What Is in the Literature

ABSTRACT

This issue of What is in the Literature focuses on the Guillain-Barré syndrome. Guillain-Barré syndrome is a monophasic illness, and there is new information about precipitating factors, changes in nerve conduction studies over time, potential biomarkers, optimal treatment, and features in uncommon patient populations.

ALSUntangled #63: ketogenic diets

ALSUntangled reviews alternative and off label treatments with a goal of helping patients make more informed decisions about them. Here we review ketogenic diets. We shows that these have plausible mechanisms, including augmenting cellular energy balance and reducing excitotoxicity, neuroinflammation and oxidative stress. We review a mouse model study, anecdotal reports and trials in ALS and other diseases. We conclude that there is yet not enough data to recommend ketogenic diets for patients with ALS, especially in light of the many side effects these can have.

Quantitative electrodiagnosis of the motor unit

Electromyography (EMG) focuses on assessment of the motor unit (MU), and a given muscle has several hundred MUs, each innervating hundreds of muscle fibers. Assessment is limited by the recording radius of electrodes, 1-2 fibers with single-fiber electrodes and 7-15 fibers with concentric or monopolar electrodes. Routine qualitative EMG studies rely on observing MUs in free-run mode and qualitatively estimating common metrics. In contrast, quantitative EMG (QEMG) applied to routine studies includes assessment of individual MUs by software available in modern EMG machines with extraction of discrete values for common metrics, and also derived metrics. This results in greater precision and statistical interpretation. Other QEMG techniques assess muscle fiber density within the MU and time variability at the neuromuscular junction. The interference pattern can also be assessed. The number of MUs innervating a muscle can be estimated. Advanced signal processing, called near-fiber EMG, allows for extraction of underlying muscle fiber contributions to MU waveforms. It is also possible to use QEMG to make statistical probabilities of the state of a muscle as to whether normal, myopathic, or neuropathic. Time to acquire QEMG data is minimal. QEMG is most useful in situations where pathology is uncertain.

What Is in the Literature

What is in the Literature focuses on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), a neuropathy with challenges in diagnosis and treatment. A recent revision of diagnostic criteria (EFN/PNS criteria) has helped define clinical features of typical and atypical variants and what is not considered CIDP. Initiating pathologic factors is not known for typical CIDP or variants. New treatment approaches are based on immunologic mechanisms. Rare patients with a CIDP-like clinical pattern are found to have antibodies to proteins at and around the node of Ranvier and are not considered to be CIDP but a nodal-paranodopathy. Although occurring mainly in adults, CIDP also occurs in children. CIDP may have clinical and electrodiagnostic features that overlap with hereditary neuropathies, and the latter might show some response to treatment. Articles published in the past year that address these issues are discussed in this review.

What Is in the Literature

This issue of What Is in the Literature focuses on articles on amyotrophic lateral sclerosis over the past year. Amyotrophic lateral sclerosis remains a challenging disorder with progression to death. Within the past year, a phase 2 trial of a drug combination showed slowing in the rate of progression. While awaiting a phase 3 trial or approval by the Food and Drug Administration, selected articles that aid the diagnosis, contribute to care, or add to general knowledge about the disease are reviewed.

Pathogenic Effect of TP73 Gene Variants in People With Amyotrophic Lateral Sclerosis

OBJECTIVE

To identify novel disease associated loci for amyotrophic lateral sclerosis (ALS), we used sequencing data and performed in vitro and in vivo experiments to demonstrate pathogenicity of mutations identified in TP73.

METHODS

We analyzed exome sequences of 87 patients with sporadic ALS and 324 controls, with confirmatory sequencing in independent ALS cohorts of >2,800 patients. For the top hit, TP73, a regulator of apoptosis and differentiation and a binding partner and homolog of the tumor suppressor gene TP53, we assayed mutation effects using in vitro and in vivo experiments. C2C12 myoblast differentiation assays, characterization of myotube appearance, and immunoprecipitation of p53-p73 complexes were performed in vitro. In vivo, we used clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 targeting of zebrafish tp73 to assay motor neuron number and axon morphology.

RESULTS

Four heterozygous rare, nonsynonymous mutations in TP73 were identified in our sporadic ALS cohort. In independent ALS cohorts, we identified an additional 19 rare, deleterious variants in TP73. Patient TP73 mutations caused abnormal differentiation and increased apoptosis in the myoblast differentiation assay, with abnormal myotube appearance. Immunoprecipitation of mutant ΔN-p73 demonstrated that patient mutations hinder the ability of ΔN-p73 to bind p53. CRISPR/Cas9 knockout of tp73 in zebrafish led to impaired motor neuron development and abnormal axonal morphology, concordant with ALS pathology.

CONCLUSION

Together, these results strongly suggest that variants in TP73 correlate with risk for ALS and indicate a role for apoptosis in ALS disease pathology.

