Senile myoclonic epilepsy in Down syndrome: a video and EEG presentation of two cases.

Myoclonic epilepsy is being increasingly recognized as a late-onset complication in middle-aged or elderly patients with Down syndrome, in association with cognitive decline. We show video and EEG recordings of two patients, both aged 56 years, diagnosed with this condition. At onset, myoclonic epilepsy in elderly DS patients may resemble, in its clinical expression, the classical juvenile myoclonic epilepsy with the characteristic occurrence of jerks on awakening. It is clearly associated with an Alzheimer-type dementia, and may also occur in non-DS patients with Alzheimer's disease: hence the possible denomination of "senile myoclonic epilepsy". [Published with video sequences].     

Progressive myoclonus epilepsy in Down syndrome patients with dementia

This study aimed to elucidate the natural history of senile myoclonic epilepsy, a type of myoclonic epilepsy associated with Alzheimer’s disease in adult Down syndrome patients. Twelve Down syndrome patients over the age of 40 years with myoclonic epilepsy and Alzheimer’s disease underwent clinical, neuropsychological, neurophysiological, and neuroradiological study. The kariotypes, APOE polymorphisms, all exons in the PSEN1 and PSEN2 genes, and exons 16 and 17 in the APP gene were determined for all patients. CSF Aβ42, p-tau₁₈₁, and t-tauAg were determined for two patients. Three main stages appeared during the course of the syndrome. The first stage was characterized by dementia onset (mean age: 51 ± 6.6 years), diffuse EEG abnormalities during sleep, and cerebral atrophy determined using neuroimaging. During the second stage, myoclonic epilepsy manifested (mean age: 51.4 ± 7.2 years) with myoclonic jerks time-locked to diffuse epileptiform abnormalities upon awakening, which was controlled with antiepileptic drugs. During the third stage (mean age: 54.8 ± 7.6 years), myoclonic seizures were replaced with nonepileptic myoclonus, and cerebellar signs, severe dementia, and photosensitivity developed. All patients showed complete trisomy 21. Mutations were ruled out on the APP, PSEN1, and PSEN2 genes, and APOE analysis revealed ε3/ε3 homozygosity. CSF biomarkers showed a decrease in Aβ42 and an increase in p-tau₁₈₁. The natural history of senile myoclonic epilepsy is consistent with progressive myoclonus epilepsy. Chromosome 21 is implicated in its pathophysiology; however, other genetic and/or environmental risk factors cannot be excluded. The absence of the APOE type 4 allele could predict its progression.     

Neuroaxonal dystrophy (Seitelberger's disease) with late onset, protracted course and myoclonic epilepsy.

We present the pathologic findings, including electron microscopy, in one of two affected borthers with severe progressive myoclonus epilepsy, beginning in our patient at the age of 10 and leading to death at age 23. At autopsy there was widespread and marked neuroaxonal dystrophy, severe cerebellar atrophy, and tract degenerations in the gracilis columns and the lateral corticospinal tracts in the spinal cord. There was no increased pigmentation in the globus pallidus or reticular zone of the substantia nigra, on gross or microscopic examination. We regard this case as an example of a juvenile form of neuroaxonal dystrophy (Seitelberger's disease). The absence of pallido-nigral hyperpigmentation distinguishes this disease from Hallervorden-Spatz disease, which we regard as a separate disease entity.     

Familial adult onset myoclonic epilepsy associated with migraine.

We report a new type of migraine associated epileptic syndrome in a family: adult onset myoclonic epilepsy with benign course and migraine. Affected members of the family had myoclonic and rare generalised tonic-clonic seizures. Most of the patients, but not all, had a history of migraine. Also, some cases of the family had only migraine. This family will be discussed because of two distinct features. Firstly, in this family a different type of epilepsy, adult onset myoclonic epilepsy was diagnosed that has not been classified in the ILAE 1989, classification(s), but was similar to that previously reported in Japanese families. Secondly, in most of the cases migraine was associated with the epilepsy.     

