Benjamin Bollens

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Series of motor outputs generated by cyclic movements are typically complex, suggesting that the correlation function of the time series spans over a large number of consecutive samples. Famous examples include inter-stride intervals, heartbeat variability, spontaneous neural firing patterns or motor synchronization with external pacing. Long-range(More)
BACKGROUND Selective neurotomy is a permanent treatment of focal spasticity, and its effectiveness in treating spastic equinovarus of the foot (SEF) was previously suggested by a few nonrandomized and uncontrolled case-series studies. OBJECTIVES This study is the first assessor-blinded, randomized, controlled trial evaluating the effects of this(More)
Stride duration variability is considered a marker of gait balance and can be investigated in at least two different ways. Fluctuation magnitude can be addressed by classical mathematical methods, whereas fluctuation dynamics between strides can be characterized using the autocorrelation function. Although each approach has revealed changes of these(More)
Stride duration of young healthy subjects walking at spontaneous speed fluctuates over the long-term in a very complex way. The presence of long-range autocorrelations among these fluctuations has already been highly suggested for subjects walking on level ground, but the mathematical methods used among studies are variable. Moreover, despite the frequent(More)
Long-range dependency has been found in most rhythmic motor signals. The origin of this property is unknown and largely debated. There is a controversy on the influence of voluntary control induced by requiring a pre-determined pace such as asking subjects to step to a metronome. We studied the cycle duration variability of 15 men pedaling on an ergometer(More)
OBJECTIVE Gait instability and fall risk are major concerns in Parkinson's disease. This study shows that the temporal organization of gait variability can represent a marker of gait instability that complements standard assessment of motor deficits in Parkinson's disease. METHODS Temporal organization (long-range autocorrelation; LRA) of stride duration(More)
OBJECTIVE Spastic equinovarus foot is a major cause of disability for neurorehabilitation patients, impairing their daily activities, social participation and general quality of life. Selective tibial nerve neurotomy is a neurosurgical treatment for focal spasticity, whose acceptance as treatment for spastic equinovarus foot remains controversial. We(More)
Information from the central and peripheral nervous systems is continuously integrated to produce a stable gait pattern. However, stride duration fluctuates in a complex manner in healthy subjects, exhibiting long-range autocorrelations that can span over hundreds of consecutive strides. The present study was conducted to explore the mechanisms controlling(More)
Long-range autocorrelations (LRA) are a robust feature of rhythmic movements, which may provide important information about neural control and potentially constitute a powerful marker of dysfunction. A clear difficulty associated with the assessment of LRA is that it requires a large number of cycles to generate reliable results. Here we investigate how(More)