Brainstem Reflexes in Patients With Chronic Tension-Type Headache

The global prevalence rate of tension headache ranges between 35% to 80%. It is hypothesized that brainstem interneurons are crucial for pain modulation and nociceptive transmission in chronic tension-type headache (CTTH). We aim to better understand the pathophysiology of CTTH focusing on the involvement of the trigeminal system using brainstem reflexes and their relevance to pain using Headache Impact Test (HIT-6) severity scoring. The study included 152 participants, of which 72 had been diagnosed with CTTH, and 80 served as healthy volunteers. The disease duration ranges from 3 to 24 months. Clinical neurological examinations were completed, along with electrophysiological testing such as bilateral blink reflex (BR), masseter inhibitory reflex (MIR), trigeminocervical reflex (TCR), and HIT-6 headache severity scoring. The patients demonstrate reduced right sided R1 latency, reduced SP1 duration bilaterally and prolonged SP2 latencies bilaterally of MIR. TCR latencies were not different between the two groups. The left MIR SP1 duration and left BCR cR2 latency were both positively correlated with the patient's age. Disease duration and the HIT-6 severity scores were positively related to left MIR SP2 latency and negatively with TCR latency bilaterally. Patients with CTTH showed the most significant changes in the MIR components. The HIT-6 severity scores and disease duration had a greater impact on TCR latencies.