Exploratory Pain Profiling With Quantitative Sensory Testing (QST) in Episodic and Chronic Migraine

BACKGROUND: Migraine pain profiling studies vary by sensory modalities, methods, anatomical sites and characteristics. This exploratory study aimed to identify pain profiling parameters using quantitative sensory testing (QST) for episodic migraine (EM) and chronic migraine (CM) and investigate potential differences, given conflicting results from previous EM versus CM comparisons.

METHODS: A total of 59 migraineurs, including 29 with EM and 30 with CM, were enrolled at Leiden Headache Center. QST was performed on the cheek and hand utilising various test stimuli. Normalised control values adjusted for sex, age, location were used to convert the measurement outcomes to Z-scores. Key outcomes included mean Z-scores and the prevalence of abnormal Z-scores (< -1.96 or > 1.96) in migraineurs. Z-scores > 1.96 indicate heightened sensation (lower threshold), while Z-scores < -1.96 indicate diminished sensation (higher threshold). EM and CM were compared.

RESULTS: The threshold for pressure pain (PPT) was lower in 39.0% (hand) and 32.8% (cheek) (all p < 0.001) in individuals with migraine. Cold detection threshold (CDT) was higher in 18.6% (hand) and 25.4% (cheek), while the warm detection threshold (WDT) was higher in 15.2% (hand) (all p < 0.001) in migraineurs. Mechanical pain sensitivity (MPS) was increased in 17.0% (hand) and the vibration detection threshold (VDT) was higher in 18.6% (cheek) (all p < 0.001). No differences, including for temporal summation (TS), were found between EM and CM.

CONCLUSIONS: In this exploratory analysis, no QST profile differences were found between EM and CM. One-third of migraineurs have increased pressure pain sensitivity in both trigeminal and distal regions, but decreased cold, warmth, vibration and mechanical detection, indicating complex sensory processing.

SIGNIFICANCE: This is the first exploratory study to compare episodic migraine (EM) and chronic migraine (CM) patients using a comprehensive battery of quantitative sensory tests (QST). The aim of this study was to explore various aspects of somatosensory function in individuals with EM and CM, with a particular focus on identifying differences between the two groups. Given that sensory thresholds may fluctuate at different stages of the disease, additional data are needed to clarify these distinctions.