Early and late intracortical inhibition in juvenile myoclonic epilepsy

PURPOSE: We investigated 15 patients with juvenile myoclonic epilepsy (JME) by subjecting them to single and paired transcranial magnetic stimulation to test the hypothesis that motor cortical inhibition may be abnormal in this form of benign epilepsy. METHODS: Different conditioning paradigms of paired transcranial magnetic stimulation were used with interstimulus intervals (ISIs) of varying lengths (1 to 400 milliseconds) to investigate changes in balance between excitatory and inhibitory intracortical circuits. RESULTS: Motor evoked potential (MEP) inhibition at ISIs of 1 to 4 milliseconds was significantly lower in JME patients than in age-matched healthy controls (p < 0.001), whereas no significant differences in MEP inhibition were noted at long ISIs (100 to 150 milliseconds). This pattern was observed in both hemispheres in seven of seven patients studied bilaterally and was present in both treated and untreated patients. There were no group differences between JME patients and controls in intracortical facilitation, motor threshold, MEP amplitude, and cortical silent period. CONCLUSIONS: We documented a different pattern of MEP inhibition in JME patients, suggesting impaired functioning of inhibitory interneuronal circuits, which may account for the hyperexcitability of the motor system in this form of epilepsy.     

The clinical and neurobehavioral course of Down syndrome and dementia with or without new-onset epilepsy

BackgroundAdult patients with Down syndrome (DS) are at higher risk of developing Alzheimer-type dementia and epilepsy. The relationship between developing dementia and the risk of developing seizures in DS is poorly characterized to date. In addition, treatment response and medication tolerability have not been rigorously studied.MethodsWe identified 220 patients with a diagnosis of DS and dementia. Those without a history of developing seizures (DD) were compared to patients with new-onset seizures (DD + S) after the age of 35. Electronic records were reviewed for demographics, seizure characteristics, cognitive status, and psychiatric comorbidities.ResultsOf the patients included for analysis, twenty-six out of 60 patients had new-onset seizures or developed seizures during the follow-up period (the DD + S group) with a median onset of 2.0 years after the dementia diagnosis. Generalized tonic–clonic seizures were the most common seizure type (61.5% of DD + S). Sixteen (61.5%) patients were reported to have myoclonus. Levetiracetam was the most commonly used initial medication, with the majority (73%) of patients treated achieving partial or complete seizure control. The DD + S patients tended to have a similar burden of new-onset neuropsychiatric symptoms compared to the DD group.DiscussionNew-onset epilepsy seems to occur early in the course of dementia in DS patients. Patients generally respond to treatment. A great burden of neuropsychiatric symptoms is seen. Future studies need to explore the relationship between β-amyloid accumulation and epileptiform activity and attend to the care and needs of DS patients with dementia and seizures.     

Adult myoclonic epilepsy: a distinct syndrome of idiopathic generalized epilepsy

The authors present 11 cases of idiopathic generalized epilepsy that began in adulthood at a mean age of 39 years. All patients had myoclonic jerks, five had absence seizures, and nine had infrequent generalized tonic-clonic seizures. A majority had a family history of seizures. EEG in all patients showed generalized epileptiform abnormalities, whereas neuroimaging and neurologic examination results were normal. This series appears to represent a previously undescribed idiopathic generalized epilepsy syndrome of adult myoclonic epilepsy.     

Ten year cumulative incidence of dementia after late onset epilepsy of unknown etiology

