Standard procedures for the diagnostic pathway of sleep-related epilepsies and comorbid sleep disorders: an EAN, ESRS and ILAE-Europe consensus review.

BACKGROUND AND PURPOSE: Some epilepsy syndromes (sleep-related epilepsies, SREs) have a strong link with sleep. Comorbid sleep disorders are common in patients with SRE and can exert a negative impact on seizure control and quality of life. Our purpose was to define the standard procedures for the diagnostic pathway of patients with possible SRE (scenario 1) and the general management of patients with SRE and comorbidity with sleep disorders (scenario 2). METHODS: The project was conducted under the auspices of the European Academy of Neurology, the European Sleep Research Society and the International League Against Epilepsy Europe. The framework entailed the following phases: conception of the clinical scenarios; literature review; statements regarding the standard procedures. For the literature search a stepwise approach starting from systematic reviews to primary studies was applied. Published studies were identified from the National Library of Medicine's MEDLINE database and Cochrane Library. RESULTS: Scenario 1: Despite a low quality of evidence, recommendations on anamnestic evaluation and tools for capturing the event at home or in the laboratory are provided for specific SREs. Scenario 2: Early diagnosis and treatment of sleep disorders (especially respiratory disorders) in patients with SRE are likely to be beneficial for seizure control. CONCLUSIONS: Definitive procedures for evaluating patients with SRE are lacking. Advice is provided that could be of help for standardizing and improving the diagnostic approach of specific SREs. The importance of identifying and treating specific sleep disorders for the management and outcome of patients with SRE is underlined.

[Sleep-disordered breathing as a consequence of vagus nerve stimulation]. / Alteraciones respiratorias durante el sueño a consecuencia de la estimulación del nervio vago.

INTRODUCTION: Vagus nerve stimulation (VNS) is indicated in cases of refractory epilepsy. Its side effects are frequently minor, however, breathing disturbances during sleep have been previously reported. CASE REPORTS: Our three cases are representative of sleep-disordered breathing that occurred as a consequence of VNS activity in patients with refractory epilepsy. Sleep apnoea was observed in two patients and stridor in one patient. CONCLUSIONS: Given the high prevalence of sleep apnoea-hypopnoea syndrome in patients with refractory epilepsy, implantation of VNS should be ideally preceded by an assessment of the breathing during sleep. Furthermore, sleep-disordered breathing should be considered as a rare complication of VNS, and sleep apnoea should be investigated alongside data regarding VNS firing.

TITLE: Alteraciones respiratorias durante el sueño a consecuencia de la estimulación del nervio vago.Introducción. La estimulación del nervio vago (ENV) es una terapia utilizada en casos de epilepsia refractaria. Sus efectos secundarios son, con frecuencia, leves; sin embargo, se han descrito previamente alteraciones respiratorias durante el sueño. Casos clínicos. Los tres casos incluidos son representativos de alteraciones respiratorias durante el sueño (apnea del sueño y estridor) que surgen a consecuencia de la actividad de la ENV. Conclusiones. Dada la elevada prevalencia del síndrome de apnea/hipopnea durante el sueño en pacientes con epilepsia refractaria, debería estudiarse su posible preexistencia en candidatos a ENV y considerarse su potencial aparición como consecuencia de la ENV en el seguimiento de pacientes con ENV activa.

Clinical utility of EEG in diagnosing and monitoring epilepsy in adults.

Electroencephalography (EEG) remains an essential diagnostic tool for people with epilepsy (PWE). The International Federation of Clinical Neurophysiology produces new guidelines as an educational service for clinicians to address gaps in knowledge in clinical neurophysiology. The current guideline was prepared in response to gaps present in epilepsy-related neurophysiological assessment and is not intended to replace sound clinical judgement in the care of PWE. Furthermore, addressing specific pathophysiological conditions of the brain that produce epilepsy is of primary importance though is beyond the scope of this guideline. Instead, our goal is to summarize the scientific evidence for the utility of EEG when diagnosing and monitoring PWE.

