B-27 Free Communication/Poster - Motor Control: MAY 27, 2009 1:00 PM - 6:00 PM ROOM: Hall 4F
Gait initiation (GI) and turning while walking have been widely investigated in older adults and more recently in Parkinson's disease (PD) patients. Previously, we have shown that persons with PD have difficulty initiating gait 90° to the side of the stepping leg. However, whether these findings carry over to other perhaps more functional turning angles (open 45° and cross over 45°) is unknown.
PURPOSE: To examine the differences in dynamic stability during multi-directional GI among three groups: Healthy Young Adults (HYA), Healthy Older Adults (HOA) and Persons with Parkinson's (PWP).
METHODS: Nine HYA (age: 28.4 + 4y), nine HOA (age: 56.6 + 9.7y) and 11 PWP (age: 63 + 2; Modified Hoehn & Yahr stage of 1 to 3) participated. An 8-camera motion capture system was used to capture the kinematic data at 120 Hz. Center of pressure (COP) data were collected using two force platforms at 1560 Hz. The whole body center of mass (COM) location was computed as the weighted sum of each body segments COM from a 15 segment biomechanical model using the collected kinematics and subject anthropometrics. Participants performed five GI trials in each of four directions: stepping 45° medially (crossing in front of the body, c45), open-stepping 45° laterally (O45), open-stepping 90° (O90) and straight (ST). The magnitude of the COP-COM moment arm was evaluated in three distinct phases (postural, weigh shift, and locomotor) of the GI cycle.
RESULTS: The MANOVA results indicated a significant interaction effect in all the three phases. Postural: PWP produced the smallest resultant and AP COP-COM moment arms across C45, O45 and ST directions (P<0.05). However, for the O90 direction, the PWP produced the greatest resultant and ML COP-COM moment arm (P<0.05). Weight shift: PWP had a smaller AP COP-COM moment arm than HYA and HOA groups across all directions (P<0.05). Locomotor phase: PWP exhibited lowest resultant moment arm in all the directions except C45 direction (P>0.05). Similarly, the PWP group had lowest AP moment arms in C45, ST and O45 directions (P<0.05), but the greatest moment arm in O90 direction (P<0.05).
CONCLUSION: The results indicate that PWP have deficits in multi-directional GI when compared to their aged-matched counterparts and HYA, placing greater emphasis on maintaining stability than momentum generation.