Background: Abnormal posture (AP) is often seen in Parkinson's disease (PD), and marked forms known as dropped head syndrome and camptocormia encumber daily living activities. Unlike other motor disabilities such as bradykinesia or muscular rigidity, AP is not always improved but rather deteriorated by PD medication.
Purpose: To clarify factors associated with neck and thoracolumbar AP.
Methods: Neck flexion (NF) and thoracolumbar (TL) angles were measured in 216 consecutive PD patients and 175 elderly healthy controls. The differences in NF and TL angles between PD patients and controls were designated as ΔNFA and ΔTLA, respectively. The association of ΔNFA or ΔTLA and predictable factors such as age, sex, duration of PD, Hoehn Yahr (H-Y) stage, Unified Parkinson's Disease Rating Scale Part 3 (UPDRS-3), daily dose of dopamine agonists, and comorbid orthopedic spinal lesions was investigated in PD patients. Patients were divided into quartiles according to ΔNFA or ΔTLA. The association between predictable factors and ΔNFA or ΔTLA was estimated as odds ratio (OR), comparing with the lowest quartile as the reference by multivariate regression analysis.
Results: Compared with controls, distributions of all three posture angles were significantly shifted rightward in PD patients. Although there were no difference in UPDRS-3 scores in the quartiles of ΔNFA, the highest quartile was associated with H-Y stage ≥3 [OR 2.99, 95% confidence interval (CI) 1.33-6.70, p = 0.008] after adjustment for age, sex and comorbid orthopedic spinal lesions. The highest quartile of ΔTLA was associated with comorbid orthopedic spinal lesions [OR 5.83 (1.42-23.8), p = 0.014], and UPDRS-3 score [OR 3.04 (1.80-5.15)/10 points, p<0.0001].
Conclusion: Thoraco-lumbar AP was associated with UPDRS-3 scores and orthopedic spinal lesions, and in contrast, neck AP was not associated with these factors, suggesting that they had different pathomechanisms.