Interictal Examination Research Articles

High-field MRI findings in epileptic dogs with a normal inter-ictal neurological examination.

Epilepsy is one of the most common chronic neurological conditions affecting dogs. Previous research exploring the likelihood of a structural cause of epilepsy specifically in dogs with a normal inter-ictal examination is limited to a small population of dogs using low-field MRI. The aims of this study were to establish high-field (1.0T and 1.5T) MRI findings in dogs presenting with epileptic seizures and a normal inter-ictal examination. Medical records were retrospectively searched for dogs presenting with at least two epileptic seizure events more than 24 h apart. To be included in the study, patients had to have a normal neurological examination, high-field MRI of the brain and have had metabolic and toxic causes excluded. Four hundred and twelve dogs were eligible for inclusion. Crossbreeds were most commonly affected (n = 63, 15.3%) followed by Border collies (n = 39, 9.5%) and Labrador retrievers (n = 26, 6.3%). Seventy-six dogs (18.5%) had abnormalities detected on MRI, 60 (78.9%) of which were considered to be incidental. Overall, 16 dogs (3.9%) had a structural cause of their epileptic seizures including neoplasia (n = 13, 81.3%), anomalous (n = 2, 12.5%) and meningoencephalitis of unknown origin (MUO) (n = 1, 6.3%). When split into age group at first epileptic seizure structural lesions were documented in 0/66 dogs aged <1 year, 4/256 (1.6%) dogs aged ≥1 year ≤6 years (three neoplastic and one anomalous), 3/51 (5.9%) aged >6 years ≤8 years (two neoplastic and one MUO), and 9/39 (23.1%) dogs aged >8 years (eight neoplastic, one anomalous). Multivariate analysis identified two risk factors for structural disease: increasing age at first epileptic seizure (p < 0.001, OR = 4.390, CI 2.338-8.072) and a history of status epilepticus (p = 0.049, OR = 4.389, CI 1.010-19.078). Structural lesions are an uncommon cause of epilepsy at any age in dogs with a normal inter-ictal examination.

Periodic electroencephalographic discharges and epileptic spasms involve cortico-striatal-thalamic loops on Arterial Spin Labeling Magnetic Resonance Imaging.

Periodic discharges are a rare peculiar electroencephalogram pattern, occasionally associated with motor or other clinical manifestations, usually observed in critically ill patients. Their underlying pathophysiology remains poorly understood. Epileptic spasms in clusters and periodic discharges with motor manifestations share similar electroencephalogram pattern and some aetiologies of unfavourable prognosis such as subacute sclerosing panencephalitis or herpes encephalitis. Arterial spin labelling magnetic resonance imaging identifies localizing ictal and inter-ictal changes in neurovascular coupling, therefore assumed able to reveal concerned cerebral structures. Here, we retrospectively analysed ictal and inter-ictal arterial spin labelling magnetic resonance imaging in patients aged 6 months to 15 years (median 3 years 4 months) with periodic discharges including epileptic spasms, and compared these findings with those of patients with drug-resistant focal epilepsy who never presented periodic discharges nor epileptic spasms as well as to those of age-matched healthy controls. Ictal electroencephalogram was recorded either simultaneously with arterial spin labelling magnetic resonance imaging or during the close time lapse of patients' periodic discharges, whereas inter-ictal examinations were performed during the patients' active epilepsy but without seizures during the arterial spin labelling magnetic resonance imaging. Ictal arterial spin labelling magnetic resonance imaging was acquired in five patients with periodic discharges [subacute sclerosing panencephalitis (1), stroke-like events (3), West syndrome with cortical malformation (1), two of them also had inter-ictal arterial spin labelling magnetic resonance imaging]. Inter-ictal group included patients with drug-resistant epileptic spasms of various aetiologies (14) and structural drug-resistant focal epilepsy (8). Cortex, striatum and thalamus were segmented and divided in six functional subregions: prefrontal, motor (rostral, caudal), parietal, occipital and temporal. Rest cerebral blood flow values, absolute and relative to whole brain, were compared with those of age-matched controls for each subregion. Main findings were diffuse striatal as well as cortical motor cerebral blood flow increase during ictal examinations in generalized periodic discharges with motor manifestations (subacute sclerosing panencephalitis) and focal cerebral blood flow increase in corresponding cortical-striatal-thalamic subdivisions in lateralized periodic discharges with or without motor manifestations (stroke-like events and asymmetrical epileptic spasms) with straight topographical correlation with the electroencephalogram focus. For inter-ictal examinations, patients with epileptic spasms disclosed cerebral blood flow changes in corresponding cortical-striatal-thalamic subdivisions (absolute-cerebral blood flow decrease and relative-cerebral blood flow increase), more frequently when compared with the group of drug-resistant focal epilepsies, and not related to Vigabatrin treatment. Our results suggest that corresponding cortical-striatal-thalamic circuits are involved in periodic discharges with and without motor manifestations, including epileptic spasms, opening new insights in their pathophysiology and new therapeutical perspectives. Based on these findings, we propose a model for the generation of periodic discharges and of epileptic spasms combining existing pathophysiological models of cortical-striatal-thalamic network dynamics.

TRPM7 as a Candidate Gene for Vestibular Migraine.

