European perspective of perampanel response in people with Intellectual Disability

BACKGROUND

Epilepsy prevalence is over 20% for those with ID. It is difficult to diagnose and treat and more likely to be treatment resistant. The evidence informing prescribing is sparse, particularly for new drugs such as perampanel (PMP).

AIMS OF THE STUDY

This study seeks to strengthen the research evidence regarding PMP for people with ID by pooling information from two isolated and separately conducted studies: the UK-based Epilepsy Database Register (Ep-ID) and the data from the Kempenhaeghe clinic in the Netherlands.

METHODS

A single data set of comparable data was created and analysed under agreement and supervision of a UK statistician.

RESULTS

Seizure reduction within twelve months was evident in 62% of Dutch and 47% of UK patients. Retention rates were higher for those in the UK (P = .01) and for patients with moderate to profound ID, whilst side effects were more prominent in the Dutch cohort.

CONCLUSIONS

Comparable rates of seizure reduction are in line with estimates for non-ID patients, adding to the evidence suggesting that PMP has a similar impact on those with ID. Taking a European perspective and sharing data across centres can help strengthen the evidence for prescribing antiepileptic drugs in the ID population.

Breath analysis in detecting epilepsy

The aim of this proof of concept study is to investigate if an electronic nose (eNose) is able to make a distinction between breath profiles of diagnosed epilepsy patients and epilepsy-free control subjects. An eNose is a non-invasive device, with a working mechanism that is based on the presence of volatile organic compounds (VOCs) in exhaled breath. These VOCs interact with the sensors of the eNose, and the eNose has to be trained to distinguish between breath patterns from patients with a specific disease and control subjects without that disease. During the measurement participants were asked to breathe through the eNose for five minutes via a disposable mouthpiece. Seventy-four epilepsy patients and 110 control subjects were measured to train the eNose and create a classification model. To assess the effects of anti-epileptic drugs (AEDs) usage on the classification, additional test groups were measured: seven patients who (temporarily) did not use AEDs and 11 patients without epilepsy who used AEDs. The results show that an eNose is able to make a distinction between epilepsy and control subjects with a sensitivity of 76%, a specificity of 67%, and an accuracy of 71%. The results of the two additional groups of subjects show that the created model classifies one out of seven epilepsy patients without AEDs and six out of 13 patients without epilepsy but with AEDs correctly. In this proof of concept study, the Aeonose^TM is able to differentiate between epilepsy patients and control subjects. However, the number of false positives and false negatives is still high, which suggests that this first model is still mainly based on the usage of various AEDs.

Classification of intellectual disability according to domains of adaptive functioning and between-domains discrepancy in adults with epilepsy

BACKGROUND

In the Diagnostic and Statistical Manual of Mental Disorders-Fifth edition (DSM-5), the diagnostic criteria of intellectual disability (ID) include three domains of adaptive deficits: the conceptual, social and practical. Substantial intra-individual differences between domains can be considered an ID domain discrepancy.

METHOD

We explored the associations between ID domains, discrepancies and epilepsy in 189 adults (mean age = 47.9; SD = 15.6). Each DSM-5 ID domain was assessed separately, using subscales of the Vineland II for the social and practical domains, and psychological instruments, including intelligence tests, for the conceptual domain. A set of standardised criteria is proposed to identify an ID domain discrepancy.

RESULTS

An ID domain discrepancy seemed to be present in about one-third of subjects and was particularly present in subjects with moderate ID (53.4%). Impairment in the social domain was most often the reason for the discrepancy. The presence of a discrepancy was significantly related to a focal (localised) epilepsy type (OR = 2.3, P = .028) and a mixed seizure type (OR = 1.4, P = .009). Epilepsy characteristics that are indicative of a more severe and refractory epilepsy, including various seizure types, a high seizure frequency, a combined epilepsy type (both focal and generalised epilepsy) and an early age at onset, were significantly related to more severe impairments in conceptual, social and practical adaptive behaviour (all P values <.01).

CONCLUSIONS

With a substantial proportion of the subjects who had both ID and epilepsy with an ID discrepancy, professionals should be aware of this and take all domains of ID into account when studying or working with this vulnerable population.

De Novo Pathogenic Variants in CACNA1E Cause Developmental and Epileptic Encephalopathy with Contractures, Macrocephaly, and Dyskinesias

Developmental and epileptic encephalopathies (DEEs) are severe neurodevelopmental disorders often beginning in infancy or early childhood that are characterized by intractable seizures, abundant epileptiform activity on EEG, and developmental impairment or regression. CACNA1E is highly expressed in the central nervous system and encodes the α₁-subunit of the voltage-gated Ca_V2.3 channel, which conducts high voltage-activated R-type calcium currents that initiate synaptic transmission. Using next-generation sequencing techniques, we identified de novo CACNA1E variants in 30 individuals with DEE, characterized by refractory infantile-onset seizures, severe hypotonia, and profound developmental impairment, often with congenital contractures, macrocephaly, hyperkinetic movement disorders, and early death. Most of the 14, partially recurring, variants cluster within the cytoplasmic ends of all four S6 segments, which form the presumed Ca_V2.3 channel activation gate. Functional analysis of several S6 variants revealed consistent gain-of-function effects comprising facilitated voltage-dependent activation and slowed inactivation. Another variant located in the domain II S4-S5 linker results in facilitated activation and increased current density. Five participants achieved seizure freedom on the anti-epileptic drug topiramate, which blocks R-type calcium channels. We establish pathogenic variants in CACNA1E as a cause of DEEs and suggest facilitated R-type calcium currents as a disease mechanism for human epilepsy and developmental disorders.

