Transient inhibitory seizures mimicking crescendo TIAs

Usefulness of EEG for the differential diagnosis of possible transient ischemic attack

OBJECTIVE

EEG value in possible transient ischemic attacks (TIA) is unknown. We aim to quantify focal slow wave activity (FSWA) and epileptiform activity (EA) frequency in possible TIA, and to analyse its contribution to the final diagnosis of seizures and/or definitive TIA.

METHODS

Prospective longitudinal study of possible TIA patients evaluated at a tertiary centre during 36 months and with 1-3 months follow-up. EEG was performed as soon as possible (early EEG) and one month later (late EEG). A stroke neurologist established final diagnosis after reassessing all clinical and diagnostic tests.

RESULTS

80 patients underwent an early EEG (45.8 h after possible TIA): 52 had FSWA and 6 of them also EA. Early FSWA was associated with epileptic seizure or definitive TIA final diagnosis (p = .041). Patients with these diagnoses had more frequently early FSWA (19/23; 82.6%) than EA (6/23; 26.1%). 6/13 (46.2%) patients with epileptic seizure final diagnosis had EA.In the late EEG, 43 (58.1%) patients demonstrated persistent FSWA and 3 of them also EA. Persistent FSWA in the late EEG was more frequent in seizures than in TIA patients (91.7% vs. 45.5%). FSWA disappearance was associated with acute vascular lesion on neuroimage.

CONCLUSIONS

FSWA was the commonest EEG abnormality found in the early EEG of patients with possible TIA, but did not distinguish between TIA and seizure patients. In patients with seizures, FSWA was more common than EA and its presence in the late EEG was more likely in patients with epileptic seizures than with TIA.

SIGNIFICANCE

The majority of possible TIA patients with the final diagnosis of epileptic seizures do not have EA in the early or late EEG.

[Differential diagnosis of epileptic seizures]

The differential diagnoses of epileptic seizures depend on the different semiologies of the respective seizures. Patient history and history of witnesses are of foremost importance in the differentiation. When seizures recur, they are more easily distinguished than single seizures. Diagnostic methods like EEG and eventually EEG video monitoring will help in the differentiation when clinical information and patient history do not allow a clear diagnosis. We present the most common differential diagnoses and their differences compared to epileptic seizures.

Ictal paralysis with tonic eye gazing mimicking a pontine infarction

PURPOSE

Concomitant positive and negative motor phenomena in a single seizure have not been reported before.

METHOD

We used an extensive history review, neurological examination, EEG, MRI and SPECT study to demonstrate a rare combination of motor presentations as an ictal phenomenon.

RESULT

A 64-year-old male was brought to the emergency room with dizziness, progressive drowsiness and left hemiparesis. A spontaneous eye deviation to the left side with nystagmus was observed. A right pontine lesion was tentatively diagnosed. However, a focal motor seizure of the patient's left face and limbs occurred 3.5h later. A brain MRI revealed a high signal in the right amygdala, hippocampus and thalamus, instead of the pons. An EEG showed periodic epileptic discharges in the right posterior temporal parietal region. Regional hyperperfusion was found by brain SPECT. The level of consciousness improved dramatically after adequate phenytoin treatment.

CONCLUSION

A posterior temporal-parietal seizure can present with a prolonged ictal paralysis, a positive ocular nystagmoid deviation and an altered level of consciousness. The EEG is essential for a correct diagnosis, especially with a negative or an unexplainable MRI study. The SPECT has an additional role for the differential diagnosis.

Delayed transient worsening of neurological deficits after ischaemic stroke

BACKGROUND

Although the causes of stroke recurrence are well known, no particular study deals with the specific issue of late-onset transient worsening of the neurological deficit (TWND) after an ischaemic stroke.

PATIENTS AND METHODS

In this retrospective study the aetiology of the TWNDs in 101 patients was compared to the causes of transient ischaemic attacks (TIAs) in 115 patients. All patients had a full cardiovascular and neuroimaging examination according to current guidelines. An electroencephalogram (EEG) was performed when necessary. The diagnosis of inhibitory seizures was retained when the EEG showed periodic lateralized epileptiform discharges or intermittent rhythmic delta activities, or when the patient developed typical seizures afterwards.

