Safety and efficacy of botulinum toxin A for the treatment of spasticity in amyotrophic lateral sclerosis: results of a pilot study

Primary Lateral Sclerosis: An Overview

Primary lateral sclerosis (PLS) is a rare neurodegenerative disorder which causes the selective deterioration of the upper motor neurons (UMNs), sparing the lower motor neuron (LMN) system. The clinical course is defined by a progressive motor disability due to muscle spasticity which typically involves lower extremities and bulbar muscles. Although classically considered a sporadic disease, some familiar cases and possible causative genes have been reported. Despite it having been recognized as a rare but distinct entity, whether it actually represents an extreme end of the motor neuron diseases continuum is still an open issue. The main knowledge gap is the lack of specific biomarkers to improve the clinical diagnostic accuracy. Indeed, the diagnostic imprecision, together with some uncertainty about overlap with UMN-predominant ALS and Hereditary Spastic Paraplegia (HSP), has become an obstacle to the development of specific therapeutic trials. In this study, we provided a comprehensive analysis of the existing literature, including neuropathological, clinical, neuroimaging, and neurophysiological features of the disease, and highlighting the controversies still unsolved in the differential diagnoses and the current diagnostic criteria. We also discussed the current knowledge gaps still present in both diagnostic and therapeutic fields when approaching this rare condition.

The Role of Specialty Palliative Care for Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a progressive and incurable neurodegenerative disease resulting in the loss of motor neurons, eventually leading to death. ALS results in complex physical, emotional, and spiritual care needs. Specialty Palliative Care (SPC) is a medical specialty for patients with serious illness that provides an extra layer of support through complicated symptom management, goals of care conversations, and support to patients and families during hard times. Using MEDLINE, APA Psychinfo, and Dynamed databases, we reviewed the literature of SPC in ALS to inform and support an expert opinion perspective on this topic. This manuscript focuses on several key areas of SPC for ALS including insurance and care models, advance care planning, symptom management, quality of life, caregiver support, and end-of-life care. Recommendations to improve specialty palliative care for patients with ALS are reviewed in the discussion section.

Neurotrophic effects of Botulinum neurotoxin type A in hippocampal neurons involve activation of Rac1 by the non-catalytic heavy chain (HCC/A)

Botulinum neurotoxins (BoNTs) are extremely potent naturally occurring poisons that act by silencing neurotransmission. Intriguingly, in addition to preventing presynaptic vesicle fusion, BoNT serotype A (BoNT/A) can also promote axonal regeneration in preclinical models. Here we report that the non-toxic C-terminal region of the receptor-binding domain of heavy chain BoNT/A (HCC/A) activates the small GTPase Rac1 and ERK pathway to potentiate axonal outgrowth, dendritic protrusion formation and synaptic vesicle release in hippocampal neurons. These data are consistent with HCC/A exerting neurotrophic properties, at least in part, independent of any BoNT catalytic activity or toxic effect.

Comparison of Two Clinical Upper Motor Neuron Burden Rating Scales in ALS Using Quantitative Brain Imaging