Challenging behavior in adults with epilepsy and intellectual disability: An analysis of epilepsy characteristics

PURPOSE

The study aimed to describe the frequency and severity of self-injurious, stereotyped, and aggressive/destructive behavior in adults with both epilepsy and intellectual disability (ID) who reside at a tertiary epilepsy center and to investigate the associations between challenging behavior and epilepsy and ID characteristics.

METHOD

The frequency and severity of self-injurious, (motoric) stereotyped, and aggressive/destructive behavior among 189 patients was assessed using the Behavior Problem Inventory. Comparisons were made with an adult reference population with ID, based on gender, to determine whether the behavior was clinically deviant. Epilepsy characteristics, including age at onset, epilepsy type, seizure types, seizure frequency, and use of antiepileptic drugs (AEDs), were retrieved from patient files. The level of ID was classified using the Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition (DSM-5) and an ID domain discrepancy was allocated if there was a substantial difference between two domains of adaptive behavior within a subject.

RESULTS

Self-injurious behavior was present in 35% of subjects, stereotyped behavior in 60%, and aggressive/destructive behavior in 63%. The behavior exceeded clinical norms in 7%, 18%, and 12%, respectively. Aggression was the behavior evaluated most often as being problematic, despite its reported frequency being the lowest. When adjusting for level of ID and use of psychotropic medication, logistic regression analyses showed that self-injurious behavior was significantly associated with a lower number of AEDs (odds ratio (OR) = 0.4); that stereotyped behavior was significantly associated with a higher number of seizure types (OR = 1.4) and a lower number of AEDs (OR = 0.4); and that aggression was significantly associated with the presence of an ID domain discrepancy (OR = 3.1).

CONCLUSION

Challenging behavior is a serious issue among adults with epilepsy and ID. Although some of the epilepsy and ID characteristics seemed to contribute independently to these types of challenging behavior, the effects of epilepsy-related characteristics are modest when compared with ID.

Phenytoin as a last-resort treatment in SCN8A encephalopathy

SCN8A encodes Nav1.6, one of the main voltage‐gated sodium channel subunits in the brain, and SCN8A mutations lead to epileptic encephalopathy. Particular mutations render the mutant channel more susceptible to inhibition by phenytoin. Yet, the potentially severe side effects of phenytoin maintenance therapy, especially cognitive impairment, are undesirable in these already cognitively impaired patients. We describe a 5‐year‐old patient with SCN8A encephalopathy in whom phenytoin proved successful as emergency treatment to prevent clustering of seizures and status epilepticus, thus hospital stays. The ketogenic diet, levetiracetam, zonisamide, topiramate, and phenytoin maintenance therapy resulted in adverse reactions not previously documented in SCN8A encephalopathy.

Effect of Presymptomatic Body Mass Index and Consumption of Fat and Alcohol on Amyotrophic Lateral Sclerosis

IMPORTANCE

Because dietary intake may influence pathophysiologic mechanisms in sporadic amyotrophic lateral sclerosis (ALS), the association between premorbid dietary intake and the risk of sporadic ALS will provide insight into which mechanisms are possibly involved in ALS pathophogenesis.

OBJECTIVE

To systematically determine the association between premorbid dietary intake and the risk of sporadic ALS.

DESIGN, SETTING, AND PARTICIPANTS

A population-based case-control study was conducted in a general community setting in the Netherlands from January 1, 2006, to September 30, 2011. Analysis was conducted April 1, 2013, to November 15, 2014. All patients with a new diagnosis of possible, probable (laboratory supported), or definite ALS according to the revised El Escorial criteria were included and multiple sources were used to ensure complete case ascertainment. Of 986 eligible patients, 674 gave informed consent and returned a complete questionnaire; 2093 controls randomly selected from the general practitioners' registers and frequency matched to the patients for sex and age were included.

MAIN OUTCOMES AND MEASURES

We studied the premorbid intake of nutrients in association with the risk of ALS by using a 199-item food frequency questionnaire adjusted for confounding factors and corrected for multiple comparisons while minimizing recall bias.

RESULTS

Presymptomatic total daily energy intake in patients, reported as mean (SD), was significantly higher compared with controls (2258 [730] vs 2119 [619] kcal/day; P < .01), and presymptomatic body mass index (calculated as weight in kilograms divided by height in meters squared) was significantly lower in patients (25.7 [4.0] vs 26.0 [3.7]; P = .02). With values reported as odds ratio (95% CI), higher premorbid intake of total fat (1.14; 1.07-1.23; P < .001), saturated fat (1.43; 1.25-1.64; P < .001), trans-fatty acids (1.03; 1.01-1.05; P < .001), and cholesterol (1.08; 1.05-1.12; P < .001) was associated with an increased risk of ALS; higher intake of alcohol (0.91; 0.84-0.99; P = .03) was associated with a decreased risk of ALS. These associations were independent of total energy intake, age, sex, body mass index, educational level, smoking, and lifetime physical activity. No significant associations between dietary intake and survival were found.