RESULTS

Arterial hypertension and diabetes were more prevalent vascular risk factors in TWND patients. Small-vessel disease and inhibitory seizures were a more frequent cause of TWNDs than of TIAs. Extracranial large-vessel disease predominates in TIA patients. The global prevalence of cardiac diseases as cause of TIAs and TWNDs was the same, although severe ulcerous plaques of the aortic arch and patent foramen ovale with atrial septum aneurysm occurred more frequently in TWND patients.

CONCLUSIONS

The most frequent causes of late-onset TWNDs were different from those of TIAs. Apart from repeated neuroimaging of the brain, exhaustive cardiac investigations and EEG are mandatory in TWND patients.

Poststroke Epilepsy

Seizures and status epilepticus can be a presenting feature of acute stroke. They may occur in its early (<7 days) clinical course or be a remote (>7 days) complication. Most seizures are single, either partial or generalised. Early and remote seizures seem to have different predictors and pathogenesis. Seizures are more frequent in severe and disabling strokes, haemorrhagic strokes and those with cortical involvement. The risk of epilepsy is higher for patients with early seizures, cortical infarctions and lobar haemorrhages and in dependent patients. Early or remote seizures do not have a significant influence on dependency or mortality, although seizures and status epilepticus can be a direct cause of death. Treatment can be started after a first or a recurrent seizure. Treatment options include phenytoin, carbamazepine, valproic acid (valproate sodium) and the new antiepileptic drugs (AEDs). New AEDs can be used to decrease the likelihood of drug interactions and adverse effects in patients who do not tolerate the classic AEDs and in treatment failures with classic AEDs. Large observational studies to define prognostic factors for poststroke seizures in specific stroke subtypes are needed. Randomised controlled trials of AED prophylaxis for acute and remote seizures are essential to improve the evidence level of current guidelines and recommendations.

[Is epilepsy in the elderly overlooked? An investigation in a home for the aged]

The symptoms of epileptic seizures in old patients differ from those in younger patients. Therefore, these seizures may be misinterpreted as symptoms of other "typical" diseases in old people. In an old people's home, we assessed whether a standardized questionnaire is able to reveal undiagnosed epilepsy in the elderly. Reported sudden falls, loss of consciousness, and cramps were the criteria for further diagnostic procedures. We found epilepsy in 11 of 389 study participants. In four of them (1% of the total sample), the epilepsy was newly diagnosed; five more cases remained unclear. Therefore, the total number of epileptic patients might have been even higher. Most of the reported sudden falls and unconsciousness (89%) were due to internal medical or other neurological or orthopaedic causes. Once these have been excluded, the diagnosis of epilepsy should be considered. The results of our pilot study suggest that epilepsy in old people's homes is often unrecognised. Early diagnosis and treatment of epilepsy in the elderly is important to improve prognosis and social consequences for affected persons.

Ictal deafness--a report of three cases

Though negative phenomena like motor inhibition, blindness or aphasia are described as an ictal manifestation of seizures, ictal deafness has not been reported so far. We observed transient ictal deafness in three cases of partial seizures. One of them had seizure spread to the temporal lobe to produce a complex partial seizure. Two of them have CT-detected lesions in the left temporal/parietal area. The other one had left temporal focus on EEG with a normal imaging study. The mechanism of such ictal negative phenomena is unclear. An epileptic focus around the primary auditory cortex, dampening its receptive ability may manifest as cortical deafness.

Functional differentiation of multiple perilesional zones after focal cerebral ischemia

Transient and permanent focal cerebral ischemia results in a series of typical pathophysiologic events. These consequences evolve in time and space and are not limited to the lesion itself, but they can be observed in perilesional (penumbra) and widespread ipsi- and sometimes contralateral remote areas (diaschisis). The extent of these areas is variable depending on factors such as the type of ischemia, the model, and the functional modality investigated. This review describes some typical alterations attributable to focal cerebral ischemia using the following classification scheme to separate different lesioned and perilesional areas: (1) The lesion core is the brain area with irreversible ischemic damage. (2) The penumbra is a brain region that suffers from ischemia, but in which the ischemic damage is potentially, or at least partially, reversible. (3) Remote brain areas are brain areas that are not directly affected by ischemia. With respect to the etiology, several broad categories of remote changes may be differentiated: (3a) remote changes caused by brain edema; (3b) remote changes caused by waves of spreading depression; (3c) remote changes in projection areas; and (3d) remote changes because of reactive plasticity and systemic effects. The various perilesional areas are not necessarily homogeneous; but a broad differentiation of separate topographic perilesional areas according to their functional state and sequelae allows segregation into several signaling cascades, and may help to understand the functional consequences and adaptive processes after focal brain ischemia.

