Quantitative Sensory Testing Identifies Altered Thermal and Pain Processing in Trigeminal Neuralgia

Area of Science:

• Neurology
• Neuroscience
• Pain Medicine

Background:

• Trigeminal neuralgia (TN) presents with complex somatosensory alterations.
• Understanding these sensory changes is crucial for effective treatment.

Purpose of the Study:

• Assess somatosensory function in TN patients using quantitative sensory testing (QST) and phenotyping.
• Correlate sensory findings with clinical characteristics like etiology, pain type, and treatment response.

Main Methods:

• Sixty-five TN patients underwent QST and sensory phenotyping.
• Sensory alterations were quantified using z-scores and a validated algorithm.
• Clinical data and treatment responses were systematically recorded.

Main Results:

• Bilateral thermal hypoesthesia and pain hyperesthesia were observed.
• Classical TN showed reduced cold detection threshold (CDT) on the affected side.
• Idiopathic TN had elevated wind-up ratio; paroxysmal pain was linked to heat pain threshold gain.
• Mechanical and thermal hyperalgesia were predominant phenotypes.
• Sensory loss phenotype correlated with poor response to sodium channel blockers.

Conclusions:

• TN involves complex, bilateral sensory alterations, possibly indicating central nervous system changes.
• Asymmetrical CDT reduction may suggest peripheral Aδ-fiber dysfunction.
• Sensory profiling can identify patient subgroups with distinct treatment responses, particularly to sodium channel blockers.