Abnormal gait pattern emerges during curved trajectories in high-functioning Parkinsonian patients walking in line at normal speed

Abstract

BackgroundSeveral patients with Parkinson´s disease (PD) can walk normally along straight trajectories, and impairment in their stride length and cadence may not be easily discernible. Do obvious abnormalities occur in these high-functioning patients when more challenging trajectories are travelled, such as circular paths, which normally implicate a graded modulation in the duration of the interlimb gait cycle phases?MethodsWe compared a cohort of well-treated mildly to moderately affected PD patients to a group of age-matched healthy subjects (HS), by deliberately including HS spontaneously walking at the same speed of the patients with PD. All participants performed, in random order: linear and circular walking (clockwise and counter-clockwise) at self-selected speed. By means of pressure-sensitive insoles, we recorded walking speed, cadence, duration of single support, double support, swing phase, and stride time. Stride length-cadence relationships were built for linear and curved walking. Stride-to-stride variability of temporal gait parameters was also estimated.ResultsWalking speed, cadence or stride length were not different between PD and HS during linear walking. Speed, cadence and stride length diminished during curved walking in both groups, stride length more in PD than HS. In PD compared to HS, the stride length-cadence relationship was altered during curved walking. Duration of the double-support phase was also increased during curved walking, as was variability of the single support, swing phase and double support phase.ConclusionThe spatio-temporal gait pattern and variability are significantly modified in well-treated, high-functioning patients with PD walking along circular trajectories, even when they exhibit no changes in speed in straight-line walking. The increased variability of the gait phases during curved walking is an identifying characteristic of PD. We discuss our findings in term of interplay between control of balance and of locomotor progression: the former is challenged by curved trajectories even in high-functioning patients, while the latter may not be critically affected.

Proposal of a new conceptual gait model for patients with Parkinson’s disease based on factor analysis

“…Finally, the double support time variable is represented in the pace/rhythm factor. This variable is reported to be increased in patients with PD, not only in linear walking [34], but also in curved trajectories [45]. Double support time is a phase of gait cycle considered to be a stabilizing component of gait [46]: not unexpectedly, fallers usually have an increased double support time.…”

“…The variability factor refers to unsteadiness and arrhythmic pattern of stepping [47]. The increased gait variability and impaired rhythmicity in PD worsen as the PD progresses [45,48,49] and may reflect reduced automaticity and damaged locomotor synergies [50,51]. Increased gait variability is usually associated with an increased fall risk in both elderly individuals [52] and patients with PD [53], suggesting that increased variability may be a very useful element in fall risk assessment.…”

“…In keeping with different brain networks regulating gait speed and variability, it has been shown that, among gait variability parameters, swing time variability is independent from gait speed both in patients with PD and in healthy subjects [55]. Indeed, swing time variability is determined predominantly by balance-control mechanisms [45,57]. On the other hand, it seems that other gait variability measures such as step length CV, known to be increased in PD as a function of the Hoehn and Yahr stage [58], are predominantly determined by the gait-patterning mechanism.…”

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

“…If these adaptations can be considered trivial for healthy people, they represent an actual challenge for the elderly [ 1 , 6 , 7 ] and for patients with neurological disorders [ 8 , 9 , 10 , 11 ]. Furthermore, even if it is not clear if falls are more frequent during turns, it has been shown that falling during a turn has an increased risk of serious injury [ 12 ], and that staggering when turning is a prominent characteristic of recurrent fallers [ 13 ].…”

Validation of IMU-Based Gait Event Detection During Curved Walking and Turning in Older Adults and Parkinson's Disease Patients

“…Whether IMU-based GE detection is still valid in more complex walking tasks is yet to be shown. Daily-life gait is likely influenced by obstacle negotiation (approximately 30% of daily-life gait is spent along curved trajectories [22]) and dual-/multi-tasking [5].…”