C. P. Panayiotopoulos

Juvenile Myoclonic Epilepsy: A 5-Year Prospective Study

Summary: We made a long term prospective study of 66 patients with juvenile myoclonic epilepsy (JME). Prevalence was 10.2% among 672 patients with epilepsies. Sex distribution was equal. Sixty‐three were not diagnosed on referral; JME was not initially recognized in the epilepsy clinic in 22. Clinical typical absence seizures were reported in 33.3%, myoclonic jerks in 97% and generalized tonic‐clonic seizures (GTC) in 78.8% of the patients. Mean age (±SD) at onset was 10.5 ± 3.4 years (range 5–16 years) for absence seizures, 15 ± 3.5 years (range 8–26 years) for myoclonic jerks, and 16 ± 3.5 years (9–28) for GTC. Absence predated myoclonic jerks by 3.9 ± 2.3 years (range‐1–9 years) and GTC by 4.4 ± 2.7 years (range 1–8 years) in 14 (21.2%) patients who manifested all three types of seizure. Absence were never antedated by myoclonic jerks or GTC. Myoclonic jerks occurred on awakening in 87.5% of the patients. GTC occurred mainly on awakening, but other patients had nocturnal or diurnal GTC with no circadian distribution. Neurologic examination was normal for all patients except for tremor of the hands similar to essential tremor, noted in 35% of patients. Computed tomography (CT) brain scans were normal: 93% of patients had precipitating factors: sleep deprivation (89.5%), fatigue (73.7%), photosensitivity (36.8%; television and video games 8.8%), menstruation (24.1% of women), mental concentration (22.8%), and stress (12.3%). Incidence of JME among siblings (13 of 41 examined families) implies an autosomal recessive mode of inheritance for this Arab population. EEGs were frequently normal in treated patients. At least one abnormal EEG was recorded in 56 (84.9%) patients. Abnormalities consisted mainly of generalized discharges of spike/double spike and/or polyspike and slow wave. Frequent multiple spikes and discharge fragmentations varied from 0.5to 20‐s duration (mean 6.8 s). Twenty (30.3%) had focal abnormalities, and 18 (27.3%) had photoconvulsive discharges. Eighty‐eight percent of patients remained seizure‐free for 3 years of follow‐up. Effective treatment was achieved with valproate (VPA); control of myoclonic jerks was improved with clonazepam (CZP). CZP monotherapy did not consistently prevent GTC. Adding small doses of CZP with simultaneous reduction of VPA was the most effective and better tolerated form of medication, particularly in patients demonstrating an adverse reaction or requiring a large VPA dosage. VPA dosage was successfully reduced in 15 patients who were seizure‐free for >2 years and had infrequent seizures before treatment, but 9 of 11 patients relapsed after VPA discontinuation.

Elementary visual hallucinations, blindness, and headache in idiopathic occipital epilepsy: Differentiation from migraine.

This is a qualitative and chronological analysis of ictal and postictal symptoms, frequency of seizures, family history, response to treatment, and prognosis in nine patients with idiopathic occipital epilepsy and visual seizures. Ictal elementary visual hallucinations are stereotyped for each patient, usually lasting for seconds. They consist of mainly multiple, bright coloured, small circular spots, circles, or balls. Mostly, they appear in a temporal hemifield often moving contralaterally or in the centre where they may be flashing. They may multiply and increase in size in the course of the seizure and may progress to other non-visual occipital seizure symptoms and more rarely to extra-occipital manifestations and convulsions. Blindness occurs usually from the beginning and postictal headache, often indistinguishable from migraine, is common. It is concluded that elementary visual hallucinations in occipital seizures are entirely different from visual aura of migraine when individual elements of colour, shape, size, location, movement, speed of development, duration, and progress are synthesised together. Postictal headache does not show preference for those with a family history of migraine. Most of the patients are misdiagnosed as having migraine with aura, basilar migraine, acephalgic migraine, or migralepsy simply because physicians are not properly informed of differential diagnostic criteria. As a result, treatment may be delayed for years. Response to carbamazepine is excellent and seizures may remit.

F-waves in clinical neurophysiology: a review, methodological issues and overall value in peripheral neuropathies

This report comments on methodological issues related to the use of F-wave in clinical neurophysiology. An F-wave study aims to describe with relative accuracy the properties of the compound F-wave population which is the population of F-waves consecutively recorded from a muscle. This can only be achieved if an adequate number of F-waves is sampled. In order to avoid inaccuracies, correction of F-wave latency measurements for height or limb length and age is also required. Differences in the recording procedure could account for the variability in F-wave measurements. The usefulness of F-wave parameters other than latency is discussed. F-chronodispersion and F-tacheodispersion are more sensitive than conventional neurophysiological methods in detecting mild nerve lesions. F-persistence provides valuable information only if the findings are interpreted in correlation with the particular clinical setting. The suitability of the F-wave technique for routine studies is examined and a current view on the clinical applications is briefly recounted. There is an urgent need for the standardization of F-wave methodology.

