Effects of postural changes on balance due to ankylosing spondylitis

Ankylosing spondylitis is a chronic-inflammatuary rheumatic disease which leads to limited movements in spinal mobility and structural deformity by affecting axial skeleton in the first place. Limited movements in spinal mobility is the classical sign of this disease and problems related to balance and postural stability control can occur due to this pathology. Deterioration at the postural stability can lead to balance problems and falls. The aim of this study is to investigate the effect of postural changes on the balance at ankylosing spondylitis patients. Age and weight adjusted thirty-four ankylosing spondylitis patients and 34 control subjects are enrolled to this study. Balance measurement tests carried out with comprehensive musculoskeletal examination to both of the groups. Patients also have been evaluated for the presence or absence of knee and hip flexion contracture. Berg balance scale, anterior and right-left side functional reach test and static balance index have been used to assess the balance. Postural sway was calculated by Emed-SX system. The static balance index, eyes open anteroposterior center of pressure sway and eyes closed anteroposterior center of pressure sway have been found significantly higher at the patients? group (p<0,05). When the patients with and without contracture of knee and/or hip were compared; lomber schoeber, traguswall distance, occiput-wall distance, and Bath Ankylosing Spondylitis Metrology Index scores were found significantly higher and left-sided functional reach test score was found significantly lower (p<0,05) in the contracture positive group. But Berg balance scale scores, anteroposterior and mediolateral postural sway distance measures, anterior and right-sided functional reach test scores and static balance index score differences between two groups were statistically nonsignificant (p>0.05). Results of correlation analyses between balance tests and spinal mobility parameters demonstrated that Berg balance scale score and anterior, two- sided functional reach tests were negatively correlated with occiput-wall and tragus-wall distances and positive correlated with lomber schoeber. Static balance index score was positively correlated with Bath Ankylosing Spondylitis Metrology Index and hand-ground distance and negatively correlated with lomber schoeber. All these results support the negative effect of the limited movements in spinal mobility on balance. Balance deterioration due to postural changes at the ankylosing spondylitis patients has shown in our study. Therefore, the treatment strategy of this patient population should include disease specific exercise prescription and educations oriented towards balance for the prevention of falling risk and to increase the life quality, as well. Key words: Ankylosing Spondylitis, balance, posture