Which medical condition is characterized by a loss of motor control and spasticity as a primary symptom?

Multiple sclerosis is primarily characterized by a loss of motor control and spasticity due to the degeneration of myelin in the central nervous system. This demyelination disrupts the communication between the brain and the muscles, leading to various symptoms including muscle weakness, spasms, and difficulties with coordination and balance. The presence of spasticity, which is an increase in muscle tone leading to stiffness and involuntary muscle contractions, is particularly prominent in individuals with this condition.

In contrast, Parkinson's disease primarily involves motor symptoms such as tremors and rigidity, but spasticity is not a defining feature. Alzheimer's disease is primarily associated with cognitive decline and memory loss rather than motor control issues. Epilepsy involves seizures, which can affect motor function during an episode but is not characterized by consistent loss of motor control and spasticity as seen in multiple sclerosis. Thus, multiple sclerosis is the medical condition that fits the description of loss of motor control and spasticity as a primary symptom.