"Experimental Study on Stroke Rehabilitation Based on Dual-Task Exercises"

Participants allocated to the intervention arm will receive a combined cognitive-motor dual-task rehabilitation protocol combining Perturbation-Based Balance Training (PBT) delivered simultaneously with computerized cognitive stimulation via the NeuronUP online neurorehabilitation platform.

The motor component consists of structured treadmill- or platform-based postural perturbational challenges designed to evoke reactive balance responses. Concurrently, participants will perform computerized cognitive exercises displayed on an eye-level screen targeting four core cognitive domains: memory, attention, language, and reasoning.

To ensure both standardization across subjects and individualized progression, participants will execute a fixed set of five validated NeuronUP tasks during every session:

Forming Sentences. Interview. Traffic Fines. Bottle Caps. Pass the Ball

Participants allocated to the control arm will receive a single-task motor rehabilitation protocol focused exclusively on Perturbation-Based Balance Training (PBT) delivered via the BalanceTutor system.

To serve as an active comparator, participants in this group will undergo an identical motor perturbation protocol on the BalanceTutor system-matching the intensity, frequency, direction, and magnitude of postural perturbations received by the experimental group-but without any concurrent cognitive stimulation or tasks (i.e., without the NeuronUP platform). Training will be administered in individual sessions, 3 times per week, for a total duration of 16 to 24 weeks, under direct supervision of a physical therapist.

Statistically significant improvements in functional balance recovery are expected in favor of the intervention group compared to the control group. Furthermore, a higher proportion of subjects in the experimental group is expected to achieve the Minimal Clinically Important Difference (MCID)-defined as an increase of ≥6 points on the Berg Balance Scale (BBS)-and to demonstrate a favorable transition toward lower fall-risk categories (BBS scores >41 points).

• Evaluation Tool: Wechsler Adult Intelligence Scale - Fourth Edition (WAIS-IV), Digit Span Subtest.

• Variable Type: Quantitative continuous / Primary secondary outcome.

• Domain & Construct Assessed: Auditory short-term memory, focused attention, verbal working memory, and executive control in post-stroke individuals.

• Measurement Sub-domains & Metrics:

  1. Digit Span Forward: Measures immediate auditory retention and short-term memory capacity. Metrics recorded include total raw score (correct trials) and memory span (maximum sequence length accurately repeated in direct order).
  2. Digit Span Backward: Measures working memory capacity, mental manipulation, and executive control. Metrics recorded include total raw score (correct trials) and memory span (maximum sequence length accurately repeated in reverse order).
  3. Total Digit Span Raw Score: Cumulative composite raw score combining correct trials from both Forward and Backward modalities.

Outcome Measure Title: Functional Mobility, Frailty, and Overall Health Status.

Variable Type: Quantitative continuous

Domain Assessed: Dynamic balance, functional mobility, gait speed, overall health deterioration, and frailty status in post-stroke individuals.

Operational Metric: Time recorded in seconds (s) required for the participant to stand up from a standard armchair, walk 3 meters at a comfortable and safe pace, turn around, walk back to the chair, and sit down again.

The 10-Meter Walk Test (10MWT) assesses walking speed in meters per second (m/s) over a short distance. Participants are instructed to walk along a 10-meter pathway at their [comfortable / maximum] self-selected pace. Acceleration and deceleration distances of 2 meters each are provided at the start and end of the course; only the central 6 meters are timed using a digital stopwatch. The primary outcome metric is the mean walking speed (m/s) calculated from [e.g., two / three] trials.

Assessment of frailty status using Fried's Frailty Phenotype model, which evaluates five criteria: unintentional weight loss (>10 lbs or >5% of body weight in the past year), self-reported exhaustion, low physical activity level, slow gait speed, and weak handgrip strength.

