A 71-nucleotide deletion in the periaxin gene in an Italian patient with late-onset slowly progressive demyelinating Charcot-Marie-Tooth disease.

BACKGROUND: Charcot-Marie-Tooth disease (CMT) constitutes a group of heterogeneous hereditary motor and sensor neuropathies. Mutations in the periaxin (PRX) gene cause CMT4F with an autosomal recessive early-onset demyelinating neuropathy and are extremely rare in a non-Romani white population. METHODS: We report on a 66-year-old Italian man presenting with slowly progressive and late-onset demyelinating CMT. The molecular analysis was performed using a custom panel containing 39 genes associated with the CMT phenotype. RESULTS: The patient harbored a homozygous PRX 71-nucleotide deletion (c.3286_3356del71, I1096fsX17). CONCLUSIONS: This is the first report that describes such a genetic mutation in a population of non-Romani origin.

Time to generalization and prediction of survival in patients with amyotrophic lateral sclerosis: a retrospective observational study.

BACKGROUND AND PURPOSE: A strong association between time to generalization (TTG), considered as the time of spreading of the clinical signs from spinal or bulbar localization to both, and survival was recently identified in patients with amyotrophic lateral sclerosis (ALS). Thus, TTG may be used as an early to intermediate end-point in survival studies. The aim of the present study was to test TTG as a predictor of survival in ALS. METHODS: This was an observational retrospective study of ALS patients from a tertiary referral centre over a 5-year follow-up period. RESULTS: In 212 ALS patients, TTG was associated with time to death/tracheostomy [R 0.62, 95% confidence interval (CI) 0.53-0.70; P < 0.001]. In a time-to-event analysis, longer TTG resulted in lower risk to reach a composite outcome (death or tracheostomy) both in univariate [hazard ratio (HR) 0.98, 95% CI 0.97-0.99] and multivariate Cox analyses (HR 0.98, 95% CI 0.96-0.99). TTG predicted death/tracheostomy at 4 years (C-statistic 0.58; 95% CI 0.53-0.63) and at 5 years (C-statistic 0.58; 95% CI 0.53-0.62). CONCLUSIONS: Based on the present results from a large clinical cohort, TTG may be used as a new early to intermediate end-point to describe the ALS natural history. TTG may be potentially useful as a new primary outcome measure for clinical trials.

Cerebrospinal fluid neurofilament tracks fMRI correlates of attention at the first attack of multiple sclerosis.

BACKGROUND: Identifying markers of cognitive dysfunction in multiple sclerosis (MS) is extremely challenging since it means supplying potential biomarkers for neuroprotective therapeutic strategies. OBJECTIVE: The aim of this study is to investigate the relationship between fMRI correlates of attention performance and cerebrospinal fluid (CSF) neurofilament light chain (NFL) levels in patients with clinically isolated syndrome (CIS) suggestive of MS. METHODS: Twenty-one untreated, cognitively preserved CIS patients underwent BOLD-fMRI while performing the Variable Attentional Control (VAC) task, a cognitive paradigm requiring increasing levels of attentional control processing. CSF NFL was assessed by ELISA technique. SPM8 random-effects models were used for statistical analyses of fMRI data (p<0.05 corrected). RESULTS: Repeated-measures ANOVA on imaging data showed an interaction between attentional control load and NFL levels in the right putamen. At the high level of attentional control demand CIS patients with "low NFL levels" showed greater activity in the putamen compared with subjects with "high NFL levels" (p=0.001). These results are independent of cognitive impairment index. CONCLUSIONS: Our findings suggest a relationship between CSF NFL levels and load-dependent failure of putaminal recruitment pattern during sustained attention in CIS and suggest a role of CSF NFL as a marker of subclinical abnormality of cognitive pathway recruitment in CIS.

Cerebrospinal fluid neurofilament light chain levels: marker of progression to generalized amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: To evaluate whether cerebrospinal fluid (CSF) neurofilament light chain (NFL) levels could predict the time to generalization (TTG) in amyotrophic lateral sclerosis (ALS). METHODS: Cerebrospinal fluid NFL levels of 37 cases of sporadic ALS were measured and the time of symptom spreading from spinal or bulbar localization to both (TTG) was evaluated in all patients. RESULTS: Kaplan-Meier analysis showed a short TTG in patients with high NFL levels (log-rank test chi-squared = 19.4, P < 0.0001). In a multivariate regression model patients with NFL levels above the median had an eight-fold higher risk of generalization (adjusted hazard ratio 7.9, 95% confidence interval 2.9-21.4, P < 0.0001) compared with those with NFL levels below the median. CONCLUSIONS: This study shows that in sporadic ALS NFL, a marker of neurodegeneration, is correlated with TTG, a clinical intermediate parameter of survivorship.

