Effects of Combined vs. Sequential Attentional Focus Instructions on Upper Extremity Function in Subacute Stroke

Stroke is a major global cause of long-term disability. Upper extremity deficits are particularly common, affecting nearly 80% of individuals after stroke and manifesting as weakness, impaired selective motor control, abnormal muscle tone, sensory disturbances, and reduced coordination. These deficits cause substantial limitations in functional reach, grasp, and object manipulation, and they persist more severely compared with lower extremity impairments. Although most stroke survivors regain some degree of independent ambulation, only a minority recover meaningful functional use of the paretic upper limb, resulting in a disproportionately higher disability burden for the upper extremity.

Conventional rehabilitation often shows limited effectiveness in improving upper extremity outcomes because training intensity is typically insufficient, task specificity is restricted, and interventions do not consistently apply established motor learning principles. These challenges underscore the need for new therapeutic perspectives that more effectively harness neuroplasticity through high-intensity, task-oriented, and motor learning-based approaches tailored to the complex demands of upper extremity recovery.

Upper-extremity motor functions, which are often severely impaired in the acute phase of stroke, gradually begin to recover during the transition into the subacute period as spontaneous neurobiological repair processes become more active. Subacute stroke refers to the recovery phase that begins after the first week post-onset and extends through the early months, during which spontaneous biological recovery and neuroplasticity remain highly active. Although many frameworks define the core subacute window as the first 3 months, functional recovery and rehabilitation responsiveness continue meaningfully up to 6 months, which is widely accepted as the upper limit of the subacute period in clinical research and guideline-based stroke classification. Therefore, including patients within the first 6 months post-stroke ensures enrolment during a period of high rehabilitative potential.

In recent years, the integration of physical exercise and cognitive training has emerged as a promising strategy for enhancing both cognitive and motor functions in rehabilitation. One example of combining motor tasks with cognitive components is attentional focus training, which includes external and internal attentional focus strategies. External attentional focus directs the learner's attention to the effects of movement (e.g., "focus on the movement of the ball") and has been consistently shown to enhance movement efficiency and task performance. This effect is believed to occur through increased motor automaticity and reduced conscious interference. Conversely, internal attentional focus emphasizes the mechanical components of body movements (e.g.,'focus on your hand position') and can support the development of foundational motor control, particularly during the early stages of motor learning and recovery.

Recent evidence suggests that both internal and external attentional focus strategies can complement each other in therapeutic contexts. Internal focus (IF) supports early stroke rehabilitation by enhancing basic motor control, whereas external focus (EF) improves movement efficiency and functional parameters in later stages. EF has also been reported to outperform IF in improving upper extremity performance in stroke populations. These findings suggest that combining IF and EF-either simultaneously or in a structured progression-may better align with the evolving demands of stroke recovery.

In terms of enhancing upper extremity function and overall motor recovery, two primary approaches have been explored: sequential and combined attentional focus training. Combined attentional focus instruction involves delivering internal and external focus cues within the same training session or task-either concurrently or in close temporal proximity-allowing patients to benefit from both improved motor control and enhanced movement efficiency. In contrast, Sequential attentional focus instruction involves providing internal and external focus cues in a structured order-typically beginning with internal focus to establish basic motor control, followed by external focus as movement efficiency and automaticity improve. Although both approaches show promise, their comparative effectiveness has not been directly examined in stroke populations, indicating a clear need for research evaluating these instructional strategies within stroke rehabilitation.

Our primary aim is to compare the effects of combined and sequential attentional focus instructions on upper extremity motor function in patients with subacute stroke. We hypothesize that implementing combined attentional focus instructions (internal attentional focus instructions in the early stages of recovery, followed by a combination with external attentional focus instructions in later stages) will lead to greater improvements in upper extremity function.

Inclusion criteria

• Age 40-80 years at enrollment (Kwakkel et al., 1996; Coupar et al., 2012).
• Stroke diagnosed by a neurologist between 1 week and 6 months before enrollment (Langhorne et al., 2020; Bernhardt et al., 2017).
• Medically stable, as confirmed by a neurologist, with controlled and non-fluctuating vital signs (Stinear et al., 2020; Powers et al., 2019; Winstein et al., 2016).
• Sufficient cognitive function to follow instructions, sustain attention, and actively participate in rehabilitation, as judged by the treating therapist (Stinear et al., 2020; Boyd et al., 2018).
• Brunnstrom stage 2-5 in the affected upper limb (Brunnstrom, 1970; Langhorne et al., 2020).
• Individuals with a Modified Ashworth Scale (MAS) score <3: Participants were required to have a MAS score of less than 3 in both the upper and lower extremities to ensure that spasticity remained at a manageable level and to allow safe participation in upper-limb motor rehabilitation (Pandyan et al., 2005; Li & Francisco, 2015; Ada et al., 2020).
• Preserved corticospinal tract integrity, confirmed by a positive Motor Evoked Potential (MEP) response (Stinear et al., 2017; Byblow et al., 2015; Stinear et al., 2020).
• Moderate to severe upper-extremity motor impairment, determined by Fugl-Meyer Assessment (FMA) scores of 0-47 (0-19 severe, 20-47 moderate) (Fugl-Meyer et al., 1975).

Exclusion criteria

• Spasticity level: Individuals with a Modified Ashworth Scale (MAS) score ≥3 in either the upper or lower extremities were excluded, as marked hypertonicity and severe spastic contractions could negatively affect proximal stabilization and movement strategies, thereby interfering with upper-limb task performance (Pandyan et al., 2005).
• Fractures: Participants with a current or recent fracture on the affected side of the body were excluded from the study.
• Botulinum toxin injections: Individuals who had received Botulinum Toxin (Botox) injections within the previous three months were excluded due to the potential effects of the intervention on muscle tone and motor performance.
• Communication disorders: Participants with motor or global aphasia, or other communication impairments that could interfere with understanding instructions or performing the required tasks, were excluded.
• Concurrent rehabilitation: Individuals who were concurrently receiving rehabilitation treatment at another facility were excluded to prevent potential confounding effects from parallel interventions (Winstein et al., 2016).
• Non-adherence to treatment sessions: Participants who failed to attend all required treatment sessions were excluded to ensure consistency and fidelity of the intervention protocol (Winstein et al., 2016).