 Medications that have been associated include Lithium, sulpiride, and a meperidine analog, 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine.ALO is often a benign and unilateral condition, and extensive evaluation may not be necessary.The diagnosis may be a clinical diagnosis based on a thorough history and physical exam, and being able to exclude other diagnoses and pathology.