Examining interference of different cognitive tasks on voluntary balance control in aging and stroke

Factors associated with balance impairments in the community-dwelling elderly in urban China

BACKGROUND

Identification of factors relevant to balance performance impairments in the elderly population was critical for developing effective interventions and preventions. However, there have been very limited data available based on large scale studies. The present study identified factors that independently contributed to performance impairments in overall balance, domains of static balance, postural stability, and dynamic balance, and individual items.

METHODS

A total of 1984 community-dwelling Chinese elderly from urban areas of Shanghai were recruited. Information on demographic characteristic, exercise, and health status were collected with a face-to-face interview. Balance performances were assessed on site by trained investigators based on the X16 balance testing scale. To identify the effectors, ordinal logistic regression analysis was applied for overall balance, static balance, postural stability, and dynamic balance. Binary logistic regression analysis was used for 16 items.

RESULTS

The community-dwelling elderly residents were aged from 60 to 97 years old. With increases of age, risks of impairments in overall balance increased gradually (ORs from 1.26 to 3.20, all P < 0.01). In the elderly with overweight and obesity, there was higher proportion of balance impairments compared to the elderly with normal BMI (OR = 1.26, P < 0.001). Regular exercise every week was associated with reduced risks of balance impairments (ORs from 0.63 to 0.73, all P < 0.001). Presences with vision lesion (ORs from 1.28 to 1.59, all P < 0.001), moderate hearing impairment (OR = 1.54, P < 0.001), somesthesis dysfunction (ORs from 1.59 to 13.26, all P < 0.001), and cerebrovascular disease (OR = 1.45, P = 0.001) were related to increased risks of balance impairments. Likewise, age, exercise, vision, hearing, somesthesis, and cerebrovascular disease were significantly associated with static balance, postural stability, and dynamic balance. Both overweight and obesity and underweight were associated with higher proportions of dynamic balance impairments. Regular exercise was significantly related to reduced risks of impairments in 15 out of the 16 items.

CONCLUSIONS

In the elderly, age, overweight and obesity, exercise, vision, hearing, somesthesia, and cerebrovascular disease were dominant factors associated with impairments in overall balance, domains of static balance, postural stability, and dynamic balance, and most individual items.

TRIAL REGISTRATION

Not applicable.

Language-Specific Dual-Task Effects After Stroke: A Systematic Review

PURPOSE

The dual-task paradigm has been frequently used to examine stroke-related deficits because it samples behavioral performance under conditions of distraction similar to functioning in real-life environments. This original systematic review synthesizes studies that examined dual-task effects involving spoken language production in adults affected by stroke, including transient ischemic attack (TIA) and poststroke aphasia.

METHOD

Five databases were searched (inception to March 2022) for eligible peer-reviewed articles. The 21 included studies reported a total of 561 stroke participants. Thirteen studies focused on single word production, for example, word fluency, and eight on discourse production, for example, storytelling. Most studies included participants who had suffered a major stroke. Six studies focused on aphasia, whereas no study focused on TIA. A meta-analysis was not appropriate because of the heterogeneity of outcome measures.

RESULTS

Some single word production studies found dual-task language effects whereas others did not. This finding was compounded by the lack of appropriate control participants. Most single word and discourse studies utilized motoric tasks in the dual-task condition. Our certainty (or confidence) assessment was based on a methodological appraisal of each study and information about reliability/fidelity. As 10 of the 21 studies included appropriate control groups and limited reliability/fidelity information, the certainty of the findings may be described as weak.

CONCLUSIONS

Language-specific dual-task costs were identified in single word studies, especially those that focused on aphasia as well as half of the nonaphasia studies. Unlike single word studies, nearly all studies of discourse showed dual-task decrements on at least some variables.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23605311.

Post-stroke cognitive impairments and responsiveness to motor rehabilitation: A review

PURPOSE OF REVIEW

a)This review discusses the prevalence of cognitive deficits following stroke and their impact on responsiveness to therapeutic intervention within a motor learning context.

RECENT FINDINGS

b)Clinical and experimental studies have established that post-stroke cognitive and motor deficits may impede ambulation, augment fall risk, and influence the efficacy of interventions. Recent research suggests the presence of cognitive deficits may play a larger role in motor recovery than previously understood.

SUMMARY

c)Considering that cognitive impairments affect motor relearning, post-stroke motor rehabilitation therapies may benefit from formal neuropsychological testing. For example, early work suggests that in neurotypical adults, cognitive function may be predictive of responsiveness to motor rehabilitation and cognitive training may improve mobility. This sets the stage for investigations probing these topics in people post-stroke. Moreover, the neural basis for and extent to which these cognitive impairments influence functional outcome remains largely unexplored and require additional investigation.

Effects of trying 'not to move' instruction on cortical load and concurrent cognitive performance

Motor and cognitive tasks often interfere when performed concurrently. The amount of interference typically scales with difficulty of the tasks involved. Thus, supposedly 'easy' motor tasks with restricted movement amplitude, like sitting on a chair, should show little or no interference with cognitive tasks at all. We measured the processing load induced by different postural tasks and their effect on cognitive performance under cognitive-motor dual-task conditions. Sixteen subjects performed postural motor tasks in three different positions: 'Lying in a sun lounger', 'Sitting on a bike saddle', and 'Upright on feet'. In each position, three different movement instructions were given; 'Stay stock-still', 'Relax', 'Move easily'. Each combination of position and instruction was performed as single task but also in a dual-task condition with a concurrent calculation task. Brain activity in the right prefrontal cortex was monitored using functional near-infrared spectroscopy. The instruction to 'Stay stock-still' produced higher cortical loads in single-task conditions for all positions compared to all other instructions. The calculation task induced additional brain activity in the same prefrontal area as the motor task. Calculation performance tended to be reduced in the 'Lying'-'Stay stock-still' condition. We discuss the relevance of these findings for learning scenarios in school.