Hypoxic-ischaemic brain injury: imaging and neurophysiology abnormalities related to outcome.

BACKGROUND: The outcome for patients with hypoxic-ischaemic brain injury (HIBI) is often poor. It is important to establish an accurate prognosis as soon as possible after the insult to guide management. Clinical assessment is not reliable and ancillary investigations, particularly imaging and EEG, are needed to understand the severity of brain injury and the likely outcome. METHODS: We undertook a retrospective study of 39 patients on an intensive therapy unit (ITU) with HIBI who were referred for MRI. The patients were seen consecutively >57 months. HIBI was due to a variety of insults causing cardiac arrest, hypoperfusion or isolated hypoxia. RESULTS: The outcome was poor, 29 patients died, 7 were left severely disabled and only 3 made a good recovery. Characteristic imaging changes were seen on MRI. These included extensive changes in the cortex and the deep grey matter present on diffusion-weighted imaging (DWI) and T2-weighted imaging within 6 days of the insult. In other patients, different patterns of involvement of the cortex and basal ganglia occurred. There was no significant difference in the outcome or imaging appearances according to aetiology. A poor prognosis was consistently associated with a non- or poorly responsive EEG rhythm and the presence of periodic generalized phenomena with a very low-voltage background activity. CONCLUSION: In this retrospective study of patients with HIBI, MRI and EEG provided valuable information concerning prognosis.

Effect of age on subjective complaints and objective severity of carpal tunnel syndrome: prospective study.

OBJECTIVES: Older patients with carpal tunnel syndrome who are resistant to conservative treatment often have a less than satisfactory outcome after surgery. We therefore investigated whether the age of the patient affects the subjective complaints or the objective severity of the nerve entrapment prior to surgery in patients younger than 40 years compared with those above 70 years of age. DESIGN: Prospective study. SETTING: NHS specialist neurophysiology department. PARTICIPANTS: One hundred and six splint-resistant patients scored their subjective complaints and scores were then compared with the neurophysiology results. MAIN OUTCOME MEASURES: Nerve conduction speeds and subjective visual analogue score of pain, sensation and motor function. RESULTS: Conduction speeds were significantly more affected in patients over 70 years of age than in those under 40 years. Older patients scored their subjective complaints lower than younger patients. CONCLUSIONS: Older patients' subjective complaints misrepresent the severity of the nerve entrapment. Clinicians should have a lower threshold for objective investigation of patients older than 70 years of age to minimize development of irreversible nerve damage.

Stimulus-induced bilateral central periodic discharges, cortical myoclonus and arousal responses in mild reversible coma.

OBJECTIVE: To study the association between stimulus-induced periodic epileptiform discharges (PEDs), arousal EEG responses and limb jerking in a comatose patient with reversible viral encephalitis. METHODS: We recorded video EEG in Intensive Care Unit (ICU) for strictly clinical purposes. Back averaging was performed off-line using Neuroscan 4.3. RESULTS: We recorded spontaneous and stimulus-induced bilateral central PEDs (bi-central PEDs) that were followed by phasic vertex potentials, customarily considered as EEG arousal responses. Bi-central PEDs were associated with myoclonus when provoked by strong and protracted stimuli, but remained subclinical when elicited by auditory or mild tactile stimuli. Spontaneous and stimulus-induced bi-central PEDs disappeared after full neurological recovery. CONCLUSION: These findings link stimulus-induced PEDs to epileptic cortical myoclonus, and further suggest that in certain comatose patients they may represent reflex epileptic activity, even when clinically silent. The term "reflex seizures of the critically ill" may be appropriate in such patients. Our findings may also provide a model of the reciprocal relationship between arousals and epileptiform activity. SIGNIFICANCE: Consideration of the possibility that stimulus-induced PEDs are reflexive epileptic phenomena in some comatose ICU patients may rationalise further their acute management, including antiepileptic treatment.

Neuropsychological effects associated with temporal lobectomy and amygdalohippocampectomy depending on Wada test failure.

