Clinical characteristics of patients with refractory non-epileptic seizures

OBJECTIVES

This incidence of non-epileptic seizures (NES) is estimated at 1-35 per 100,000 population. While many patients achieve remission, a significant fraction of patients have a poor prognosis despite optimal interventions. This study reports on the characteristics of patients with refractory NES diagnosed and treated at a comprehensive epilepsy centre.

METHODS

A retrospective review of admissions to the Epilepsy Monitoring Unit identified patients diagnosed with NES over a 6-year period. Patients with refractory NES were identified through review of medical files. A diagnosis of refractory NES was assigned when patients experienced ongoing NES at least 1 year after diagnostic video-EEG monitoring. Data pertaining to predisposing, precipitating and perpetuating factors was collected on all patients and a comparative analysis was conducted between refractory and non-refractory cases.

RESULTS

66 patients with NES were identified, 35% were deemed refractory. There was no significant difference amongst predisposing factors between the groups. Psychosocial adversity and a clear precipitant proximate to the onset of NES were significantly more common in the refractory cohort. Unemployment at time of diagnosis was a significant perpetuating factor associated with poor outcome.

CONCLUSION

This study provides insight into the features associated with refractory NES and may serve to improve prognostication and management in this disabling condition.

Clinical outcomes among initial survivors of cryptogenic new-onset refractory status epilepsy (NORSE)

OBJECTIVE

New-onset refractory status epilepticus (NORSE) is a rare but severe clinical syndrome. Despite rigorous evaluation, the underlying cause is unknown in 30%-50% of patients and treatment strategies are largely empirical. The aim of this study was to describe clinical outcomes in a cohort of well-phenotyped, thoroughly investigated patients who survived the initial phase of cryptogenic NORSE managed in specialist centers.

METHODS

Well-characterized cases of cryptogenic NORSE were identified through the EPIGEN and Critical Care EEG Monitoring Research Consortia (CCEMRC) during the period 2005-2019. Treating epileptologists reported on post-NORSE survival rates and sequelae in patients after discharge from hospital. Among survivors >6 months post-discharge, we report the rates and severity of active epilepsy, global disability, vocational, and global cognitive and mental health outcomes. We attempt to identify determinants of outcome.

RESULTS

Among 48 patients who survived the acute phase of NORSE to the point of discharge from hospital, 9 had died at last follow-up, of whom 7 died within 6 months of discharge from the tertiary care center. The remaining 39 patients had high rates of active epilepsy as well as vocational, cognitive, and psychiatric comorbidities. The epilepsy was usually multifocal and typically drug resistant. Only a minority of patients had a good functional outcome. Therapeutic interventions were heterogenous during the acute phase of the illness. There was no clear relationship between the nature of treatment and clinical outcomes.

SIGNIFICANCE

Among survivors of cryptogenic NORSE, longer-term outcomes in most patients were life altering and often catastrophic. Treatment remains empirical and variable. There is a pressing need to understand the etiology of cryptogenic NORSE and to develop tailored treatment strategies.

Vagus nerve stimulation in refractory idiopathic generalised epilepsy: An Irish retrospective observational study

OBJECTIVE

Refractory idiopathic generalised epilepsy (IGE; also known as genetic generalised epilepsy) is a clinical challenge due to limited available therapeutic options. While vagus nerve stimulation (VNS) is approved as an adjunctive treatment for drug-resistant focal epilepsy, there is limited evidence supporting its efficacy for refractory IGE.

METHODS

We conducted a single-centre retrospective analysis of adult IGE patients treated with VNS between January 2003 and January 2022. We analysed the efficacy, safety, tolerability, stimulation parameters and potential clinical features of VNS response in this IGE cohort.

RESULTS

Twenty-three IGE patients were implanted with VNS between January 2003 and January 2022. Twenty-two patients (95.65%) were female. The median baseline seizure frequency was 30 per month (interquartile range [IQR]= 140), including generalised tonic-clonic seizures (GTCS), absences, myoclonus, and eyelid myoclonia with/without absences. The median number of baseline anti-seizure medications (ASM) was three (IQR= 2). Patients had previously failed a median of six ASM (IQR= 5). At the end of the study period, VNS therapy remained active in 17 patients (73.9%). amongst patients who continued VNS, thirteen (56.5% of the overall cohort) were considered responders (≥50% seizure frequency reduction). Amongst the clinical variables analysed, only psychiatric comorbidity correlated with poorer seizure outcomes, but was non-significant after applying the Bonferroni correction. Although 16 patients reported side-effects, none resulted in the discontinuation of VNS therapy.

SIGNIFICANCE

Over half of the patients with refractory IGE experienced a positive response to VNS therapy. VNS represents a viable treatment option for patients with refractory IGE, particularly for females, when other therapeutic options have been exhausted.

Everolimus precision therapy for the GATOR1-related epilepsies: A case series

BACKGROUND

Pathogenic variants in the GAP activity towards RAGs 1 (GATOR1) complex genes (DEPDC5, NPRL2, NPRL3) cause focal epilepsy through hyperactivation of the mechanistic target of rapamycin pathway. We report our experience using everolimus in patients with refractory GATOR1-related epilepsy.

METHODS

We performed an open-label observational study of everolimus for drug-resistant epilepsy caused by variants in DEPDC5, NPRL2 and NPRL3. Everolimus was titrated to a target serum concentration (5-15 ng/mL). The primary outcome measure was change in mean monthly seizure frequency compared with baseline.

