Final answer:
A post-rotary nystagmus lasting greater than 10 seconds indicates vestibular dysfunction. This can be caused by various conditions and may require further evaluation and treatment.
Step-by-step explanation:
A post-rotary nystagmus lasting greater than 10 seconds indicates vestibular dysfunction. Nystagmus refers to involuntary eye movement, and the post-rotary nystagmus is a type of nystagmus that occurs after spinning or rotational movement. In a normal vestibular system, the nystagmus should only last a few seconds after spinning, but if it lasts longer than 10 seconds, it suggests an abnormal response.
Vestibular dysfunction refers to problems with the vestibular system, which is responsible for maintaining balance and spatial orientation. It can be caused by various conditions such as inner ear disorders, head injuries, medication side effects, or neurological disorders. Persistent post-rotary nystagmus can be a sign of underlying vestibular dysfunction and may require further evaluation and treatment.