Motor-evoked potentials in amyotrophic lateral sclerosis: potential implications in detecting subclinical UMN involvement in lower motor neuron phenotype.

BACKGROUND: In amyotrophic lateral sclerosis (ALS), the involvement of lower motor neuron is well defined by electromyography, whereas a reliable marker of upper motor neuron (UMN) damage still lacks. Aim of the study was to estimate the role of transcranial magnetic stimulation (TMS)-induced motor-evoked potentials (MEPs) as marker of subclinical UMN involvement. METHODS: Clinical evidence of UMN damage was prospectively compared to MEPs in 176 ALS patients diagnosed between 2011 and 2014, and classified according to existing diagnostic criteria. Finally, we evaluated the appearance of clinical UMN signs and the level of diagnostic certainty in ALS after 1 year of follow-up. RESULTS: At presentation, abnormal MEPs were found in 80% of patients with clinical evidence of UMN damage and in 72% of patients without clinical involvement of UMN. Among these latter, 61% showed appearance of UMN clinical signs after 1 year. Approximately 70% of patients with clinical lower motor neuron (LMN) phenotype showed MEP abnormalities, while they were considered not classifiable ALS according to Airlie house or Awaji criteria. Furthermore, abnormal MEPs in absence of clinical UMN signs at baseline were found in 80% of spinal ALS that after 1-year developed UMN signs at limbs, compared to 50% of bulbar ALS. CONCLUSIONS: TMS is a reliable marker of subclinical UMN damage particularly among LMN phenotype and ensure an early ALS diagnosis in ~ 70% of such cases.

Diagnostic and prognostic power of CSF Tau in amyotrophic lateral sclerosis.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that still lacks reliable diagnostic biomarkers. This study aims to evaluate the diagnostic and prognostic potential of CSF total Tau (t-Tau), phospho-Tau (p-Tau) and p-Tau/t-Tau ratio in ALS patients using CSF neurofilament light (NFL) as the reference biomarker. METHODS: Eighty-five incident ALS, 30 ALS-mimicking (AM) diseases and 51 other non-neurodegenerative diseases (ONND) were included in the study. RESULTS: ALS patients had higher levels of CSF t-Tau and lower p-Tau/t-Tau ratio than AM (p = 0.005 and p = 0.006) and ONND (p < 0.001). CSF t-Tau levels discriminated ALS from AM with a sensitivity of 69% and specificity of 60%, and from ONND with a sensitivity of 88% and specificity of 51%. These values were lower than the accuracy of CSF NFL in ALS (sensitivity 86% and specificity 87% in distinguishing ALS from AM and sensitivity 83% and specificity 75% from ONND); CSF t-Tau correlated with progression rate and SNIP. CSF p-Tau did not show relation with any ALS clinical features. CSF NFL significantly correlated with all considered clinical parameters. High levels of CSF t-Tau and NFL were related to poor survival. CONCLUSION: CSF t-Tau showed no reliable diagnostic significance but the relation between the high levels of CSF t-Tau and short survival suggests the potential prognostic role of this biomarker in ALS. However, CSF NFL was confirmed to be the most reliable and efficient tool for diagnosis and prediction of clinical progression and survival in ALS patients.

Adherence to riluzole in patients with amyotrophic lateral sclerosis: an observational study.

OBJECTIVE: Riluzole is the first drug approved to treat amyotrophic lateral sclerosis (ALS). Recently, an oral suspension (OS) of riluzole was made available. Thus, the aim of our study was to evaluate the adherence to 2 formulations of riluzole in patients with ALS. PATIENTS AND METHODS: We enrolled 45 consecutive patients with ALS. At disease diagnosis, riluzole was prescribed in 2 different formulations depending on the severity of dysphagia (27/45 patients received tablets and 18/45 patients received OS). Side effects (SEs) and treatment adherence were investigated using a clinical questionnaire including the ©Morisky 8-item Medication Adherence Questionnaire. RESULTS: Gastroenteric complaints were the most frequent SEs (58% in the tablet group and 48% in the OS group), followed by those at the nervous system (29% and 40%, respectively). No serious SEs related to treatment were reported. The rate of adherence to riluzole was independent of the formulation of the drug and consistent with other medications assumed for comorbidities (p=0.004). In the tablet group, low adherence was caused by SEs in 55.6% and by dysphagia in 44.4% of patients. In the OS group, SEs caused low adherence in 75% of patients. Independently of the drug formulation, patients with high or medium adherence to riluzole had a higher progression rate (p=0.002 and p=0.009, respectively) and a shorter time to generalization (TTG; p=0.01), compared to those with low adherence. CONCLUSION: Gastroenteric symptoms were the most frequent SE related to tablet as well as OS. The rate of adherence was independent of the formulation of riluzole and the number of medications assumed for comorbidities, and it was consistent with the severity of the disease. The low adherence was caused by dysphagia and SEs in the tablet group, whereas it was caused prevalently by SEs in the OS group.