RESULTS

Five patients were treated with everolimus. All had highly active (median baseline seizure frequency, 18/month) and refractory focal epilepsy (failed 5-16 prior anti-seizure medications). Four had DEPDC5 variants (three loss-of-function, one missense) and one had a NPRL3 splice-site variant. All patients with DEPDC5 loss-of-function variants had significantly reduced seizures (74.3%-86.1%), although one stopped everolimus after 12 months due to psychiatric symptoms. Everolimus was less effective in the patient with a DEPDC5 missense variant (43.9% seizure frequency reduction). The patient with NPRL3-related epilepsy had seizure worsening. The most common adverse event was stomatitis.

CONCLUSIONS

Our study provides the first human data on the potential benefit of everolimus precision therapy for epilepsy caused by DEPDC5 loss-of-function variants. Further studies are needed to support our findings.

Germline mosaicism in a family with MBD5 haploinsufficiency

Haploinsufficiency of the methyl-CpG-binding domain protein 5 (MBD5) gene causes a neurodevelopmental disorder that includes intellectual disability, developmental delay, speech impairment, seizures, sleep disturbances, and behavioral difficulties. Microdeletion of 2q23.1 is the most common cause of haploinsufficiency, although MBD5 haploinsufficiency may also cause this genetic disorder. We report a family harboring a heterozygous loss-of-function variant in MBD5 (NM_018328.5:c.728delC; p.Pro243Hisfs*26), which includes three affected siblings with varying phenotypic features. Both parents were phenotypically normal but deep coverage sequencing of the parents showed germline mosaicism in the mother.

Association between social deprivation and incidence of first seizures and epilepsy: a prospective population based cohort

OBJECTIVE

Epidemiologic studies have investigated whether social deprivation is associated with a higher incidence of epilepsy and results are conflicting, especially in children. The mechanisms underlying a potential association are unclear. This study examines whether there is an association between social deprivation and the incidence of first seizures (unprovoked and provoked) and new diagnosis of epilepsy by comparing incidence across an area-level measure of deprivation in a population-based cohort.

METHODS

Multiple methods of case identification followed by individual case validation and classification were carried out in a defined geographical area (population 542,868) to identify all incident cases of first provoked and first unprovoked seizures and new diagnosis of epilepsy presenting during the calendar year 2017. An area-level relative deprivation index, based on ten indicators from census data, was assigned to each patient according to registered address and categorised into quintiles from most to least deprived.

RESULTS

The annual incidence of first unprovoked seizures (n=372), first provoked seizures (n=189) and new diagnosis of epilepsy (n=336) was highest in the most deprived areas compared to the least deprived areas (incidence ratios of 1·79 (95%CI 1·26, 2·52), 1·55 (95%CI 1·04, 2·32) and 1·83 (95%CI 1·28, 2·62), respectively). This finding was evident in both adults and children and in those with structural and unknown aetiologies of epilepsy.

SIGNIFICANCE

The incidence of first seizures and new diagnosis of epilepsy is associated with more social deprivation. The reason for this higher incidence is likely multifactorial.

Extending the phenotype of posterior column ataxia with retinitis pigmentosa caused by variants in FLVCR1

Posterior column ataxia with retinitis pigmentosa (PCARP) is a rare autosomal recessive condition due to variants in the Feline Leukemia Virus Subgroup C Cellular Receptor 1 (FLVCR1) gene which was first described in 1997. In this article, we describe a young female patient with a childhood diagnosis of retinitis pigmentosa and learning disability, presenting with progressive ataxia from her late teens. Examination revealed spastic lower limbs with absent reflexes, and reduced vibration and joint position sensation. Magnetic resonance imaging showed normal cerebellar volume and linear signal abnormality within the posterior columns of her spinal cord. Trio exome analysis confirmed two variants in FLVCR1. Our case extends the phenotype of PCARP to include learning disability and developmental delay, and highlights the importance of considering this rare condition in young adults or children with visual impairment and ataxia.

Causes and classification of first unprovoked seizures and newly-diagnosed epilepsy in a defined geographical area- an all-comers analysis

PURPOSE

The ILAE recently updated the operational definition of epilepsy and the classifications of seizures and epilepsy incorporating aetiology into the classification framework. To date, these classifications have not been applied in any whole population incidence study.

METHODS

Multiple overlapping methods of case identification were applied to a defined geographical area (population 542,868 adults and children) to identify all first unprovoked seizures and new diagnosis of epilepsy presenting during the calendar year 2017. The 2017 ILAE classification frameworks were applied. Incidence was age-standardised to the 2013 Standard European Population.

RESULTS

The annual incidence per 100,000 population was 44 for focal epilepsy, 6.8 for generalized epilepsy and 10.9 for unclassified epilepsy (age standardized 56, 6.9 and 11.4, respectively). Focal epilepsy was diagnosed in all age groups, though incidence increased in those ≥55 years of age. Primary generalised epilepsy accounted for 10% (n = 32) of newly diagnosed epilepsy. The most frequently diagnosed aetiology was structural (54%, n = 182). In 30% (n = 102) of newly diagnosed epilepsy, aetiology was not established.

CONCLUSION

We report on the causes of incident first unprovoked seizures and epilepsy in accordance with recently updated ILAE definitions and classification systems employing standard diagnostic investigations. We report a higher proportion of structural aetiology than previous studies, which may reflect incorporation of imaging in aetiology classification. Despite improved access to diagnostic testing, aetiology of a large fraction of first seizures and newly diagnosed epilepsy remains unknown.