Objectives: Vestibular migraine (VM) is a common vestibular disorder, and familial aggregation of VM with autosomal-dominant inheritance has been described, which supports a genetic background. This study aimed to describe the clinical phenotype of a family with VM, and identify a candidate gene for VM.Methods: We recruited six individuals (four affected and two unaffected) from three consecutive generations of a Korean family with VM, and performed whole-exome sequencing to search for candidate genes.Results: All affected individuals presented with recurrent vertigo, headache, and nausea/vomiting that fulfilled the diagnostic criteria of VM. Two individuals also experienced transient hemiparesis or dysarthria during the episodes. The symptoms were triggered by physical or emotional stress. Interictal examinations showed uni- or bi-directional horizontal gaze-evoked nystagmus in three of the individuals. They had no causative mutations in genes causing familial hemiplegic migraine or episodic ataxia. Through whole-exome sequencing from three affected individuals, we identified a nonsense mutation c.3526C>T in TRPM7 that encodes a cation channel selective to Ca2+ and Mg2+.Conclusions: Alterations in intracellular Ca2+ and Mg2+ homeostasis by TRPM7 mutation may contribute to the development of the VM phenotype. Our result suggest that TRPM7 is a novel candidate gene for VM.

Characterization of Paroxysmal Gluten-Sensitive Dyskinesia in Border Terriers Using Serological Markers.

BackgroundParoxysmal gluten‐sensitive dyskinesia (PGSD) in border terriers (BTs) results from an immunologic response directed against transglutaminase (TG)2 and gliadin. Recent evidence suggests that PGSD is only one aspect of a range of possible manifestations of gluten sensitivity in the breed.Hypothesis/ObjectivesGluten sensitivity in BTs is a heterogeneous disease process with a diverse clinical spectrum; to characterize the phenotype of PGSD using TG2 and gliadin autoantibodies as diagnostic markers.AnimalsOne hundred twenty‐eight client‐owned BTs with various disorders.MethodsProspective study. BTs with paroxysmal episodes and a normal interictal examination were phenotyped using footage of a representative episode and assigned to 3 groups: idiopathic epilepsy (IE), paroxysmal dyskinesia (PD), or other. Owners of each dog completed a questionnaire to obtain information regarding clinical signs. Healthy BTs formed a control group. Serum antibodies against TG2 and AGA were measured in all dogs.ResultsOne hundred twenty‐eight BTs were enrolled; 45 with PD, 28 with IE, 35 with other conditions, and 20 controls. Three overlapping phenotypes were identified; PD, signs suggestive of gastrointestinal disease, and dermatopathy. AGA‐IgG concentrations were increased in PD, compared with IE (P = 0.012), controls (P < 0.0001) and other (P = 0.018) conditions. Anti‐canine TG2‐IgA concentrations were increased in PD, compared with IE (P < 0.0001), controls (P < 0.0001) and other (P = 0.012) conditions. Serological markers are highly specific for PGSD but lack sensitivity.ConclusionsPGSD appears part of a syndrome of gluten intolerance consisting of episodes of transient dyskinesia, signs suggestive of gastrointestinal disease, and dermatological hypersensitivity.

A New Episodic Ataxia Syndrome With Linkage to Chromosome 19q13

Multiple episodic ataxia phenotypes and genotypes have been described. To describe a new episodic ataxia syndrome. Genomewide linkage analysis with dense single nucleotide polymorphism arrays. University clinic. Patients Family with lifelong episodes of ataxia and normal interictal examination results. Suggestive linkage (logarithm of odds score, 3.27) to a 10-centimorgan region on chromosome 19q13. A new dominantly inherited episodic ataxia syndrome is linked to chromosome 19q.

Combined electroencephalography and measurements of transcranial blood flow velocity during orthostatic testing--a new approach to assess syncope of unknown origin?

Differential diagnosis of syncope and seizures frequently imposes a major problem, particularly if interictal examinations are normal. We performed orthostatic testing combined with surface electroencephalography (EEG) and non-invasive measurements of cerebral blood flow velocity. Ten healthy controls, ten patients with confirmed diagnosis of epilepsy and 25 patients with history of syncope of unknown origin were examined. The following parameters were evaluated continuously and simultaneously during orthostatic challenge: computerized EEG with synchronous video-monitoring, transcranial Doppler sonography (TCD), heart rate and blood pressure. Isolated cerebrovascular dysregulation (i.e. a drop in cerebral perfusion despite the absence of a significant drop in peripheral blood pressure) occurred in 2/10 controls, 3/10 patients with epilepsy and 11/25 patients with syncope of unknown origin. The combined EEG and TCD measurements represent a new approach to the work-up of patients with otherwise unexplained syncope, helping us to understand the interdependence of neuronal activity and peripheral/cerebrovascular autoregulation under postural stress.

Low-Grade Gliomas

Supratentorial low-grade gliomas comprise a group of primary central nervous system neoplasms with characteristics of neuroglial cells (i.e., astrocytes and oligodendrocytes) and relatively low anaplastic potential, although through time they tend to behave more aggressively. Immediate surgical intervention and subsequent radiation therapy are advocated by some workers; at present, however, it remains unclear whether early intervention prolongs survival or changes the natural history of the disease, especially in those patients who present with a seizure and a normal interictal examination.

Bradycardia, an epileptic ictal manifestation

Two patients with recurrent paroxysmal cardio-vascular symptoms are described. The first, an adult, suffered from syncopal events which did not respond to carbamazepine treatment and had a normal interictal EEG and ECG. The second, a child, presented with attacks of cyanosis, apnoea, and non-responsiveness in clusters, with normal interictal examinations. In both patients, prolonged simultaneous EEG and ECG monitoring demonstrated ictal bradycardia accompanied by paroxysmal discharges in the left temporal area.