What is in the Literature

This edition of What is in the Literature focuses on chronic immune neuropathies as they represent treatable conditions. There are formal criteria to solidify the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but patients are encountered who have clinical and electrodiagnostic features of CIDP but do not fulfill diagnostic criteria. These patients are addressed in recent publications. CIDP (and variants) and other forms of immune-mediated neuropathies (multifocal motor neuropathy) are responsive early on to treatment, but long-term factors are less well described, and a number of publications focus on extended consequences. Acute immune neuropathies have been described in the setting of viral illness, and recent publications look at the question as to whether they are associated with the COVID-19 pandemic. Finally, idiopathic sensory neuropathies are the most common polyneuropathy, and consensus efforts to codify features into subtypes can be used clinically for a more precise diagnosis.

The motor unit and quantitative electromyography

Electromyography (EMG) assesses the anatomic motor unit (A-MU), but knowledge of its anatomy, physiology, and changes with pathology is limited. The electrophysiological motor unit (E-MU) and its motor unit potential (E-MUP) represents a fraction of the A-MU. Routine EMG assesses a limited number of E-MUP waveform characteristics (metrics) and their magnitudes qualitatively scaled in a nonlinear manner. Another approach is quantitative EMG (QEMG), whereby 20⁺ E-MUPs are extracted and both basic and derived metrics obtained and values expressed quantitatively. In diseased muscle, many E-MUP metrics may be normal, which complicates diagnostic interpretation. In QEMG, E-MUP metrics can be clustered and statistical analyses performed to assign probabilities that E-MUPs (and the muscle) are normal, neuropathic, or myopathic. In this article we review what is known about the A-MU, the restricted E-MU, E-MUP metrics, and what QEMG offers currently and in the future.

Hydration measured by doubly labeled water in ALS and its effects on survival

We present a study of hydration in ALS patients and its effects on survival. This was a multicenter study over 48 weeks in 80 ALS patients who underwent 250 individual measurements using doubly labeled water (DLW). Total body water (TBW) and water turnover (a surrogate for water intake) were 3.4% and 8.6% lower, respectively, in patients compared to age- and gender-matched healthy controls, and both significantly decreased over study duration. In 20% of patients, water turnover measured over 10 d was 2 standard deviations below the mean value in healthy controls. In a separate clinic cohort of 208 patients, water intake estimated from a de novo equation created from common clinical endpoints was a prognostic indicator of survival. Regardless of nutritional state assessed by BMI, survival was two-fold longer in the group above the median for estimated water intake, suggesting that hydration may be a more important predictor of survival than malnutrition. Risk factors for poor hydration were identified. Water intake equations recommended by US Centers for Medicare and Medicaid Services in healthy elderly were inaccurate for use in ALS patients. We developed equations to estimate TBW and water intake in ALS patients for use in clinics to accurately estimate hydration and improve clinical care.

What is in the Literature?

This edition of "What is in the Literature?" will focus on motor neuron disease (MND), including adult forms [amyotrophic lateral sclerosis (ALS), progressive muscular atrophy (PMA), primary lateral sclerosis (PLS), progressive bulbar palsy (PBA), and monomelic mononeuropathy (MMND)], and childhood forms [spinal muscle atrophy (SMA)].

Physician perceptions about living organ donation in patients with Amyotrophic Lateral Sclerosis

OBJECTIVES

Patients with Amyotrophic Lateral Sclerosis (ALS) have expressed desire to become living organ donors but are unable to do so with current organ donation policies. Our objective is to assess ALS patient's interest in organ donation, and perceived concerns of this practice by ALS neurologists.

PATIENTS AND METHODS

An electronic survey was administered to ALS neurologists across the United States regarding living organ donation in ALS patients prior to respiratory failure.

RESULTS

52 complete responses were received from 121 invites. 67% (35/52) of neurologists expressed no concerns about living organ donation in ALS patients, and 33% had concerns. The concerns related to respiratory failure, anesthesia exposure and renal dysfunction. With their concerns addressed, 71% of neurologists reported that they would endorse living organ donation. 49% of neurologists reported being asked by a patient for information regarding living organ donation. ALS neurologists felt that 22.8% of ALS patients (median 19%) would be interested in learning more about organ donation, while only 6% of neurologists broach this subject with their patients.

CONCLUSION

Our results indicate that 1 in every 4 ALS patients may be interested in exploring options for living organ donation, and this topic is not routinely addressed by ALS clinics. These results indicate an unexplored area of patient interest. To honor a patient's wishes to donate, the transplant community will have to accommodate living organ donation from terminally ill patients, and address neurologist concerns. Such a practice could benefit two groups of patients.

The evolving genetic risk for sporadic ALS

OBJECTIVE

To estimate the genetic risk conferred by known amyotrophic lateral sclerosis (ALS)-associated genes to the pathogenesis of sporadic ALS (SALS) using variant allele frequencies combined with predicted variant pathogenicity.