CONCLUSIONS AND RELEVANCE

The combination of independent positive associations of a low premorbid body mass index and a high fat intake together with prior evidence from ALS mouse models transgenic for SOD1 and earlier reports on premorbid body mass index support a role for increased resting energy expenditure before clinical onset of ALS.

A LRSAM1 mutation links Charcot-Marie-Tooth type 2 to Parkinson's disease

LRSAM1 mutations have been found in recessive and dominant forms of Charcot–Marie–Tooth disease. Within one generation of the original Dutch family in which the dominant LRSAM1 mutation was identified, three of the five affected family members have developed Parkinson's disease between ages 50 and 65 years, many years after neuropathy onset. We speculate that this late‐onset parkinsonism is part of the LRSAM1 phenotype, thus associating a hitherto peripheral nerve disease with a central nervous system phenotype. How the mutated Lrsam1 protein, which normally has E3 ubiquitin ligase activity and is expressed in the nervous system, impacts on substantia nigra neurons is unclear.

Autism and behavior in adult patients with Dravet syndrome (DS)

INTRODUCTION

Autism and behavioral characteristics in adults with Dravet syndrome (DS) have rarely been systematically studied.

METHOD

Three scales were used to assess the outcomes of DS in adulthood in terms of autism and behavior. All the adult patients with DS, nine male and four female, aged between 18 and 60 years, living at the Epilepsy Center Kempenhaeghe in The Netherlands were included in the study. In addition, the past medical history of each patient was systematically screened for diagnoses like autism, Pervasive Development Disorder-Not Otherwise Specified (PDD-NOS), autism spectrum disorder (ASD), hyperactivity, Attention Deficit Hyperactivity Disorder (ADHD), and self-mutilation. Information concerning past and current use of psychoactive drugs was also evaluated.

RESULTS

Eight patients (61.5%) were classified as having autism spectrum disorder (ASD) according to the AVZ-R or according to the medical record. Self-mutilation was seen in four patients (30.8%), hyperactivity in none. Three patients (23.1%) currently used psychoactive drugs.

CONCLUSION

Autism spectrum disorders persist in adult patients with DS, while certain characteristics associated with behavioral problems, such as hyperactivity or use of psychoactive medication, seem to be less prominent than in childhood.

Carbamazepine and oxcarbazepine in adult patients with Dravet syndrome: Friend or foe?

PURPOSE

In newly diagnosed patients with Dravet syndrome sodium channel blockers are usually avoided. However, in many adult patients the diagnosis was made long after the initiation of therapy. The purpose of our study was to acquire information concerning the potential risks and benefits of (ox)carba(ma)zepine withdrawal in adult patients with genetically confirmed Dravet syndrome.

METHOD

We identified 16 adults with Dravet syndrome, living in a tertiary care facility for people with epilepsy and an intellectual disability. We reviewed clinical history, genetic findings, the type and duration of sodium channels blockers that were used, seizure types and frequency, and the effect of a change in these medications.

RESULTS

The study population consisted of 9 men and 7 women. Median age was 35 years (range 20-61 years). An attempt to withdraw carbamazepine (CBZ) was made in 9 patients. In 3 of these patients an increase in tonic-clonic seizures was observed. An attempt to withdraw oxcarbazepine (OXC) was made in 3 patients, leading to a complete stop in 2 patients. 3 of the 4 deaths in the withdrawal-group were related to epilepsy.

CONCLUSION

In adult patients with Dravet syndrome withdrawal of CBZ or OXC is not without risks. We suggest that (ox)carba(ma)zepine withdrawal should be considered in these patients but only if there is a good reason to do so and only if they are closely monitored.

Cumulative effect of 5 daily sessions of θ burst stimulation on corticospinal excitability in amyotrophic lateral sclerosis

INTRODUCTION

Excitotoxicity plays an important role in the pathogenesis of the preferential motor neuron death observed in amyotrophic lateral sclerosis (ALS). Continuous theta burst stimulation (cTBS) by transcranial magnetic stimulation has an inhibitory effect on corticospinal excitability (CSE). We characterized the neurophysiological changes induced by cTBS in ALS.

METHODS

The patients received 5 daily sessions of cTBS. CSE was assessed at baseline and after each session of cTBS.

RESULTS

The amplitude of a single pulse motor evoked potential was significantly decreased (34%) over the days. The amplitude returned to baseline a week after the last session. The resting motor threshold increased significantly, whereas intracortical inhibition and facilitation did not change over the sessions.

CONCLUSIONS

Daily cTBS has a cumulative depressing effect on CSE in patients with ALS. These results suggest that modulation of CSE in ALS is possible, but repetitive sessions are needed to maintain the effect.