Unanticipated improvement in seizure control in drug-resistant epilepsy- real world observations

OBJECTIVES

To determine the clinical features and anti-seizure medication (ASM) strategies associated with an unanticipated substantial improvement in seizure control in patients with drug-resistant epilepsy (DRE).

METHODS

This retrospective analysis of patients attending a tertiary care epilepsy clinic between 2008 and 2017 identified all patients with active DRE (at least 1 seizure per month for 6 months, despite treatment with 2 different ASMs). All treatment interventions were recorded from when DRE was first identified to the end of the study. The primary end points were seizure freedom or meaningful reduction in seizure frequency (greater than 75 %) sustained for at least 12 months after a treatment intervention.

RESULTS

Three hundred and twenty-two patients were included in the analysis. Overall, 10 % became seizure free following ASM adjustment and an additional 10 % had a greater than 75 % improvement in seizure control (median follow-up, 4 years). An ASM introduction was ten times more likely than an ASM dose increase to improve seizure control. Combined focal and generalized epilepsy, intellectual disability and prior treatment with more than 5 ASMs were more frequently observed in those with continued pharmacoresistance. ASM responders were more likely to have primary generalized epilepsy. Rational polytherapy (combining ASMs with different mechanisms of action) was almost ubiquitous amongst ASMs responders (95 % taking at least 2 drugs with different mechanistic targets). Of the ASM additions that heralded improved seizure control, 85 % were maintained at submaximal doses.

CONCLUSIONS

This retrospective analysis of a large number of 'real-world' patients provides evidence to persist with ASM trials in DRE. Early rotation of ASMs if a clinical response is not observed at a substantial dose and rational ASM polytherapy may yield better clinical outcomes in patients with DRE, although a prospective study would need to be conducted to validate these findings.

Ataxia pancytopenia syndrome due to SAMD9L mutation presenting as demyelinating neuropathy

Ataxia pancytopenia (ATXPC) syndrome due to gain-of-function pathogenic variants in the SAMD9L gene has been described in 38 patients to date. It is characterized by variable neurological and hematological phenotypes including ataxia, pyramidal signs, cytopenias, and hematological malignancies. Peripheral neuropathy with slowing of conduction velocities has been reported in only two affected individuals. We describe a female with childhood onset neuropathy diagnosed as Charcot-Marie-Tooth disease type 1 with onset of cerebellar ataxia in her 50s. Cerebellar, pyramidal, and neuropathic features were found on examination. Additionally, she also had conjunctival telangiectasia. Nerve conduction studies confirmed a demyelinating neuropathy. MRI brain showed cerebellar atrophy with diffuse white matter hyperintensities. OCT demonstrated global thinning of the retinal nerve fiber layer (RNFL). Full blood count has always been normal. A previously described pathogenic variant in SAMD9L [c.2956C>T p.(Arg986Cys)] was identified on whole exome sequencing. This case extends the previously described phenotype to include conjunctival telangiectasia and RNFL thinning and suggests that ATXPC syndrome should be considered in the differential for inherited demyelinating neuropathies.

Incidence of first seizures, epilepsy, and seizure mimics in a geographically defined area

OBJECTIVE

To determine the incidence of first seizures, epilepsy, and seizure mimics in a geographically defined area using the updated 2014 International League Against Epilepsy (ILAE) definition, which allows an epilepsy diagnosis after a single seizure when the risk of further seizures over the next 10 years is ≈60% or greater. This replaced the 1993 definition by which epilepsy was diagnosed when a person had ≥2 seizures separated by 24 hours.

METHODS

Using multiple overlapping methods of case ascertainment followed by individual case classification by an epileptologist, we identified all first seizures, new diagnosis of epilepsy, and seizure mimics occurring in a defined geographic area (population 542,868) from January 1, 2017, to December 31, 2017. Incidence was age standardized to the Standard European Population. We compared incidence rates using the 2014 and 1993 ILAE definitions.

RESULTS

When the 2014 ILAE definition of epilepsy was applied, the incidence of new diagnosis of epilepsy was 62 per 100,000 (age standardized 74) compared to 41 per 100,000 (age standardized 48) when the 1993 definition was applied, and the difference was more pronounced at older ages. The incidence of all first seizures and of seizure mimics was 102 per 100,000 (age standardized 123) and 94 per 100,000 (age standardized 111), respectively. The most frequently encountered seizure mimic was syncope.

CONCLUSION

Application of the 2014 ILAE definition of epilepsy resulted in a higher incidence of new diagnosis of epilepsy compared to the 1993 definition. The incidence of seizure mimics almost equals that of all first seizures. Seizures, epilepsy, and seizure mimics represent a significant burden to health care systems.

Diagnostic Yield of Routine EEG in Adults with Active Epilepsy

Routine electroencephalogram (rEEG) is an important investigation in suspected seizures but can be normal in people with epilepsy. The diagnostic yield of rEEG varies considerably according to the patient group studied. We aimed to estimate the diagnostic yield of rEEG in a real-world cohort of adults with active epilepsy—a population not previously reported. This single centre study evaluated neurophysiology findings for adults with prolonged inpatient video EEG (vEEG)-confirmed active epilepsy, who had at least one prior rEEG. Sixty-eight patients had a total of 171 rEEGs, of which 93 (54.4%) were normal, 42 (24.6%) found non-specific abnormalities and 36 (21.1%) captured interictal epileptiform abnormalities (IIEAs). Serial rEEGs revealed a 22.1% yield of IIEAs on the first test, with the cumulative yield peaking at 33.8% on the fourth rEEG. This study adds to existing evidence regarding the limited diagnostic usefulness of serial rEEG in patients with active epilepsy.