METHODS

Whole exome sequencing and repeat expansion PCR of C9orf72 and ATXN2 were performed on 87 patients of European ancestry with SALS seen at the University of Utah. DNA variants that change the protein coding sequence of 31 ALS-associated genes were annotated to determine which were rare and deleterious as predicted by MetaSVM. The percentage of patients with SALS with a rare and deleterious variant or repeat expansion in an ALS-associated gene was calculated. An odds ratio analysis was performed comparing the burden of ALS-associated genes in patients with SALS vs 324 normal controls.

RESULTS

Nineteen rare nonsynonymous variants in an ALS-associated gene, 2 of which were found in 2 different individuals, were identified in 21 patients with SALS. Further, 5 deleterious C9orf72 and 2 ATXN2 repeat expansions were identified. A total of 17.2% of patients with SALS had a rare and deleterious variant or repeat expansion in an ALS-associated gene. The genetic burden of ALS-associated genes in patients with SALS as predicted by MetaSVM was significantly higher than in normal controls.

CONCLUSIONS

Previous analyses have identified SALS-predisposing variants only in terms of their rarity in normal control populations. By incorporating variant pathogenicity as well as variant frequency, we demonstrated that the genetic risk contributed by these genes for SALS is substantially lower than previous estimates.

Population-based risks for cancer in patients with ALS

OBJECTIVE

To estimate the risks for cancer (overall and site-specific) in an amyotrophic lateral sclerosis (ALS) cohort.

METHODS

In this observational longitudinal study, ALS and cancer cases were identified in a computerized Utah genealogy database (Utah Population Database) linked to a statewide cancer registry and death certificates. Hazard ratios (HRs) were estimated as the ratio of observed to expected number of cancers. Site-specific rates for cancer were estimated within the Utah Population Database; sex, birth year (5-year range), and birth state (Utah or not) cohorts were used to estimate the expected number of cancers among ALS cases. To account for an overall shortened lifespan, Cox regression was used to include years at risk in estimation of cancer risks for ALS cases.

RESULTS

An overall decreased hazard (hazard ratio [HR] 0.80, p = 0.014, 95% confidence interval [CI] 0.66-0.96) was found for cancer of any site in 1,081 deceased patients with ALS. A decreased hazard was found for lung cancer (HR 0.23, p = 0.002, CI 0.05-0.63). An increased hazard was found for salivary (HR 5.27, p = 0.041, 95% CI 1.09-15.40) and testicular (HR 3.82, p = 0.042, 95% CI 1.06-9.62) cancers. A nonsignificant hazard was observed for cutaneous malignant melanoma (HR 1.62, p = 0.12, 95% CI 0.88-2.71) for which increased risk has previously been reported.

CONCLUSIONS

Using a unique population database, the overall risk of cancer of any site was found to be significantly reduced in cases with ALS, as was the risk of lung cancer. Significantly increased risk was observed for salivary and testicular cancers.

Relationship of creatine kinase to body composition, disease state, and longevity in ALS

Our objective was to explore if creatine kinase (CK) levels correlate with survival in amyotrophic lateral sclerosis (ALS), and whether a correlation is independent of other well-studied predictors such as location of onset, gender, age, fat free mass, spasticity, cramps, and fasciculations. We analyzed data from 80 ALS patients from a 48-week non-interventional longitudinal multicenter nutrition study with long term follow-up. The overall mean CK was 214 ± 191.8 U/l (range 22-1992 U/l). Forty-five percent of patients had at least one high CK value (> 200 U/l), and about half maintained a high CK value, but there was no trend over the study period. Male gender and extremity onset were significantly associated with high CK. In univariate analysis, age, bioelectric impedance spectroscopy (BIS) fat free mass, spasticity, and fasciculations were not associated with CK level. There was an association between CK and muscle cramps (p < 0.001). In survival analysis, low CK (≤ 200 U/l) was associated with a longer overall survival (p = 0.02), when adjusting for location of onset, age, race, gender, BIS fat free mass, and study site. In conclusion, CK may be a useful marker for ALS survival, which has implications for clinical care and the design of future clinical trials.

Practical rules for electrodiagnosis in suspected multifocal motor neuropathy

Multifocal motor neuropathy (MMN) with conduction block (CB) is a rare chronic immune-mediated neuropathy, but important to diagnose as it is treatable. The key features in prototypic MMN are electrodiagnostic demonstration of focal CB away from common sites of entrapment and normal sensory conduction across these sites. However, there are challenges in distinguishing CB from the effects of abnormal temporal dispersion. Consensus electrodiagnostic criteria, reinforced by modeling studies, are available to support definite or probable CB. In addition, consideration of technical issues can guard against false-positive and false-negative conclusions. These include limb temperature, stimulus site, inadvertent stimulating electrode movement, and supramaximal and submaximal responses, as well as the possibility of Martin-Gruber anastamosis. Robust evidence supports the treatment of MMN with intravenous immunoglobulin, and guidelines have been developed. Application of practical and simple rules including a 4-step diagnostic algorithm can help practitioners correctly diagnose this treatable condition and improve patient outcomes.