Several clinical upper motor neuron burden scales (UMNSs) variably measure brain dysfunction in amyotrophic lateral sclerosis (ALS). Here, we compare relationship of two widely used clinical UMNSs in ALS (Penn and MGH UMNSs) with (a) neuroimaging markers of brain dysfunction and (b) neurological impairment status using the gold-standard functional measure, the revised ALS Functional Rating Scale (ALSFRS-R). MGH UMNS measures hyperreflexia alone, and Penn UMNS measures hyperreflexia, spasticity, and pseudobulbar affect. Twenty-eight ALS participants underwent both Penn and MGH UMNSs, at a matching time-point as a simultaneous [¹¹C]PBR28 positron emission tomography (PBR28-PET)/Magnetic Resonance scan and ALSFRS-R. The two UMNSs were compared for localization and strength of association with neuroimaging markers of: (a) neuroinflammation, PBR28-PET and MR Spectroscopy metabolites (myo-inositol and choline) and (b) corticospinal axonal loss, fractional anisotropy (FA), and MR Spectroscopy metabolite (N-acetylaspartate). Among clinical UMN manifestations, segmental hyperreflexia, spasticity, and pseudobulbar affect occurred in 100, 43, and 18% ALS participants, respectively. Pseudobulbar affect did not map to any specific brain regional dysfunction, while hyperreflexia and spasticity subdomains significantly correlated and colocalized neurobiological changes to corticospinal pathways on whole brain voxel-wise analyses. Both UMNS total scores showed significant and similar strength of association with (a) neuroimaging changes (PBR28-PET, FA, MR Spectroscopy metabolites) in primary motor cortices and (b) severity of functional decline (ALSFRS-R). Hyperreflexia is the most frequent clinical UMN manifestation and correlates best with UMN molecular imaging changes in ALS. Among Penn UMNS's subdomains, hyperreflexia carries the weight of association with neuroimaging markers of biological changes in ALS. A clinical UMN scale comprising hyperreflexia items alone is clinically relevant and sufficient to predict the highest yield of molecular neuroimaging abnormalities in ALS.

Prevalence of spasticity and spasticity-related pain among patients with Amyotrophic Lateral Sclerosis

Although they are common symptoms of ALS, there is little information on the prevalence of spasticity and spasticity-related pain. Consecutive patients were prospectively recruited from an ALS referral center. Clinical assessment, functional scores, features of spasticity-related pains has been recorded. In a cohort of 150 patients, 36% presented with spasticity. Spastic patients were younger, with a longer duration of disease. Spasticity accelerates the functional decline of patients. Spasticity-related pain was reported in 42.5% of spastic patients with mild pain. However, 16.7% of spastic patients presented significant pain with numeric rating scale≥4. More clinical trials are needed to treat spasticity more effectively and to relieve ALS patients.

Magnetization transfer ratio: a quantitative imaging biomarker for 5q spinal muscular atrophy

BACKGROUND AND PURPOSE

We quantified peripheral nerve lesions in adults with 5q-linked spinal muscular atrophy (SMA) type 3 by analysing the magnetization transfer ratio (MTR) of the sciatic nerve, and tested its potential as a novel biomarker for macromolecular changes.

METHODS

Eighteen adults with SMA 3 (50% SMA 3a, 50% SMA 3b) and 18 age-/sex-matched healthy controls prospectively underwent magnetization transfer contrast imaging in a 3-Tesla magnetic resonance scanner. Two axial three-dimensional gradient echo sequences, with and without an off-resonance saturation rapid frequency pulse, were performed at the right distal thigh. Sciatic nerve regions of interest were manually traced on 10 consecutive axial slices in the images generated without off-resonance saturation, and then transferred to corresponding slices generated by the sequence with the off-resonance saturation pulse. Subsequently, MTR and cross-sectional areas (CSAs) of the sciatic nerve were analysed. In addition, detailed neurologic, physiotherapeutic and electrophysiologic examinations were conducted in all patients.

RESULTS

Sciatic nerve MTR and CSA reliably differentiated between healthy controls and SMA 3, 3a or 3b. MTR was lower in the SMA 3 (P < 0.0001), SMA 3a (P < 0.0001) and SMA 3b groups (P = 0.0020) than in respective controls. In patients with SMA 3, MTR correlated with all clinical scores, and arm nerve compound motor action potentials (CMAPs). CSA was lower in the SMA 3 (P < 0.0001), SMA 3a (P < 0.0001) and SMA 3b groups (P = 0.0006) than in controls, but did not correlate with clinical scores or electrophysiologic results.

CONCLUSIONS

Magnetization transfer ratio is a novel imaging marker that quantifies macromolecular nerve changes in SMA 3, and positively correlates with clinical scores and CMAPs.