Load-dependent dysfunction of the putamen during attentional processing in patients with clinically isolated syndrome suggestive of multiple sclerosis.

BACKGROUND: Load-related functional magnetic resonance imaging (fMRI) abnormalities of brain activity during performance of attention tasks have been described in definite multiple sclerosis (MS). No data are available in clinically isolated syndrome (CIS) suggestive of MS. OBJECTIVES: The objective of this research is to evaluate in CIS patients the fMRI pattern of brain activation during an attention task and to explore the effect of increasing task load demand on neurofunctional modifications. METHODS: Twenty-seven untreated CIS patients and 32 age- and sex-matched healthy controls (HCs) underwent fMRI while performing the Variable Attentional Control (VAC) task, a cognitive paradigm requiring increasing levels of attentional control processing. Random-effects models were used for statistical analyses of fMRI data. RESULTS: CIS patients had reduced accuracy and greater reaction time at the VAC task compared with HCs (p=0.007). On blood oxygenation level-dependent (BOLD)-fMRI, CIS patients had greater activity in the right parietal cortex (p=0.0004) compared with HCs. Furthermore, CIS patients had greater activity at the lower (p=0.05) and reduced activity at the greater (p=0.04) level of attentional control demand in the left putamen, compared with HCs. CONCLUSIONS: This study demonstrates the failure of attentional control processing in CIS. The load-related fMRI dysfunction of the putamen supports the role of basal ganglia in the failure of attention observed at the earliest stage of MS.

Clinical Profiles and Patterns of Neurodegeneration in Amyotrophic Lateral Sclerosis: A Cluster-Based Approach Based on MR Imaging Metrics.

BACKGROUND AND PURPOSE: The previous studies described phenotype-associated imaging findings in amyotrophic lateral sclerosis (ALS) with a prior categorization of patients based on clinical characteristics. We investigated the natural segregation of patients through a radiologic cluster-based approach without a priori patient categorization using 3 well-known prognostic MR imaging biomarkers in ALS, namely bilateral precentral and paracentral gyrus cortical thickness and medulla oblongata volume. We aimed to identify clinical/prognostic features that are cluster-associated. MATERIALS AND METHODS: Bilateral precentral and paracentral gyri and medulla oblongata volume were calculated using FreeSurfer in 90 patients with amyotrophic lateral sclerosis and 25 healthy controls. A 2-step cluster analysis was performed using precentral and paracentral gyri (averaged pair-wise) and medulla oblongata volume. RESULTS: We identified 3 radiologic clusters: 28 (31%) patients belonged to "cluster-1"; 51 (57%), to "cluster 2"; and 11 (12%), to "cluster 3." Patients in cluster 1 showed statistically significant cortical thinning of the analyzed cortical areas and lower medulla oblongata volume compared with subjects in cluster 2 and cluster 3, respectively. Patients in cluster 3 exhibited significant cortical thinning of both paracentral and precentral gyri versus those in cluster 2, and this latter cluster showed lower medulla oblongata volume than cluster 3. Patients in cluster 1 were characterized by older age, higher female prevalence, greater disease severity, higher progression rate, and lower survival compared with patients in clusters 2 and 3. CONCLUSIONS: Patients with amyotrophic lateral sclerosis spontaneously segregate according to age and sex-specific patterns of neurodegeneration. Some patients with amyotrophic lateral sclerosis showed an early higher impairment of cortical motor neurons with relative sparing of bulbar motor neurons (cluster 3), while others expressed an opposite pattern (cluster 2). Moreover, 31% of patients showed an early simultaneous impairment of cortical and bulbar motor neurons (cluster 1), and they were characterized by higher disease severity and lower survival.

Elevated cerebrospinal fluid neurofilament light levels in patients with amyotrophic lateral sclerosis: a possible marker of disease severity and progression.