Patient demographics and health plan paid costs in chronic inflammatory demyelinating polyneuropathy

INTRODUCTION

We determined health plan paid costs and healthcare resource usage of patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

CIDP patients from 9 U.S. commercial health plans with claims in 2011 were identified from the Accordant Health Services claims database. We examined demographics, prevalence of comorbidities, prescribed drugs, place of service, and mean annual health plan paid costs per patient.

RESULTS

From 6.5 million covered lives, 73 (56% men; mean age 47) met study entry criteria. The most prescribed therapies were intravenous immunoglobulin (IVIg) (26% of patients), gabapentin (26%), and prednisone (16%). The annual health plan paid cost was $56,953. Pharmacy cost was the major cost driver (57% of the total), and IVIg totaled 90% of the pharmacy costs.

CONCLUSIONS

Healthcare costs for CIDP patients are substantial, with a large burden in pharmacy usage. Studies are needed to determine optimal long-term treatment strategies for CIDP, particularly related to IVIg.

Estimating daily energy expenditure in individuals with amyotrophic lateral sclerosis

BACKGROUND

Patients with amyotrophic lateral sclerosis (ALS) experience progressive limb weakness, muscle atrophy, and dysphagia, making them vulnerable to insufficient energy intake. Methods to estimate energy requirements have not been devised for this patient group.

OBJECTIVE

The goal was to develop equations to estimate energy requirements of ALS patients.

DESIGN

We enrolled 80 ALS participants at varying stages of their illness and studied them every 16 wk over 48 wk. At each time, we determined total daily energy expenditure (TDEE) in the home setting over a 10-d period by using the doubly labeled water method. We then developed statistical models to estimate TDEE by using factors easily obtained during a routine clinical visit.

RESULTS

The most practical TDEE models used the Harris-Benedict, Mifflin-St Jeor, or Owen equations to estimate resting metabolic rate (RMR) and 6 questions from the revised ALS Functional Rating Scale (ALSFRS-R) that relate to physical activity. We developed a Web-based calculator to facilitate its use. In the research setting, measuring body composition with bioelectrical impedance spectroscopy enabled the estimation of RMR with the Rosenbaum equation and the same 6 questions from the ALSFRS-R to estimate TDEE. By using these models, the estimate of TDEE for nutritional maintenance was ±500 kcal/d across the spectrum of ALS progression.

CONCLUSIONS

Our results emphasize the importance of physical function and body composition in estimating TDEE. Our predictive equations can serve as a basis for recommending placement of a feeding gastrostomy in ALS patients who fail to meet their energy requirements by oral intake.

Familial clustering of ALS in a population-based resource

OBJECTIVE

To determine the extent of an inherited contribution to amyotrophic lateral sclerosis (ALS) mortality.

METHODS

Death certificates (DCs) from 1904 to 2009 were analyzed from patients with at least 3 generations recorded in the Utah Population Database, a genealogic and medical database of more than 2 million Utah residents. Among probands whose DCs listed ALS, the relative risk (RR) of death with ALS was determined among spouses and first- through fifth-degree relatives, using birth year-, sex-, and birthplace-matched cohorts.

RESULTS

Eight hundred seventy-three patients with ALS met the inclusion criteria. Among 3,531 deceased first-degree relatives of probands, the RR of dying with ALS was increased compared with control cohorts (RR = 4.91, 95% confidence interval 3.36, 6.94). The RR of dying with ALS was also increased among 9,386 deceased second-degree relatives (RR = 2.85, 95% confidence interval 2.06, 3.84). The RR of dying with ALS was not increased among third- through fifth-degree relatives. More affected first-degree relatives were male (p = 0.014). No cases of conjugal ALS were observed.

CONCLUSIONS

This study is suggestive of familial clustering in excess of expected for ALS. Our results confirm the results of prior studies of familial ALS, suggesting applicability of our findings to other mixed European populations. Furthermore, this work expands on previous studies by quantifying the RR of ALS among more distant relatives. The use of mortality data obtained from DCs reduces the ascertainment and recall bias of many previous studies. Finally, the excess of ALS among second-degree relatives and lack of conjugal ALS are strongly supportive of a genetic contribution.

Three cases of acute myositis in adults following influenza-like illness during the H1N1 pandemic

Acute viral myositis is a rare condition that occurs during the recovery phase of an illness, most commonly influenza. It is characterized by muscle pain and weakness with an isolated laboratory finding of elevated serum creatine kinase (CK). We describe three previously healthy patients who were hospitalized after developing myositis following influenza-like illness during the 2009 influenza A (H1N1) virus pandemic. All experienced myalgias and weakness in all four extremities, including distal upper extremities, associated with an elevated CK level that resolved along with their myalgias and weakness within one week with supportive care. These cases serve as a reminder that influenza-related myositis may have atypical characteristics depending on the strain of influenza, and clinicians should be open to this possibility when new outbreaks occur.