Inhibitory simple partial (non-convulsive) status epilepticus after intracranial surgery

OBJECTIVES

To report on five patients who developed, 2 to 4 days after an intracranial neurosurgical procedure, new, persistent, focal neurological deficits which were due to inhibitory simple partial (non-convulsive) status epilepticus, and resolved with anticonvulsant treatment.

METHODS

The age range of the five patients was 15-74 years. The operations were: aneurysm clipping (three patients) and resections of an oligodendroglioma and a cavernous haemangioma (one patient each). The new focal deficits were: right hemiparesis and aphasia (two patients), aphasia alone (two patients), and left hemiparesis (one patient). The deficits were not explained by CT (obtained in all patients) or cerebral angiography (performed in two).

RESULTS

Electroencephalography showed, in all patients, continuous or intermittent focal seizures arising from cortex regionally relevant to the clinical dysfunction. Subtle positive epileptic phenomena (jerking) occurred intermittently in three patients as a late concommitant. Administration of anticonvulsant drugs resulted in significant improvement within 24 hours in four patients, with parallel resolution of ictal EEG activity. The fifth patient improved more slowly. Two patients relapsed when anticonvulsant concentrations fell, and improved again when they were raised.

CONCLUSIONS

It is suggested that inhibitory simple partial (non-convulsive) status epilepticus be considered in the differential diagnosis when a new unexplained neurological deficit develops after an intracranial neurosurgical procedure. An EEG may help to diagnose this condition, leading to definitive treatment.

Epilepsy in elderly people

The prevalence and incidence of epilepsy are highest in later life with around 25% of new cases occurring in elderly people, many of whom will have concomitant neurodegenerative, cerebrovascular, or neoplastic disease. Difficulties accepting the diagnosis are frequently compounded by its unpredictable nature. Those affected commonly lose confidence and independence. Seizures in older people can result in physical injury, adding to low morale. Complete control is achievable in around 70% of patients with antiepileptic drug treatment. Optimum management requires rapid investigation, accurate diagnosis, effective treatment, sympathetic education, and assured support. The emergence of seizure disorders in old age places an increasing burden on health-care facilities and costs. A coordinated programme among health-care workers is advised to maintain the independence and improve the quality of life of this vulnerable patient population.

Lesion-induced plasticity as a potential mechanism for recovery and rehabilitative training

Brain lesions not only cause a functional deficit in the lesion area, but also affect the structurally intact brain network connected to the lesion. In brain areas surrounding the lesion, as well as those remote from it, the structural and functional plasticity of the brain is increased because of an alteration of transmitter receptor expression and membrane properties of neurones. Within the penumbra of brain ischaemia, as well as after trauma, an additional perilesional dysfunctional zone is found that contributes to the neurological deficit. The lesion-induced plasticity can be used for adaptation, which also may restore function in the perilesional zone, if adequate rehabilitative training is performed.

Antibodies to GM1 and Gal(beta 1-3)GalNAc at the nodes of Ranvier in human and experimental autoimmune neuropathy

Autoantibodies to Gal(beta 1-3)GalNAc epitopes on glycolipids and glycoproteins are associated with motor neuron disease and motor or sensorimotor neuropathy. These epitopes are ubiquitously distributed on cell surfaces. In the nervous system they are present on axons and myelin, specifically also at the nodes of Ranvier. Binding of GM1 antibodies to the nodal area may contribute to disease development in some of these conditions.

Ictal contralateral paresis in complex partial seizures

Certain behaviors that occur during a complex partial seizure (CPS) are useful in lateralizing the side of seizure onset. In 5 (5.3%) of 94 consecutive patients with partial epilepsy, we observed ictal unilateral arm and hand paresis during 27 of 34 CPS. In all these seizures, this behavior occurred contralateral to an epileptogenic temporal lobe, as determined by video-EEG monitoring and surgical outcome. In 5 of the 27 seizures, an observer demonstrated that the paretic arm and hand were flaccid. None of these patients had postictal (Todd's) paralysis. In most of the seizures, the arm ipsilateral to seizure onset had simultaneous purposeful movements or automatisms, sometimes with awkward posturing. Ictal unilateral paresis is distinctly different from ictal dystonia or postictal paralysis and consistently lateralizes seizure onset to the contralateral temporal lobe. Recognition of this particular ictal behavior and comparison to other simultaneous behaviors can aid in the lateralization and possibly localization of the epileptogenic zone.