BACKGROUND: To date there are no biomarkers with proven reliability as a measure of disease burden in amyotrophic lateral sclerosis (ALS). The aim of our study is to assess the neurofilament light chain (NFL) in cerebrospinal fluid (CSF) samples as a measure of disease activity and progression in ALS. METHODS: Thirty-seven consecutive patients with ALS, 25 with chronic inflammatory demyelinating polyneuropathy and 21 with other neurodegenerative diseases were evaluated. CSF NFL levels were assayed by two-site solid-phase sandwich ELISA. In patients with ALS, neurological status was assessed by the revised ALS Functional Rating Scale (ALSFRS-r) and the Medical Research Council scale, and the progression of the disease was evaluated using the 'diagnostic delay' and the 'progression rate'. RESULTS: Cerebrospinal fluid NFL levels were higher in ALS cases than in controls (P < 0.0001). Using receiver operating curve analysis, an optimal NFL cut-off of 1981 ng/l discriminated between patients with ALS and neurological controls, with a sensitivity of 78.4% and specificity of 72.5%. Multivariate logistic regression confirmed the association between CSF NFL levels and the presence of ALS (age and sex adjusted odds ratio for ALS 8.9; 95% CI 3.1-25.8; P < 0.0001). In ALS, CSF NFL negatively correlated with the diagnostic delay (P < 0.0001) and the ALSFRS-r (P = 0.014) and positively with the progression rate (P < 0.0001). CONCLUSIONS: High CSF NFL levels were found in patients with ALS, reflecting the burden of neurodegeneration. The significant relation between CSF NFL levels and disease progression suggests that NFL may be a useful marker of disease activity and progression in ALS.

Trauma and amyotrophic lateral sclerosis: a case-control study from a population-based registry.

BACKGROUND AND PURPOSE: Published reports on the association between amyotrophic lateral sclerosis (ALS) and trauma are controversial suggesting the need for a new case-control study done in a large population. METHODS: A case-control study was undertaken in Italy to assess this association. Cases were patients with newly diagnosed ALS from four population-based registries. For each case, two hospital controls were selected, matched for age, sex, and province of residence, one with a neurological (non-degenerative) disease and one with a non-neurological disease (other than orthopedic or surgical). Traumatic events (defined as accidental events causing injuries requiring medical care) were recorded with details on type, site, timing, severity, and complications. The risks were assessed as odds ratios (ORs) with 95% confidence intervals (CI), crude and adjusted for age, sex, education, interviewee (patient or surrogate), physical activity, smoking, alcohol, and coffee. RESULTS: The study population comprised 377 patients in each of the three groups. One or more traumatic events were reported by 225 cases (59.7%), 191 neurological controls (50.7%), and 179 non-neurological controls (47.5%) (P < 0.01) (OR 1.63; 95% CI 1.25-2.14) (P < 0.01). The ORs were 3.07 (95% CI 1.86-5.05) for patients reporting 3+ traumatic events and 2.44 (95% CI 1.36-4.40) for severe traumatic events. The ORs remained significant when the analysis was limited to events that occurred 5+ and 10+ years before ALS onset, to incident ALS, and direct informant. CONCLUSION: Antecedent trauma, repeated trauma, and severe trauma may be risk factors for ALS.

The incidence of major stroke subtypes in southern Italy: a population-based study.

BACKGROUND AND PURPOSE: Stroke is characterized by well-defined clinical major subtypes, but there are few studies on incidence rates, aetiologies and outcomes in population-based setting. We assessed the age/sex incidence of the major stroke subtypes in a region of Southern Italy. METHODS: We established a multisource, prospective population-based register in Puglia, Southern Italy to identify all residents with a first-ever stroke between 1 January 2001 and 31 December 2002. RESULTS: One hundred and twenty-seven first-ever strokes were diagnosed, and stroke subtype was defined in 119 cases. The incidence rates per 100 000 adjusted to the European population (AEP) were 112 for cerebral infarction (CI), 30 for intracerebral haemorrhage (IH), four for subarachnoid haemorrhage (SH) and nine for undetermined stroke (US). The incidence rates for CI, IH and US approximately doubled with each decade of life and were higher in men. AEP incidence rates for CI in the age groups 45-84 were lower compared to other studies, whilst the corresponding rates for IH were higher. CONCLUSIONS: This population had a lower incidence of CI compared to other population-based studies from Northern Europe and the United States. Furthermore, with the projected increase in the segment of the very old in the general population, our data indicate that both CI and IH will dramatically increase in the near future.

Analysis of survival and prognostic factors in amyotrophic lateral sclerosis: a population based study.