Investment in epilepsy monitoring units improves epilepsy care-experience in a regional neuroscience centre

An evaluation of the clinical yield of inpatient long-term video-EEG (vEEG) in a new epilepsy monitoring unit (EMU) was undertaken, with findings compared to the centre's prior method of bedside vEEG recording in a standard neurology ward, as reported in 2004. A retrospective analysis of neurophysiology reports for all adults who underwent elective vEEG monitoring in the EMU at Cork University Hospital between January 2015 and July 2016 was conducted. Of 115 vEEG studies in the EMU, 100 (87.0%) were deemed diagnostically conclusive, 14 (12.2%) failed to catch any clinical events and showed normal EEG throughout, and one (0.9%) captured spells of unclear clinical significance - the corresponding figures reported in 2004 for bedside vEEGs were 21.3%, 77% and 1.6%, respectively. The EMU offers a more effective method of recording inpatient vEEG, which aids decision-making and improves clinical outcomes. Some evidence-based measures which could further enhance diagnostic yield are discussed.

Economic analysis of an epilepsy outreach model of care in a university hospital setting

The prevalence of epilepsy in people with intellectual disability is higher than in the general population and prevalence rates increase with increasing levels of disability. Prevalence rates of epilepsy are highest among those living in residential care. The healthcare needs of people with intellectual disability and epilepsy are complex and deserve special consideration in terms of healthcare provision and access to specialist epilepsy clinics, which are usually held in acute hospital campuses. This patient population is at risk of suboptimal care because of significant difficulties accessing specialist epilepsy care which is typically delivered in the environs of acute hospitals. In 2014, the epilepsy service at Cork University Hospital established an Epilepsy Outreach Service providing regular, ambulatory outpatient follow up at residential care facilities in Cork city and county in an effort to improve access to care, reduce the burden and expense of patient and carer travel to hospital outpatient appointments, and to provide a dedicated specialist phone service for epilepsy related queries in order to reduce emergency room visits when possible. We present the findings of an economic analysis of the outreach service model of care compared to the traditional hospital outpatient service and demonstrate significant cost savings and improved access to care with this model. Ideally these cost savings should be used to develop novel ways to enhance epilepsy care for persons with disability. We propose that this model of care can be more suitable for persons with disability living in residential care who are at risk of losing access to specialist epilepsy care.

Can syncope cause convulsive seizures in adults?

PURPOSE

Convulsive epileptic seizures triggered by transient cerebral hypoperfusion 'reflex anoxic seizures' are well-described in children but are not commonly recognized in adults.

METHODS

We report a case series of 12 adults who presented acutely after generalized tonic-clonic seizures with a clear syncopal phase before the convulsion. We describe the aetiology, semiology and natural history of these events.

RESULTS

Four patients (33.3%) had relevant risk factors for development of seizures/active epilepsy. Five patients (41.7%) had recurrent events prior to initial review by an epileptologist, but when anti-syncope measures were instituted there were no seizure recurrences over a median follow-up period of 34.5 (interquartile range 29.3-41.8) months.

CONCLUSIONS

Syncope may be an under-recognized trigger for convulsive acute symptomatic seizures. Avoidance of syncope may be more effective than anti-seizure medications in preventing reflex anoxic seizures.

Long-term lacosamide retention-Real-world experience at a tertiary epilepsy center in Ireland

PURPOSE

To estimate the rate of long-term lacosamide retention among a real-world group of patients at a tertiary epilepsy center in Ireland.

METHODS

One-hundred adults first prescribed lacosamide for epilepsy between January 2010 and August 2014 at Cork University Hospital were randomly selected for a retrospective analysis of medical records covering two years of subsequent epilepsy clinic follow-up to ascertain whether lacosamide was continued or withdrawn.

RESULTS

Of 100 patients, (51 males, mean age 40.8years, 94 with drug-resistant epilepsy, 76 with focal epilepsy, 25 with intellectual disabilities, 34 with mental health disorders, and 42 with medical comorbidities), lacosamide was prescribed as an adjunct in 85. Lacosamide retention at 12 and 24months was 76% and 71%, respectively. Twenty-five patients stopped lacosamide due to ineffective seizure control. Adverse-effects were responsible for lacosamide discontinuation in three patients and one patient stopped lacosamide pre-pregnancy.

CONCLUSION

The relatively high retention rate at two years suggests that lacosamide is generally well tolerated among people with a range of different epilepsy subtypes, intellectual disabilities, medical comorbidities, and mental health disorders, and can aid seizure control in adult patients with a range of difficult-to-treat epilepsies.

Sexual dimorphism in clinical neurology--predictors of successful lumbar puncture in an "expanding" population

OBJECTIVE

To determine the proportion of patients who would have an unsuccessful lumbar puncture (LP) due to commonly used LP needles being too short.

METHODS

Three hundred consecutive adults (age 16-99, mean age 56) who underwent abdominal CT over a 6-month period were identified. The distance from the skin to the midpoint of the spinal canal was measured in the axial plane, at the level of the iliac crest. This was compared to the length of commonly used spinal needles (88 mm) to assess the number of patients who would have an unsuccessful LP due to this distance being greater than 88 mm from the skin.

RESULTS

In 72/300 (24%) patients, the midpoint of the spinal canal was greater than 88 mm from the skin. A total of 54/72 (75%) of those patients were female. Of the female participants, 54/159 (34%) had the midpoint of their spinal canal at a distance of greater than 88 mm from the skin. In the male patients, only 18/141 (13%) had a similar finding.

