Ocular bobbing consists of rhythmic downward jerks of the eyes followed by a slow return to the midposition. It is associated with pontine haemorrhage or infarction, which might also cause concurrent horizontal gaze palsies, and metabolic or toxic disorders1.
1. Typical bobbing (initial phase: fast and down)
Rhythmic, downward jerks, followed by slow return to mid-position. This is associated with bilateral horizontal gaze palsies (including horizontal vestibulo-ocular response with no response to caloric testing)
Causes
1. Intrinsic pontine lesion (eg, infarct or hemorrhage)
2. Cerebellar hemorrhage compressing the pons
3. Subarachnoid hemorrhage from aneurysms of the posterior circulation
(vv)bobbing.mp4(tt)
From: Wijdicks EFM. The Comatose patient. VC 3-5: Eye Movements in Coma. Oxford Medicine Online.
Retrieved from: https://oxfordmedicine.com/view/10.1093/med/9780199331215.001.0001/med-9780199331215-appendix-6
2. Aypical bobbing (initial phase: fast and down)
Identical to typical bobbing, except there is some horizontal gaze present.
3. Reverse bobbing (initial phase: fast and up)
Reverse bobbing is characterized by upward jerks, followed by a slow return to midposition.
Causes
Metabolic encephalopathes, including phenothiazine and benzodiazepine intoxication.
4. Ocular dipping or inverse bobbing (initial phase: slow and down)
Ocular dipping is characterized by slow, downward movements over 2 seconds, which remain tonically depressed for 2–10 sec, followed by rapid return to mid-position.
Causes
Anoxic coma, carbon monoxide poisoning, status epilepticus, or head trauma.