Exercise-induced seizures and lateral asymmetry in patients with temporal lobe epilepsy.

Objective: The objective of this case report is to better characterize the clinical features and potential pathophysiological mechanisms of exercise-induced seizures.

Methods: We report a case series of ten patients from a tertiary epilepsy center, where a clear history was obtained of physical exercise as a reproducible trigger for seizures.

Results: The precipitating type of exercise was quite specific for each patient, and various forms of exercise are described including running, swimming, playing netball, dancing, cycling, weight lifting, and martial arts.

Does the region of epileptogenicity influence the pattern of change in cortical excitability?

Objective: To investigate whether cortical excitability measures on transcranial magnetic stimulation (TMS) differed between groups of patients with different focal epilepsy syndromes.

Methods: 85 Patients with focal epilepsy syndromes divided into temporal and extra-temporal lobe epilepsy were studied. The cohorts were further divided into drug naïve-new onset, refractory and seizure free groups.

On the midway to epilepsy: is cortical excitability normal in patients with isolated seizures?

Paired pulse transcranial magnetic stimulation was used to investigate differences in cortical excitability between patients with isolated (unrecurrent, unprovoked) seizures and those with epilepsy. Compared to controls, cortical excitability was higher in the isolated seizure group at 250-300 ms. Compared to epilepsy, cortical excitability was lower in patients with isolated seizures also at 250 and 300 ms.

TMS, cortical excitability and epilepsy: the clinical impact.

Paired-pulse transcranial magnetic stimulation (ppTMS) is a well-established method for non-invasive measurement of cortical excitability, alterations of which are the core background of epilepsy. For the past 20 years this technique has been extensively used to assess patients with epilepsy. We present here a critical overview of these studies, with emphasis on their translation to the clinical practice.

Networks underlying paroxysmal fast activity and slow spike and wave in Lennox-Gastaut syndrome.

Objective: To use EEG-fMRI to determine which structures are critically involved in the generation of paroxysmal fast activity (PFA) and slow spike and wave (SSW) (1.5-2.5 Hz), the characteristic interictal discharges of Lennox-Gastaut syndrome (LGS).

Cortical excitability changes correlate with fluctuations in glucose levels in patients with epilepsy.

Objective: We used transcranial magnetic stimulation (TMS) to investigate motor cortical excitability changes in relation to blood glucose levels.

Methods: Twenty-two drug-naïve patients with epilepsy [11 generalized and 11 focal] and 10 controls were studied twice on the same day; first after 12h of fasting and then 2h postprandial. Motor threshold and paired-pulse TMS at a number of short and long interstimulus intervals were measured.

Patterns of cortical hyperexcitability in adolescent/adult-onset generalized epilepsies.

Purpose: To investigate whether using transcranial magnetic stimulation (TMS) to derive if measures of cortical excitability changes can distinguish between various adolescent/adult-onset generalized epilepsy syndromes at different phases of the disorder.

Methods: One hundred thirty-seven patients with adolescent/adult-onset generalized epilepsy divided into juvenile myoclonic epilepsy, juvenile absence epilepsy, and generalized epilepsy with tonic-clonic seizures only were studied. The cohorts were further divided into drug naive-new onset, refractory, and seizure-free groups.

Capturing the epileptic trait: cortical excitability measures in patients and their unaffected siblings.

We used transcranial magnetic stimulation to investigate whether the cortical excitability changes observed amongst the different generalized and focal epilepsy syndromes are reflected in their asymptomatic siblings and if these changes depended on the clinical phenotype. We studied 157 patients with epilepsy (95 generalized and 62 focal) and their asymptomatic siblings (138 and 82, respectively). Motor threshold and paired pulse transcranial magnetic stimulation at short (2, 5, 10 and 15 ms) and long (100-300 ms) interstimulus intervals were measured.

Cortical excitability and refractory epilepsy: a three-year longitudinal transcranial magnetic stimulation study.

Transcranial magnetic stimulation was used to study the effect of recurrent seizures on cortical excitability over time in epilepsy. 77 patients with firm diagnoses of idiopathic generalized epilepsy (IGE) or focal epilepsy were repeatedly evaluated over three years. At onset, all groups had increased cortical excitability.

Cortical excitability decreases in Lennox-Gastaut syndrome.

Purpose: We used transcranial magnetic stimulation (TMS) to investigate cortical excitability changes in Lennox-Gastaut syndrome (LGS), anticipating we would find a marked increase in excitability compared to other patients with refractory epilepsies.

Methods: Eighteen patients with LGS were studied. Motor threshold (MT), short intracortical inhibition (paired pulse TMS at 2 and 5 msec interstimulus intervals [ISIs]), intracortical facilitation (10 and 15 msec ISIs), and long intracortical inhibition (100-300 msec ISIs) were measured.