Amyotrophic lateral sclerosis: drug therapy from the bench to the bedside

Amyotrophic lateral sclerosis (ALS) is an unrelenting progressive neurodegenerative disease causing progressive weakness, ultimately leading to death. Despite aggressive research, the pathways leading to neuronal death are incompletely understood. Riluzole is the only drug clinically proven to enhance survival of ALS patients, but its mechanism of action is not clearly understood. In this article, the proposed pathophysiology of ALS is reviewed including glutamate excitotoxicity, oxidative stress, mitochondrial dysfunction, autoimmune mechanisms, protein aggregation, SOD1 accumulation, and neuronal death. Based on these mechanisms, past major ALS drug studies will be reviewed as well as promising current ALS drug studies, focusing on the advancement of these studies from the bench to the patient's bedside.

An electrodiagnostic approach to the evaluation of peripheral neuropathies

Electrodiagnosis, which includes nerve conduction and needle electromyographic studies, is an essential element in the evaluation of peripheral neuropathies. A systematic approach to the electrodiagnostic evaluation aids in clarifying the distribution and extent of involvement, type of nerve damage, and time course. When these data are combined with clinical information, a full characterization of the neuropathy is possible leading to a sound differential diagnosis and selection of rational tests to order. This article will discuss the relevant anatomy and physiology of peripheral nerves and the principles of nerve conduction and needle electromyographic studies, including how they help distinguish between prototypic examples of primary axonal and demyelinating neuropathies, how to plan electrodiagnostic studies, and how to interpret data from outside studies.

The role of a clinical pharmacist in a multidisciplinary amyotrophic lateral sclerosis clinic

Patients with ALS have complicated medication regimens and many questions about medications. Our multidisciplinary ALS clinic includes a clinical pharmacist, and the purpose of this study was to assess the types and outcomes of consultative interactions. This was a prospective, data collection study of patients seen by the pharmacist at a single ALS clinic visit. The following data were obtained: 1) current medications; 2) number and types of pharmacy interventions; 3) amount of time spent by the pharmacist with each patient. Thirty-seven patients were included. The average number of prescriptions used per patient was 3.59 (0-10) with 1.75 (0-9) used for ALS related indications. The average number of pharmacist interventions was two per patient, with the majority related to medication monitoring and optimizing drug therapy for ALS symptoms. The pharmacist provided education on an average of 2.5 topics per patient. The pharmacist spent an average of 21 (5-50) min with each patient. In conclusion, a clinical pharmacist contributes to the team by: 1) optimizing drug therapy for ALS symptoms; 2) providing medication-related education to patients; 3) allowing more time for the neurologist to attend to neurologic issues; and 4) discussing general medicine issues.

Nonsense mutation-associated Becker muscular dystrophy: interplay between exon definition and splicing regulatory elements within the DMD gene

Nonsense mutations are usually predicted to function as null alleles due to premature termination of protein translation. However, nonsense mutations in the DMD gene, encoding the dystrophin protein, have been associated with both the severe Duchenne Muscular Dystrophy (DMD) and milder Becker Muscular Dystrophy (BMD) phenotypes. In a large survey, we identified 243 unique nonsense mutations in the DMD gene, and for 210 of these we could establish definitive phenotypes. We analyzed the reading frame predicted by exons flanking those in which nonsense mutations were found, and present evidence that nonsense mutations resulting in BMD likely do so by inducing exon skipping, confirming that exonic point mutations affecting exon definition have played a significant role in determining phenotype. We present a new model based on the combination of exon definition and intronic splicing regulatory elements for the selective association of BMD nonsense mutations with a subset of DMD exons prone to mutation-induced exon skipping.

Reducing bodies and myofibrillar myopathy features in FHL1 muscular dystrophy

OBJECTIVE

Some pathologic features of the FHL1 myopathies and the myofibrillar myopathies (MFMs) overlap; we therefore searched for mutations in FHL1 in our cohort of 50 patients with genetically undiagnosed MFM.

METHODS

Mutations in FHL1 were identified by direct sequencing. Polymorphisms were excluded by using allele-specific PCR in 200 control subjects. Structural changes in muscle were analyzed by histochemistry, immunocytochemistry, and electron microscopy.