CONCLUSION

This is the first high-quality study to demonstrate that 24% of the population will have an unsuccessful LP procedure if commonly available spinal needles. We demonstrated that 34% of female patients would have an unsuccessful procedure while, in contrast, a successful LP should be possible in 87% of male patients.

Oxidative injury in epilepsy: potential for antioxidant therapy?

Biological ill effects of oxidative injury from excess free radical production are implicated in many human conditions. Epilepsy is a chronic, dynamic neurological disorder associated with ongoing neuronal damage, particularly when uncontrolled. Oxidative injury may play a role in the initiation and progression of epilepsy, and therapies aimed at reducing oxidative stress may ameliorate tissue damage and favorably alter the clinical course. There is abundant in vivo evidence of oxidative injury in animal models of epilepsy and for efficacy of antioxidant therapy in reducing this injury in animal models of epileptogenesis. However, there is sparse direct clinical data on the use of antioxidants in human epilepsy. This review examines the evidence for the role of oxidative injury in epilepsy, the rationale for use of antioxidant therapy in epilepsy and appraises the current clinical performance of the studies of antioxidant therapies.

Transplantation of novel human GDF5-expressing CHO cells is neuroprotective in models of Parkinson's disease

Growth/differentiation factor 5 (GDF5) is a neurotrophic factor that promotes the survival of midbrain dopaminergic neurons in vitro and in vivo and as such is potentially useful in the treatment of Parkinson's disease (PD). This study shows that a continuous supply of GDF5, produced by transplanted GDF5-overexpressing CHO cells in vivo, has neuroprotective and neurorestorative effects on midbrain dopaminergic neurons following 6-hydroxydopamine (6-OHDA)-induced lesions of the adult rat nigrostriatal pathway. It also increases the survival and improves the function of transplanted embryonic dopaminergic neurons in the 6-OHDA-lesioned rat model of PD. This study provides the first proof-of-principle that sustained delivery of GDF5 in vivo may be useful in the treatment of PD.

Mutation of SCARB2 in a patient with progressive myoclonus epilepsy and demyelinating peripheral neuropathy

OBJECTIVE

To report the detection of mutations in the SCARB2 gene in a previously described patient with progressive myoclonus epilepsy (PME) and demyelinating peripheral neuropathy.

DESIGN

Case report.

SETTING

Epilepsy Genetics Research Laboratory and Epilepsy Service in a tertiary care center.

PATIENT

A 27-year old male patient with PME with preserved intellect and peripheral neuropathy.

RESULTS

We have solved a previously reported case of PME, preserved intellect, and demyelinating peripheral neuropathy. The patient is a compound heterozygote for 2 mutations in the SCARB2 gene, which has recently been found to be a cause of PME.

CONCLUSIONS

Demyelinating neuropathy is a clinical clue to the presence of SCARB2 mutations in PME.

Prognostic implications of periodic epileptiform discharges

BACKGROUND

Periodic epileptiform discharges (PEDs) are an abnormal finding on electroencephalograms (EEGs), the significance of which is uncertain.

OBJECTIVE

To investigate long-term outcome in patients with PEDs.

DESIGN

We retrospectively analyzed the outcomes of patients who had PEDs diagnosed during a 7-year period. We abstracted and tabulated clinical parameters from the time of EEG, imaging findings, EEG measurements, and subsequent clinical outcome from medical records. We used descriptive, inferential, and logistic regression analysis to determine the factors associated with clinical outcomes in patients with PEDs. We divided PEDs into the following subgroups: periodic lateralized epileptiform discharges (PLEDs), generalized PEDs, and bilateral PEDs and analyzed these subgroups individually.

SETTING

University-affiliated teaching hospital. Subjects One hundred sixty-two patients with PEDs.

RESULTS

We obtained complete clinical, neuroimaging, neurophysiologic, and long-term outcome data in 118 patients. In the subgroup of patients with PLEDs, absence of seizures at onset (odds ratio, 0.21 per point; 95% confidence interval, 0.04-0.97) and an acute etiology for the PLEDs (odds ratio, 0.14 per point; 95% confidence interval, 0.03-0.72) were associated with death. A nonneoplastic cause for PLEDs was associated with independent functionality (odds ratio, 0.45 per point; 95% confidence interval, 0.3-0.67).

CONCLUSION

In patients with PLEDs, the absence of clinical seizures at the time of detection and presumed acute etiology are associated with death, whereas a nonneoplastic etiology was associated with a good clinical outcome.

How seizure detection by continuous electroencephalographic monitoring affects the prescribing of antiepileptic medications

OBJECTIVES

To assess the effect of continuous electroencephalographic monitoring on the decision to treat seizures in the inpatient setting, particularly in the intensive care unit.

DESIGN

Retrospective cohort study.

SETTING

Medical and neuroscience intensive care units and neurological wards.

PATIENTS

Three hundred consecutive nonelective continuous electroencephalographic monitoring studies, performed on 287 individual inpatients over a 27-month period.

MAIN OUTCOME MEASURES

Epileptiform electroencephalographic abnormalities and changes in antiepileptic drug (AED) therapy based on the electroencephalographic findings.

RESULTS

The findings from the continuous electroencephalographic monitoring led to a change in AED prescribing in 52% of all studies with initiation of an AED therapy in 14%, modification of AED therapy in 33%, and discontinuation of AED therapy in 5% of all studies. Specifically, the detection of electrographic seizures led to a change in AED therapy in 28% of all studies.

