Research sheds light on how neurons control muscle movement

Stanford: New research involving people diagnosed with Lou Gehrig’s disease sheds light on how individual neurons control muscle movement in humans — and could help in the development of better brain-controlled prosthetic devices. Stanford University researchers studying how the brain controls movement in people with paralysis, related to their diagnosis of Lou Gehrig’s disease, have found that groups of neurons work together, firing in complex rhythms to signal muscles about when and where to move.

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive muscular paralysis reflecting degeneration of motor neurones. The mean age of onset is about 60. ALS usually present with dysarthria and dysphagia for solid or liquids (bulbar onset), and limb symptoms (muscle weakness and spasticity). Paralysis is progressive and leads to death due to respiratory failure within 2–3 years for bulbar onset cases and 3–5 years for limb onset ALS cases.
More about  amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (in short)

• Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive muscular paralysis reflecting degeneration of motor neurones in the primary motor cortex, corticospinal tracts, brainstem and spinal cord. 
• Incidence (average 1.89 per 100,000/year) and prevalence (average 5.2 per100,000) are relatively uniform in Western countries, although foci of higher frequency occur in the Western Pacific. 
• The mean age of onset for sporadic ALS is about 60 years. 
• Overall, there is a slight male prevalence (M:F ratio~1.5:1). 
• Approximately two thirds of patients with typical ALS have a spinal form of the disease (limb onset) and present with symptoms related to focal muscle weakness and wasting, where the symptoms may start either distally or proximally in the upper and lower limbs. 
• Gradually, spasticity may develop in the weakened atrophic limbs, affecting manual dexterity and gait.
• Patients with bulbar onset ALS usually present with dysarthria and dysphagia for solid or liquids, and limbs symptoms can develop almost simultaneously with bulbar symptoms, and in the vast majority of cases will occur within 1–2 years. 
• Paralysis is progressive and leads to death due to respiratory failure within 2–3 years for bulbar onset cases and 3–5 years for limb onset ALS cases. 
• Most ALS cases are sporadic but 5–10% of cases are familial, and of these 20% have a mutation of the SOD1 gene and about 2–5% have mutations of the TARDBP (TDP-43) gene. Two percent of apparently sporadic patients have SOD1 mutations, and TARDBP mutations also occur in sporadic cases. 
• The diagnosis is based on clinical history, examination, electromyography, and exclusion of 'ALS-mimics' (e.g. cervical spondylotic myelopathies, multifocal motor neuropathy, Kennedy's disease) by appropriate investigations. 
• The pathological hallmarks comprise loss of motor neurones with intraneuronal ubiquitin-immunoreactive inclusions in upper motor neurones and TDP-43 immunoreactive inclusions in degenerating lower motor neurones. 
• Signs of upper motor neurone and lower motor neurone damage not explained by any other disease process are suggestive of ALS. 
• The management of ALS is supportive, palliative, and multidisciplinary. Non-invasive ventilation prolongs survival and improves quality of life. 
• Riluzole (Rilutek, Riluzole Zentiva) is the only drug that has been shown to extend survival. 

Source: Lokesh C Wijesekera and P Nigel Leigh. Orphanet Journal of Rare Diseases

Amyotrophic lateral sclerosis

Source: Lokesh C Wijesekera and P Nigel Leigh. Orphanet Journal of Rare Diseases

 

Disease names

Amyotrophic lateral sclerosis (ALS), Motor neurone disease (MND), Charcot's disease, Lou Gehrig's disease

Included diseases

Amyotrophic lateral sclerosis (ALS) is a term used to cover the spectrum of neurodegenerative syndromes characterised by progressive degeneration of motor neurones. However, it is also the term used in modern clinical practice to indicate the commonest form of the disease, Classical (Charcot's) ALS.