Postural deformities in Parkinson's disease -Mutual relationships among neck flexion, fore-bent, knee-bent and lateral-bent angles and correlations with clinical predictors.

BACKGROUND Various postural deformities appear during progression of Parkinson's disease (PD), but the underlying pathophysiology of these deformities is not well understood. The angle abnormalities seen in individual patients may not be due to distinct causes, but rather they may have occurred in an interrelated manner to maintain a balanced posture. METHODS We measured the neck flexion (NF), fore-bent (FB), knee-bent (KB) and lateral-bent (LB) angles in 120 PD patients, and examined their mutual relationships, and correlations with clinical predictors such as sex, age, disease duration, Hoehn and Yahr (H&Y) stage, medication dose (levodopa equivalent dose, LED; total dose of dopamine agonists, DDA). The relationship between the side of the initial symptoms and the direction of LB angle was also investigated. RESULTS Our main findings were: (1) Significant relationships between NF and KB, NF and LB, FB and KB, KB and LB were observed. (2) NF angle was larger in males than in females, but FB, KB and LB angles showed no significant difference between the sexes. (3) FB and KB angles became larger with advancing age. (4) NF and FB angles were associated with disease duration. (5) NF, FB, KB and LB angles all increased significantly with increase of H&Y stage. (6) FB angle was significantly associated with LED, but DDA did not show a significant relationship with any of the measured angles. (7) Direction of LB angle was not associated with the side of initial symptoms. CONCLUSIONS Postural abnormalities are interrelated, possibly to maintain a balanced posture.