Final answer:
Resting nystagmus usually indicates a condition in the vestibular system or brain stem such as Ménière's disease or brain stem damage affecting eye movement control.
Step-by-step explanation:
Resting nystagmus is typically suggestive of a condition affecting the vestibular system or brain stem. This involuntary eye movement, if present at rest, may be indicative of vestibular damage, such as that seen in conditions like Ménière's disease. It can also be related to damage in the dorsal brain stem which would affect the eye movement nuclei or their connections through the Medial Longitudinal Fasciculus (MLF). In cases of internuclear ophthalmoplegia, one eye may fail to abduct while the other adducts, causing the patient to experience diplopia, or double vision. The proper function of the eye movement nuclei and MLF is essential for stable and conjugate eye movements which are necessary to maintain a fixed visual field during head movement.