Which motor functions are preserved in amyotrophic lateral sclerosis (ALS)?

Updated: Jun 14, 2018
  • Author: Carmel Armon, MD, MSc, MHS; Chief Editor: Nicholas Lorenzo, MD, MHCM, CPE, FAAPL  more...
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Certain motor neurons usually are spared in ALS, which means that some functions are preserved. Most patients retain extraocular movements and bowel and bladder control. With progressive disease, patients may develop problems with urge incontinence and constipation because of weak abdominal musculature, but sphincter control generally is unaffected.

Since the disease primarily involves motor neurons, sensory function typically is preserved, although a minority of patients complains of some numbness and paresthesias. Abnormalities have been reported on sensory nerve conduction studies in a small number of patients with ALS, [159] but these findings often reflect the presence of an unrelated, coexistent condition.

Skin integrity in ALS usually is maintained, primarily due to the combination of preserved sensory function and continued control of bowel and bladder function. Some studies of patients with ALS have found morphologic changes in the skin that are complex and poorly understood but that may contribute to preservation of skin integrity.

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