RESULTS

We detected 2 novel and 1 previously identified missense mutation in 5 patients. Patients 1-4 presented before age 30, display menadione-nitro blue tetrazolium-positive reducing bodies, and harbor mutations in the FHL1 LIM2 domain. Patient 5 presented at age 75 and has no reducing bodies, and his mutation is not in a LIM domain. The clinical features include progressive muscle weakness, hypertrophied muscles, rigid spine, and joint contractures, and 1 patient also has peripheral neuropathy. High-resolution electron microscopy reveals the reducing bodies composed of 13-nm tubulofilaments initially emanating from Z-disks. At a more advanced stage, abundant reducing bodies appear in the cytoplasm and nuclei with concomitant myofibrillar disintegration, accumulation of cytoplasmic degradation products, and aggregation of endoplasmic reticulum and sarcotubular profiles.

CONCLUSIONS

FHL1 dystrophies can be associated with MFM pathology. Mutations in the LIM2 domain are associated with reducing bodies composed of distinct tubulofilaments. A mutation extraneous to LIM domains resulted in a mild late-onset phenotype with MFM pathology but no reducing bodies.

Phase II screening trial of lithium carbonate in amyotrophic lateral sclerosis: examining a more efficient trial design

OBJECTIVE

To use a historical placebo control design to determine whether lithium carbonate slows progression of amyotrophic lateral sclerosis (ALS).

METHODS

A phase II trial was conducted at 10 sites in the Western ALS Study Group using similar dosages (300-450 mg/day), target blood levels (0.3-0.8 mEq/L), outcome measures, and trial duration (13 months) as the positive trial. However, taking riluzole was not a requirement for study entry. Placebo outcomes in patients matched for baseline features from a large database of recent clinical trials, showing stable rates of decline over the past 9 years, were used as historical controls.

RESULTS

The mean rate of decline of the ALS Functional Rating Scale-Revised was greater in 107 patients taking lithium carbonate (-1.20/month, 95% confidence interval [CI] -1.41 to -0.98) than that in 249 control patients (-1.01/month, 95% CI -1.11 to -0.92, p = 0.04). There were no differences in secondary outcome measures (forced vital capacity, time to failure, and quality of life), but there were more adverse events in the treated group.

CONCLUSIONS

The lack of therapeutic benefit and safety concerns, taken together with similar results from 2 other recent trials, weighs against the use of lithium carbonate in patients with ALS. The absence of drift over time and the availability of a large database of patients for selecting a matched historical control group suggest that use of historical controls may result in more efficient phase II trials for screening putative ALS therapeutic agents.

CLASSIFICATION OF EVIDENCE

This study provided Class IV evidence that lithium carbonate does not slow the rate of decline of function in patients with ALS over 13 months.

Neurology Academic Advisory Committee: a strategy for faculty retention and advancement

Major effort and expense are devoted to faculty recruitment. Subsequent direction, support, and guidance of faculty members for retention and academic advancement are often inconsistent and ineffective. Individual mentorship is widely endorsed as an important element in advancement but often does not occur or is uneven in its pragmatic benefit. We formed a Departmental Academic Advisory Committee to provide individualized advice and guidance about career development and institutional promotion, retention, and tenure procedures. To assess the effectiveness of this process, a survey was sent to faculty members. A 100% response rate was achieved. The results of the survey demonstrated high levels of acceptance by faculty members and described benefits experienced by faculty, including better understanding of promotion and tenure policies and specific actions taken to achieve professional goals. An academic advisory committee can be a valuable adjunct to individual mentorship and to meetings with department chairs to enhance faculty satisfaction and advancement of neurology faculty members.

SMA CARNIVAL TRIAL PART II: a prospective, single-armed trial of L-carnitine and valproic acid in ambulatory children with spinal muscular atrophy

Background

Multiple lines of evidence have suggested that valproic acid (VPA) might benefit patients with spinal muscular atrophy (SMA). The SMA CARNIVAL TRIAL was a two part prospective trial to evaluate oral VPA and l-carnitine in SMA children. Part 1 targeted non-ambulatory children ages 2–8 in a 12 month cross over design. We report here Part 2, a twelve month prospective, open-label trial of VPA and L-carnitine in ambulatory SMA children.

Methods

This study involved 33 genetically proven type 3 SMA subjects ages 3–17 years. Subjects underwent two baseline assessments over 4–6 weeks and then were placed on VPA and L-carnitine for 12 months. Assessments were performed at baseline, 3, 6 and 12 months. Primary outcomes included safety, adverse events and the change at 6 and 12 months in motor function assessed using the Modified Hammersmith Functional Motor Scale Extend (MHFMS-Extend), timed motor tests and fine motor modules. Secondary outcomes included changes in ulnar compound muscle action potential amplitudes (CMAP), handheld dynamometry, pulmonary function, and Pediatric Quality of Life Inventory scores.

Results

Twenty-eight subjects completed the study. VPA and carnitine were generally well tolerated. Although adverse events occurred in 85% of subjects, they were usually mild and transient. Weight gain of 20% above body weight occurred in 17% of subjects. There was no significant change in any primary outcome at six or 12 months. Some pulmonary function measures showed improvement at one year as expected with normal growth. CMAP significantly improved suggesting a modest biologic effect not clinically meaningful.

