight patients; the other eight had normal EEGs. The major sites of epileptogenic activity were over the unilateral temporal regions (in 40% of patients). Neuroimaging studies available for 12 patients (four cranial computed tomography and eight cranial magnetic resonance imaging scans) revealed normal findings. Seizure control in patients who were followed up was achieved by reducing the temperature or the duration of the bath or shower; several of the patients required medication.Conclusions: The major findings of this study are that HWE has a male preponderance, can be self-induced, is often done for pleasure, has complex triggering factors, and shows temporally located abnormalities in the EEGs. Although HWE is generally known to be self-limited, antiepileptic drug treatment may sometimes be necessary to control seizures. Hot water epilepsy should be classified separately among the epileptic syndromes.

SUMMARYObjective: Neuronal antibodies have been identified in patients with seizures as the main or sole symptom. Our aim was to investigate the prevalence of these autoantibodies in patients with focal epilepsy of unknown cause (FEoUC) and in the group having mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). Methods: We studied anti-neuronal antibodies of consecutive adult patients diagnosed with FEoUC and MTLE-HS in our epilepsy center. The clinical and laboratory features of antibody-positive patients were compared with those of seronegative patients. The responses to therapy have also been investigated. Results: Sera from 81 patients with epilepsy were tested. We found antibodies against glycine receptor (GLY-R) in 5 (6.2%), contactin-associated protein 2 (CASPR-2) in 4 (4.9%), N-methyl-D-aspartate receptor (NMDA-R) in 2 (2.5%), and voltage-gated potassium channel (VGKC)-complex in 2 (2.5%) of our patients with epilepsy. Psychotic attacks and nonspecific magnetic resonance imaging (MRI) white matter changes (WMCs) showed significant associations in seropositive patients (p = 0.003 and p = 0.03, respectively). Poor drug-response rates and total seizure counts were also higher in the seropositive patients but without reaching statistical significance. Three seropositive patients with previous epilepsy surgery showed typical histopathologic results for MTLE-HS, but not inflammatory changes. Moreover, some patients harboring these antibodies partly benefited from immunotherapy. Significance: We detected neuronal antibodies in one sixth of patients with focal epilepsy, GLY-R antibodies being the leading one. Psychosis or nonspecific MRI WMCs were frequent in the seropositive group. Our results suggested that relevant antibodies should be screened for a treatment possibility in these groups. KEY WORDS: Epilepsy, Autoantibodies, Glycine receptor, Voltage-gated potassium channel, N-methyl-D-aspartate receptor.Epilepsy is a common neurologic disorder showing resistance to antiepileptic drugs (AEDs) in at least 25-30% of the cases, and its etiology is still unknown.1,2 On the other hand, there is growing evidence that autoimmunity might play a role in epilepsy. A variety of serum antibodies to specific neuronal proteins has recently been identified in ordinary patients with epilepsy. Other than the first reported typical cases with limbic encephalitis or encephalopathy,

High-frequency oscillations in local field potentials recorded with intracranial EEG are putative biomarkers of seizure onset zones in epileptic brain. However, localized 80-500 Hz oscillations can also be recorded from normal and non-epileptic cerebral structures. When defined only by rate or frequency, physiological high-frequency oscillations are indistinguishable from pathological ones, which limit their application in epilepsy presurgical planning. We hypothesized that pathological high-frequency oscillations occur in a repetitive fashion with a similar waveform morphology that specifically indicates seizure onset zones. We investigated the waveform patterns of automatically detected high-frequency oscillations in 13 epilepsy patients and five control subjects, with an average of 73 subdural and intracerebral electrodes recorded per patient. The repetitive oscillatory waveforms were identified by using a pipeline of unsupervised machine learning techniques and were then correlated with independently clinician-defined seizure onset zones. Consistently in all patients, the stereotypical high-frequency oscillations with the highest degree of waveform similarity were localized within the seizure onset zones only, whereas the channels generating high-frequency oscillations embedded in random waveforms were found in the functional regions independent from the epileptogenic locations. The repetitive waveform pattern was more evident in fast ripples compared to ripples, suggesting a potential association between waveform repetition and the underlying pathological network. Our findings provided a new tool for the interpretation of pathological high-frequency oscillations that can be efficiently applied to distinguish seizure onset zones from functionally important sites, which is a critical step towards the translation of these signature events into valid clinical biomarkers.awx374media15721572971001.

The current study was conducted using iEEG data collected in realistic clinical conditions without channel pre-exclusion. HFOs were investigated with novel features extracted from the entire frequency band, and were correlated with SOZ in different states. The results indicate that automatic HFO detection with unsupervised clustering methods exploring the time-frequency content of raw iEEG can be efficiently used to identify the epileptogenic zone with an accurate and efficient manner.