Miles E. Drake

Electrocardiography in epilepsy patients without cardiac symptoms.

Sudden unexpected death in epilepsy (SUDEP) has been ascribed to cardiac arrhythmia, possibly triggered by cerebral events. Young, noncompliant, substance-abusing males with convulsions may be at risk. EEG/ECG studies have not shown significant cardiac arrhythmias in these and other seizure patients. We reviewed resting ECGs in 75 epilepsy patients and compared ventricular rate, PR interval, QRS duration, and QT interval corrected for heart rate (QTC) with normal ECGs recorded in age-matched patients without cardiac or neurologic disorders. No potentially lethal arrhythmias were noted in the seizure patients. Patients who fit the previously-described profile of high risk of SUDEP had more abnormal ECGs and ventricular rate was faster in these patients than in other epileptics. Patients with complex partial and secondarily generalized seizures had faster ventricular rates than other epileptics. No differences were noted in QRS duration or PR interval. QT was longer in patients with complex partial seizures than in control ECGs or other epileptic patients. These findings suggest that resting ECG has low diagnostic yield in epilepsy patients without cardiac symptoms. The factors possibly predisposing to SUDEP may relatively increase resting heart rate, however, and relatively increased QT interval with complex partial seizures may indicate some differences, possibly neurally-mediated, in cardiac excitability which could contribute to SUDEP.

Neuropsychiatric aspects of psychogenic status epilepticus

We studied 20 patients with continuous repetitive psychogenic seizures simulating status epilepticus. Most patients received intravenous doses of multiple anticonvulsants. Our definition used for status epilepticus was that of Delgado-Escueta et al,1 at least 30 minutes of repetitive seizures without regaining consciousness. Nineteen of 20 patients were young women, all but one under 40 years of age. Sixteen of these patients had a history of childhood seizures. In over 50% of patients, seizures continued until respiratory arrest and intubation occurred. Thorough neuropsychological testing and psychiatric interview were done after cessation of the acute episode. Long-term outcome and prognosis depended on definitive psychiatric diagnosis. Repetitive psychogenic seizures simulating status epilepticus are not uncommon, and such patients may incur serious iatrogenic complications from treatment for status epilepticus. Appropriate management and long-term prognosis may be determined by the type and severity of the underlying psychiatric disorder.

Pediatric Migraine Prophylaxis With Divalproex

We followed 23 patients with pediatric migraine, ranging in age from 7 to 17 years, who were treated with preventive divalproex sodium for migraine prophylaxis. Patients were evaluated for the presence or absence of comorbid psychiatric disorders or epilepsy to assess the possible differential effects of divalproex therapy. Doses ranged from 3.1 to 32.9 mg/kg/day. Seven patients had comorbid psychiatric disorders, whereas six patients had epilepsy (three rolandic, two generalized, and one indeterminate). Fifteen patients had a greater than 50% reduction in migraine; six patients became headache free. Divalproex doses used were not statistically different among the three groups. A favorable response and headache freedom were more likely in patients with migraine alone or with comorbid epilepsy, and less likely in patients with psychiatric comorbidity. Divalproex was well tolerated, and no significant side effects were reported. No notable changes were noted in behavioral problems, and patients with epilepsy were well controlled. In our cohort of patients, divalproex was most effective in patients with migraine alone or comorbid epilepsy. (J Child Neurol 2001;16:731-734).

Nocturnal Sleep Recording with Cassette EEG in Chronic Headaches

SYNOPSIS

Long-latency Auditory Event Related Potentials in Migraine†

SYNOPSIS

Interictal quantitative EEG in epilepsy

The interictal EEG is often normal in epilepsy patients, particularly with partial seizures of extratemporal origin. Quantitative techniques of EEG analysis may increase the yield of diagnostic abnormality in such patients. Thirty patients with partial seizures of frontal or temporal origin had EEG recorded from left frontal (F7-C3), right frontal (F8-C4), left posterior (T5-O1), and right posterior (T6-O2) derivations. Four-second epochs were used to compute power in the delta (0.25-4.0 Hz), theta (4.25-8.0 Hz), alpha (8.25-13 Hz), and beta (13.25-30 Hz) bands. The ratio of high (8.25-30 Hz) to low (0.25-8 Hz) power on the left and the right was measured, as was the ratio between the left and the right hemisphere total power. The mean frequency deviation in the alpha band between the left and the right hemispheres was also measured, and spectral mobility was determined in the right and the left frontal regions. These values were also calculated in normal subjects and tension headache patients with normal EEGs. Seizure patients with abnormal interictal EEGs had decreased ratios of high to low power, greater asymmetry of total power and alpha frequency, and reduced spectral mobility on the side of their EEG foci. Epileptics with normal interictal EEGs had lower ratios of high to low power, greater alpha frequency asymmetry, and lower spectral mobility than did headache patients or normal controls. Power and frequency measurements, and determination of spectral measures such as mobility, can be done with commercially available digital EEG equipment. They may demonstrate otherwise obscure asymmetries in the interictal EEG and thereby aid in epilepsy diagnosis and classification.