Conclusions

This study, coupled with the CARNIVAL Part 1 study, indicate that VPA is not effective in improving strength or function in SMA children. The outcomes used in this study are feasible and reliable, and can be employed in future trials in SMA.

Trial Regsitration

Clinicaltrials.gov NCT00227266

A survey of stress among amyotrophic lateral sclerosis care providers

Amyotrophic lateral sclerosis (ALS) is a uniformly fatal disease. In the US, care is concentrated in specialized clinics. ALS health care providers likely experience stress, but levels and associated factors and methods to manage them are not known. A questionnaire was designed to assess levels of emotional stress among ALS clinic providers (neurologists and clinic managers) at time of diagnosis, during care of the patient, and at time of the patient's death. Also included were questions about diagnostic practice patterns. Sixty-eight Muscular Dystrophy Association and ALS Association certified clinics were surveyed with a 47% response rate. Stress levels ranged from very severe to none at the various clinical stages but did not differ significantly between neurologists and managers. Stress tended to be lower in more experienced providers, although not uniformly so for all situations and time-points. Stress reduction techniques were rated as more effective for managers than for neurologists. Providers reported high levels of job satisfaction but a significant number gave consideration to leaving their positions due to stress and operational issues. In conclusion, stress is experienced by ALS clinic providers and managed by a variety of methods but with limited success.

Nerve conduction pitfalls and pearls in the diagnosis of peripheral neuropathies

Nerve conduction studies are an integral component of the evaluation of a peripheral neuropathy. While routine in nature, they require attention to detail. This article focuses on operator and machine errors that can affect the correct interpretation of nerve conduction data and the nature of a neuropathy.

An approach to the evaluation of peripheral neuropathies

Requests for an evaluation for a peripheral neuropathy are common in the clinic and electrodiagnostic laboratory. Lists of types of neuropathies are long as are diagnostic tests. An approach to the evaluation of peripheral neuropathies is valuable as it permits full characterization of the neuropathy after which the lists of possible types and tests becomes much shorter and manageable. In this article, the author presents such an approach, focusing on the clinical aspects.

SMA CARNI-VAL trial part I: double-blind, randomized, placebo-controlled trial of L-carnitine and valproic acid in spinal muscular atrophy

Background

Valproic acid (VPA) has demonstrated potential as a therapeutic candidate for spinal muscular atrophy (SMA) in vitro and in vivo.

Methods

Two cohorts of subjects were enrolled in the SMA CARNIVAL TRIAL, a non-ambulatory group of “sitters” (cohort 1) and an ambulatory group of “walkers” (cohort 2). Here, we present results for cohort 1: a multicenter phase II randomized double-blind intention-to-treat protocol in non-ambulatory SMA subjects 2–8 years of age. Sixty-one subjects were randomized 1∶1 to placebo or treatment for the first six months; all received active treatment the subsequent six months. The primary outcome was change in the modified Hammersmith Functional Motor Scale (MHFMS) score following six months of treatment. Secondary outcomes included safety and adverse event data, and change in MHFMS score for twelve versus six months of active treatment, body composition, quantitative SMN mRNA levels, maximum ulnar CMAP amplitudes, myometry and PFT measures.

Results

At 6 months, there was no difference in change from the baseline MHFMS score between treatment and placebo groups (difference = 0.643, 95% CI = −1.22–2.51). Adverse events occurred in >80% of subjects and were more common in the treatment group. Excessive weight gain was the most frequent drug-related adverse event, and increased fat mass was negatively related to change in MHFMS values (p = 0.0409). Post-hoc analysis found that children ages two to three years that received 12 months treatment, when adjusted for baseline weight, had significantly improved MHFMS scores (p = 0.03) compared to those who received placebo the first six months. A linear regression analysis limited to the influence of age demonstrates young age as a significant factor in improved MHFMS scores (p = 0.007).

Conclusions

This study demonstrated no benefit from six months treatment with VPA and L-carnitine in a young non-ambulatory cohort of subjects with SMA. Weight gain, age and treatment duration were significant confounding variables that should be considered in the design of future trials.

Trial Registry

Clinicaltrials.gov NCT00227266

The SEIQoL-DW for assessing quality of life in ALS: strengths and limitations

The Schedule for the Evaluation of the Individual Quality of Life-Direct Weighting (SEIQoL-DW) has been used to measure quality of life (QoL) in small cohorts of individuals with ALS, but its suitability for assessing aggregate QoL for between-group comparisons is uncertain. We undertook a prospective study in which 120 patients with ALS completed two measures of QoL, the SEIQoL-DW and the McGill Quality of Life Single-Item Scale (MQoL-SIS). There was a weak correlation between the SEIQoL-DW index score and the MQoL-SIS. Only three of five cues accounted for a significant amount of variance in the MQoL-SIS, and even those accounted for only 12.8%-13.9% of the variance. Cues relating to family or significant other were chosen by over 90% of patients, and were the most heavily weighted. This study demonstrates that the SEIQoL-DW is of great value in identifying those factors which contribute to the psychosocial well-being of an individual with ALS. However, SEIQoL index scores may not reflect aggregate QoL of groups of patients with ALS, and may be measuring a construct other than QoL. Caution should be exercised in using the SEIQoL index score to measure QoL of groups, such as would be needed in interventional trials.