Participants are classified based on the number of criteria present:

Robust / Non-frail: 0 criteria met

Pre-frail: 1 or 2 criteria met

Frail: 3 or more criteria met

Assessment of depression severity using the [17-item / 21-item] Hamilton Depression Rating Scale (HDRS). The scale evaluates depressive symptoms including mood, feelings of guilt, suicide ideation, insomnia, work and activities, agitation, anxiety, somatic symptoms, and loss of weight.

Items are scored on either a 3-point (0 to 2) or 5-point (0 to 4) Likert scale. The total score ranges from 0 to [52 para 17 items / 66 para 21 items], with higher scores indicating greater severity of depressive symptoms.

Score interpretation (for the 17-item version):

0-7: Normal / Remission

8-13: Mild depression

14-18: Moderate depression

19-22: Severe depression

≥23: Very severe depression

Assessment of anxiety severity using the 14-item Hamilton Anxiety Rating Scale (HAM-A). The scale evaluates both psychic anxiety (mental agitation and psychological distress) and somatic anxiety (physical complaints related to anxiety).

Each item is scored on a 5-point Likert scale ranging from 0 (not present) to 4 (severe). The total score ranges from 0 to 56, with higher scores indicating greater severity of anxiety symptoms.

Score interpretation:

< 17: Mild anxiety severity

17-24: Mild to moderate anxiety severity

25-30: Moderate to severe anxiety severity

> 30: Severe anxiety

Assessment of muscle spasticity using the Modified Ashworth Scale (MAS). The scale measures resistance encountered during passive muscle stretching in the target muscle groups [e.g., upper/lower limb flexors or extensors].

The scale ranges from 0 to 4 across 6 scoring categories:

0: No increase in muscle tone.

1: Slight increase in muscle tone, manifested by a catch and release or by minimal resistance at the end of the range of motion (ROM).

1+: Slight increase in muscle tone, manifested by a catch, followed by minimal resistance throughout the remainder (less than half) of the ROM.

2: More marked increase in muscle tone through most of the ROM, but affected part(s) easily moved.

3: Considerable increase in muscle tone, passive movement difficult.

4: Affected part(s) rigid in flexion or extension.

Higher scores indicate greater muscle spasticity.

Assessment of motor recovery following stroke using the Brunnstrom Stages of Motor Recovery for the affected limbs [e.g., upper extremity, lower extremity, hand]. The scale evaluates the progression of voluntary movement control from reflex-dominated movement to normal voluntary function.

The scale consists of 6 sequential stages (1 to 6):

Stage 1: Flaccidity; no voluntary movement in the affected limb.

Stage 2: Basic limb synergies appear; spasticity begins to develop.

Stage 3: Voluntary control of movement synergies; spasticity reaches its peak.

Stage 4: Movement combinations out of synergy begin to develop; spasticity begins to decline.

Stage 5: More complex movement combinations learned; basic synergies lose dominance.

Stage 6: Spasticity disappears; individual joint movements become possible and coordination approaches normal.

Higher stages indicate greater motor recovery and voluntary motor control (range: 1 to 6).

Assessment of health-related quality of life (HRQoL) using the 38-item Stroke-Specific Quality of Life Scale (Escala de Calidad de Vida para el Ictus - ECVI-38). The scale evaluates eight domains: Physical Function, Feelings, Communication, Cognition, Family Relationships, Social Relationships, Socio-Economic Function, and Work/Productivity.

Each item is rated on a 5-point Likert scale ranging from 1 to 5. Domain scores and the overall mean score are normalized on a scale from 0 to 100, where higher scores indicate poorer quality of life / greater impairment.

Will be utilized to evaluate functional independence, motor efficiency, and cognitive performance in daily activities. The FIM is an 18-item, 7-level ordinal scale instrument designed to assess the level of burden of care required by individuals with neurological impairments. Each item is scored from 1 (Total Assistance) to 7 (Complete Independence) . The total score ranges from 18 to 126, with higher scores indicating greater functional autonomy.

