Internuclear ophthalmoplegia is most commonly associated with which condition?

Internuclear ophthalmoplegia (INO) is most commonly associated with multiple sclerosis, a condition known for causing demyelination in the central nervous system. INO occurs due to a lesion in the medial longitudinal fasciculus (MLF), a pathway that coordinates horizontal eye movements. In multiple sclerosis, demyelination can affect this pathway, leading to the inability to adduct one eye when the other moves laterally, along with potential nystagmus in the abducting eye.

While some other disorders can impact eye movements, they are not typically associated with the specific pattern of eye movement seen in INO. In patients with amyotrophic lateral sclerosis, myasthenia gravis, or Huntington's chorea, the motor pathways may be compromised in different ways that do not specifically lead to the classic presentation of INO. Thus, multiple sclerosis stands out as the primary condition linked to this neurological phenomenon. The choice of multiple sclerosis as the correct answer highlights the importance of understanding how demyelination affects eye movement coordination.