Gait Variability in Chronic Back Pain Sufferers With Experimentally Diminished Visual Feedback: A Pilot Study

Hamacher, Dennis; Krowicki, Martin; Schega, Lutz

doi:10.1080/00222895.2015.1073136

Cited by 20 publications

(19 citation statements)

References 17 publications

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“…These results corroborate both the tendency towards small MTC decreases observed during diverse dual-task experiments (answering questions 45 , serial subtractions 21 ) and MTC increases during visual blurring or restriction 29, 46 . In keeping with earlier research, MTC CoV during normal walking showed a significant increase with age 22, 31 yet was not significantly modified by cognitive loading 21 or visual restriction 28 . This suggests that a strategy of reducing overall MTC variability to minimise critically low MTC values described elsewhere 23 is not, in fact, utilised by healthy adults under increased cognitive load.…”

Section: Discussionsupporting

confidence: 91%

“…4d). In contrast to the more automatic pattern under cognitive load, walking without visual feedback results in highly skewed MTC distributions in keeping with cautious, tight control of MTC reliant on the other senses available to the CNS 28, 52 . Unlike cognitive distraction, participants were keenly aware that their locomotor system was being challenged and likely switched conscious attention to control of MTC.…”

Section: Discussionmentioning

confidence: 75%

“…Although also cognitively demanding, walking with restricted vision appears to be associated with minimal gait adaptations in healthy older adults 27 and with a slightly increased mean MTC relative to normal walking 28–30 . This discrepancy may be due to attention being consciously diverted towards walking during a restricted vision task, rather than away from it, as when performing an unrelated cognitive task, resulting in tighter, conscious control of MTC.…”

Section: Introductionmentioning

confidence: 93%

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Minimum toe clearance: probing the neural control of locomotion

Killeen

Easthope

Demkó

et al. 2017

Sci Rep

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Minimum toe clearance (MTC) occurs during a highly dynamic phase of the gait cycle and is associated with the highest risk of unintentional contact with obstacles or the ground. Age, cognitive function, attention and visual feedback affect foot clearance but how these factors interact to influence MTC control is not fully understood. We measured MTC in 121 healthy individuals aged 20–80 under four treadmill walking conditions; normal walking, lower visual field restriction and two Stroop colour/word naming tasks of two difficulty levels. Competition for cognitive and attentional resources from the Stroop task resulted in significantly lower mean MTC in older adults, with the difficult Stroop task associated with a higher frequency of extremely low MTC values and subsequently an increased modelled probability of tripping in this group. While older adults responded to visual restriction by markedly skewing MTC distributions towards higher values, this condition was also associated with frequent, extremely low MTC values. We reveal task-specific, age-dependent patterns of MTC control in healthy adults. Age-related differences are most pronounced during heavy, distracting cognitive load. Analysis of critically-low MTC values during dual-task walking may have utility in the evaluation of locomotor control and fall risk in older adults and patients with motor control deficits.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 93%

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Minimum toe clearance: probing the neural control of locomotion

Killeen

Easthope

Demkó

et al. 2017

Sci Rep

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“…These alterations in body representations have sometimes been reported to be associated with the severity of motor disturbances observed in chronic pain populations (Bank et al, 2013; Hamacher et al, 2016). In healthy volunteers, the induction of experimental acute pain can also transiently alter body representations, as shown by shifts in the subjective body midline toward the painful side (Bouffard et al, 2013), overestimation of the size of the painful limb (Gandevia and Phegan, 1999) and altered sense of position (Eva-Maj et al, 2013) Finally, patients with chronic pain have altered somatosensory (Flor et al, 1997; Di Pietro et al, 2013) and motor (Lotze et al, 2001; Maihöfner et al, 2007) cortical representations.…”

Section: Introductionmentioning

confidence: 98%

Sensory Disturbances, but Not Motor Disturbances, Induced by Sensorimotor Conflicts Are Increased in the Presence of Acute Pain

Brun

Gagné

McCabe

et al. 2017

Front. Integr. Neurosci.

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Incongruence between our motor intention and the sensory feedback of the action (sensorimotor conflict) induces abnormalities in sensory perception in various chronic pain populations, and to a lesser extent in pain-free individuals. The aim of this study was to simultaneously investigate sensory and motor disturbances evoked by sensorimotor conflicts, as well as to assess how they are influenced by the presence of acute pain. It was hypothesized that both sensory and motor disturbances would be increased in presence of pain, which would suggest that pain makes body representations less robust. Thirty healthy participants realized cyclic asymmetric movements of flexion-extension with both upper limbs in a robotized system combined to a 2D virtual environment. The virtual environment provided a visual feedback (VF) about movements that was either congruent or incongruent, while the robotized system precisely measured motor performance (characterized by bilateral amplitude asymmetry and medio-lateral drift). Changes in sensory perception were assessed with a questionnaire after each trial. The effect of pain (induced with capsaicin) was compared to three control conditions (no somatosensory stimulation, tactile distraction and proprioceptive masking). Results showed that while both sensory and motor disturbances were induced by sensorimotor conflicts, only sensory disturbances were enhanced during pain condition comparatively to the three control conditions. This increase did not statistically differ across VF conditions (congruent or incongruent). Interestingly however, the types of sensations evoked by the conflict in the presence of pain (changes in intensity of pain or discomfort, changes in temperature or impression of a missing limb) were different than those evoked by the conflict alone (loss of control, peculiarity and the perception of having an extra limb). Finally, results showed no relationship between the amount of motor and sensory disturbances evoked in a given individual. Contrary to what was hypothesized, acute pain does not appear to make people more sensitive to the conflict itself, but rather impacts on the type and amount of sensory disturbances that they experienced in response to that conflict. Moreover, the results suggest that some sensorimotor integration processes remain intact in presence of acute pain, allowing us to maintain adaptive motor behavior.

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“…1 Moreover, alterations of the sense of position have been associated with the severity of motor deficits. 1,7 However, only 1 previous study has assessed the sense of limb movement during active movement and found that individuals with chronic low back pain tend to overestimate their trunk flexion compared with painfree controls. 27 Importantly, in that study, the flexionextension movement was continuous, to ensure that judgment relied on a continuous comparison between sensory input and motor output rather than on a comparison of final (static) postures.…”

mentioning

confidence: 99%