Botulinum Toxin Type A and Physiotherapy in Spasticity of the Lower Limbs Due to Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease (unknown pathogenesis) of the central nervous system that causes death within 1-5 years. Clinically, flabby paralysis, areflexia, muscular atrophy, and muscle fasciculations, signs of II motor neuron damage, appear. Sometimes, clinical manifestations of damage of the I motor neuron come out in lower limbs; spastic paralysis, iperflexia, and clonus emerge, and they impair deambulation and management of activities of daily living, such as personal hygiene or dressing. Thus, the first therapeutic approach in these patients involves antispasmodic drugs orally followed by botulinum toxin type A injection (BTX-A). In this study, we study the efficacy of BTX-A and physiotherapy in lower limb spasticity due to ALS and no response to treatment with oral antispastic drugs. We evaluated 15 patients (10 male and five female), with a mean age of 48.06 ± 5.2 with spasticity of adductor magnus (AM), at baseline (T0, before BTX-A treatment) and in the following three follow-up visits (T1 30 days, T2 60 days, and T3 90 days after infiltration). We evaluated myometric measure of muscle tone, the Modified Ashworth Scale of AM, Barthel Index, Adductor Tone Rating Scale, and Hygiene Score. The study was conducted between November 2018 and April 2019. We treated AM with incobotulinum toxin type A (Xeomin®, Merz). Spasticity (myometric measurement, Adductor Tone Rating Scale, and Modified Ashworth Scale) and clinical (Barthel Index and Hygiene Score) improvements were obtained for 90 days after injection (p < 0.05). Our study shows the possibility of using BTX-A in the treatment of spasticity in patients with ALS and no response to oral antispastic drugs, with no side effects. The limitation of the study is the small number of patients and the limited time of observation; therefore, it is important to increase both the number of patients and the observation time in future studies.

Motor neurone disease

Motor neurone disease (MND) patients exhibit poor gait, balance, and postural control, all of which significantly increases their risk of falling. Falls are frequent in the MND population, and are associated with an increased burden of disease. The complex interplay of both motor and extramotor manifestations in this disease contributes to the heterogeneous and multifactorial causes of such dysfunction. This review highlights the pathophysiologic influence of motor degeneration in gait disturbance, but also the additional influence on postural instability from other inputs such as cognitive impairment, autonomic dysregulation, cerebellar dysfunction, sensory impairment, and extrapyramidal involvement. In various combinations, these impairments are responsible for reduced gait speed and alteration in gait cycle, as well as structurally more variable and disorganized gait patterns. Based on these features, this chapter will also provide disease-specific interventions to assess, manage, and prevent falls in the MND cohort.

Disease-modifying and symptomatic treatment of amyotrophic lateral sclerosis

In this review, we summarize the most important recent developments in the treatment of amyotrophic lateral sclerosis (ALS). In terms of disease-modifying treatment options, several drugs such as dexpramipexole, pioglitazone, lithium, and many others have been tested in large multicenter trials, albeit with disappointing results. Therefore, riluzole remains the only directly disease-modifying drug. In addition, we discuss antisense oligonucleotides (ASOs) as a new and potentially causal treatment option. Progress in symptomatic treatments has been more important. Nutrition and ventilation are now an important focus of ALS therapy. Several studies have firmly established that noninvasive ventilation improves patients' quality of life and prolongs survival. On the other hand, there is still no consensus regarding best nutritional management, but big multicenter trials addressing this issue are currently ongoing. Evidence regarding secondary symptoms like spasticity, muscle cramps or sialorrhea remains generally scarce, but some new insights will also be discussed. Growing evidence suggests that multidisciplinary care in specialized clinics improves survival.

Care management in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive and fatal neurodegenerative disease characterized by progressive weakness of voluntary muscles of movement as well as those for swallowing, speech and respiration. In the absence of curative treatment, care can improve quality of life, prolong survival, and support ALS patients and their families, and also help them to anticipate and prepare for the end of life. Multidisciplinary management in tertiary centers is recommended in close collaboration with general practitioners, home carers and a dedicated health network. Patients' follow-up deals mainly with motor impairment and physical disability, adaptation, nutrition and respiratory function. Involvement of palliative care as part of the multidisciplinary team management offers patients the possibility of discussing their end of life issues. This review summarizes the different aspects of ALS care, from delivering the diagnosis to the end of life, and the organization of its management.