Amyotrophic Lateral Sclerosis: Understanding Its Symptoms And Effects

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease, typically manifests in middle age and is more common in men than women, with a prevalence ratio of approximately (1.2–2.5):1. Classified as a rare condition, ALS often presents without clear symptoms in its early stages. As the disease progresses, however, noticeable signs such as muscle weakness, atrophy, and pyramidal tract involvement may appear. While most patients experience motor-related symptoms, a smaller percentage may develop atypical features such as cognitive decline and sensory disturbances, which can affect mobility and daily functioning.

Primary Symptoms Of ALS

Muscle Weakness And Atrophy

One of the earliest and most common symptoms is muscle weakness and atrophy, which can lead to clumsiness and reduced strength in one or both hands. As the condition worsens, the muscles of the hand may experience significant wasting, especially in the thenar and hypothenar eminences. Over time, this atrophy can progress, causing the hands to take on a claw-like appearance known as "eagle claw deformity." The muscle degeneration often extends to the forearm and upper arm, further limiting movement. When the muscles involved in speech, swallowing, and breathing are affected, patients may develop dysphagia, dysarthria, respiratory difficulties, and in severe cases, respiratory failure.

Muscle Twitching (Fasciculations)

Damage to motor neurons can cause visible muscle twitching, known as fasciculations. These involuntary contractions can occur in various muscle groups and are often an early indicator of ALS, although they may also be present in other neuromuscular conditions.

Pyramidal Tract Involvement

When the pyramidal tracts are affected, patients may develop spastic paralysis, characterized by increased muscle tone, hyperactive reflexes, and positive pathological signs such as the Babinski reflex. These neurological changes contribute to difficulties in coordination and movement control.

Less Common Symptoms

In addition to the primary motor symptoms, some individuals may experience non-motor manifestations. These can include cognitive impairments such as dementia, extrapyramidal symptoms similar to Parkinson's disease, sensory abnormalities, and issues with bladder and bowel function. A small percentage of patients may also develop oculomotor dysfunction, affecting the movement of the eyes. When these atypical symptoms are present alongside classic ALS features, the condition is referred to as atypical motor neuron disease, highlighting its complex and variable presentation.