Lighten Up: Specific Postural Instructions Affect Axial Rigidity and Step Initiation in Patients With Parkinson's Disease

Abstract

Background: Parkinson's disease (PD) is associated with stooped postural alignment, increased postural sway, and reduced mobility. The Alexander Technique (AT) is a mindfulness-based approach to improving posture and mobility by reducing muscular interference while maintaining upward intentions. Evidence suggests that AT can reduce disability associated with PD, but a mechanism for this effect has not yet been established.

Objective: We investigated whether AT-based instructions reduce axial rigidity and increase upright postural alignment, and whether these instructions have different effects on postural alignment, axial rigidity, postural sway, and mobility than effort-based instructions regarding posture.

Method: Twenty subjects with PD practiced 2 sets of instructions and then attempted to implement both approaches (as well as a relaxed control condition) during quiet standing and step initiation. The "Lighten Up" instructions relied on AT principles of reducing excess tension while encouraging length. The "Pull Up" instructions relied on popular concepts of effortful posture correction. We measured kinematics, resistance to axial rotation, and ground reaction forces.

Results: Both sets of experimental instructions led to increases in upright postural alignment relative to the control condition. Only the Lighten Up instructions led to reduced postural sway, reduced axial postural tone, greater modifiability of tone, and a smoother center of pressure trajectory during step initiation, possibly indicating greater movement efficiency.

Conclusion: Mindful movement approaches such as AT may benefit balance and mobility in subjects with PD by acutely facilitating increased upright postural alignment while decreasing rigidity.

Keywords: Alexander Technique; Parkinson’s disease; gait initiation; mindfulness; postural alignment; postural sway; rigidity.

© The Author(s) 2015.

Figures

Figure 1

A. Peak Torque (Nm) in the three conditions. Error bars indicate ±1 standard error after grand mean differences among subjects were removed. * indicates significant difference after correcting for multiple comparisons. # indicates significant differences before correcting for multiple comparisons. B. Number of subjects with highest phase lead in each condition. * indicates significant difference from expected proportion.

Figure 2

Postural sway in the three conditions. Error bars indicate ±1 standard error after grand mean differences among subjects were removed. * indicates significant difference after correcting for multiple comparisons. A. anteroposterior amplitude (m/s2). B. mediolateral amplitude (m/s2).

Figure 3

A. Placement of reflective markers on head and shoulders, from which vertical and horizontal distances were computed. B–D. Postural alignment in the three conditions. Error bars indicate ±1 standard error after grand mean differences among subjects were removed. Error bars are not shown in B and C because they were too small to see. * indicates significant difference after correcting for multiple comparisons. # indicates significant difference before correcting for multiple comparisons. B. anteroposterior amplitude (m/s2). C. mediolateral amplitude (m/s2). D. anteroposterior velocity (m/s). E. mediolateral velocity (m/s).

Figure 4

Step Initiation. A. Peak backward displacement of center of pressure (CoP) during initial weight shift. B. Peak lateral displacement of CoP during initial weight shift. C. Ratio of A to B. D. Total jerk of CoP trace during step initiation (see method section for detail). Error bars indicate ±1 standard error after grand mean differences among subjects were removed. * indicates significant difference after correcting for multiple comparisons. # indicates significant difference before correcting for multiple comparisons.

Figure 5

Subjective reports. Error bars indicate ±1 standard error after grand mean differences among subjects were removed. * indicates significant difference after correcting for multiple comparisons. # indicates significant difference before correcting for multiple comparisons.