Amyotrophic Lateral Sclerosis Signs and Symptoms

Once a motor neuron degenerates completely, the muscle that it controls no longer receives impulses from the brain. Approximately 60% of ALS patients experience muscle weakness and stiffness as the initial symptom. Usually the first muscles affected are those in the arms and legs. Walking or climbing stairs may be difficult. The patient may drop things, fall, experience muscle cramps, and laugh or cry uncontrollably. The arms and legs may feel especially tired. If the hands are affected, the patient may have difficulty picking up small objects or turning keys. Speech problems, such as slurring, hoarseness, or decreased volume may also occur.

ALS signs and symptoms include the following:

  • Absence of spinal reflexes (areflexia)
  • Loss of muscle tone (hypotonia)
  • Muscle twitching (fasciculations)
  • Muscle wasting (atrophy)

The signs that the upper motor neurons are affected include the following:

  • Excessive salivation
  • Extension of the big toe and abduction of the rest of the toes in response to lightly stroking the sole of the foot (Babinski's sign)
  • Frontotemporal dementia (FTD)
  • Hyperactive tendon reflexes
  • Impaired speech (dysarthria)
  • Impaired swallowing (dysphagia)
  • Increased muscle tone and rigidity (spasticity)
  • Rapidly alternating muscle contractions and relaxations (clonus)

As symptoms progressively worsen, the patient's muscles atrophy causing spasticity, stiffness, abnormal movements, and alterations in gait and manual dexterity. Twitching may occur in the tongue and in affected limbs. The patient may experience muscle pain and muscle cramps. Some patients experience more difficulty swallowing saliva and liquids than solid food. Excessive salivation and difficulty swallowing may cause drooling. When respiratory muscles weaken, the patient may require a ventilator.

ALS patients often experience fear, anxiety, and depression.

Publication Review By: Gordon R. Kelley, M.D., Stanley J. Swierzewski, III, M.D.

Published: 02 Jan 2000

Last Modified: 28 Nov 2011