OBJECTIVE: To measure survivorship and predictors of prognosis of amyotrophic lateral sclerosis (ALS). METHODS: Incident cases, diagnosed in the 1998-1999 period and classified according to the El Escorial criteria, were enrolled from a prospective population based registry established in Puglia, Southern Italy, with a reference population of 4,025,329. Cases were followed up until death or 30 June 2004. RESULTS: We identified 130 incident cases of ALS while four were lost to follow-up. Median survival was 28 months from first symptoms and 16 months from diagnosis, while cumulative survivorship at 4 years was approximately 30%. Advanced age (>75 years: hazard ratio (HR) 7.5; 95% CI 1.9 to 29.6; p = 0.004) and bulbar or generalised (HR 1.8; 95% CI 1.1 to 3.0; p = 0.01) onset of symptoms were independent predictors of adverse survival. After stratifying patients according to site of first symptoms, age was a predictor of death among spinal (HR for patients aged >75 years compared with patients aged 45 years or less: HR 11; 95% CI 1.5 to 78.5; p = 0.01) but not among bulbar ALS (HR 4.5; 95% CI 0.4 to 46.5; p = 0.2). Among spinal onset cases, cases with predominant upper motoneuronal (UMN) involvement presented with a borderline significant better survivorship (HR 0.5; 95% CI 0.2 to 1.3; p = 0.1) CONCLUSIONS: Bulbar signs and advanced age among subjects with spinal onset were indicators of poor prognosis while El Escorial category at entry did not predict survival. Among subjects with spinal onset of the disease, a trend for a better survivorship of subjects with UMN signs was noted.

Riluzole and amyotrophic lateral sclerosis survival: a population-based study in southern Italy.

Riluzole is to date the only treatment that prolongs amyotrophic lateral sclerosis (ALS) survival. However, results on the efficacy of riluzole in observational population-based studies with a longer follow-up are conflicting and it is still unclear if the effect of the drug is limited to an early stage of the disease and to some specific subgroups of patients. The objective is: (i) to evaluate the effect of riluzole on ALS survival in a cohort of incident cases; (ii) to examine whether bulbar-ALS benefits from the medication to a greater extent and (iii) to assess the efficacy of the drug in elderly patients. Source of the study was a prospective population-based registry of ALS established in Puglia, Southern Italy. We examined survival of 126/130 incident ALS cases diagnosed during the period 1998-1999. Seventy-three patients were prescribed riluzole and the remaining 53 were not. Riluzole therapy increased survival rates at 12 months by approximately 10% and prolonged survival by 6 months (18.2 months vs. 12.4; peto-test: 2.78; P = 0.09). This beneficial effect was present amongst bulbar-onset ALS (peto-test: 4.11; P = 0.042), but not in subjects with limb-onset (peto-test: 0.48; P = 0.4). In patients aged >70 years riluzole treatment was associated with an 8 months longer median survival time [15.4 months vs. 7.1] and a reduction in mortality rate at 12 months by 27%, regardless of site of symptoms onset. In multivariate analysis, riluzole use was an independent predictor of survival at 12 months from the diagnosis with borderline significance (P = 0.06). Riluzole was effective amongst cases with bulbar-onset ALS (P = 0.04), whereas in subjects with limb-onset there was no effect on survival at 12 months (P = 0.5). In each model riluzole did not influence survival at 24 months. Conversely, riluzole use was associated with an improvement in survival amongst elderly patients both at 12 (P = 0.07), at 24 months (P = 0.03) and in the entire follow-up period (P < 0.04). In this population-based series, we found that riluzole therapy improves ALS survival. The efficacy of the drug was present amongst bulbar-onset ALS and older patients, but not in subjects with limb-onset. The favourable effect of the drug was transient, as it was lost in prolonged follow-up. Our observations support the use of riluzole at an early stage of ALS in bulbar and elderly patients. However, the appropriate duration of riluzole treatment remains to be established.

Lymphocyte subsets as biomarkers of therapeutic response in Fingolimod treated Relapsing Multiple Sclerosis patients.

We investigated, lymphocyte count (LC) and lymphocyte subpopulations (LS) in a real life setting of Fingolimod (FTY) treated Relapsing MS (RMS) patients. Peripheral blood counts with LS, relapses and MRI scans were recorded in a cohort of 119 FTY patients, during one year of treatment. Simple and multivariate logistic regression models, were performed. ROC analysis identified cut-off values of LS predicting a higher risk of relapses and of Gd+ lesions. We demonstrated a FTY-induced re-modulation of the immune system, suggesting that LS in RMS FTY treated patients can predict the clinical response to the drug.

Signs and symptoms at diagnosis of amyotrophic lateral sclerosis: a population-based study in southern Italy.