OBJECTIVE: To compare the neuropsychological effects of temporal lobectomy (TL) and amygdalohippocampectomy (AH), depending on whether the patients had passed or failed the Wada test. METHODS: We compared changes in neuropsychological scores in patients who underwent TL (n = 91) or AH (n = 15), and had passed or failed the Wada test. Comparisons were carried out in all 106 patients and among the 20 patients who failed the Wada test (12 who had TL and 8 who had AH). RESULTS: No patient became globally amnesic after surgery. Among all patients, no differences were found in pre-surgical or change scores (percentage of change after surgery compared with preoperative values) of neuropsychological tests between patients who underwent TL or AH. Among patients who failed the Wada test, those in the TL group showed higher visual memory impairment (p<0.05). There was a strong trend suggesting that TL is associated with higher verbal memory deficits than AH (p = 0.07). Of those TL patients who failed the Wada test, the contralateral Wada score correlated with change scores in verbal intelligence quotient (p<0.01), and there was a strong trend towards a correlation with the logical memory immediate recall version subtest of the Wechsler Memory Scale (p = 0.06). CONCLUSIONS: No profound changes in intelligence quotient or memory scores were found after TL or AH. Nevertheless, patients who underwent TL and failed the Wada test showed more deficits than those who passed the test or those who had AH. The presence of a correlation between contralateral Wada scores and verbal deficits in TL patients who failed the Wada test but not among AH patients suggests that, if temporal surgery is required, AH might be preferred to TL in patients who fail the Wada test.

VNS in patients with previous unsuccessful resective epilepsy surgery: antiepileptic and psychotropic effects.

OBJECTIVES: To assess the efficacy of vagus nerve stimulation (VNS) in patients with medically and surgically intractable complex partial seizures (CPS). PATIENTS AND METHODS: Sixteen patients with previous temporal [15] and frontal [one] resections were treated with VNS between 1994 and 1999 at King's College Hospital, London, UK. Post-operative video-electroencephalogram telemetry had shown that CPS started from the operated side in 12 patients, contralaterally in three and bilaterally independently in one. RESULTS: Three patients (18.75%) had 50% or more reduction in seizure frequency, but one showed severe worsening of epilepsy, which remitted upon VNS discontinuation. The antiepileptic effect of VNS was not different with respect to the type of operation (anterior temporal lobectomy vs amygdalohippocampectomy), the side of operation, or the side of seizure onset. We observed psychotropic effects in two patients with post-ictal psychosis, in two others with depression, and in a child with severe behavioral disorder. CONCLUSIONS: VNS may have a rather limited antiepileptic role to play in patients with persistent seizures following epilepsy surgery, but may independently possess useful antipsychotic and mood-stabilizing properties.

Postictal psychosis after temporal lobectomy.

Three of 282 consecutive patients who had temporal resections for intractable epilepsy developed postoperative postictal psychosis. These three patients had seizure recurrence contralateral to the resection, whereas none of the patients with ipsilateral seizure recurrence developed any psychiatric symptoms after surgery. Two had left amygdalo-hippocampectomy and one right temporal lobectomy. The de novo occurrence of postoperative postictal psychosis is a well-defined complication of surgery for temporal lobe epilepsy, and may relate to contralateral epileptogenesis.

Relevance of residual histologic and electrocorticographic abnormalities for surgical outcome in frontal lobe epilepsy.

