Correspondence of the Boston Carpal Tunnel Questionnaire with severity of median neuropathy.

The Boston Carpal Tunnel Questionnaire is one of the most popular patient-reported outcome measures designed specifically for people with idiopathic median neuropathy at the carpal tunnel. We used electrophysiological and ultrasound measures of median neuropathy from one hand in 185 people to create a single measure of median neuropathy severity as a continuum (through exploratory factor analysis). We assessed if our single measure of median neuropathy severity is independently associated with Boston Carpal Tunnel Questionnaire item groupings. Median neuropathy severity measured as a continuum had modest independent associations with Boston Carpal Tunnel Questionnaire magnitude of capability (adjusted R² 0.063) and paraesthesia intensity (adjusted R² 0.12) items but not with items related to pain intensity. Considering the lack of association of Boston Carpal Tunnel Questionnaire pain items with objective pathophysiology, combined with their notable association with mental health measures in previous studies, it is probably best to omit items related to pain.Level of evidence: III.