Which neurological symptom is commonly associated with hyperthyroidism?

• A. Insomnia
• B. Eye fatigue
• C. Blurred or double vision
• D. Tremors

Answer: (D)

Excess thyroid hormone heightens nervous system excitability and amplifies sympathetic nervous system effects, so a fine tremor is a classic neurological sign of hyperthyroidism. The hormones increase the responsiveness of beta-adrenergic receptors in muscle and neural tissue, leading to a rapid, small-amplitude hand tremor that may be most evident when the arms are held outstretched or during voluntary tasks. This tremor reflects the overall adrenergic overactivity and often improves with beta-blocker therapy, which counteracts the heightened adrenergic signaling.

Other options are less characteristic. Insomnia can occur because of the hypermetabolic state and restlessness, but it’s less specifically tied to a discrete neurological sign. Eye fatigue or blurred/double vision point more to Graves ophthalmopathy and extraocular muscle involvement, which are ocular manifestations rather than a primary neurological symptom of the hyperthyroid state.