Amyotrophic lateral sclerosis (ALS) diagnostic criteria are used to select patients for clinical trials based on different levels of diagnostic certainty, according to the spread of upper (UMN) and lower motoneuron (LMN) signs in different anatomic regions. However, the clinical presentation of ALS patients is extremely variable and this can delay the time to diagnosis and decrease the likelihood for trial entry. The aims of the study were to describe the signs and symptoms of diagnosis in a population-based incident cohort of ALS cases, using the El Escorial (EEC) and the Revised Airlie Diagnostic Criteria (AHC). The source of the study was a prospective population-based registry established in Puglia, southern Italy, in 1997. The diagnosis and the classification of the cases were based on EEC and AHC. All incident ALS cases during the period 1998-1999 were enrolled and followed up. During the surveillance period, we identified 130 ALS incident cases, and bulbar-ALS represented 20% of our cohort. The highest risk for bulbar onset was among subjects aged >75 years [RR: 20.1, 95% confidence interval (CI) 3.4-118.0] compared with subjects aged <55 years and among females compared with males (Relative risk (RR): 2.75, 95% CI: 1-7.3). The vast majority of patients (72%) referred progressive muscle weakness in the limbs as the presenting symptom. Eighty percent of cases presented contemporary bulbar or spinal involvement; UMN signs in the bulbar region were present in 24% of cases and any motoneuronal sign in thoracic region in only 15% of the cases. In this population-based series, progressive muscle weakness was the most common presenting sign; bulbar onset was associated with advanced age and female sex. UMN signs in the bulbar region and any motoneuronal sign in the thoracic region were observed in 20% of our case series. This may represent the main limitation to show the spread of signs during diagnostic assessment for inclusion in epidemiological studies and clinical trials.

Plasma homocysteine levels in Parkinson's disease: role of antiparkinsonian medications.

Elevated plasma homocysteine (Hcy) concentrations have been reported in L-dopa treated Parkinson's disease (PD) patients, suggesting that L-dopa treatment is an acquired cause of hyperhomocysteinemia. Aim of this study is to evaluate the effects of different antiparkinsonian drugs on Hcy concentrations. We compared Hcy, B(12) and folate levels in 45 PD patients (15 treated with dopamine-agonists, 15 with L-dopa and 15 with L-dopa plus a catechol-O-methyltransferase-inhibitor (COMT-I) and in 15 controls. Analysis of data revealed that L-dopa administration significantly increases Hcy concentrations and that the addition of COMT-I effectively reduces the homocysteinemia.

Elevated homocysteine levels in Parkinson's Disease: is there anything besides L-dopa treatment?

BACKGROUND: Homocysteine (Hcy) exerts multiple neurotoxic mechanisms that have been linked to the pathogenesis of neurodegenerative disorders. Several studies observed elevated plasma Hcy levels in Parkinson's Disease (PD) patients treated with L-dopa, compared to healthy controls and to patients with other neurodegenerative disorders. OBJECTIVE: We performed an overview of published evidences assessing the possible correlations between Hcy levels and the incidence or pathogenesis of PD. METHODS: A Medline literature search was performed to identify all available studies on Hcy and the incidence or pathophysiology of PD up to 30/09/2009. RESULTS: 30 studies were included in this overview (20 studies on humans, 10 experimental studies). The relationship between metilentetrahydrofolate-reductase genotype (the most common genetic cause of hyperhomocysteinemia) and the development of PD was contradictory. Dietary patterns and B-vitamins levels (important determinants of Hcy levels) were associated with a not-significant increased risk of PD in three prospective studies. Investigations on plasma and cerebrospinalfluid Hcy concentrations in L-dopa naive PD patients gave conflicting results; some studies observed increased Hcy levels in L-dopa naïve PD patients compared to controls, while others found no difference. In vitro, Hcy caused dose-dependent depletion of dopaminergic mesencephalic neurons, by numerous pathogenetic mechanisms. In vivo brain administration of Hcy induced motor and behavioural changes, similar to those observed in animal models of PD. CONCLUSIONS: Based on the available data, the possibility that the hyperhomocysteinemia may contribute to the pathogenesis of PD remains uncertain. L-dopa treatment represents the major determinant of the hyperhomocysteinemia observed in PD.

Hyperhomocysteinemia in L-dopa treated patients with Parkinson's disease: potential implications in cognitive dysfunction and dementia?