Recent epidemiological studies suggest late life onset epilepsy of unknown etiology (LOEU) is a risk factor for future dementia. These studies rely on inclusion and exclusion of multiple diagnostic codes rather than structured data and neuroimaging findings, and thus challenging to interpret clinically. We assessed the cumulative incidence of dementia in patients with LOEU diagnosed through admission data and neuroimaging over a 10-year follow-up and compared baseline characteristics that distinguish group level incident dementia. We screened our hospital records for patients aged 55–69 with new epilepsy, admitted between 2000 and 2008, and excluded patients diagnosed with epilepsy from an underlying cause on medical records or neuroimaging. We used retrospective hospital data to follow patients for incident dementia or mortality at 10 years and compared baseline (demographics, depression or anxiety, vascular risk factors, results of electroencephalogram (EEG) studies, antidepressant use and type of ant seizure medication) and follow up (seizure recurrence, incident cerebrovascular disease) characteristics for patients with and without incident dementia.Fifty-four LOEU cases were screened, age at first seizure was 61 ± 5. The 10-year cumulative incidence of dementia was 22.20% (95% Confidence Interval 22.08–23.10%) and time to dementia diagnosis was 5.4 ± 3.9 years. Patients with incident dementia were more likely to be women (83% vs 38%, p = 0.002), have interictal epileptic form discharges (IED) on baseline EEG (70% vs 29%, p = 0.011) and depression or anxiety (50% vs 18%, p = 0.026). No differences were found in other baseline or follow up characteristics. Our results support recent findings of dementia incidence in LOEU. Prospective studies on LOEU should evaluate phenotypic determinants of individuals with late life epilepsy and the rate of progression to dementia.     

Late-onset Leigh syndrome with myoclonic epilepsy with ragged-red fibers

We report the case of a boy with myoclonic epilepsy with ragged-red fibers (MERRF) who had astatic seizures since 2 years of age and later developed ataxia, absence seizures, and myoclonus. Almost homoplasmic A8344G mutation of mitochondrial DNA (m.8344A>G mutation) was detected in lymphocytes. He developed late-onset Leigh syndrome (LS) when he contracted pneumonia at 6 years. He developed bulbar palsy and deep coma. MRI demonstrated lesions in the brainstem, basal ganglia, and cerebral cortex. Three similar cases have been reported; two carried the almost-homoplasmic m.8344A>G mutation in muscle tissue. These suggested that almost homoplastic m.8344A>G mutation developed clinical phenotype of MERRF in the early stage and late-onset Leigh syndrome in the late course of the disease.     

Progressive myoclonic epilepsies syndrome (Ramsay Hunt syndrome) with mental disorder: report of two cases

Ramsay Hunt syndrome (RHS) is a rare condition within the progressive myoclonic epilepsies syndrome (PME), with a triad of action myoclonus, grand mal seizure and severe cerebellar ataxia. There are few reports about the psychiatric disturbances associated with PME or RHS. The present study examines the evidence that RHS may accompany an organic mental syndrome, ethanol's effective suppression of myoclonus, and the possible resultant problem of alcohol dependence in RHS patients. Two brothers with the previous long-standing diagnosis of RHS and their mental symptoms of persecutory delusion and depression are reported, as well as the additional problem of alcohol dependence in one of them. The cerebellar dysfunction found in RHS may be associated with an underlying organic condition. Determination of the relationship between cerebellar dysfunction and psychosis in RHS will require further study. Although the mechanism of the suppression of myoclonus by alcohol remains unclear, patients should be allowed to drink socially, and alcohol consumption should not be totally prohibited. However, effective treatment of the problems of alcohol tolerance, abuse, or dependence requires the cooperation of both neurologists and psychiatrists.     

Reflex writing seizures in two siblings with juvenile myoclonic epilepsy

We report on two siblings who presented with juvenile myoclonic epilepsy, and in whom myoclonic jerks of the right arm and hand were also triggered by writing tasks. Both patients underwent intensive video-electroencephalography monitoring, with simultaneous neuropsychological tests. In both patients, reflex epileptic myoclonus was more easily triggered by writing that required a higher degree of concentration. Conversely, other cognitive tasks, such as reading, typing, thinking, or calculation never elicited any seizures or myoclonus. Valproate was effective in controlling both spontaneous and reflex epileptic seizures. The results of this study further support the notion that 'praxis-induced' reflex epilepsy precipitated by specific stimuli occurs in the context of idiopathic generalized epilepsy. Our results also illustrate that writing tasks are more effective in eliciting seizures when they require higher levels of concentration and mental elaboration.