Training-related changes in dual-task walking performance of elderly persons with balance impairment: A double-blind, randomized controlled trial
Introduction
An impaired ability to maintain balance while simultaneously performing cognitive tasks has been associated with adverse outcomes, such as falls [1], [2], [3], [4], and physical and cognitive functional decline [5], [6], [7] in elderly people. Despite the potential importance of interventions to improve dual-task balance performance [8], [9], there have been very few studies [10], [11], [12] evaluating the efficacy of strategies to train balance under dual-task conditions. Previous studies have included either a small sample size [11], or have focused on healthy young adults [10] or patients with stroke [12]. None of those studies was directly designed to uncover the mechanisms underlying dual-task balance processing.
It has been suggested that understanding the mechanisms of dual-task processing will lead to the development of an optimal strategy to improve dual-task performance [13], [14]. Although the mechanisms underlying changes in dual-task performance in postural control are not known, there is information on dual-task processing using non-balance-related tasks. At least two models have been proposed to account for the training-related changes in dual-task performance [14], [15]. The task-automatization model proposes that improved dual-task performance is the result of increased automatization of the individual tasks. This model predicts comparable improvement in dual-task performance with either single-task (ST) or dual-task training. Alternatively, the task-integration model suggests that an efficient integration of the two tasks acquired during dual-task training is crucial for the improvement of dual-task performance. Consequently, improvement in dual-task performance would be observed only following dual-task training, not single-task training.
The ability to modulate attention may also play an important role in the acquisition of dual-task coordination skill. Kramer et al. compared dual-task training under two instructional sets; the variable-priority (VP) group members were required to vary their priorities between the two tasks, whereas the fixed-priority (FP) group members were instructed to equally emphasize both tasks [16]. The two non-postural related tasks trained in their study included a monitoring task in conjunction with an alphabet–arithmetic task. Results showed that the VP group improved (i.e. increased accuracy and decreased response time) significantly more than the FP group and the dual-task processing skills learned during VP training transferred to novel tasks. It is not known, however, whether similar training effects would be observed when training balance under dual-task conditions.
Thus, the purpose of this study was to compare the efficiency of three different training strategies in an effort to understand the mechanisms underlying changes in dual-task balance performance of older adults with balance impairment. Specifically, the effect of training on dual-task balance performance and the generalizability of dual-task processing skills to novel tasks were examined. In accordance with the task-automatization hypothesis, we predicted equivalent training benefits in dual-task balance performance from both single-task and dual-task training groups. Alternatively, based on the task-integration hypothesis, it was expected that there would be improvement in dual-task balance performance only following dual-task training. In addition, it was predicted that dual-task training using VP strategy would be superior to training using FP and ST strategies, and the dual-task processing skills acquired during VP training would generalize to novel dual-task balance conditions.
Section snippets
Participants
Elderly persons were recruited through flyers in the surrounding communities. Inclusion criteria included age ≥65, able to walk 10 m, no neurological or musculoskeletal diagnosis, met the criteria of balance impairment, and scored >24 on the mini mental state examination [17]. Balance impairment was determined using the berg balance scale (BBS) [18], [19], and self-selected gait speed [20], [21], previously shown to correlate with balance during stance [19] and gait [22], [23]. Persons were
Results
Fifty older adults were recruited for the study, 17 did not meet the inclusion criteria and 10 declined to participate (Fig. 2). Twenty-three eligible older adults were randomly assigned to one of three training groups; 21 completed the training program. There were no significant group differences in any baseline characteristics (P > .05). In addition, no training effect was found for gait temporal-distance measurements in any condition (Table 1).
Discussion
The goal of this study was to compare the effects of three types of training on balance performance in single- and dual- (practiced and novel) task conditions among older adults with impaired balance. Results indicated that type and magnitude of benefits vary by training type. Dual-task training with VP instruction was more effective in improving both balance and cognitive performance under a dual-task condition than either the ST or the FP training strategies.
Participants in all groups
Conclusions
This is the first study to examine the mechanisms underlying training-related changes in dual-task balance performance of older adults with impaired balance. The results suggested that a VP training strategy was more effective in improving both balance and cognitive performance under a dual-task condition than the ST and FP training strategies. However, the dual-task balance processing skills acquired during training did not generalize to a novel dual-task condition. Finally, the overall data
Conflict of interest statement
None.
Acknowledgements
This study was funded by a grant from the National Institutes of Health (AG-021598) to M. Woollacott. We thank Cooper Boydston for assistance with data collection. We acknowledge Charlene Halterman, Teresa Hawkes, Chu-jui Chen, and Sujitra Boonyong for their assistance with training sessions.
References (27)
- et al.
Stops walking when talking as a predictor of falls in elderly people
Lancet
(1997) - et al.
Dual-task exercise improves walking ability in chronic stroke: a randomized controlled trial
Arch Phys Med Rehabil
(2007) - et al.
Mini-mental state. A practical method for grading the cognitive state of patients for the clinician
J Psychiatr Res
(1975) - et al.
Detection of gait instability using the center of mass and center of pressure inclination angles
Arch Phys Med Rehabil
(2006) - et al.
Age-related reduction in sagittal plane center of mass motion during obstacle crossing
J Biomech
(2004) - et al.
Center of mass and ankle inclination angles: an alternative detection of gait instability
J Biomech
(2007) - et al.
Dual task-related changes in gait performance in older adults: a new way of predicting recurrent falls?
J Am Geriatr Soc
(2008) - et al.
Multitasking: association between poorer performance and a history of recurrent falls
J Am Geriatr Soc
(2007) - et al.
Application of the voluntary step execution test to identify elderly fallers
Age Ageing
(2007) - et al.
Association of executive function and performance of dual-task physical tests among older adults: analyses from the InChianti study
Age Ageing
(2006)
Impact of cognitive task on the posture of elderly subjects with Alzheimer's disease compared to healthy elderly subjects
Mov Disord
Effect of divided attention on gait in subjects with and without cognitive impairment
J Geriatr Psychiatry Neurol
Relationship between dual-task related gait changes and intrinsic risk factors for falls among transitional frail older adults
Aging Clin Exp Res
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