Parental age and the risk of amyotrophic lateral sclerosis

Sporadic ALS is a multifactorial disease for which there are probably multiple genetic risk factors. An association with increased parental age might suggest there is a role for specific (epi)genetic changes. Previous studies have shown conflicting results on the association between parental age and the risk of ALS. A large, population based study might help in the search for specific (epi)genetic risk factors. We performed a population based, case-control study in the Netherlands. Date of birth of both mother and father was retrieved from the National Register. Multivariate logistic regression analysis was performed in 769 patients with sporadic ALS, 49 patients with a hexanucleotide repeat expansion in C9orf72, and 1929 age-, gender- and geographically-matched controls. Multivariate analyses showed no difference in either paternal or maternal age at delivery (adjusted for age of subject, age of other parent at delivery, and level of education) in patients with sporadic ALS, nor in patients with a hexanucleotide repeat expansion in C9orf72 compared to controls. In conclusion, parental age was not associated with an increased risk of ALS in our study. (Epi)genetic alterations that are associated with increased parental age are not, therefore, likely to contribute to the aetiology of sporadic ALS.

Is the Frontal Assessment Battery reliable in ALS patients?

The assessment of frontal functions in ALS patients is important because of the overlap with the behavioural variant of frontotemporal dementia (bvFTD). We investigated the applicability and reliability of the Frontal Assessment Battery (FAB) within a cohort of predominantly prevalent ALS patients. The FAB was administered to 85 ALS patients and eight ALS-bvFTD patients. Original scores and the percentage of items that could be performed were recorded. Item-adjusted scores of the FAB were calculated. The ALS Functional Rating Scale-Revised version (ALSFRS-R) was used to assess disease severity. Eighty-seven patients (94%) had ALS symptoms of more than one year. Twenty patients (21.5%) were not able to perform one or more FAB items. The original FAB score correlated with the ALSFRS-R score (r = 0.30; p < 0.01), while the item-adjusted FAB score did not. In contrast to the original FAB scores, the item-adjusted FAB score was lower in ALS-bvFTD patients (66.7, range 33.3-100) compared to ALS patients without bvFTD (94.4, range 38.9-100; p < 0.01). In summary, 20% of prevalent ALS patients could not complete the FAB, which limits its use in ALS and emphasizes the importance of disease specific instruments and adjusting for motor impairment in cognitive and behavioural examinations of ALS patients.

TDP-43 plasma levels are higher in amyotrophic lateral sclerosis

Our objective was to investigate TDP-43 plasma levels in patients with amyotrophic lateral sclerosis (ALS). TDP-43 has been identified as a major component of protein inclusions in the brain of patients with ALS; mutations in the corresponding gene (TARDBP) have also been identified. Although increased TDP-43 levels have been reported in the cerebrospinal fluid, plasma levels have not yet been assessed in patients with ALS. TDP-43 levels were quantified by sandwich ELISA in plasma of 219 patients and 100 controls. In addition, we sequenced exon 6 of TARDBP, and performed longitudinal TDP-43 plasma measurements in a subset of patients. Results showed that TDP-43 plasma levels were significantly increased in patients with ALS (p=0.023) and we found a positive correlation with age in patients and controls. Longitudinal measurements of TDP-43 plasma levels showed an increase in only one patient, with stable levels in five others. Three TARDBP variations were identified in the ALS group (1.7%), but the association with TDP-43 plasma levels was ambiguous. In conclusion, our data indicate that TDP-43 plasma levels may have potential as a marker for ALS. A genotype-phenotype relationship could not, however, be established in this cohort.

Lithium lacks effect on survival in amyotrophic lateral sclerosis: a phase IIb randomised sequential trial

OBJECTIVES

To determine the safety and efficacy of lithium for the treatment of amyotrophic lateral sclerosis (ALS) in a randomised, placebo controlled, double blind, sequential trial.

METHODS

Between November 2008 and June 2011, 133 patients were randomised to receive lithium carbonate (target blood level 0.4-0.8 mEq/l) or placebo as add-on treatment with riluzole. The primary endpoint was survival, defined as death, tracheostomal ventilation or non-invasive ventilation for more than 16 h/day. Secondary outcome measures consisted of the revised ALS Functional Rating Scale and forced vital capacity. Analysis was by intention to treat and according to a sequential trial design.

RESULTS

61 patients reached a primary endpoint, 33 of 66 in the lithium group and 28 of 67 patients in the placebo group. Lithium did not significantly affect survival (cumulative survival probability of 0.73 in the lithium group (95% CI 0.63 to 0.86) vs 0.75 in the placebo group (95% CI 0.65 to 0.87) at 12 months and 0.62 in the lithium group (95% CI 0.50 to 0.76) vs 0.67 in the placebo group (95% CI 0.56 to 0.81) at 16 months). Secondary outcome measures did not differ between treatment groups. No major safety concerns were encountered.

CONCLUSIONS

This trial, designed to detect a modest effect of lithium, did not demonstrate any beneficial effect on either survival or functional decline in patients with ALS.

TRIAL REGISTRATION NUMBER

NTR1448. Name of trial registry: Lithium trial in ALS.

