Walking Along Curved Trajectories. Changes With Age and Parkinson's Disease. Hints to Rehabilitation

Abstract

In this review, we briefly recall the fundamental processes allowing us to change locomotion trajectory and keep walking along a curved path and provide a review of contemporary literature on turning in older adults and people with Parkinson's Disease (PD). The first part briefly summarizes the way the body exploits the physical laws to produce a curved walking trajectory. Then, the changes in muscle and brain activation underpinning this task, and the promoting role of proprioception, are briefly considered. Another section is devoted to the gait changes occurring in curved walking and steering with aging. Further, freezing during turning and rehabilitation of curved walking in patients with PD is mentioned in the last part. Obviously, as the research on body steering while walking or turning has boomed in the last 10 years, the relevant critical issues have been tackled and ways to improve this locomotor task proposed. Rationale and evidences for successful training procedures are available, to potentially reduce the risk of falling in both older adults and patients with PD. A better understanding of the pathophysiology of steering, of the subtle but vital interaction between posture, balance, and progression along non-linear trajectories, and of the residual motor learning capacities in these cohorts may provide solid bases for new rehabilitative approaches.

Does Curved Walking Sharpen the Assessment of Gait Disorders? An Instrumented Approach Based on Wearable Inertial Sensors

“…The results show that significant differences between straight and curved paths exist for both spatiotemporal and gait quality indices in CG and sTBI-S, whereas no statistical difference exists between the two walking modalities in sTBI-VS, indicating that this group of patients presents similar biomechanical patterns in the two conditions. This is in agreement with the existing literature focusing on straight versus curved walking and confirms that: (i) curved walking requires different adaptations (with respect to straight walking) in order to fit the biomechanical constraints imposed by linear and rotational dynamics of turning [ 2 , 31 ]; (ii) since these adaptations rely on the central nervous system which, during curved walking, takes over the control of locomotion at the expenses of the spinal automatisms [ 31 ], people with neurological disorders might encounter difficulties in managing the interplay between balance control and center of mass progression when steering and turning [ 8 ]; and, (iii) the kind and entity of the abovementioned adaptations depend on walking velocity [ 2 , 31 ]: when walking speed is very low (below 0.9 m·s −1 during straight walking), differences in the spatiotemporal and gait quality-related parameters between straight and curved locomotion may become negligible [ 31 ].…”

“…Similar to healthy adults, in fact, they exhibited different walking patterns when performing straight and curvilinear paths. Specifically, consistent with what has been reported in previous literature [ 31 ], the more challenging gait modality induces a decrease in walking speed, an increase in stride duration, and a decrease in the stride frequency, with respect to the straight path ( Figure 2 ). This confirms that human subjects adapt their locomotor velocity to the radius of curvature of the path they are following, with the velocity that tends to increase when the trajectory becomes straighter and decrease when it becomes more curved [ 5 ].…”

“…A hypothesis is that very severe patients substantially perform straight and curved trajectories with a very similar approach, covering a curvilinear path as it was made by consecutive small straight paths. This seems also confirmed by the results obtained for gait symmetry parameters ( Figure 3 D): no significant difference was found between 10 mWT and F8WT in very severe patients, indicating that this group of patients does not present the intrinsic asymmetric motion of the lower limbs that was generally observed during curved walking [ 2 , 3 , 31 ].…”

“…Consistently, the very severe TBI sub-group considered in the present study was reported to walk at a very low speed (0.56 and 0.42 m·s −1 for the linear and curvilinear walking, respectively), likely as an expression of the motor deficit and to counteract the fear of falling, or because of post-traumatic parkinsonism features [ 32 , 33 ]. On the other hand, less severely affected patients displayed a median speed value of 1.15 m·s −1 during straight walking, which is higher than the abovementioned threshold [ 31 ]. Similar to healthy adults, in fact, they exhibited different walking patterns when performing straight and curvilinear paths.…”

Human Balance in Response to Continuous, Predictable Translations of the Support Base: Integration of Sensory Information, Adaptation to Perturbations, and the Effect of Age, Neuropathy and Parkinson’s Disease

“…This article will not address the mechanisms responsible for the maintenance of the erect stance under static conditions, either, even if during quiet stance, antero-posterior sway of the body occurs and can be easily detected [3]. Besides, this article will not deal with the automatic postural activities accompanying gait, be it simple walking along a linear path or more demanding walking as when we move along curved trajectories (e.g., [4,5]). As a further stipulation, we will not deal here with another type of perturbation, which has been popular in the past, consisting of the toe-up or toe-down tilt of the supporting platform.…”