Impaired trunk position sense and its relationship with trunk control and balance in cervical dystonia patients.

Background: Trunk position sense is an essential component of proprioception for maintaining balance. Although the loss of balance is a well-documented phenomenon in cervical dystonia (CD) patients, the evaluation of trunk position sense in this population remains a gap in the existing research.

Aims: The primary aim of this study was to compare trunk position sense between CD patients and healthy people. The secondary aim was to investigate the relationship between trunk position sense and trunk control, balance, and disease severity in CD patients.

Methods: This cross-sectional study included 34 CD patients and 34 healthy people. Trunk position sense was evaluated with a digital inclinometer, which measures the amount of trunk reposition error (TRE). Trunk control was assessed with the Trunk Impairment Scale (TIS), while balance was evaluated with the Berg Balance Scale (BBS), the One Leg Stance Test (OLST), the Four Square Step Test (FSST), and the Activities-specific Balance Confidence Scale (ABC). The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) was used to determine disease severity.

Results: CD patients had higher scores on the TRE compared to healthy people (p = 0.007). The TRE value had a fair to moderate correlation with the TIS total, TIS-dynamic sitting subscale, FSST, BBS, ABC, TWSTRS-total, TWSTRS-severity subscale, and TWSTRS-disability subscale scores in CD patients (p < 0.05). There was no correlation between the TRE value and the TIS-static sitting subscale, TIS-coordination subscale, OLST, and TWSTRS pain subscale scores (p > 0.05) in CD patients.

Conclusions: Trunk position sense was reduced in CD patients. Trunk position sense was also associated with trunk control, balance, and disease severity. These findings suggest that the assessment of trunk position sense should be taken into consideration in the rehabilitation of CD patients.