Differential diagnosis of sleep disorders, non-epileptic attacks and epileptic seizures

Psychogenic non-epileptic seizures: aetiology, diagnosis and management

Psychogenic non-epileptic seizures (PNES) have a significant impact on most patients in terms of distress, disability, loss of income and iatrogenic harm. Three-quarters of patients with PNES are initially misdiagnosed and treated for epilepsy. Misdiagnosis exposes patients to multiple iatrogenic harms and prevents them from accessing psychological treatment. In most cases, the patient's history (and witness accounts) should alert clinicians to the likely diagnosis of PNES. Since this diagnosis may be resisted by patients and may involve ‘un-diagnosing’ epilepsy, video-electroencephalogram recording of typical seizures is often helpful. The underlying causes of PNES are diverse: a model combining predisposing, precipitating and perpetuating factors is a useful way of conceptualising their aetiology. The initial step of treatment should be to limit iatrogenic harm. There is some evidence for the effectiveness of psychotherapy.

Advances in electrophysiology in the diagnosis of behavioral disorders

INTRODUCTION

Diagnosis in psychiatry remains largely subjective. Developing biological observations in psychiatric disorders into laboratory-based diagnostic tests can significantly impact diagnosis and management of these disorders. Diagnostic electrophysiological techniques are non-invasive and relatively inexpensive.

AREAS COVERED

In this review, the authors propose that enough knowledge has accumulated to allow the establishment of psychiatry-based clinical electrophysiology laboratories (PCELs). A brief summary of established clinical indications for electrophysiology tests, summary of highly promising technologies and a presentation of a proposed four-step approach to facilitate the translation of promising biological observations into diagnostic tests are provided. The reader should develop an appreciation of the current status of the clinical applications of psychiatric electrophysiology. The authors propose to capitalize on the widely accepted indication to rule out medical causes of psychiatric symptoms (e.g., epileptic activity) to begin developing PCELs as the equipment and skills necessary are basic to the entire discipline. The potential impact of the growing knowledge on the practice of psychiatry is explored to update clinicians and administrators as they develop laboratory and service plans.

EXPERT OPINION

Psychiatric electrophysiology currently plays a limited role in the diagnosis and management in psychiatry. This status is not supported by the existing literature. The underutilization of electrophysiological tests in psychiatry is propagated by the fact that the laboratories providing the service are not managed by psychiatrists. The authors propose that the first steps are to establish such laboratories and train psychiatrists to competently provide the service.

Parkinson's disease and deep brain stimulator placement

Deep brain stimulation (DBS) has added to the comfort and quality of life for an increasing number of Parkinson's disease (PD) patients. The anesthesiologist needs to understand the pathophysiology of the disease, the surgical procedure, and its postoperative implications to most effectively manage these patients. This article examines the role of the anesthesiologist in the pre- and perioperative management of patients undergoing DBS procedures. In terms of the general anesthetic management of PD patients, it is clear that no simple anesthetic regimen exists. Anesthesiologists can provide the best care through preoperative assessment, maintenance of PD drug therapy, and avoidance of known precipitating agents.

Paroxysmal Motor Disorders of Sleep: The Clinical Spectrum and Differentiation from Epilepsy

The diagnosis of paroxysmal events in sleep represents a significant challenge for the clinician, with the distinction of nocturnal epilepsy from nonepileptic sleep disorders often the primary concern. Diagnostic error or uncertainty is not uncommon in this situation, particularly with respect to nocturnal frontal lobe epilepsy (NFLE), which has a variable and often unusual presentation. Such errors can be minimized if the range of nonepileptic disorders with motor activity in sleep is fully appreciated. Here we review these disorders, before discussing the important clinical and electrographic features that allow their accurate differentiation from seizures. Particular emphasis is placed on the differentiation of nocturnal frontal lobe epilepsy from non-rapid eye movement (NREM) arousal disorders and other parasomnias. The value of recording episodes with video EEG polysomnography is discussed.

Novel seizure phenotype and sleep disruptions in knock-in mice with hypersensitive alpha 4* nicotinic receptors