A survey of clinicians' practice in the symptomatic treatment of ALS

Symptomatic management is the mainstay of ALS patient care, but there are few controlled trials of drugs and interventions for common symptoms.

METHODS

We queried ALS clinic neurologists to determine drugs and interventions of choice and neurologists' perceived efficacy for 14 symptoms.

RESULTS

The results are tabulations of the physicians' four most frequent choices for each symptom, the physicians' perception of efficacy, the average doses and average daily costs. A wide range of drugs and interventions were nominated for management of ALS symptoms. Consensus on treatment was rare for individual symptoms, and efficacy for any symptom was judged moderate at best. A few drugs were recommended for multiple symptoms. Comparisons of perceived efficacy compared to drug costs are informative.

DISCUSSION

The results of the survey emphasize the challenges of symptom management in ALS. These data aid clinical management and guide rational choices for randomized controlled trials.

Inter-evaluator reliability of the ALS Functional Rating Scale

The ALS Functional Rating Scale-Revised (ALSFRS-R) is used in the clinic to chart progression and as a primary endpoint measure in clinical trials. In the original description of the scale, evaluations were to be performed by the patient or caregiver, but ratings are commonly performed by health care providers. We determined whether there are differences in scoring based on whether the provider, patient or caregiver performed the evaluation. Overall, all evaluators assessed similar changes in function over time, but significant visit-specific differences were found with higher scores when the patient and provider were the evaluators. We modeled how a change in evaluators at the end of a 9-month trial would influence statistical analysis, if the patient was unable to travel to the study site and the final assessment was performed by telephone. If 25% of the final visit assessments were performed by the patient, in place of the provider, the change in score is less than one point on the ALSFRS-R (-0.7: 95% Confidence Interval -2.1 to 0.3). We conclude that the ALSFRS-R can be successfully used even if evaluators change.

Phase II open label study of valproic acid in spinal muscular atrophy

Preliminary in vitro and in vivo studies with valproic acid (VPA) in cell lines and patients with spinal muscular atrophy (SMA) demonstrate increased expression of SMN, supporting the possibility of therapeutic benefit. We performed an open label trial of VPA in 42 subjects with SMA to assess safety and explore potential outcome measures to help guide design of future controlled clinical trials. Subjects included 2 SMA type I ages 2–3 years, 29 SMA type II ages 2–14 years and 11 type III ages 2–31 years, recruited from a natural history study. VPA was well-tolerated and without evident hepatotoxicity. Carnitine depletion was frequent and temporally associated with increased weakness in two subjects. Exploratory outcome measures included assessment of gross motor function via the modified Hammersmith Functional Motor Scale (MHFMS), electrophysiologic measures of innervation including maximum ulnar compound muscle action potential (CMAP) amplitudes and motor unit number estimation (MUNE), body composition and bone density via dual-energy X-ray absorptiometry (DEXA), and quantitative blood SMN mRNA levels. Clear decline in motor function occurred in several subjects in association with weight gain; mean fat mass increased without a corresponding increase in lean mass. We observed an increased mean score on the MHFMS scale in 27 subjects with SMA type II (p≤0.001); however, significant improvement was almost entirely restricted to participants <5 years of age. Full length SMN levels were unchanged and Δ7SMN levels were significantly reduced for 2 of 3 treatment visits. In contrast, bone mineral density (p≤0.0036) and maximum ulnar CMAP scores (p≤0.0001) increased significantly.

Conclusions

While VPA appears safe and well-tolerated in this initial pilot trial, these data suggest that weight gain and carnitine depletion are likely to be significant confounding factors in clinical trials. This study highlights potential strengths and limitations of various candidate outcome measures and underscores the need for additional controlled clinical trials with VPA targeting more restricted cohorts of subjects.

Trial Registration

ClinicalTrials.gov

Acute neuropathies

Acute neuropathies, defined as symptoms progressing over 4 weeks with a degree of spontaneous recovery, include the Guillain-Barré syndrome and its variants and acute brachial and lumbosacral plexopathies. An immune-mediated mechanism is postulated from clinical features and with the Guillain-Barré syndrome from direct evidence implicating molecular mimicry between epitopes on bacteria related to antecedent illnesses and nerve cell gangliosides. There are little data to guide immune-modulating treatment but there is frequent pain at onset that should be treated aggressively. This chapter will review the clinical features, diagnostic process, pathophysiologic features and treatment data.