PURPOSE: To estimate the significance of residual electrocorticographic and neuropathologic abnormalities on seizure control after surgery for frontal lobe epilepsy with the purpose of determining their relevance in deciding the extent of the surgical procedure. METHODS: The presence of epileptiform discharges in intraoperative electrocorticograms (ECoGs) and the nature and extent of neuropathologic abnormalities were reviewed for 35 patients who underwent frontal lobe resections for the treatment of epilepsy at our institution. The relations between surgical outcome and presence of the following features were studied: (a) presence of abnormal tissue at the limits of the resection; (b) presence of sporadic spikes and seizure patterns in the preresection ECoG; (c) their abolition in the postresection ECoG; and (d) the topography of residual discharges with respect to the margins of the resection. RESULTS: On neuropathologic examination, 18 patients showed focal cortical dysplasia (CD), and 17 showed other abnormalities (non-CD). Ten CD patients and 11 non-CD patients experienced a favourable outcome. Seizure patterns were significantly more common in patients with focal cortical dysplasia than in those without, with a sensitivity of 94% and a specificity of 75%. Abolition of seizure patterns was associated with a favourable surgical outcome (p = 0.031). Abolition of sporadic spikes or their presence in the postresection ECoG did not influence outcome. There was no clear relation between outcome and location of residual sporadic discharges. Seizure patterns persisted in the postresection ECoG in three CD patients, were located at the margins of the resection in all three, and these patients had a poor outcome. Incomplete removal of abnormal tissue was not associated with a poorer outcome in either patient group or in the complete sample. CONCLUSIONS: Seizure patterns were significantly more common in patients with cortical dysplasia, and their abolition on postresection ECoG recordings was associated with a favourable surgical outcome. Persistence of sporadic ECoG spikes and incomplete removal of histologic abnormalities did not affect outcome significantly.

Idiopathic generalised epilepsy with phantom absences and absence status in a child.

A syndrome of idiopathic generalised epilepsy with phantom absences of undetermined onset has been recently described. This syndrome clinically becomes apparent in adulthood with generalised tonic clonic seizures and frequently absence status epilepticus. We report an 11 year-old normal girl with frequent episodes of absence status and no other overt clinical manifestations. However, appropriate video-EEG recordings documented that she had frequent absence seizures that were so mild as to escape recognition by her and the parents. These consisted of mild impairment of cognition and eyelid fluttering during brief generalised discharges of spike/multiple spike and slow waves. No further seizures occurred and the EEG normalised after appropriate drug treatment. Thus, it appears that this syndrome of phantom absences and absence status may start much earlier, in late childhood. Appropriate video-EEG documentation is needed for the recognition of these patients that may be more common than it appears from the few published cases (with Video).

Tooth brushing-induced seizures: a case report.

We report a 28-year-old woman of normal intellect, who had three late-onset seizures with unusual ictal features and secondary generalization during prolonged and vigorous tooth brushing. Neurologic examination and brain magnetic resonance imaging (MRI) were normal, but interictal EEG showed left frontal epileptiform activity. Reasonable precautions (regular but briefer and less vigorous brushing of her teeth) combined with a moderate dose of carbamazepine effectively prevented seizure recurrence. This case may be an example of cryptogenic form of reflex epilepsy with seizures induced exclusively by tooth brushing.

Postoperative myoclonus simulating seizure recurrence: a rare complication of anterior temporal lobectomy.

The unusual case of newly-emerged bilateral myoclonus in a 39-year-old man following anterior temporal lobectomy, which cured his temporal lobe epilepsy, is reported. The possible causes and differential diagnosis between epileptic and non-epileptic myoclonus following epilepsy surgery are presented and a brief review of the available literature on the subject is reported.

Psychomotor EEG variant of Gibbs: an association with underlying structural pathology.

OBJECTIVE: To describe the association between a unilateral mid-temporal rhythmic theta discharge ("psychomotor variant of Gibbs") with neuroimaging-demonstrated underlying mass lesion. METHODS: Standard routine awake and scalp electroencephalography, continuous video-EEG monitoring and magnetic resonance brain imaging were employed in the diagnostic work-up of a 9-year-old boy with a severe behavioural disturbance and episodic outbursts of aggression. RESULTS: EEG showed a unilateral mid-temporal rhythmic discharge which was continuous in drowsiness and which remained confined to the right hemisphere. MRI showed a lesion in the temporal horn of the right lateral ventricle displacing superiorly the white matter stem of the right temporal lobe. CONCLUSION: A rhythmic mid-temporal theta discharge, commonly regarded as a benign EEG variant, may, in some patients, reflect underlying structural pathology. Neuroimaging should be considered particularly when this EEG pattern remains confined to one hemisphere.