A leucine to alanine substitution (L9'A) was introduced in the M2 region of the mouse alpha4 neuronal nicotinic acetylcholine receptor (nAChR) subunit. Expressed in Xenopus oocytes, alpha4(L9'A)beta2 nAChRs were > or =30-fold more sensitive than wild type (WT) to both ACh and nicotine. We generated knock-in mice with the L9'A mutation and studied their cellular responses, seizure phenotype, and sleep-wake cycle. Seizure studies on alpha4-mutated animals are relevant to epilepsy research because all known mutations linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) occur in the M2 region of alpha4or beta2 subunits. Thalamic cultures and synaptosomes from L9'A mice were hypersensitive to nicotine-induced ion flux. L9'A mice were approximately 15-fold more sensitive to seizures elicited by nicotine injection than their WT littermates. Seizures in L9'A mice differed qualitatively from those in WT: L9'A seizures started earlier, were prevented by nicotine pretreatment, lacked EEG spike-wave discharges, and consisted of fast repetitive movements. Nicotine-induced seizures in L9'A mice were partial, whereas WT seizures were generalized. When L9'A homozygous mice received a 10 mg/kg nicotine injection, there was temporal and phenomenological separation of mutant and WT-like seizures: an initial seizure approximately 20 s after injection was clonic and showed no EEG changes. A second seizure began 3-4 min after injection, was tonic-clonic, and had EEG spike-wave activity. No spontaneous seizures were detected in L9'A mice during chronic video/EEG recordings, but their sleep-wake cycle was altered. Our findings show that hypersensitive alpha4* nicotinic receptors in mice mediate changes in the sleep-wake cycle and nicotine-induced seizures resembling ADNFLE.

Comorbidité psychiatrique au cours des événements non épileptiques : étude rétrospective dans un centre de vidéo-EEG

INTRODUCTION

Pseudoseizures involve a group of paroxysmal behavioral symptoms mimicking an epileptic seizure, but without modifications of cerebral electrical activity.

PATIENTS AND METHOD

In this retrospective study focusing on mental disorders, 37 patients with pseudoseizures were recorded during video-EEG procedure.

RESULTS

According to DSM-IV criteria, 70 percent of the patients had at least one mental disorder when evaluated. Diagnoses were, in decreasing order of frequency: post-traumatic stress disorders, other anxious disorders, somatoform disorders, dissociative disorders, and mood disorders.

CONCLUSION

The strong association between pseudoseizures and post-traumatic stress disorders is discussed. Our results argue in favor of a systematic evaluation of psychiatric comorbidity.

Psychogenic nonepileptic seizures: review and update

The population incidence of psychogenic nonepileptic seizures (PNES) may be only 4% that of epilepsy, but many patients with PNES have a tendency to seek medical attention, and PNES make up a larger share of the workload of neurologists and emergency and general physicians. Although a great number of publications describe how PNES can be distinguished from epileptic seizures, it usually takes several years to arrive at this diagnosis, and three-quarters of patients (with no additional epilepsy) are treated with anticonvulsants initially. However, the management of PNES as epileptic seizures can lead to significant iatrogenic harm. Moreover, the failure to recognize the psychological cause of the disorder detracts from addressing associated psychopathology and enhances secondary somatization processes. This review provides an overview of studies of the diagnosis, etiology, treatment, and prognosis of PNES. Physicians should always consider PNES in the differential diagnosis of a seizure disorder. If a diagnosis of PNES is possible, or a diagnosis of epilepsy in doubt, a clear diagnostic categorization should be sought. This should involve the assessment of the patient by a physician versed in the diagnosis of seizure disorders and, in many cases, the documentation of a typical seizure by video-EEG. Outcome may be improved if the diagnosis is more actively sought, made earlier, and communicated more convincingly.

Sleep and epilepsy

Sleep disturbance in patients with epilepsy is frequently overlooked, but may contribute to decreased daytime functioning and increased seizure activity. Although complicated, the relationship between sleep and epilepsy is becoming clearer. Sleep, and particularly deep non-rapid-eye-movement sleep, increase interictal epileptiform activity. Sleep increases certain seizure types and the rate of generalization of partial seizures, however rapid-eye-movement sleep seems to suppress seizures. Sleep disorders, particularly sleep apnea, exacerbate seizures. Seizures, in turn, can disrupt sleep structure, particularly rapid-eye-movement sleep. An understanding of these relationships is important in seizure control and in maximizing the quality of life for patients with epilepsy.

Ion channels and the genetic contribution to epilepsy

Recent application of genetic analysis to rare, hereditary epilepsies has resulted in the identification of mutations in genes encoding ion channels or functionally related proteins in several human and animal syndromes. Reviewed here are selected human and murine epilepsies that result from ion channel mutations. In humans, three autosomal-dominant disorders--benign familial neonatal convulsions, nocturnal frontal lobe epilepsy, and "generalized epilepsy with febrile seizures plus"--result from mutations affecting voltage-sensitive potassium channels, a central nicotinic acetylcholine receptor, and a voltage-sensitive sodium channel, respectively. In mice, four genetically distinct, autosomal-recessive models of absence epilepsy are caused by mutations in genes encoding three types of calcium channel subunits and a sodium-hydrogen ion exchanger. These findings suggest that variation in genes encoding ion channels could determine susceptibility to common human epilepsies.