Validation of the Polish version of the Boston Carpal Tunnel Questionnaire, and the influence of treatment for disordered sleep and daytime sleepiness in carpal tunnel syndrome

Purpose
Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, with paresthesias and pain in the hand and wrist. CTS is also associated with insomnia and excessive daytime sleepiness (EDS) resulting from the nocturnal exacerbation of symptoms. The Boston Carpal Tunnel Questionnaire (BCTQ) was developed for the assessment of therapeutic outcomes. It consists of two subscales: the Symptom Severity Scale (SSS) and the Functional Status Scale (FSS). The aim of this study was to perform an adaptation and validation of the Polish language version of BCTQ (pBCTQ). A second aim was to investigate the influence of treatment of CTS on insomnia and EDS.

Methods
The validation of the pBCTQ followed the widely accepted recommendations. In our consecutive sampling survey 130 patients with CTS filled out the pBCTQ, EQ-5D-5L quality of life questionnaire, the Athens Insomnia Scale (AIS) and the Epworth Sleepiness Scale (ESS). 26 of them filled out pBCTQ once again, two weeks later, and 35 filled out the pBCTQ and other items after therapy.

Results
The pBCTQ showed good internal consistency: 0.91 for SSS and 0.93 for FSS (Cronbach’s α). The test-retest reliability showed an intraclass coefficient of 0.69 for SSS and 0.55 for FSS. Both subscales correlated also with nerve conduction studies (NCS) as well as with the EQ-5D-5L, AIS, and ESS. After therapy, both subscales and AIS significantly decreased. Improvement was also seen in the NCS and EQ-5D-5L, but not in the ESS.

Conclusions
The pBCTQ is a reliable, valid, and responsive tool for measuring the outcome of CTS. Therapy for CTS leads to the improvement of concurrent insomnia but may not change daytime sleepiness.