Chronic encephalitis and temporal lobe epilepsy: a variant of Rasmussen's syndrome?

The authors report two adult patients with chronic temporal lobe epilepsy and pathologic features consistent with Rasmussen's encephalitis. Although seizures persisted after temporal lobe surgery no progressive cognitive or neurologic deficit has emerged. Prominent auditory auras in each suggested a persisting epileptogenic focus in the superior temporal gyrus. The current findings expand the clinical spectrum of Rasmussen's encephalitis and suggest that chronic nonprogressive encephalitis may serve as the pathologic substrate of medically intractable temporal lobe epilepsy.

Lateralizing and localizing values of ictal onset recorded on the scalp: evidence from simultaneous recordings with intracranial foramen ovale electrodes.

PURPOSE: The value of scalp recordings to localize and lateralize seizure onset in temporal lobe epilepsy has been assessed by comparing simultaneous scalp and intracranial foramen ovale (FO) recordings during presurgical assessment. The sensitivity of scalp recordings for detecting mesial temporal ictal onset has been compared with a "gold standard" provided by simultaneous deep intracranial FO recordings from the mesial aspect of the temporal lobe. As FO electrodes are introduced via anatomic holes, they provide a unique opportunity to record simultaneously from scalp and mesial temporal structures without disrupting the conducting properties of the brain coverings by burr holes and wounds, which can otherwise make simultaneous scalp and intracranial recordings unrepresentative of the habitual EEG. METHODS: Simultaneous FO and scalp recordings from 314 seizures have been studied in 110 patients under telemetric presurgical assessment for temporal lobe epilepsy. Seizure onset was identified on scalp records while blind to recordings from FO electrodes and vice versa. RESULTS: Bilateral onset (symmetric or asymmetric) was more commonly found in scalp than in FO recordings. The contrary was true for unilateral seizure onset. In seizures with bilateral asymmetric onset on the scalp, the topography of largest-amplitude scalp changes at onset does not have localizing or lateralizing value. However, 75-76% of seizures showing unilateral scalp onset with largest amplitude at T1/T2 or T3/T4 had mesial temporal onset. This proportion dropped to 42% among all seizures with a unilateral scalp onset at other locations. Of those seizures with unilateral onset on the scalp at T1/T2, 65.2% showed an ipsilateral mesial temporal onset, and 10.9% had scalp onset incorrectly lateralized with respect to the mesial temporal onset seen on FO recordings. In seizures with a unilateral onset on the scalp at electrodes other than T1/T2, the proportions of seizures with correctly and incorrectly lateralized mesial temporal onset were 37.5 and 4.2%, respectively. Thus the ratio between incorrectly and correctly lateralized mesial temporal onsets is largely similar for seizures with unilateral scalp onset at T1/T2 (16.7%) and for seizures with unilateral scalp onset at electrodes other than T1/T2 (11.2%). The onset of scalp changes before the onset of clinical manifestations is not associated with a lower proportion of seizures with bilateral onset on the scalp, or with a higher percentage of mesial temporal seizures or of mesial temporal seizures starting ipsilateral to the side of scalp onset. In contrast, the majority (78.4%) of mesial temporal seizures showed clinical manifestations starting after ictal onset on FO recordings. CONCLUSIONS: A bilateral scalp onset (symmetric or asymmetric) is compatible with a mesial temporal onset, and should not deter further surgical assessment. Although a unilateral scalp onset at T1/T2 or T3/T4 is associated with a higher probability of mesial temporal onset, a unilateral onset at other scalp electrodes does not exclude mesial temporal onset. A unilateral scalp onset at electrodes other than T1/T2 is less likely to be associated with mesial temporal onset, but its lateralizing value is similar to that of unilateral scalp onset at T1/T2. The presence of clinical manifestations preceding scalp onset does not reduce the localizing or lateralizing values of scalp recordings.