Prognostic value of decreased tongue strength on survival time in patients with amyotrophic lateral sclerosis

Decreased tongue strength (TS) might herald bulbar involvement in patients with amyotrophic lateral sclerosis (ALS) well before dysarthria or dysphagia occur, and as such might be prognostic of short survival. The purpose of this study was to investigate the prognostic value of a decreased TS, in addition to other prognostic factors, such as site of onset, bulbar symptoms, bulbar signs, age, sex, maximum phonation time, time from symptoms to diagnosis, and gastrostomy, for survival time in patients with ALS. TS was measured in four directions in 111 patients who attended the diagnostic outpatient motor neuron clinic of our university hospital. Of these patients, 54 were diagnosed with ALS. TS was considered abnormal if the strength in minimally one direction was at least two standard deviations below the reference values obtained from comparable age category and sex-groups of healthy controls (n = 119). Twenty of the patients with ALS had a decreased TS. Multivariable analysis showed that, in addition to age, TS was an independent prognostic factor for survival time in patients with ALS.

Structural MRI reveals cortical thinning in amyotrophic lateral sclerosis

OBJECTIVES

Amyotrophic lateral sclerosis (ALS) is a fatal disease characterised by combined upper and lower motor neuron degeneration. An early and accurate diagnosis is important for patient care and might facilitate the search for a more effective therapy. MRI was used to study the whole cortical mantle, applying an unbiased surface based approach to identify a marker of upper motor neuron involvement in ALS.

METHODS

Surface based cortical morphology analyses were performed on structural, 3T MRI data of 45 patients with ALS and 25 matched healthy controls in a case control study design. These analyses consisted of measuring cortical thickness, surface area and volume. The effects of disease progression were examined by correlating cortical measures with progression rate and by longitudinal measures in 20 patients.

RESULTS

Cortical morphology analyses revealed specific thinning in the precentral gyrus, considered the primary motor cortex, in patients with ALS compared with controls (p=6.3×10(-8)). Surface area was reduced in the right inferior parietal region (p=0.049) and volume--the product of cortical thickness and surface area--was reduced in the right precentral gyrus (p=0.031). From these findings, it appears that cortical thickness is superior in detecting the degenerative effects of ALS. Relative cortical thinning in temporal regions was related to faster clinical progression (right inferior temporal gyrus: p=3.3×10(-4)).

CONCLUSIONS

Cortical thinning of the primary motor cortex might be a diagnostic marker for upper motor neuron degeneration in ALS. Relative thinning in temporal regions was associated with a rapidly progressive disease course.

A frameshift mutation in LRSAM1 is responsible for a dominant hereditary polyneuropathy

Despite the high number of genes identified in hereditary polyneuropathies/Charcot-Marie-Tooth (CMT) disease, the genetic defect in many families is still unknown. Here we report the identification of a new gene for autosomal dominant axonal neuropathy in a large three-generation family. Linkage analysis identified a 5 Mb region on 9q33-34 with a LOD score of 5.12. Sequence capture and next-generation sequencing of the region of interest identified five previously unreported non-synonymous heterozygous single nucleotide changes or indels, four of which were confirmed by Sanger sequencing. Two sequence variants co-segregated with the disease, and one, a 2 bp insertion in the last exon of LRSAM1, was also absent in 676 ethnicity-matched control chromosomes. This frameshift mutation (p.Leu708Argfx28) is located in the C-terminal RING finger motif of the encoded protein. Ubiquitin ligase activity in transfected cells with constructs carrying the patient mutation was affected as measured by a higher level of abundance of TSG101, the only reported target of LRSAM1. Injections of morpholino oligonucleotides in zebrafish embryos directed against the ATG or last splice site of zebrafish Lrsam1 disturbed neurodevelopment, showing a less organized neural structure and, in addition, affected tail formation and movement. LRSAM1 is highly expressed in adult spinal cord motoneurons as well as in fetal spinal cord and muscle tissue. Recently, a homozygous mutation in LRSAM1 was proposed as a strong candidate for the disease in a family with recessive axonal polyneuropathy. Our data strongly support the hypothesis that LRSAM1 mutations can cause both dominant and recessive forms of CMT.

Population based epidemiology of amyotrophic lateral sclerosis using capture-recapture methodology

BACKGROUND

Variation in the incidence rate in epidemiological studies on amyotrophic lateral sclerosis (ALS) may be due to a small population size and under ascertainment of patients. The previously reported incidence decline in the elderly and a decrease in the male:female ratio in postmenopausal age groups have yet to be confirmed.

METHODS

ALS epidemiology in a large population based register in The Netherlands was studied between 1 January 2006 and 31 December 2009, and applied capture-recapture methodology in separate age and gender groups to adjust for the number of unobserved patients.

RESULTS

1217 incident patients were observed, and a capture-recapture incidence of 2.77 per 100 000 person-years (95% CI 2.63 to 2.91). Prevalence on 31 December 2008 was 10.32 per 100 000 individuals (95% CI 9.78 to 10.86). The incident cohort had a higher median age at onset (63.0 vs 58.1 years) and more bulbar onset patients (30.0% vs 19.1%) compared with the prevalent cohort. Incidence and prevalence peaked in the 70-74 year age group followed by a rapid decline in older age. The male:female ratio in the premenopausal age group (1.91, 95% CI 1.32 to 2.79) was not significantly higher than that in the postmenopausal age group (1.50, 95% CI 1.34 to 1.67).

