What are the key clinical features to assess when evaluating a patient with suspected cranial nerve palsy?

When evaluating a patient with suspected cranial nerve palsy, key clinical features to assess include the specific cranial nerve(s) involved, the pattern and severity of motor or sensory deficits, and associated symptoms such as diplopia, facial weakness, or sensory changes to help localize the lesion and determine urgency of referral ¹. Assessment should focus on detailed ocular motor examination for nerves III, IV, and VI palsies, including evaluation of eye movements, ptosis, and pupil size/reactivity, as isolated abducens nerve palsies often present with horizontal diplopia and impaired lateral gaze (Tan and Lin, 2025). Facial nerve palsy assessment involves checking for asymmetry in facial expression, taste disturbance, and hyperacusis, while trigeminal nerve involvement requires sensory testing of the face and corneal reflex ¹. Additional features to assess include the onset and progression of symptoms, presence of pain or headache, and any systemic signs that may suggest underlying causes such as infection, inflammation, or neoplasm ¹. Recent literature highlights that in the context of COVID-19, isolated cranial nerve palsies, particularly abducens nerve palsy, may occur with a relatively benign course but still require thorough neurological evaluation to exclude other causes (Tan and Lin, 2025). Overall, a comprehensive neurological examination combined with detailed history-taking is essential to guide appropriate urgent referral and management ¹.