The scale is structured into two main domains and six subdomains:

Motor Domain (13 items, score range: 13-91):

Self-Care (eating, grooming, bathing, dressing upper body, dressing lower body, toileting)

Sphincter Control (bladder management, bowel management)

Transfers (bed/chair/wheelchair, toilet, tub/shower)

Locomotion (walking/wheelchair mobility, stairs)

Cognitive Domain (5 items, score range: 5-35):

Communication (comprehension, expression)

Social Cognition (social interaction, problem-solving, memory).

Measures the time (in seconds) required for a participant to perform five consecutive sit-to-stand-to-sit cycles as quickly as possible.

Procedure: The participant starts seated on a standard armless chair (height: 43-45 cm) with arms crossed over the chest. Upon the command "Go," the timer starts and stops when the participant's buttocks touch the seat at the end of the fifth repetitio.

Clinical Relevance: assesses movement speed, motor strategy, dynamic balance, and fall risk in individuals post-stroke. A execution time exceeding >12 seconds is indicative of increased fall risk in stroke populations.

General global cognitive function and specific executive performance will be assessed using the Montreal Cognitive Assessment (MoCA).

The MoCA is a widely validated, 30-point screening tool designed to detect mild cognitive impairment (MCI) and subtle post-stroke executive dysfunction with greater sensitivity than traditional screening instruments (such as the Mini-Mental State Examination).

Domain Architecture and Scoring

The assessment evaluates multiple cognitive domains across a total of 30 maximum points:

Visuospatial / Executive Functioning (5 points) Memory / Delayed Recall (5 points). Attention and Working Memory (6 points). Language (3 points) Abstraction (2 points) Orientation (6 points)

Cognitive processing speed, selective attention, response inhibition, and resistance to cognitive interference will be evaluated using the UD Interference Test.

The UD Interference Test is a validated, Stroop-based neuropsychological instrument specifically designed to overcome conventional visual and reading limitations. By utilizing highly contrastable, easily distinguishable colors, enlarged font typography, and a reduced administration time, this instrument minimizes sensory confounding factors such as color blindness (daltonism) or post-stroke visual/reading deficits.

The test consists of three primary conditions administered sequentially under timed constraints:

Word Reading / Word Condition Color Naming / Color:Condition Interference Condition

Visuoperceptual processing speed, visual search, motor tracking, divided attention, and executive cognitive flexibility will be evaluated using the Trail Making Test (TMT), comprising Part A (TMT-A) and Part B (TMT-B).

The TMT is a widely accepted, standardized neuropsychological instrument highly sensitive to prefrontal cortex dysfunction, cognitive slowing, and executive impairment following post-stroke cerebrovascular accidents.

The instrument evaluates cognitive integrity across six primary subscales:

Temporal and Spatial Orientation (10 points) Registration / Immediate Memory (6 points) Attention and Calculation (7 points)

Recall / Delayed Memory (3 points)

Language (8 points) Visuospatial / Constructive Praxis

The Barthel Index is a widely validated, ordinal scale instrument designed to quantify the degree of physical assistance required by an individual with neurological impairment to perform essential basic ADLs (BADLs).

The standard scale evaluates 10 basic personal care and mobility tasks, scored in 5-point increments according to the level of physical assistance required (0, 5, 10, or 15 points per item):

Feeding (0, 5, 10 points) Bathing (0, 5 points) Grooming (0, 5 points) Dressing (0, 5, 10 points) Bowel Control (0, 5, 10 points) Bladder Control (0, 5, 10 points) Toilet Use (0, 5, 10 points) Transfers (Bed to Chair and Back) (0, 5, 10, 15 points) Mobility / Ambulation (0, 5, 10, 15 points) Stairs (0, 5, 10 points)

0 - 20 points Total dependence 21 - 60 points Severe dependence 61 - 90 points Moderate dependence 91 - 99 points Slight / Mild dep 100 points Complete functional independence (in BADLs)