Abstract
PURPOSE: Up to 90% of patients with postural tachycardia syndrome (PoTS) report headaches, and comorbid migraine headaches are common. Given this, pathophysiological interaction is possible, which may reveal key aspects of disease expression and treatment opportunities. We hypothesized that PoTS subjects-both with and without migraine-would show features of central sensitization, including allodynia and photophobia. METHODS: Eighty participants were evaluated, including 30 PoTS, 30 chronic migraine (CM), and 20 non-headache healthy controls (NH), using tilt table testing, psychophysical assessment of sensory sensitivity thresholds, and an online questionnaire to assess measures of headache burden and associated symptoms. Clinical characteristics and sensory thresholds were compared between disease groups and controls, as well as in a subgroup analysis within the PoTS group, based on headache phenotype. RESULTS: Sensory sensitivity thresholds were significantly lower and symptom scores were higher in both the PoTS and CM groups compared to controls. However, the patterns of expression differed between PoTS and CM, with pain threshold reductions in the forearm only of PoTS subjects (non-trigeminal sensory sensitization), compared to both periorbital and forearm sites in CM. Unexpectedly, light sensitivity thresholds were significantly lower in PoTS than in both CM and NH. CONCLUSIONS: These findings reveal an underappreciated aspect of disease burden in PoTS, and suggest network sensitization similar to, but separable from, that of migraine. The presence of both photophobia and allodynia in PoTS is reflective of exteroceptive rather than strictly interoceptive disruption, and expands our fundamental understanding of the disorder.