Focal Electroencephalographic Abnormalities in Juvenile Myoclonic Epilepsy

Summary: A detailed study of EEGs of patients with an unequivocal diagnosis of juvenile myoclonic epilepsy (JME) showed a high prevalence of focal EEG abnormalities. Focal slow waves, spikes, and sharp waves and focal onset of the generalized discharge were present in 36.7% of EEGs in our patients with JME. In more than half of the patients, at least one EEG showed focal abnormalities. These features should not be misconstrued as indicative of partial epilepsy.

Juvenile Myoclonic Epilepsy: Factors of Error Involved in the Diagnosis and Treatment

Summary: Juvenile myoclonic epilepsy (JME), a common form of idiopathic generalized epilepsy, has a distinct clinical and electroencephalographic profile. Often JME is not recognized, with serious consequences on the sufferers. We examined factors contributing to the missed diagnosis even in an epilepsy clinic. Of 70 JME patients, 66 (91.4%) were not diagnosed on referral and 22 (33%) were not initially recognized in the epilepsy clinic. The correct diagnosis was established after a mean of 8.3 ± 5.5 years from disease onset and an interval of 17.7 ± 10.4 months from first evaluation in the epilepsy clinic. Myoclonic jerks, the hallmark of the disease, were not usually reported by patients. Similarly, relevant questioning may not be included in the history. Absence seizures antedating jerks by many years, myoclonic jerks reported as unilateral, generalized tonic‐clonic seizures occurring during sleep and focal EEG abnormalities are other factors contributing to not recognizing JME. Our study reempha‐sizes the need to have not only a correct seizure diagnosis but also a correct epilepsy‐disease diagnosis.

Lamotrigine as an add-on drug in typical absence seizures

Introduction ‐ Lamotrigine is licenced in many countries for use in patients with partial seizures. Evidence suggests that it may also be effective in generalised epilepsies. Material & methods ‐ We analysed retrospectively our patients with idiopathic generalised epilepsy with refractory absences. Results ‐ Fifteen patients with idiopathic generalised epilepsies were identified who had been treated with lamotrigine for 3 months or more. All patients were also treated with sodium valproate. Fourteen patients had active absences. Nine (64%) had a total or virtual cessation of absences and in a further patient they became milder and less frequent. One patient reported an increase in seizures. The effective dose of lamotrigine was 1.6‐3.0 mg/kg/day in children and 25‐50 mg/day in adults. Patients who responded did so after the first or second dose. Lamotrigine was well tolerated. Conclusion ‐ Low‐dose lamotrigine added to sodium valproate appears to be effective in typical absence seizures. A therapeutic interaction of the two drugs seems likely.

Typical Absence Status in Adults: Diagnostic and Syndromic Considerations

Summary: Purpose: To study the electroclinical features of typical absence status (TAS) in adults with syndromes of idio‐pathic generalized epilepsies (IGEs).

Juvenile myoclonic epilepsy: a study in Saudi Arabia.

Summary: We studied 50 patients in Saudi Arabia with juvenile myoclonic epilepsy (JME). There was a high positive family history of epilepsy (48.7%) and a high prevalence (10.7%) of other forms of epilepsy. JME was unrecognized at the time of referral for all patients. Age at onset varied from 6 to 28 years with an average of 15.5 years. Treatment was effective with valproate or with clonazepam; 42 patients were seizure‐free for a minimum of 6 months of follow‐up. EEG abnormalities were recorded in 37 patients; photoconvulsive responses were elicited in 15 patients but only 1 was clinically photosensitive.

Benign Nocturnal Childhood Occipital Epilepsy: A New Syndrome with Nocturnal Seizures, Tonic Deviation of the Eyes, and Vomiting

An epileptic syndrome of benign nocturnal childhood occipital epilepsy with excellent prognosis is described. The syndrome is characterized by a clinical ictal triad of nocturnal seizures, tonic deviation of the eyes, and vomiting. There may be marching to involve the head and limbs, ending with a generalized tonic-clonic seizure. Consciousness is usually, but not invariably, disturbed. Infrequent daytime fits may develop one to two years after remission of the nocturnal seizures. Age of onset is usually from 3 to 5 years. Both sexes are involved. There is no family history of epilepsy or migraine. No definite causative factor was detected. The frequency of the seizures is very low with two children having only solitary ones. The interictal electroencephalographic features consist of repetitive occipital spike and slow wave complexes that are induced by closed eyes and darkness and are inhibited by open eyes and fixation with visual cues. It is proposed that this is a new idiopathic age-related-onset syndrome of the localization-related epilepsies. (J Child Neurol 1989;4:43-48).

Elementary visual hallucinations in migraine and epilepsy.

A comparison of the elementary visual hallucinations of 50 patients with migraine and 20 patients with occipital epileptic seizures showed that epileptic seizures are predominantly multi-coloured with circular or spherical patterns as opposed to the predominantly black and white linear patterns of migraine. This simple clinical symptom of the elementary visual hallucinations may be helpful in distinguishing between classic or basilar migraine and visual partial epileptic seizures, particularly in children. Claims that epileptic seizures are triggered or caused by migraine may be artificial, reflecting problems in the differential diagnosis between the two diseases.