CONCLUSIONS

The findings of continuous electroencephalographic monitoring resulted in a change in AED prescribing during or after half of the studies performed. Most AED changes were made as a result of the detection of electrographic seizures.

Progressive myoclonus epilepsy with demyelinating peripheral neuropathy and preserved intellect: a novel syndrome

BACKGROUND

The progressive myoclonic epilepsies (PMEs) are a disparate group of syndromes whose common features include disabling myoclonus, progressive cognitive decline, and seizures, typically with a relentless deterioration over time.

OBJECTIVE

To report a novel PME syndrome.

DESIGN

Case report.

SETTING

Epilepsy service in a tertiary care urban medical center.

PATIENT

A 24-year-old man with progressive myoclonus, seizures, and unique features of preserved intellect and demyelinating peripheral neuropathy.

MAIN OUTCOME MEASURE

Detailed clinical assessment, electrophysiologic studies, and survey of the literature.

RESULTS

We characterize an unusual PME phenotype with unique features of preserved intellect and electrophysiologic evidence of a generalized demyelinating peripheral neuropathic condition. An extensive diagnostic evaluation did not reveal an underlying cause, and a literature survey did not identify other, similar clinical reports.

CONCLUSION

We describe a novel PME syndrome with preserved intellect and demyelinating peripheral neuropathy.

Infantile spasms in tuberous sclerosis complex: prognostic utility of EEG

PURPOSE

To assess cognitive and epilepsy outcomes in tuberous sclerosis complex (TSC) patients with a history of infantile spasms (IS), in relation to spasm history, electroencephalography (EEG) characteristics, genetic mutation, and treatment history.

METHODS

The authors conducted a retrospective review of 45 children and adults with TSC and a history of IS. EEG reports from the time of spasms were evaluated for all patients, and EEG tracings were accessible and evaluated for 20 patients.

RESULTS

Clinical outcome was unfavorable for the majority of patients. However, 33% had experienced at least one year of seizure freedom at follow-up, and 24% of those tested had IQs above 70. Hypsarrhythmia severity scores varied widely, with some EEGs severely hypsarrhythmic and others essentially normal. Lower IQ was significantly associated with higher hypsarrhythmia severity scores on EEG report, the presence of background disorganization on EEG report, the absence of normal sleep patterns on EEG, and a lower degree of treatment success on vigabatrin. A relationship between poor cognitive outcome and poor epilepsy outcome was confirmed. The correlation between poor epilepsy outcome and a greater degree of background disorganization on EEG approached significance, as did the association between subsequent intractable epilepsy and an older age at IS cessation. A greater than expected ratio of TSC2 to TSC1 patients was observed across this IS population.

DISCUSSION

Early detection and successful treatment portend a more favorable outcome in TSC patients with IS. Although EEG findings in these patients vary, specific characteristics may serve as clinically useful prognostic markers.

Treatment of acute seizures and status epilepticus

Overt status epilepticus and persistent obtundation after a witnessed clinical seizure are neurologic emergencies. Early recognition and intervention in the electroclinical syndrome of status epilepticus reduces morbidity, although treatment of the underlying etiology is also critical. This review outlines key concepts related to status epilepticus, delineates an approach to the early management of status epilepticus, and highlights novel but practical approaches in the evaluation and treatment of refractory status epilepticus, emphasizing the use of a treatment algorithm. This review is written from the perspective of the intensive care unit clinician, and the approach and opinions expressed stem from clinical experience and review of the current literature. Particular attention is given to an overall approach to the management of convulsive status epilepticus in adults and older children as well as exploring novel approaches and diagnostic tools that may prove useful in difficult-to-control status epilepticus.

Stereotactic cortical resection in non-lesional extra-temporal partial epilepsy

The presentation and treatment of a patient with extra-temporal non-lesional partial epilepsy is discussed herein. His clinical semiology was consistent with supplementary motor area seizures; however, MR imaging did not demonstrate a lesion. A region of stable cortical glucose hypermetabolism in the left frontal region was noted with 2-fluoro-2-deoxy-D-glucose (FDG)-PET. This was consistent with the frequent interictal discharges evident over the left fronto-temporal region and the stereotypic high amplitude ictal discharges arising with highest amplitude from the left frontal region. Epileptiform activity evident on an intracranial 64-point subdural recording grid placed over the left dorsolateral frontal cortex confirmed a distribution concordant with FDG-PET findings. The subsequent resection was guided by the PET and EEG findings rather than structural MR imaging, and a limited cortical resection led to an immediate and substantial reduction in seizure frequency.

Efficacy of Surgical Treatment of De Novo, Adult-Onset, Cryptogenic, Refractory Focal Status Epilepticus

BACKGROUND

There have been few published reports of successful surgical treatment of focal status epilepticus. Surgical intervention is considered a last resort after medical strategies have been exhausted.

OBJECTIVE

To report a case of an adult who was initially seen with de novo, medically refractory, cryptogenic focal status epilepticus and underwent resection of an electrographically defined portion of the left middle frontal gyrus with multiple subpial transections of the adjacent cortex resulting in termination of the electroclinical seizure activity.

DESIGN

Report of a case of successful surgical treatment of cryptogenic focal status epilepticus.

INTERVENTION

After an initial 35 days of oral antiepileptic drug therapy and subsequent 16 days of continuous electroencephalography-guided intravenous antiepileptic drug therapy in an intensive care unit setting, and after extensive preoperative and intraoperative characterization of the epileptogenic zone, a tailored resection of the left middle frontal gyrus with multiple subpial transections of the surrounding cortex was performed.

