Deficits in stepping response time are associated with impairments in balance and mobility in people with Huntington disease

Abstract

Huntington disease (HD) is a disorder characterized by chorea, dystonia, bradykinesia, cognitive decline and psychiatric comorbidities. Balance and gait impairments, as well as falls, are common manifestations of the disease. The importance of compensatory rapid stepping to maintain equilibrium in older adults is established, yet little is known of the role of stepping response times (SRTs) in balance control in people with HD. SRTs and commonly-used clinical measures of balance and mobility were evaluated in fourteen symptomatic participants with HD, and nine controls at a university mobility research laboratory. Relative and absolute reliability, as well as minimal detectable change in SRT were quantified in the HD participants. HD participants exhibited slower SRTs and poorer dynamic balance, mobility and motor performance than controls. HD participants also reported lower balance confidence than controls. Deficits in SRT were associated with low balance confidence and impairments on clinical measures of balance, mobility, and motor performance in HD participants. Measures of relative and absolute reliability indicate that SRT is reliable and reproducible across trials in people with HD. A moderately low percent minimal detectable change suggests that SRT appears sensitive to detecting real change in people with HD. SRT is impaired in people with HD and may be a valid and objective marker of disease progression.

Postural deficits in Huntington's disease when performing motor skills involved in daily living

“…While this result is consistent with reports of reduced strength in the lower limbs of HD patients [22], the observed force deficit did not generalize to the STS test where the amount of force (reported here as rising index) was comparable for both groups. The contrast in force production by HD patients for the two tasks may reflect the use of different muscle synergies that are adaptively regulated to match different functional tasks [23,24].…”

“…These values represent relative increases in movement time of 60%, 53% and 70%, which are comparable to percent increases reported other syndromes in which the CNS is compromised such as fetal alcohol syndrome [20] and Parkinson's disease [21]. Delays of this magnitude in symptomatic HD patients result in impaired balance and mobility [10] and have possible significance for clinicians who design rehabilitation therapies for this clinical group. When performing the ST test, bradykinesia contributed most to the observed deficit in the HD patients and clinicians should target this parameter to maximize improved motor performance.…”

“…HD patients with histories of frequent falls have reduced balance compared to nonfallers [3] and manifest greater instability on standard tests, such as the Tinetti Mobility Test [4]. With regard to unimpeded walking, studies reveal a range of atypical response characteristics in HD patients, including decreased gait velocity and stride length, increased double support time and more variable stride length and step time [5][6][7][8][9][10][11][12][13]. Delval et al [14] adopted a different approach to the study of gait and investigated how HD patients transition from quiet stance to walking.…”

Direction specific preserved limits of stability in early progressive supranuclear palsy: A dynamic posturographic study

“…When the COG falls outside the LOS area, neither hip nor ankle strategies will restore the balance and additional stepping strategies may be necessary to restore the balance or avoid falls. Studies have shown a strong correlation between the stepping capabilities and balance in older adults [16,17] and lack of stepping response is associated with impairments of balance, mobility, and motor performance in Huntington's disease [18], which is a progressive neurodegenerative disorder affecting the extrapyramidal system. Information on stepping response in PSP is not available.…”

Introduction of a Complex Reaction Time Tester Instrument

“…In most of the cases, the task is to simply press or release a button or a pedal in a few cm range of the finger or feet [16][17][18]. The instrument form [16] called American Educational (Hubbard Scientific 6027) Reaction Timer is shown in Fig.…”