Does severity of motor impairment affect reactive adaptation and fall-risk in chronic stroke survivors?

Abstract

BackgroundA single-session of slip-perturbation training has shown to induce long-term fall risk reduction in older adults. Considering the spectrum of motor impairments and deficits in reactive balance after a cortical stroke, we aimed to determine if chronic stroke survivors could acquire and retain reactive adaptations to large slip-like perturbations and if these adaptations were dependent on severity of motor impairment.MethodsTwenty-six chronic stroke participants were categorized into high and low-functioning groups based on their Chedoke-McMaster-Assessment scores. All participants received a pre-training, slip-like stance perturbation at level-III (highest intensity/acceleration) followed by 11 perturbations at a lower intensity (level-II). If in early phase, participants experienced > 3/5 falls, they were trained at a still lower intensity (level-I). Post-training, immediate scaling and short-term retention at 3 weeks post-training was examined. Perturbation outcome and post-slip center-of-mass (COM) stability was analyzed.ResultsOn the pre-training trial, 60% of high and 100% of low-functioning participants fell. High-functioning group tolerated and adapted at training-intensity level-II but low-functioning group were trained at level-I (all had > 3 falls on level-II). At respective training intensities, both groups significantly lowered fall incidence from 1st through 11th trials, with improved post-slip stability and anterior shift in COM position, resulting from increased compensatory step length. Both groups demonstrated immediate scaling and short-term retention of the acquired stability control.ConclusionChronic stroke survivors are able to acquire and retain adaptive reactive balance skills to reduce fall risk. Although similar adaptation was demonstrated by both groups, the low-functioning group might require greater dosage with gradual increment in training intensity.

Adaptation of balancing behaviour during continuous perturbations of stance. Supra-postural visual tasks and platform translation frequency modulate adaptation rate

“…Continuous perturbations of stance have positive effects in the rehabilitation of balance in ageing [126], patients with neurological or vestibular deficits [127], cerebellar disease [128], stroke [83], Parkinson´s disease [6]. Exercises based on head movement have been beneficial in patients with vestibulopathy [129].…”

“…Therefore, we would suggest that the time course (but not the quality) of the adaptation process is partly set by the number of cycles and is based either or both on the sensory inputs originating during each cycle and on the anticipatory adjustments preceding the anterior and posterior dead points of each translating cycle. A broadly similar number of events has been counted in other balance adaptation studies [ 32 , 47 , 53 , 55 , 65 , 80 – 83 ], including events of perturbed gait ([ 84 ], for a recent review). The main process of adaptation would be relatively independent from the time elapsing from the beginning of the sequence of perturbation but be calibrated on the frequency of discrete changes in the direction of the AP platform translations.…”

Improving Trip- and Slip-Resisting Skills in Older People: Perturbation Dose Matters

“…Nevisipour et al (38) reported that in people who have had a stroke, a training session of 15 posterior treadmill translation perturbations during stance resulted in reduced trunk flexion during recovery from a similar but untrained perturbation, indicating a training-related improvement, but trunk flexion velocity, reaction time, step duration, step length, and stability did not improve. Bhatt et al (39) applied repeated anterior surface translation perturbation (initiating backward balance loss) to stance in people who have had a stroke with both higher and lower motor impairment. Both groups improved in their ability to cope with the perturbations (fewer falls and better stability control), but there was a slower rate of adaptation over the trials in people with more severe motor impairment.…”

The Association Between an Antecedent of Transient Ischemic Attack Prior to Onset of Stroke and Functional Ambulatory Outcome

“…[9][10][11][12][13] These measures are based on clinical characteristics of the patient and provide cumulative evaluations for the management of poststroke treatment care. Accurate predictions of ambulatory functions are needed as well, so that clinicians can help patients set motor recovery goals to improve activities of daily living [14][15][16][17][18] following thrombolysis therapy.…”