Inhibitory motor seizures: correlation with centroparietal structural and functional abnormalities

Six adults and 2 children with focal inhibitory motor seizures (ictal paralysis) were evaluated during a 4-year period. Paresthesias at seizure onset occurred during some seizures in all patients, and focal clonic activity followed paralysis in 4. EEG-CCTV recordings of the seizures in 2 patients showed that ictal paralysis coincided with an ictal discharge starting in one centroparietal area. MRI showed centroparietal structural lesions in six patients. One patient with a normal MRI scan had right centroparietal hypometabolism on PET. Inhibitory motor seizures must be differentiated from transient ischemic attacks and migraine. In our patients a centroparietal epileptogenic focus was suggested by neuroimaging studies, and in 2 instances by ictal EEG.

Seizures with negative phenomena

Somatic inhibitory seizures and amnesic seizures are thought to occur rarely. We describe a patient with both types of seizures who initially presented with a clinical picture of transient ischemic attack. Neuroradiological investigations revealed a lesion probably a cavernoma located above the parietooccipital sulcus in the isthmus of cingulate gyrus. Anticonvulsant therapy eliminated both types of seizure.

The radiographic diagnosis and treatment of paraneoplastic central nervous system disease

Paraneoplastic nervous system syndromes are being identified with increasing frequency because of greater physician awareness and the availability of serodiagnostic tests for some syndromes. Frequently, paraneoplastic syndromes develop in the setting of an indolent, limited stage, or otherwise occult malignancy. As a result, the paraneoplastic disorder often becomes the most disabling part of a patient's disease. Effective treatment appears to require early identification. For these reasons, the ability to diagnose a paraneoplastic syndrome, follow its course, and treat it successfully are important. The authors describe four patients with neurologic paraneoplastic syndromes and identical magnetic resonance imaging abnormalities. Three patients responded to immunosuppressive or immunomodulatory therapy, and in one, corresponding radiographic improvement was documented. Strategies for early diagnosis and options for treatment of paraneoplastic nervous system disorders are discussed.

Focal inhibitory seizures as the presenting sign of ischemic cerebrovascular disease

Recurrent episodes of transient neurological dysfunction occurring in a patient with evidence of recent multiple lacunar infarctions were at first diagnosed as transient ischemic attacks (TIAs), but later proved to be due to focal inhibitory seizures. The differential diagnosis between TIAs and partial epileptic seizures in patients with ischemic cerebrovascular disease may sometimes be difficult in the presence of uncommon clinical manifestations.

Meningeal sarcoidosis, pseudo-meningioma, and pachymeningitis of the convexity

Two cases of meningeal sarcoidosis with unusual and misleading presentations are reported. In the first case, CT scan, angiographic, and MRI findings were indistinguishable from those of meningioma. CSF pleiocytosis may help in diagnosing sarcoid pseudo-meningioma. The second patient had transient focal deficits and pachymeningitis of the convexity. The transient deficits were probably of epileptic origin based on their response to antiepileptic treatment. The diagnosis of neurosarcoidosis was made only after meningeal biopsy, despite thorough investigations.

A study of unilateral brief focal atonia in childhood partial epilepsy

We studied unilateral brief focal atonia (BFA) in seven patients with childhood partial epilepsy. BFA was observed as a transient dropping of one arm lasting from 100 to 150 ms when patients were asked to keep both arms outstretched in front of the body. Close examination using simultaneous video-polygraphic recordings showed dropping of the arm to correspond exactly with a single sharp and slow wave complex arising from the contralateral centrotemporoparietal region. The BFA occasionally would progress to atonic seizures or atonic absence seizures, when the localized epileptic discharge evolved into generalized discharges. In one patient we found a positive correlation between the intensity of BFA and the amplitude of the contralateral epileptic discharges. A higher amplitude corresponded to more pronounced BFA and a lower amplitude to less pronounced BFA. These results led us to conclude that the apparently interictal single sharp and slow wave complex in the rolandic region may inhibit contralateral motor control, thus producing BFA that corresponds with the spike amplitude.

Severe anemia associated with transient neurological deficits

In two patients with carotid artery stenosis and anemia, neurological deficits appeared whenever the hemoglobin level fell below a critical level of 5-6 g/dl and resolved with correction of the anemia. Profound anemia should be considered as a cause of focal neurological deficit, especially if there is evidence of cerebral atherosclerosis.