Increased dual-task interference during upper limb movements in stroke exceeding that found in aging – a systematic review and meta-analysis

 Nothing here gets survivors recovered! What the hell is your stroke research for, if not to help survivors?

What is dual-task interference? I can't figure out how to see the illustration.

Simultaneous performance of two tasks often leads to performance deficits in the component tasks. This effect, known as dual-task interference, is thought to be a proof of capacity limitation in cognition, and the lateral prefrontal cortex (LPFC) has been highlighted as its putative neural substrate. 

Immediately post stroke I could barely walk and talk at the same time. Doing any muscle movent with the left side totally deteriorates if I do any movement with my right side.

Increased dual-task interference during upper limb movements in stroke exceeding that found in aging – a systematic review and meta-analysis

Påvel G. Lindberg^1,2*Nadia AmirShemiraniha³Carmen Krewer^3,4Marc A. Maier⁵Joachim Hermsdörfer³

• ¹Institut de Psychiatrie et Neurosciences de Paris, INSERM U1266, Université Paris Cité, Paris, France
• ²Department of Clinical Sciences, Karolinska Institutet, Danderyd University Hospital, Stockholm, Sweden
• ³Chair of Human Movement Science, Department Health and Sport Sciences, School of Medicine and Health, Technical University of Munich, Munich, Germany
• ⁴Department of Neurology, Research Group, Schoen Clinic Bad Aibling, Bad Aibling, Germany
• ⁵INCC UMR 8002, CNRS, Université Paris Cité, Paris, France

Objective: To determine whether dual-task interference during upper limb tasks is increased in patients after stroke compared to healthy older subjects and to compare magnitude of stroke-induced change in interference to that explained by aging.

Methods: We conducted a systematic literature search in MEDLINE, CINAHL, Google Scholar and PEDro databases up to October 2023 for studies on upper limb dual-tasks in stroke and elderly healthy subjects. Eleven upper limb dual-task studies in stroke patients and 11 studies in healthy older subjects were identified and systematically reviewed. A meta-analysis was performed on seven stroke studies and on five studies in healthy older subjects that included control groups.

Results: Most stroke studies investigated proximal arm movements with kinematic measures, but few studies evaluated manual dexterity. In contrast, studies in healthy older subjects used more distal (finger tapping) tasks. The meta-analysis showed that stroke patients had on average a 19% (CI 95% = 1.0–37.3) increase in dual-task interference compared to age-matched healthy controls (Z = 2.06, p = 0.04). Older healthy subjects showed greater dual-task interference compared to younger subjects (19% greater, CI 95% = 6.5–31.2, Z = 2.98, p = 0.003).

Conclusion: Meta-analysis revealed an increase in dual-task interference during upper limb movements in stroke patients, exceeding age-related changes, supporting the presence of subclinical impairments in divided attention post-stroke that may impede motor recovery.

1 Introduction

Upper limb sensorimotor impairments are common after stroke (1, 2), particularly impacting manual dexterity (3, 4). Impaired manual dexterity and finger control hampers essential grasping functions, impacting many everyday activities and autonomy (5–8). Approaches for measurement and targeted rehabilitation of dexterity are being developed, focusing on underlying impairments such as reduced finger force control, timing or independent finger movements [(9–11)]. A key aspect in these training approaches is the provision of enhanced hand and finger movement feedback, most often through enhanced visual feedback of movement performance. This increases attention to task performance, making the training more engaging (12, 13). However, attention to the task can be diminished through distraction. Visual distraction during visuomotor grip force control leads to less precise task execution in healthy subjects (14). In stroke, high distractibility is also associated with less precise grip force control (15). Performance in visuomotor tasks therefore also depends on selective (visual) attention, along with working memory and executive functions (16), which can be tested using dual-task paradigms.

Dual-task situations, i.e., concurrently performing a motor and a cognitive task, typically induce a performance decrement, even in healthy subjects, when compared to single task conditions (14, 17). This phenomenon has been termed dual-task interference and has also been demonstrated after stroke during walking (17, 18) and control of balance (19). Dual-task interference is supposed to result from limited cognitive resources (20, 21) that might affect (divided) attention, executive function, working memory and potentially other cognitive functions used during motor tasks. Many daily activities present dual-task situations (such as talking while dressing) and reduced capacity to perform dual-tasks can be detrimental for independence in daily life (22). Dual-task approaches in stroke may help elucidate the relative role and interaction of cognitive and motor dysfunction and inform on prediction of post-stroke motor recovery [(22–24)]. While dual-task interference during locomotion is well characterized in stroke patients (17, 22, 25), fewer studies have been dedicated to post-stroke dual-task interference during voluntary upper limb movements. Dexterous finger movements, being complex and involving high-level control, likely require greater cognitive resources than lower limb movements (26). Together, this suggests that upper limb dual-task interference may be greater than lower limb dual-task interference in stroke, although studies directly comparing the two are lacking. Enhancing the knowledge about cognitive mechanisms contributing to upper limb motor recovery after stroke is important to understand patients’ deficits in daily life, to devise stratification approaches for study design, for the development of prediction algorithms and for the development of targeted interventions. It is therefore central to synthesize the results on upper limb dual-task interference in stroke and to systematically review available studies and perform a quantitative meta-analysis.

To our knowledge, no systematic literature review has so far been undertaken on upper-limb dual-task interference in stroke patients. We had two aims: (1) to summarize the evidence for dual-task interference during upper limb movements in stroke patients (i.e., dual-task vs. single task) and to perform a meta-analysis on results comparing stroke patients with age-matched healthy controls, and (2) to assess dual-task interference also in healthy older persons, since most first-ever strokes occur in older persons, i.e., average age of first stroke 70y (27, 28) and to perform a meta-analysis on results comparing older versus younger healthy controls. Thus, age and stroke might be combining factors acting on dual-task interference. We asked four key questions: (i) Does dual-task interference occur in stroke patients using a dual-task paradigm including an upper limb task and a concurrent cognitive task? (ii) Is dual-task interference more marked in stroke patients compared to that in healthy age-matched control subjects? (iii) Do healthy older subjects show higher interference than healthy young subjects? And (iv) can task-or stroke-related variables be identified that influence the occurrence of dual-task interference?

We were particularly interested in studies that provide the degree (magnitude) of dual task interference for the group comparison since this permitted calculation of average degree of dual-task interference and statistical analysis through a meta-analysis. Therefore, this survey combines a systematical review with a meta-analysis in a sub-group of the selected studies.