CONCLUSION

The marked difference in patient characteristics between incident and prevalent cohorts underscores the importance of including incident patients when studying susceptibility or disease modifying factors in ALS. The incidence decline in the elderly may suggest that ALS is not merely the result of ageing. Absence of a significant postmenopausal drop in the male:female ratio suggests that the protective role of female sex hormones in ALS is limited.

Muscle changes in amyotrophic lateral sclerosis: a longitudinal ultrasonography study

OBJECTIVE

We performed a longitudinal study to assess structural muscle changes in amyotrophic lateral sclerosis (ALS) using ultrasonography.

METHODS

During a follow-up of 6 months, ultrasonography parameters (muscle thickness, echo intensity and fasciculations) were obtained from 6 muscle groups in 31 ALS patients, together with strength and scores on the revised ALS functional rating scale (ALSFRS-r).

RESULTS

At baseline, we found an increased echo intensity and decreased thickness, and these parameters correlated with lower strength. Moreover, ultrasound abnormalities were also detected in muscles with preserved strength. Longitudinal changes in echo intensity, muscle thickness and fasciculations showed large variations between patients. Rates of change in ultrasound parameters did not correlate with changes in ALSFRS-r or strength.

CONCLUSION

In patients with ALS ultrasound abnormalities can be found in muscles with preserved strength. The pattern of ultrasonographic muscle changes in ALS is highly variable and shows no evident correlation with functional measures.

SIGNIFICANCE

Ultrasonography is not suitable to monitor disease progression in ALS.

Hereditary spastic paraplegia due to SPAST mutations in 151 Dutch patients: new clinical aspects and 27 novel mutations

BACKGROUND

In the clinically and genetically heterogeneous group of the hereditary spastic paraplegias (HSPs), mutations in the SPAST gene are most frequently found and cause a pure autosomal dominant form.

OBJECTIVE

To provide the clinical and genetic characteristics of Dutch patients with HSP due to a SPAST mutation (SPG4).

METHODS

SPAST mutation carriers were identified through a comprehensive national database search. Available medical records were reviewed.

RESULTS

151 mutation carriers carried 60 different changes in the SPAST gene, of which one was a known polymorphism, and 27 were novel. Missense mutations were most frequently found (39%). Clinical information was available from 72 mutation carriers. Age at onset ranged from 1 to 63 years with a bimodal peak distribution in the first decade and above age 30. The predominantly pure spastic paraplegia was accompanied by deep sensory disturbances and sphincter problems in almost 50%. An additional hand tremor was found in 10%. Patients with missense mutations and exon deletions did not reveal a distinctive phenotype.

CONCLUSIONS

Dutch SPAST mutation carriers show a broad mutation spectrum, with 27 novel mutations in the present series. A bimodal peak distribution in age at onset was found and an accompanying tremor as peculiar feature of SPG4. The pathogenicity of S44L, the first exon 4 mutation, and a possible autosomal recessive mode of inheritance are discussed.

New cases of adult-onset Sandhoff disease with a cerebellar or lower motor neuron phenotype

Sandhoff disease is a lipid-storage disorder caused by a defect in ganglioside metabolism. It is caused by a lack of functional N-acetyl-beta-d-glucosaminidase A and B due to mutations in the HEXB gene. Typical, early-onset Sandhoff disease presents before 9 months of age with progressive psychomotor retardation and early death. A late-onset form of Sandhoff disease is rare, and its symptoms are heterogeneous. As drug trials that aim to intervene in the disease mechanism are emerging, the recognition and identification of Sandhoff disease patients-particularly those with atypical phenotypes-are becoming more important. The authors describe six new late-onset Sandhoff cases demonstrating cerebellar ataxia or lower motor neuron (LMN) involvement combined with, mostly subclinical, neuropathy. Two different mutations were found: IVS 12-26 G/A and c.1514G-->A. In patients with either progressive cerebellar ataxia or LMN disease in the setting of a possibly recessive disorder, Sandhoff disease should be suspected, even when the onset age is over 45 years.

[Amyotrophic lateral sclerosis]

Amyotrophic lateral sclerosis is one of the most severe and disabling diseases of the nervous system. Amyotrophic lateral sclerosis leads to the progressive weakening of the muscles in the arms, legs, face, mouth and trunk. The onset of the disease is insidious, starting with weakness in the hands or feet or with slurred speech. The weakness worsens and patients pass away as a result of weakness of the respiratory muscles on average within 3 years of the onset of the disease. In the Netherlands, approximately 400 patients are diagnosed with amyotrophic lateral sclerosis every year. There is no diagnostic test for this neuro-muscular disease; the diagnosis is established by excluding other disorders that resemble amyotrophic lateral sclerosis. Only one drug is able to inhibit the progression of the disease to any extent: riluzole. Treatment, therefore, is mainly focused on supportive measures and those which enhance the quality of life optimally.

