35. Oculocephalic Testing
What is Being Tested?
Careful testing of eye movements can often identify abnormalities in individual muscles or in particular cranial nerves (oculomotor, trochlear, or abducens)— in their course from the brainstem to the orbit, in the brainstem nuclei, or finally, in the higher-order centers and pathways in the cortex and brainstem that control eye movements (review Neuroanatomy Through Clinical Cases 3e, Table 2.5; see also Chapter 13 for more details). Spontaneous nystagmus can indicate toxic or metabolic conditions such as drug overdose, alcohol intoxication, or peripheral or central vestibular dysfunction (see Hearing and Vestibular Sense (CN VIII) page).