BACKGROUND: Hyperhomocysteinemia has been associated with cognitive dysfunction and dementia. The incidence of dementia in Parkinson's Disease (PD) patients is higher than in the general population and plasma Homocysteine concentrations are increased in L-dopa treated PD patients. OBJECTIVE: We evaluated the possible correlations between L-Dopa related hyperhomocysteinemia and cognitive dysfunction in PD. METHODS: A Medline literature search was performed to identify all published studies on Homocysteine and cognitive dysfunction and dementia during the course of PD from 1966 to 31/03/2010. RESULTS: Sixteen studies were found for review; ten studies focused on homocysteine and cognitive dysfunction in PD patients, five on homocysteine and PD dementia and two on homocysteine and markers of neurodegeneration in PD. The design of the study was retrospective in 14 studies, while 2 had a prospective design, with a variable follow-up period (from 24-weeks to 2 years). In most of the studies plasma homocysteine levels significantly correlated with cognitive functions, dementia and markers of neurodegeneration in PD patients. However, some studies did not confirm these findings. Several factors may concur to explain these partially conflicting results, including the retrospective design of the studies, their small sample size, their high percentage of excluded patients, and the use of a wide range of neuropsychological tasks in assessment of cognitive dysfunctions across the available studies. CONCLUSIONS: Available data seem to indicate a potential role of L-dopa related hyperhomocysteinemia on cognitive impairment and dementia during the course of PD.

Elevated plasma homocysteine levels in patients with amyotrophic lateral sclerosis.

BACKGROUND: Both in vitro and in vivo studies indicate that homocysteine (Hcy) may be directly involved in the damage of motor neurons and in several pathways implicated in amyotrophic lateral sclerosis (ALS) pathogenesis. OBJECTIVE: To determine whether plasma Hcy levels were higher in ALS patients than healthy controls and to examine the relationship between Hcy levels and clinical ALS phenotypes. METHODS: In a cross-sectional study, we compared Hcy, B(12), and folate levels in 62 patients with ALS and 88 age- and sex-matched controls recruited as outpatients in a tertiary clinical center. RESULTS: Patients with ALS had higher median plasma Hcy levels (11.2 [range 5.8 to 46] vs 9.7 [range 4.5 to 15.9] micromol/L; p = 0.0004) and lower folate levels (4.4 [range 1.7 to 22.1] vs 5.8 [range 2.3 to 21.1] ng/mL; p = 0.0003), compared with controls. Multivariate logistic regression revealed a strong direct association between plasma Hcy levels and presence of ALS (odds ratios adjusted for age, sex, and B-vitamin levels comparing the top tertile [Hcy levels >or= 11.6 micromol/L] with the bottom tertile [Hcy levels < 9.2 micromol/L]: 6.4; 95% CI 2.2 to 19.1; p for trend = 0.0008). We also found a trend for higher Hcy levels in patients with shorter interval from symptom onset to diagnosis (ODI; <14 months), compared with patients with longer ODI (>14 months; median Hcy levels 11.8 [range 5.8 to 46] vs 10.1 [range 7.2 to 17.6] micromol/L; p = 0.09). In a multivariate model, Hcy levels strongly correlated with shorter interval onset diagnosis (r(2) = 0.18; p = 0.01). CONCLUSIONS: Plasma homocysteine (Hcy) levels were significantly increased in patients with amyotrophic lateral sclerosis (ALS) compared with healthy controls. ALS cases with shorter time to diagnosis presented higher Hcy levels, suggesting that higher Hcy may be linked to faster progression of the disease.

Classification of amyotrophic lateral sclerosis cases at presentation in epidemiological studies.

Amyotrophic lateral sclerosis (ALS) diagnosis is based exclusively on clinical grounds because of the absence of biological markers and of specific neuroradiological and neurophysiological diagnostic features. A clinical classification system of cases has been introduced (El Escorial Criteria, EEC) and then revised after the inclusion of the neurophysiologic assessment (Airlie House Criteria, AHC) for enrollment of patients in clinical trials. The aim of this study is to present cases at presentation in the early stages of the disease that have difficult allocation both in EEC and AHC. All cases were subjects enrolled through SLAP, a population-based registry based in Puglia, Southern Italy. Although differential diagnosis excluded ALS-mimic syndromes, we identified four cases (out of 130 cases, 3.1%) that did not meet the EEC and AHC at the first visit. Even though the number of unclassifiable cases is small, both EEC and AHC may be restrictive. This precludes the enrollment of ALS cases at an early stage both in observational studies and clinical trials.