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.

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 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.

A novel KIF5A mutation in an Italian family marked by spastic paraparesis and congenital deafness.

Hereditary spastic paraplegia (HSP) includes a group of diseases characterized by progressive spastic weakness of the lower limbs (pure forms) with possible additional signs (complicated forms). The SPG10 form is due to alteration in the kinesin1A gene (KIF5A) that encodes the neuronal kinesin heavy chain, a protein required for the anterograde axonal transport. We performed clinical, neurophysiological and molecular studies in two siblings affected by AD-HSP complicated by deafness. The screening of the KIF5A gene revealed the novel mutation p.Leu259Gln in two affected siblings and in their father with a pure form of HSP.

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.