RESULTS

The restricted surgical resection and multiple subpial transections terminated the seizure activity. Neuropathological examination of the resected tissue revealed moderate inflammatory changes and a few abnormally located neurons without any definitive evidence of dysplasia, which was suspected preoperatively.

CONCLUSIONS

We suggest that focal cortical resection may be an appropriate intervention in medically refractory focal status epilepticus even when an overt structural etiology is not evident preoperatively and should be considered as an option at the onset of intractability.

Audit of an inpatient neurology consultation service in a tertiary referral centre: value of the consulting neurologist

The Mater Misericordiae Hospital is a 575-bed tertiary referral centre with busy medical and surgical subspecialty services (including the national cardiac, cardiothoracic, spinal cord injury and pulmonary hypertension units). An audit of in-patient referrals to a neurology service was carried out over the twelve-month period of January to December 2002 inclusively. Five hundred and seventy seven inpatients were evaluated and managed in conjunction with the referring services. Consultation by the neurological service led to a significant contribution in the management of clinical cases in one of three ways: establishing a de novo diagnosis in patients admitted with active neurological symptoms where no working diagnosis exists (40.7% of referrals), significant alteration in diagnosis where the referring service have already established a specific working diagnosis (11.1% of referrals), or offering advice in the ongoing management of active neurological symptoms when the diagnosis is historically established and secure (48.2% of referrals). In order of frequency the most common reason for referral was stroke (131 cases (22.7%)), seizures unrelated to alcohol (59 cases (10.2%)), alcohol-related neurological problems (55 cases (9.5%)), movement disorders (41 cases (7.1%)), neuromuscular (40 cases (6.9%)), coma (35 cases (6%)), disorders of cognition (31 cases (5.3%)), acute headache (28 case (4.8%)) and functional neurological syndromes (26 cases (4.5%)). This audit highlights the value of a consulting neurology service in a multidisciplinary tertiary referral setting.

Concurrent hereditary haemochromatosis and idiopathic Parkinson's disease: a case report series

Hereditary haemochromatosis (HH) is a genetic disorder in which abnormal iron handling leads to excessive iron accumulation in systemic tissues. Magnetic resonance imaging studies suggest excess iron deposition in the basal ganglia of patients with HH. The symptoms of neurological complications of HH include cognitive decline, gait difficulties, cerebellar ataxia, and extrapyramidal dysfunction, but idiopathic Parkinson's disease, in which brain iron deposition is normal, has not been reported. We describe four patients with concurrent HH and IPD. Although three of the cases had risk factors for cerebrovascular and cardiovascular disease, computed tomography did not show ischaemic changes in the basal ganglia. We speculate that in these cases, abnormal deposition of iron in the basal ganglia induced the symptoms of IPD.

Neuroprotective effects of delayed administration of growth/differentiation factor-5 in the partial lesion model of Parkinson's disease

Neurotrophic factors have the potential for therapeutic use in Parkinson's disease (PD) to support the remaining dopaminergic neurons and protect them against the ongoing disease process. We have examined the effects of the neurotrophin growth and differentiation factor-5 (GDF-5) in a rat model of Parkinson's disease, the intrastriatal 6-hydroxydopamine (6-OHDA) lesion. GDF-5 (25 microg) was injected into either the striatum or substantia nigra (SN) of adult rats at 1 or 2 weeks after 6-hydroxydopamine administration. The behavioral effects of GDF-5 treatment were examined in vivo by amphetamine-induced rotational testing. Injection of GDF-5 into the nigra at either 1 or 2 weeks, or into the striatum at 1 week, after the lesion induced significant decreases in rotations. Post-mortem immunocytochemistry after 6 weeks showed that GDF-5 administration into either site protected dopaminergic cell bodies of the nigra when injected at 1 but not 2 weeks after 6-hydroxydopamine. However, no significant protection of striatal dopaminergic fiber density was observed after GDF-5 treatment. This study shows that the delayed administration of a single dose of GDF-5 has significant protective effects on the damaged adult rat nigrostriatal pathway, reinforcing its therapeutic potential for Parkinson's disease.

Fatal presentation of ornithine transcarbamylase deficiency in a 62-year-old man and family studies

Ornithine transcarbamylase deficiency (OTCD) resulting from deficiency of the mitochondrial enzyme OTC shows extensive phenotypic heterogeneity influenced by allelic heterogeneity and modifying environmental influences such as protein intake. We report the fatal late-onset presentation of OTCD in a 62-year-old man with the V337L mutation, a previous presentation in his grandson and negative clinical and biochemical screening of the proband's three daughters.

Effect of blood pH and ischemia on kinetic constants for cerebral glucose transport

In 117 experiments, the isolated canine brain was subjected either to 4-min pulses with blood ranging from pH 6.8 to 7.8, 30 min of hypoxia (PaO2 30 mmHg or 40 mmHg), or 30 min of complete ischemia followed by 60 min of perfusion with normal oxygenated blood. Unidirectional and net glucose fluxes were measured under all experimental conditions, and kinetic constants were calculated for unidirectional transport at each pH and after ischemia. In brains perfused with blood having a PaO2 of 30 or 40 mmHg, we observed a 58 and a 55% increase, respectively, in the net flux; however, there was no significant change in the unidirectional flux either during hypoxia or during the recovery period. Exposure of the brains to blood with a pH of 6.8, 7.0, and 7.2 had no effect on the unidirectional flux; however, as pH was raised above 7.4 both the Km and Vmax increased, reaching a maximum of 12.06 +/- 2.34 mM and 2.38 +/- 0.28 mumol X g-1 X min-1, respectively, at pH 7.8. The V/K ratio was unchanged. After 30 min of ischemia, there was a significant change (P less than 0.05) in the Km of the unidirectional glucose transport process from a control value of 5.84 +/- 1.75 mM to 17.40 +/- 5.50. These studies suggest that unidirectional flux is impaired after ischemia due to a decrease in the carrier's affinity for glucose; however, the observed changes are apparently unrelated to a fall in tissue pH. A similar mechanism is believed to be responsible for the decrease in unidirectional glucose flux after hypoxia.