CSF hypocretin-1 levels are normal in patients with amyotrophic lateral sclerosis

Hypocretin (orexin) neurotransmission is not only crucially involved in the regulation of sleep and wake, but serves in multiple autonomic and cognitive functions as well. This is reflected in the widespread connections between the hypothalamic hypocretin neurons and the rest of the brain, such as dense projections to the frontal cortex. Both frontal cognitive impairment and autonomic disturbances have been described in ALS. Furthermore, in some ALS patients there may be sleep disturbances other than sleep related breathing disorders, including REM sleep behaviour disorder. In addition, a role for the hypocretin system in the regulation of motor functions has been suggested. Hypocretin defects have been described in several neurodegenerative disorders. We therefore speculated that the hypocretin system is also involved in ALS and measured hypocretin-1 levels in cerebrospinal fluid samples from 20 patients. All results were well within the normal range (>200 pg/ml) and individual values showed no correlation with age, gender and disease duration. We conclude that it is unlikely that the hypocretin system is involved in the degenerative process of ALS.

Randomized sequential trial of valproic acid in amyotrophic lateral sclerosis

OBJECTIVE

To determine whether valproic acid (VPA), a histone deacetylase inhibitor that showed antioxidative and antiapoptotic properties and reduced glutamate toxicity in preclinical studies, is safe and effective in amyotrophic lateral sclerosis (ALS) using a sequential trial design.

METHODS

Between April 2005 and January 2007, 163 ALS patients received VPA 1,500mg or placebo daily. Primary end point was survival. Secondary outcome measure was decline of functional status measured by the revised ALS Functional Rating Scale. Analysis was by intention to treat and according to a sequential trial design. This trial was registered with ClinicalTrials.gov (number NCT00136110).

RESULTS

VPA did not affect survival (cumulative survival probability of 0.72 in the VPA group [standard error (SE), 0.06] vs 0.88 in the placebo group [SE, 0.04] at 12 months, and 0.59 in the VPA group [SE, 0.07] vs 0.68 in the placebo group [SE, 0.08] at 16 months) or the rate of decline of functional status. VPA intake did not cause serious adverse reactions.

INTERPRETATION

Our finding that VPA, at a dose used in epilepsy, does not show a beneficial effect on survival or disease progression in patients with ALS has implications for future trials with histone deacetylase inhibitors in ALS and other neurodegenerative diseases. The use of a sequential trial design allowed inclusion of only half the number of patients required for a classic trial design and prevented patients from unnecessarily continuing potentially harmful study medication.

Measuring the cortical silent period can increase diagnostic confidence for amyotrophic lateral sclerosis

We evaluated a modified measurement of the cortical silent period (CSP) as a simple procedure to add further confidence in the diagnostic work-up for ALS. Thirty-seven consecutive patients with a suspicion of having ALS were included together with 25 healthy volunteers, and followed until a final diagnosis (ALS versus 'ALS mimic') was reached. Using a CSP cut-off value of 200 ms for males and 150 ms for females, the following test characteristics were obtained for ALS versus ALS mimics together with controls: sensitivity for excluding ALS 0.83, specificity 0.56 (males) and sensitivity 0.81, specificity 0.82 (females). A CSP longer than the mentioned cut-off values should alarm the clinician for the presence of a disorder other than ALS.

Differentiation of hereditary spastic paraparesis from primary lateral sclerosis in sporadic adult-onset upper motor neuron syndromes

OBJECTIVE

To study whether clinical characteristics can differentiate sporadic presentations of hereditary spastic paraparesis (HSP) from primary lateral sclerosis (PLS). Differentiation between these diseases is important for genetic counseling and prognostication.

DESIGN

Case series.

SETTING

Tertiary referral center.

PATIENTS

One hundred four Dutch patients with an adult-onset, sporadic upper motor neuron syndrome of at least 3 years' duration. Hereditary spastic paraparesis was genetically confirmed in 14 patients (7 with SPG4 and 7 with SPG7 mutations).

RESULTS

All 14 patients with the SPG4 or SPG7 mutation had symptom onset in the legs, and 1 of the patients with the SPG7 mutation also developed symptoms in the arms. Of the other 90 patients, 78 (87%) had symptom onset in the legs. Thirty-six patients developed a PLS phenotype (bulbar region involvement), 15 had a phenotype that was difficult to classify as similar to HSP or PLS (involvement of legs and arms only), and 39 continued to have a phenotype similar to typical HSP (involvement of the legs only). Median age at onset was lower in patients with the SPG4 or SPG7 mutation (39 [range, 29-69] years), but there was considerable overlap with patients with the PLS phenotype (52 [range, 32-76] years). No differences were found in the features used by previous studies to distinguish HSP from PLS, including evidence of mild dorsal column impairment (decreased vibratory sense or abnormal leg somatosensory evoked potentials), symptoms of urinary urgency, or mild electromyographic abnormalities.

CONCLUSIONS

In most patients with a sporadic adult-onset upper motor neuron syndrome, differentiation of sporadic presentations of HSP from PLS based on clinical characteristics is unreliable and therefore depends on results of genetic testing.

