Open-loop and closed-loop postural control mechanisms in Parkinson's disease: increased mediolateral activity during quiet standing

Mitchell, Susan L.; Collin, J.J.; Luca, Carlo J. De; Burrows, Adam B.; Lipsitz, Lewis A.

doi:10.1016/0304-3940(95)11924-l

Cited by 212 publications

(156 citation statements)

References 15 publications

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“…Increased power at high frequencies is indicative of instability in adults (Mauritz et al 1979), as is excessive sway in the mediolateral direction (Maki et al 1994, Mitchell et al 1995. While boys had shown age-related reductions in total power, their mean and median power frequency values were consistently lower than girls at 9 to 10 years of age.…”

Section: Years Standing With Eyes Open (Eo) and Eyes Closed (Ec)mentioning

confidence: 99%

Balance control: sex and age differences in 9- to 16-year-olds

Nolan

Григоренко

Thorstensson

2007

Developmental Medicine &Amp; Child Neurology

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This study investigated sex and age differences in standing balance. Movement of the centre of pressure (COP) was calculated from ground reaction force data collected from a force platform during bipedal stance with eyes open and eyes closed. Three groups of 60 children, with 30 girls and 30 boys in each, were assessed. Mean ages of each group were as follows: 9 years 11 months (standard deviation [SD] 3mo); 12 years 11 months (SD2mo); and 15 years 11 months (SD3mo) respectively. Summary sway parameters and frequency domain variables were calculated in the anteroposterior and mediolateral directions. Boys exhibited greater COP movement than girls at 9 to 10 years of age. Age‐related‘improvements’in sway occurred in boys, thus some aspects of postural control are still developing after 9 to 10 years of age. As very little age‐related difference was seen in girls, boys may lag behind somewhat in terms of developing postural control. Thus there is a need to study the sexes separately when investigating balance in children.

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Section: Years Standing With Eyes Open (Eo) and Eyes Closed (Ec)mentioning

confidence: 99%

Balance control: sex and age differences in 9- to 16-year-olds

Nolan

Григоренко

Thorstensson

2007

Developmental Medicine &Amp; Child Neurology

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“…7 Additionally, it was found that PD subjects had an increase in mediolateral postural sway during quiet stance when compared to age matched controls. 8 Postural responses to small, lateral perturbations with the feet in place are also smaller than normal in patients with PD. 4 We also found that PD subjects had smaller than normal postural stability margins, measured at the difference between peak center of pressure and peak center of mass displacement, in all directions but most pronounced in the posterior and lateral directions.…”

Section: Introductionmentioning

confidence: 97%

Lateral Stepping for Postural Correction in Parkinson’s Disease

King

Horak

2008

Archives of Physical Medicine and Rehabilitation

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OBJECTIVES-Effective balance rehabilitation requires an understanding of how patients with balance disorders attempt to recover equilibrium in response to external perturbations. The objective of this study is to characterize, for the first time, the lateral stepping strategies for postural correction in patients with Parkinson's Disease (PD) and the effect of their antiparkinson medication. DESIGN-Observational study. SETTING-Outpatient neuroscience laboratory.PATIENTS-Thirteen subjects with idiopathic Parkinson's disease (PD) in their ON and OFF levodopa state (PD ON and PD OFF) and 14 healthy elderly controls.INTERVENTIONS-Movable platform with lateral translations of 12 cm at 55cm/s ramp velocity. MAIN OUTCOME MEASURMENTS-The incidence and characteristics of 3 postural strategies were observed: lateral step (the limb loaded by the perturbation was unloaded and lateral base widened), cross-over step (the limb unloaded by the perturbation stepped over the front of the other foot) or no step (usually associated with a 'timber' fall). Corrective stepping was characterized by latency to step after perturbation onset, step velocity and step length. Additionally, percentages of trials resulting in falls were identified for each group.RESULTS-Whereas elderly control subjects never fell, PD subjects fell in 27% and 36% of trials in the ON and OFF states, respectively. Both PD and control subjects most often used a lateral step strategy; 70% (control), 64% (PD OFF) and 73% (PD ON) of all trials, respectively. PD subjects fell most often when using a cross-over strategy (75% of all cross-over trials) or no-step strategy (100% of all no-step trials). PD OFF subject's lateral stepping strategies were initiated later than controls (370±37 vs. 280±10 ms; p<.01), and steps were smaller (254±20 vs. 357±17 cm; p<.01) and slower (0.99±0.08 vs.1.2±0.07 cm/sec; p<.05). No differences were found between PD OFF versus PD ON in the corrective stepping characteristics. Late steps were associated with falls with a correlation of 0.79, p>0.01. Levodopa medication did not significantly affect falls, lateral step latency, velocity or amplitude (P>.05).CONCLUSIONS-PD subjects showed significantly more postural instability and falls than agematched control subjects when stepping was required for postural correction in response to lateral disequilibrium. Although PD subjects usually chose the same lateral stepping strategy as age-matched control subjects in response to lateral translations, bradykinetic characteristics of the stepping responses help explain the greater rate of falls in subjects with PD. Unlike control subjects, PD subjects were unable to maintain equilibrium when using a cross-over strategy and sometimes failed to take a step at all and fell. Levodopa replacement therapy did not change either strategy selection, stepping characteristics or number of falls, suggesting that levodopa does not improve lateral stepping responses, similar to in-place postural responses. Rehabilitation aimed at improving lateral stability...

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“…In addition to high medical expenses that falls pose to the public health service, the consequences for elderly persons are dramatic because of their association with physical and psychological trauma, reduced activity, loss of independence, decreased quality of life and even injury-related deaths. Although falling is a complex and multifactorial problem (5-7), decreased postural control is usually considered as a major contributing factor (8)(9)(10)(11)(12)(13)(14). More precisely, posturographic parameters of mediolateral (ML) postural sway measured in unperturbed stance were shown to be the most strongly associated with a history of falls and to be the best predictors for risk of falling in an elderly population (11,12).…”

Section: Introductionmentioning

confidence: 99%

“…Although falling is a complex and multifactorial problem (5-7), decreased postural control is usually considered as a major contributing factor (8)(9)(10)(11)(12)(13)(14). More precisely, posturographic parameters of mediolateral (ML) postural sway measured in unperturbed stance were shown to be the most strongly associated with a history of falls and to be the best predictors for risk of falling in an elderly population (11,12). These findings also have been extended to dynamic situations since an increased ML body motion during obstructed locomotion was demonstrated to discriminate elderly persons at greater risk of falling (15).…”

Section: Introductionmentioning

confidence: 99%