Increased blood oxygen affinity decreases canine brain oxygen consumption

We have studied the effect of increased blood O2 affinity on O2 delivery to the isolated canine brain. After surgical isolation, the brain, enclosed in the calvarium, was perfused alternately from two pump-oxygenators with normal blood (P 50 [7.4] = 30 +/- 2 torr [S.D.]) and with blood whose P50 was reduced to 18 +/- 2 torr by carbamylation. [Hb], acid-base balance, blood gases, and flow rate were carefully matched in the two circuits. Although blood [Hb] was reduced to approximately 10 gm/dl, other perfusion variables such as CBF (65 +/- 6 ml/min/100 gm) and arterial blood oxygen saturation (96% to 99%) were normal for the dog. Under these conditions cerebral VO2 (Fick) averaged 3.87 +/- 0.73 ml/min/100 mg (S.D.) with control blood and 2.94 +/- 0.69 with low P50 blood (mean delta = 24%, n = 14, p less than 0.001), and PVO2 averaged 31 +/- 2 and 21 +/- 2 torr, respectively (p less than 0.001). The fall in VO2 during low P50 perfusion was associated with a decrease in [A-V]O2 difference and a rise in CVO2 of 1.2 ml/dl, which suggests that O2 extraction at PVO2 approximately 20 torr is curtailed. The EEG, previously shown to correlate with VO2 in this model, invariably deteriorated after 30 to 60 sec of low P50 perfusion and improved in 30 to 60 sec after reperfusion with normal blood. CBV increased by 0.9 ml/100 gm during low P50 perfusion, implying capillary recruitment. In a parallel series of experiments, four brains were alternately perfused with normal blood (pH 7.41, PCO2 38 torr, P50 [7.4] = 30 torr) and alkalotic blood (pH 7.98, PCO2 39 torr, P50 [7.98] = 17.3 torr). With flow rates equal for both normal and experimental blood, PVO2 averaged 31 +/- 4 (S.D.) and 21 +/- 3 torr (p less than 0.001), respectively, and VO2 averaged 4.33 +/- 0.52 ml/min/100 gm and 3.18 +/- 0.52 (p less than 0.001). With pH at 7.4 and 7.8, VO2 averaged 4.42 +/- 0.77 ml/min/100 gm and 3.66 +/- 0.99, respectively (p less than 0.01). The data indicate that a reduced P50 limits O2 diffusion to brain at a normal but fixed blood flow rate despite capillary recruitment.

Brain metabolism after 30 minutes of hypoxic or anoxic perfusion or ischemia

In 48 separate experiments, isolated canine brain preparations were subjected to 30 min of either hypoxic (PaO2 congruent to 20 mmHg) perfusion, anoxic (PaO2 < 10 mmHg) perfusion, or total ischemia followed by reperfusion for up to 2 h with normal oxygenated blood. Unlike ischemia and anoxia, energy metabolism was sufficient during hypoxia to maintain substantial levels of ATP (48% of normal), sustain normal ion gradients, and prevent edema formation. Posthypoxia metabolism was adequate to clear accumulated lactate, enable recovery of normal tissue glucose levels, and allow return to normal levels of glycolytic intermediates. Although not as complete as that following hypoxia, recovery from cerebral edema and restoration of metabolism were better in ischemic than anoxic cortex. The reduced oxygen uptake in all groups during reoxygenation (55% of normal) indicates that all have a diminished capacity for energy metabolism. The ATP levels recovered more rapidly after 15 min of reoxygenation in the anoxic (57% of normal) than in the ischemic (21% of normal) group. Thus ATP does not appear to be directly related to recovery from edema.

Naloxone antagonizes narcotic self blockade of emesis in the cat

Morphine, levorphanol, fentanyl and methadone given by intracerebroventricular (i.c.v.) injection blocked the vomiting response to a standard emetic test dose of apomorphine subsequently injected i.c.v. Of these narcotics, only morphine initially evoked vomiting. Systemic pretreatment with naloxone (5 mg/kg i.p. or i.v.) uniformly abolished the antiemetic activity of all the represented narcotic agents, moreover, naloxone thus administered was followed consistently by emetic responses to those narcotics which separately failed to evoke vomiting. When naloxone was injected i.c.v. in addition to being given systemically, both antiemetic and emetic activities of the narcotic agents were essentially abolished, whereas apomorphine continued to evoke vomiting. In the presence of systemic naloxone, given to counteract self-blockade of vomiting, the narcotics were shown to induce vomiting through excitation of the medullary emetic chemoreceptor trigger zone and emetic receptor tolerance as well as cross-tolerance developed acutely. The present differentiation by naloxone of the emetic and antiemetic properties of narcotic agents placed in the cerebrospinal fluid indicates that the opposing narcotic actions are exercised at different sites in the brain and that the narcotic receptor specificity of the chemoreceptor trigger zone does not encompass the emetic action of apomorphine.