WAIS-R Factor Structure in Epileptic Patients

Summary: The Wechsler Adult Intelligence Scale–Revised (WAIS‐R), the newest version of the Wechsler Scales, has had several factor analytic studies, but none have been done in a sample of seizure‐disorder patients. The factor structure of the WAIS‐R was examined in this study in a sample of 107 patients with various seizure disorders. The results of this study revealed the 3‐factor solution, as has been reported in many previous studies. The most notable difference was the relatively greater prominence of the Freedom from Distractibility factor. These results are consistent with studies of the factor structure of previous editions of the Wechsler Scales in samples of epileptic patients. The relative prominence of the Distractibility factor could suggest that attentional factors are a more important influence on performance than in other patient groups. Further studies are needed to clarify the effect of various seizure‐related variables on patterns of intelligence.

Cassette EEG sleep recordings in Gilles de la Tourette syndrome

Tourette syndrome (TS) patients often complain of sleep problems, and questionnaire studies indicate that sleep disturbance is frequent. Decreased slow wave sleep and increased awakenings have been reported in laboratory polysomnography in TS patients, and a serotoninergic disorder of arousal has been postulated. We recorded outpatient sleep in 20 patients newly diagnosed with TS utilizing a 4-channel cassette EEG system. The newly-diagnosed patients were predominantly male, and ranged in age from 10 to 36 years. Some had taken psychotropic medications in the past, but none had been treated systematically for TS. Seven patients had chronic tics only, 8 had tics and attention deficit-hyperactivity, and 5 had tics plus obsessions and compulsions. None had other medical, neurologic, or psychiatric disorders. All were nocturnal sleepers, and were recorded in their usual sleeping environments and routines. TS patients had reduced sleep, decreased sleep efficiency, increased awakenings, and decreased slow wave sleep. Tic patients had increased nocturnal awakenings and movements, particularly those who had tics during sleep. Sleep fragmentation and loss of slow wave sleep was most marked in TS patients with attention deficit-hyperactivity. Sleep latency was increased, REM sleep reduced, and REM sleep latency decreased in TS patients with obsessions and compulsions. These findings accord with previous reports of sleep disturbance in TS, and suggest that these disturbances may vary with TS symptoms. Chronic tics may persist in sleep and cause awakenings, TS with attention deficit may be associated with a disorder of arousal and alertness, and obsessions and compulsions may be manifestations of a biochemical disturbance involving paradoxical sleep.

Electrophysiologic assessment of autonomic function in epilepsy

Sudden unexpected death associated with epilepsy (SUDEP) is an important clinical problem. Peri-ictal autonomic dysfunction is thought to play a role in SUDEP and few means exist for clinical identification of patients at risk. Sympathetic function was assessed by measuring sympathetic skin responses (SSR) elicited in the hand by auditory or tactile stimulation or by inspiration. Parasympathetic function was assessed by recording the R-R interval (RRI) and determining its variability in subsequent heartbeats. Fifty epilepsy patients had significantly greater SSR amplitudes and latencies than controls. The RRI was shorter in patients than in controls and the mean successive difference (MSD) was less, but significance was not reached. Twenty patients at possible risk for SUDEP (male, generalized seizures, intermittent medication noncompliance, drug and alcohol abuse, traumatic or structural aetiology) differed significantly from controls in SSR and RRI. Epilepsy patients may differ in autonomic function from the general population, and these differences may be relevant to SUDEP. The SSR and the RRI may be a simple means of assessing autonomic function in epilepsy outpatients.

Flunarizine for treatment of partial seizures Results of a concentration‐controlled trial

The National Institutes of Health sponsored a randomized, double-blind, multicenter, placebo-controlled trial of flunarizine (FNR) in epileptic patients receiving concomitant phenytoin (PHT) or carbamazepine (CBZ). Because of FNRs long half-life (up to 7 weeks), a parallel rather than crossover design was used. Each patient received an individualized loading dose and maintenance dosage targeted at a 60-ng/ml plasma FNR concentration. Of 93 patients randomized, 92 provided seizure data for the full 25-week treatment period; one placebo-treated patient dropped out for personal reasons. Fifty-four patients received CBZ only, nine received PHT only, and 30 received both CBZ and PHT. Eighty-seven patients had a history of complex partial seizures, and 60 had secondarily generalized seizures. Eight patients discontinued FNR prematurely, all because of adverse neurologic or psychiatric signs or symptoms; depression was the specific cause in three cases. Calculated maintenance dosages, based on single-dose pharmacokinetic profiles, ranged from 7 to 138 mg/day (mean, 40 mg/day). Plasma FNR concentrations generally exceeded the target, with the highest concentrations observed immediately after loading; excluding the first three treatment weeks and all concentrations after a FNR dosage change, the median plasma FNR concentration was 71.7 ng/ml. The percent reduction from baseline seizure rate was statistically greater (p = 0.002) in the FNR-treated group (mean, 24.4%) than in the placebo-treated group (mean, 5.7%).