Median sep and blink reflex in thyroid diseases

Area of Science:

• Neurology
• Endocrinology
• Neurophysiology

Background:

• Thyroid hormone imbalances are linked to nervous system dysfunction.
• Peripheral nerve conduction studies are crucial for assessing these disturbances.

Purpose of the Study:

• To investigate median nerve somatosensory evoked potentials (SEP) and blink reflex in hyperthyroid and hypothyroid patients.
• To compare electrophysiological findings between thyroid patients and a control group.

Main Methods:

• Median nerve SEP analysis included N9-N20 wave and interpeak latencies in 40 patients and 26 controls.
• Blink reflex studies assessed R1, R2, and CR2 latencies and durations in 28 patients.
• Statistical comparisons were made between patient subgroups and the control group.

Main Results:

• Hyperthyroid patients exhibited significantly prolonged N20 latency in SEPs compared to controls.
• Hypothyroid patients showed no significant differences in SEP latencies or interpeak latencies versus controls.
• Patients with hyperthyroidism demonstrated significantly shorter R2 and CR2 durations in blink reflex tests.

Conclusions:

• Hyperthyroidism is associated with delayed central sensory conduction, indicated by prolonged SEP N20 latency.
• Hyperthyroidism may also affect brainstem pathways involved in the blink reflex, evidenced by altered R2 and CR2 durations.
• Hypothyroidism did not reveal significant peripheral nerve conduction abnormalities via these electrophysiological measures.