Effect of a perturbation-based balance training program on compensatory stepping and grasping reactions in older adults: a randomized controlled trial.
Article Type: Clinical report
Subject: Aged (Training)
Falls (Accidents)
Parkinson's disease
Clinical trials
Authors: Mansfield, A.
Peters, A.L.
Liu, B.A.
Maki, B.E.
Pub Date: 11/01/2011
Publication: Name: New Zealand Journal of Physiotherapy Publisher: New Zealand Society of Physiotherapists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2011 New Zealand Society of Physiotherapists ISSN: 0303-7193
Issue: Date: Nov, 2011 Source Volume: 39 Source Issue: 3
Topic: Event Code: 280 Personnel administration
Accession Number: 288538005
Full Text: Objective

To determine whether a perturbation-based balance training programme could improve age-related impairments in compensatory stepping and handrail grasp reactions in older adults.

Methods

Double-blind randomised control trial. Thirty adults aged 64-80 years with a history of falls or postural instability during the previous five years were recruited. Participants were randomly allocated to a perturbation based balance training group using a motion platform or a control group undergoing flexibility and relaxation training. Sessions for both groups were thirty minutes, three times per week for six weeks. For the intervention group half of each session focused on stepping reactions, with the other half concentrated on handrail grasp reactions. Main outcome measures included multi step reactions, extra lateral steps following anteroposterior perturbations, foot collisions following lateral perturbations and handrail contact time. Preand post-testing was completed utilising different equipment and cable pulls to assess transference of skills.

Results

Perturbation-based balance training demonstrated a statistically significant reduction of multi step reactions (p= 0.034) using surface translation but not cable pulls, foot collisions during lateral perturbations (p= 0.0046) using surface translation but not cable pulls, and handrail contact time (p= 0.004) using cable pulls but not surface translation. No effect was shown for training on extra lateral steps during anteroposterior perturbations.

Conclusions

Training compensatory stepping and grasp reactions using perturbation-based balance training may be an effective treatment technique to help prevent falls in older adults with instability.

Commentary

Falls prevention is a big concern in the ageing population with many different interventions implemented to try and reduce the risk of falls, such as group exercise classes, strengthening programmes, Tai Chi and balance exercises. To help prevent falls people need to have effective balance strategies. Research suggests that stepping reactions are utilised much earlier in the postural response than previously thought, even if the perturbation is small (Maki and McIlroy 1997). Research looking at the difference in stepping reactions in the elderly population at risk of falls in comparison to the younger population has shown some key differences between the two age groups. Findings include reduced lateral stability with balance loss causing collision of limbs (Maki et al 2000), multiple-step reactions and reduced step length in the elderly population (McIlroy and Maki 1996).

This study was completed to assess whether these compensatory reactions in the elderly population can be improved using perturbation-based training, aiming to reduce falls risk in the future. The methodology of this study was of reasonably high quality. It was double-blind randomised control trial with both groups being similar at baseline. The sample size required to be able to detect clinically significant changes due to intervention was calculated and this number was achieved in recruitment. The intervention and control group training programmes were clearly explained, and the intervention programme was designed to encourage motor learning. Different equipment was used for testing to reduce the risk of bias due to familiarisation, and reactions to cable pulls were used to assess transference of skills from a perturbation due to surface translation compared to a centre of mass perturbation. There were some methodological limitations of this study, with some possibility of type one statistical error due to multiple statistical analyses being used. In addition, an intention to treat analysis was not used despite seven participants withdrawing and loss of some measurements due to technical difficulties.

The results of this study showed statistically significant improvements in reducing multi-step reactions and reducing foot collisions with lateral perturbations. Skill transference was only demonstrated with cable pulls in the grasp component; however the cable pulls created a less challenging perturbation that improved baseline performance reducing potential for significant improvement. Another interesting finding was that the training did not improve other aspects of balance outcomes measured in the study such as the Timed Up and Go test. This supports previous beliefs about the need for specificity in balance retraining with stepping reactions possibly being only one component of a client-centred balance training programme.

There are some aspects of this study that make it difficult to implement in clinical practice. The researchers created a pneumatic motion platform for training, which is not commonly available in clinic settings. However, previous studies in participants with Parkinson's disease using treadmill manual perturbations have also shown some positive results suggesting, these reactions can be retrained without such expensive technical equipment (Jobges et al 2004, Protas et al 2005). Due to lack of follow-up assessment we are unable to determine if the improvements were sustained over time, or whether they were short term changes. It would also be interesting to see whether these results did actually reduce falls risk or incidence in this population group and if they are applicable to patients with neurological conditions. The studies mentioned above utilised different perturbation techniques and demonstrated improvements in participants with Parkinson's disease, suggesting that training of compensatory stepping reactions may be of benefit in some neurological populations.

The results of this study support the growing body of evidence that suggests perturbation-based balance training is an effective treatment that could be used to reduce falls risk in the elderly. It is suggested that falls risk is reduced by improving compensatory reactions; however further investigation is needed to look at the long term impact on falls and whether maintenance is required to sustain improvements.

Laura Bloomfield, BPhty

Post-graduate Student, Diploma in Rehabilitation

Auckland University of Technology

REFERENCES

Jobges M, Heuschkel G, Pretzel C, Illhardt C, Renner C, Hummelsheim H (2004): Repetitive training of compensatory steps: a therapeutic approach for postural instability in Parkinson's disease. Journal of Neurology, Neurosurgery and Psychiatry 75: 1682-1687.

Maki BE, Edmondstone MA, McIlroy ME (2000): Age-related differences in laterally directed compensatory stepping behavior. Journal of Gerontology 55: 270-277

Maki BE and McIlroy WE (1997): The role of limb movements in maintaining upright stance: the "change in support" strategy. Physical Therapy 77: 488-507

McIlroy WE and Maki BE (1996): Age-related changes in compensatory stepping in response to unpredictable perturbations. Journal of Gerontology 51: 289-296

Protas EJ, Mitchell K, Williams A, Qureshy H, Caroline K, Lai EC (2005): Gait and step training to reduce falls in Parkinson's disease. Neurorehabilitation 20: 183-190.
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