Amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease of the motor neurons — the nerve cells in the brain (upper motor neurons) and spinal cord (lower motor neurons) responsible for voluntary movement. As these neurons degenerate, the muscles they control progressively weaken, atrophy, and eventually cease to function. Sensation, bladder control, eye movement, and cognition are typically spared until late in the disease.

The cause is unknown in the majority of cases (sporadic ALS), though about 5–10% are familial with identified genetic mutations (including SOD1). Both toxic, viral, and endocrine mechanisms have been proposed.

**Symptoms** depend on which motor neurons degenerate first: - Limb-onset ALS: weakness and clumsiness in a hand, arm, or leg — often the first sign - Bulbar-onset ALS: slurred speech (dysarthria) and difficulty swallowing (dysphagia) — more common in women and older patients - Muscle atrophy, fasciculations (visible muscle twitches), and cramps - Spasticity and exaggerated reflexes (from upper motor neuron loss) - Emotional lability — involuntary laughing or crying

As the disease advances, respiratory muscle weakness develops, eventually requiring mechanical ventilatory support.

**No disease-modifying cure exists.** Riluzole — the only drug shown to modestly slow ALS progression — extends survival by a few months. Management therefore focuses on: - Controlling spasticity (Botox injections, intrathecal baclofen pump) - Maintaining mobility and strength through physiotherapy - Respiratory support (non-invasive ventilation, diaphragm pacemaker in selected cases) - Nutritional support (gastrostomy when swallowing becomes unsafe) - Speech and communication aids - Neuromodulation (rTMS) for symptomatic benefit and quality of life - Psychological and social support

Early, multidisciplinary rehabilitation — including physical, adaptive, cognitive, social, functional, and speech components — is the single most effective way to preserve quality of life and reduce dependence on others.