The Lambert-Eaton myasthenic syndrome 1988-2008: a clinical picture in 97 patients

BACKGROUND

Neuromuscular symptoms in patients with Lambert-Eaton myasthenic syndrome (LEMS) and a small cell lung cancer (SCLC) develop more rapidly than in LEMS patients without a SCLC. We studied how this clinical information, which is readily available at the first consultation, can be used to predict the presence of SCLC.

PATIENTS AND METHODS

In our study we included 52 LEMS patients with SCLC and 45 non-tumor patients (NT-LEMS). We interviewed patients using a structured checklist and reviewed their clinical records. We compared frequency and onset of symptoms during the course of LEMS.

RESULTS

In the first six months, over half the SCLC-LEMS patients had developed seven separate symptoms, while NT-LEMS patients developed only two symptoms. Proximal leg weakness and dry mouth were early symptoms in both groups. Rapid involvement of proximal arm muscles (p=0.0001), distal arm muscles (p=0.0037), distal leg muscles (p=0.0002), dysartria (p=0.0091) and the presence of erectile dysfunction (p=0.007) were found significantly more often in SCLC-LEMS patients in both cohorts. Cerebellar symptoms, although present in 9% of LEMS patients, were almost exclusively related to SCLC-LEMS.

CONCLUSION

A rapidly progressive course of disease from onset in LEMS patients should raise a high suspicion of SCLC. Special attention should be paid to involvement of upper extremities, involvement of distal arm and distal leg muscles, to erectile dysfunction and probably ataxia in order to discriminate between SCLC-LEMS and NT-LEMS.

Is muscle glycogenolysis impaired in X-linked phosphorylase b kinase deficiency?

OBJECTIVE

It is unclear to what extent muscle phosphorylase b kinase (PHK) deficiency is associated with exercise-related symptoms and impaired muscle metabolism, because 1) only four patients have been characterized at the molecular level, 2) reported symptoms have been nonspecific, and 3) lactate responses to ischemic handgrip exercise have been normal.

METHODS

We studied a 50-year-old man with X-linked PHK deficiency using ischemic forearm and cycle ergometry exercise tests to define the derangement of muscle metabolism. We compared our findings with those in patients with McArdle disease and in healthy subjects.

RESULTS

Sequencing of PHKA1 showed a novel pathogenic mutation (c.831G>A) in exon 7. There was a normal increase of plasma lactate during forearm ischemic exercise, but lactate did not change during dynamic, submaximal exercise in contrast to the fourfold increase in healthy subjects. Constant workload elicited a second wind in all patients with McArdle disease, but not in the patient with PHK deficiency. IV glucose administration appeared to improve exercise tolerance in the patient with PHK deficiency, but not to the same extent as in the patients with McArdle disease. Lipolysis was higher in the patient with PHK deficiency than in controls.

CONCLUSION

These findings demonstrate that X-linked PHK deficiency causes a mild metabolic myopathy with blunted muscle glycogen breakdown and impaired lactate production during dynamic exercise, which impairs oxidative capacity only marginally. The different response of lactate to submaximal and maximal exercise is likely related to differential activation mechanisms for myophosphorylase.

Quantitative muscle ultrasonography in amyotrophic lateral sclerosis

In this study, we examined whether quantitative muscle ultrasonography can detect structural muscle changes in early-stage amyotrophic lateral sclerosis (ALS). Bilateral transverse scans were made of five muscles or muscle groups (sternocleidomastoid, biceps brachii/brachialis, forearm flexor group, quadriceps femoris and anterior tibialis muscles) in 48 patients with ALS. Twenty-five patients were also screened for fasciculations. Quantitative analysis revealed a significant increase in echo intensity in all muscles and a decrease in muscle thickness of the biceps brachii, forearm flexors and quadriceps femoris on both sides. Fasciculations were easy to detect in multiple muscles of all screened patients except one. We conclude that quantitative ultrasonography can be used to detect muscle changes caused by ALS in an early phase of the disease. (E-mail: m.zwarts@neuro.umcn.nl).

Early diagnosis of ALS: The search for signs of denervation in clinically normal muscles

AIM AND METHODS

We prospectively investigated whether early diagnosis of amyotrophic lateral sclerosis (ALS) could be facilitated by demonstrating signs of denervation in a muscle of a clinical and electromyographical unaffected region. Muscle fibre conduction velocity (MFCV) was determined in 18 patients in whom the diagnosis ALS was considered but not established beyond a level of clinically possible ALS according to the revised El Escorial criteria. A muscle biopsy was obtained from the same muscle, to demonstrate neurogenic changes. The study followed the guidelines from the STARD initiative.

RESULTS AND CONCLUSION

Results were analysed with respect to the final diagnosis. After a mean follow-up of 16 months, 9 patients developed probable or definite ALS. Sensitivity of abnormal MFCV for developing ALS was 89%. Muscle biopsy confirmed that denervation was the cause of abnormal MFCV. We concluded that MFCV can be used to detect denervation in muscles that show no clinical or electromyographical signs of lower motor neuron disease, and thus may contribute to early diagnosis of probable laboratory-supported ALS.