A man with amyotrophic lateral sclerosis (ALS). (A) He needs assistance to stand. (B) Advanced atrophy of the tongue. (C) There is upper limb and truncal muscle atrophy with a positive Babinski sign. (D) Advanced thenar muscle atrophy. Signs and symptoms depend on the specific<unk> , but<unk> s typically manifest as a group of movement-related symptoms. They come on slowly, and worsen over the course of more than three months. Various patterns of muscle weakness are seen, and muscle cramps and spasms may occur. One can have difficulty breathing with climbing stairs (exertion), difficulty breathing when lying down (orthopnea), or even respiratory failure if breathing muscles become involved. Bulbar symptoms, including difficulty speaking (dysarthria), difficulty swallowing (dysphagia), and excessive saliva production (sialorrhea), can also occur. Sensation, or the ability to feel, is typically not affected. Emotional disturbance (e.g. pseudobulbar affect) and cognitive and behavioural changes (e.g. problems in word fluency, decision-making, and memory) are also seen. There can be lower motor neuron findings (e.g. muscle wasting, muscle twitching), upper motor neuron findings (e.g. brisk reflexes, Babinski reflex, Hoffman's reflex, increased muscle tone), or both.<unk> s are seen both in children and in adults. Those that affect children tend to be inherited or familial, and their symptoms are either present at birth or appear before learning to walk. Those that affect adults tend to appear after age 40. The clinical course depends on the specific<unk> , but most progress or worsen over the course of months. Some are fatal (e.g. ALS), while others are not (e.g. PLS). Patterns of weakness Various patterns of muscle weakness occur in different<unk> s. Weakness can be symmetric or asymmetric, and it can occur in body parts that are distal, proximal, or both. According to Statland et al., there are three main weakness patterns that are seen in<unk> s, which are: # Asymmetric distal weakness without sensory loss (e.g. ALS, PLS, PMA, MMA) # Symmetric weakness without sensory loss (e.g. PMA, PLS) # Symmetric focal midline proximal weakness (neck, trunk, bulbar involvement; e.g. ALS, PBP, PLS) Lower and upper motor neuron findings<unk> s are on a spectrum in terms of upper and lower motor neuron involvement. Some have just lower or upper motor neuron findings, while others have a mix of both. Lower motor neuron (LMN) findings include muscle atrophy and fasciculations, and upper motor neuron (UMN) findings include hyperreflexia, spasticity, muscle spasm, and abnormal reflexes. Pure upper<unk> s, or those with just UMN findings, include PLS. Pure lower<unk> s, or those with just LMN findings, include PMA.<unk> s with both UMN and LMN findings include both familial and sporadic ALS.
Motor neuron disease
Vascular myelopathy
Polyneuropathy
Basal ganglia disease
Upper motor neuron syndrome
Distal hereditary motor neuronopathies
Tropical ataxic neuropathy
Amyotrophic lateral sclerosis