Physical Therapy Assistant Practice Exam 2026 – Complete Prep Guide

Multiple sclerosis is characterized by the demyelination of white matter in the central nervous system (CNS). In this condition, the immune system mistakenly attacks the myelin sheath, which is the protective covering that surrounds nerve fibers. This demyelination disrupts the normal conduction of electrical impulses between the brain and the rest of the body, leading to a wide array of neurological symptoms. These symptoms can include weakness, vision problems, sensory disturbances, and difficulties with coordination and balance. The progression and manifestation of these symptoms can vary significantly between individuals, further complicating the clinical presentation of the disease.

In contrast, the other conditions listed, while they may involve neurological symptoms, do not primarily involve the demyelination of the CNS. Huntington's disease is a genetic disorder that primarily affects movement and cognition due to neurodegeneration in specific brain areas. Guillain-Barre syndrome involves the peripheral nervous system and is characterized by rapid-onset muscle weakness, typically triggered by an infection. Myasthenia gravis is an autoimmune disorder that affects communication between nerves and muscles, primarily causing muscle weakness but not involving demyelination of CNS white matter.