Cortical excitability in migraine and epilepsy: a common feature?

Objective: There is evidence for comorbidity of migraine and epilepsy. We used transcranial magnetic stimulation (TMS) to assess cortical excitability in migraine compared with control subjects and patients with epilepsy.

Methods: Twenty-six patients drug-naive patients with newly diagnosed migraine were studied.

Inter-session repeatability of cortical excitability measurements in patients with epilepsy.

Purpose: Previous studies have evaluated the inter-session variability of motor thresholds (MT), short intracortical inhibition and intracortical facilitation using paired pulse transcranial magnetic stimulation (TMS) in normal individuals. Here we evaluate the reproducibility of a range of measures of cortical excitability in patients with epilepsy.

Methods: Twenty-four drug naïve patients with newly diagnosed epilepsy (13 idiopathic generalised epilepsy [IGE], 11 focal epilepsy) and seventeen non-epilepsy controls were studied.

A blinded comparison of continuous versus sampled review of video-EEG monitoring data.

Objective: While there are well-established guidelines for optimum video-EEG monitoring (VEM), the process of reviewing VEM data varies amongst centres. In this study, we compared continuous with sampled reviewing of VEM data to assess whether their diagnostic yield differs.

Methods: VEM data acquired from 50 consecutive patients (31 females) admitted for VEM were reviewed by two independent electroencephalographers, one using the continuous review method, and the other sampling the first five minutes of each hour together with events identified by push buttons and automated spike detection software.

Selecting patients for epilepsy surgery: identifying a structural lesion.

One of the most important components of presurgical evaluation of patients with epilepsy is structural imaging, predominantly using magnetic resonance imaging. This study is now part of the basic assessment of patients with epilepsy and is as important as the electroencephalogram. Epilepsy protocol magnetic resonance imaging studies must be part of the overall assessment of the patient.

The routine circular coil is reliable in paired-TMS studies.

Objective: Motor cortex excitability can be measured by transcranial magnetic stimulation (TMS) using different coil types, but paired-TMS was originally devised with a figure-of-eight coil. We asked whether the most popular, circular coil was suited to the every-day assessment of cortical excitability, particularly paired-TMS indexes, and if it reduced the measurement error.

Methods: We studied 12 right-handed, healthy subjects (34±7.

Can changes in cortical excitability distinguish progressive from juvenile myoclonic epilepsy?

Purpose: We used transcranial magnetic stimulation (TMS) to investigate whether there were any characteristic cortical excitability changes in progressive myoclonic epilepsy (PME) compared to juvenile myoclonic epilepsy (JME).

Methods: Six patients with PME were studied. Motor threshold (MT) at rest and recovery curve analysis using paired-pulse stimulation at a number of interstimulus intervals (ISIs) was determined.

Predicting seizure control: cortical excitability and antiepileptic medication.

Objective: Approximately 30% of patients with newly diagnosed epilepsy do not respond to antiepileptic drugs (AEDs), but this is not predictable. We used transcranial magnetic stimulation to determine the effect of AEDs on cortical excitability in patients with epilepsy and correlated this with a successful response to treatment.

Methods: Ninety-nine drug-naïve patients with newly diagnosed epilepsy (55 idiopathic generalized epilepsy, 44 focal epilepsy) were evaluated.

Does a SCN1A gene mutation confer earlier age of onset of febrile seizures in GEFS+?

SCN1A is the most clinically relevant epilepsy gene and is associated with generalized epilepsy and febrile seizure plus (GEFS+) and Dravet syndrome. We postulated that earlier onset of febrile seizures in the febrile seizure (FS) and febrile seizure plus (FS+) phenotypes may occur in the presence of a SCN1A mutation. This was because of the age-related onset of Dravet syndrome, which typically begins in the first year of life.

Cortical hyperexcitability and epileptogenesis: Understanding the mechanisms of epilepsy - part 2.

Epilepsy encompasses a diverse group of seizure disorders caused by a variety of structural, cellular and molecular alterations of the brain primarily affecting the cerebral cortex, leading to recurrent unprovoked epileptic seizures. In this two-part review we examine the mechanisms underlying normal neuronal function and those predisposing to recurrent epileptic seizures starting at the most basic cellular derangements (Part 1, Volume 16, Issue 3) and working up to the highly complex epileptic networks and factors that modulate the predisposition to seizures (Part 2). We attempt to show that multiple factors can modify the epileptic process and that different mechanisms underlie different types of epilepsy, and in most situations there is an interplay between multiple genetic and environmental factors.