Exploratory Study on the Potential Cross-System Effects of BCI-FES Hand Therapy on Dysphagia and Aphasia in Chronic Stroke Patients

Stroke is the leading cause of permanent disability worldwide. Neurorehabilitation (i.e. physical, occupational, and speech/swallowing therapy) is essential for neurological recovery after stroke. According to principles of neuroplasticity and motor learning, key elements are high-intensity training paradigms with task repetition, therapy feedback and cueing modalities. Technical equipment can assist therapists in reaching these aims, for example by facilitating self-training.

One significant technological advancement in this therapeutic field is Brain-Computer Interface (BCI). BCI most commonly uses EEG-signals (i.e. electroencephalography) to capture task related electrical brain activities related to Motor Imagery (MI) translating it for "closed" neurofeedback. Moreover, BCI is frequently coupled with Functional Electrical Stimulation (FES), which stimulates physical movement in the paretic limb while the MI-related tasks are executed. The processed signals are translated into commands to control an external device. The combination of BCI-feedback technology and FES is primarily used to ensure concurrent sensory feedback with motor intention of a goal-based task to restore sensory-motor functions. In the current approach electrical activity related to the MI of upper limb movements is captured and transferred to a corresponding avatar on a computer screen as feedback for the patient.

c-STEPS is designed as a open-label, single-centre, non-controlled, prospective explorative interventional pre-post study. The primary objective of this study is to explore changes in dysphagia or aphasia in stroke patients with arm paresis treated with a closed-loop BCI-FES therapy (used within the intended purpose for hand rehabilitation). Further study objectives are to assess the impact of established treatment protocols on overall independence, disease severity and quality of life related to dysphagia and aphasia, and to investigate simultaneous recovery patterns in hand motor function, dysphagia, and aphasia using a BCI-FES system.

c-STEPS will enroll 10 participants (+2 potential replacements) who are in the chronic post-stroke phase (≥3 months after an ischemic or haemorrhagic stroke). Participants must present with residual arm paresis and either dysphagia (MUCCS-N ≥2) and/or aphasia (AAT ≤3).

Key exclusion criteria include cognitive impairments affecting compliance, brainstem/cerebellar strokes, previous disabling stroke, uncontrolled epilepsy, pacemakers or implanted devices incompatible with FES, severe neglect or anosognosia, and ongoing botulinum toxin treatment. Participants with severe cardiovascular or respiratory conditions (NYHA IV, COPD IV) or other medical risks affecting safety will also be excluded.

The participants will undergo 25 BCI-FES therapy sessions over 13 weeks (twice a week, 45-minute sessions). Throughout the intervention period, interim assessments will be conducted at predefined time points to evaluate treatment progress. A post-treatment assessment will be performed one week after the final therapy session, with additional follow-up assessments at 4 weeks and 26 weeks post-treatment. The overall study duration per participant is 48 weeks.

Inclusion criteria

• Age: Participants must be aged 18 years or older.
• Post-Stroke Phase: Participants must be within the chronic post-stroke phase (time since ischemic or haemorrhagic stroke greater than 3 months).
• Motor Impairment: Participants must exhibit disabling left or right residual arm paresis ("left/right arm motor drift" part of the NIHSS score ≥1).
• Speech/Swallowing Impairment: Participants must have:

• Aphasia (AAT-Skala zum Kommunikationsverhalten score ≤3), and/or
• Dysphagia (MUCCS-N score ≥2).
• Stable Neurological Status: No relevant changes in neurological status in the past 4 weeks (self-reported).
• Motor Function: Participants must be able to raise at least 1 block similar to the ones in Box-and-Block-Test.
• Cognitive Understanding: Participants must be able to understand basic spoken instructions.
• Sitting Tolerance: Participants must be able to maintain a sitting position for at least 60 minutes.
• Willingness to Participate: Participants must be willing to participate in the study and able to understand and sign the informed consent.

Exclusion criteria

• Cognitive Impairments: Cognitive impairments that, in the investigator's judgment, could limit understanding of task instructions.
• Stroke Location: Participants with a brainstem and/or cerebellar stroke.
• Previous Stroke: Participants with a previous disabling stroke.
• Hemi-Neglect: Pronounced hemi-neglect at the last documented therapy visit that limits compliance with treatment intervention (investigator's judgment).
• Anosognosia: Pronounced anosognosia at the last documented therapy visit that limits compliance with treatment intervention (investigator's judgment).
• Spasticity: Severe spasticity in the affected limb, resulting in complete rigidity in flexion or extension.
• Seizure Disorders: Participants with uncontrolled epilepsy (investigator's judgement) or epileptic seizure within the last month.
• Intracranial Pressure: Known ongoing elevated intracranial pressure.
• Implanted Medical Devices: Participants with implanted medical devices with contraindication for FES such as pacemakers.
• Metallic Fragments: Participants with implanted metallic fragments in the extremity planned for FES that would limit the use of functional electrical stimulation (FES).
• Unhealed Injuries: Unrecovered fractures or skin/tissue lesions in the FES stimulated extremity.
• Joint Issues: Ossification, contraction, or stiffness of the wrist joint in the FES stimulated extremity that would limit treatment.
• Botulinum Toxin: Participants who received botulinum-toxin treatment within 6 weeks prior to study inclusion and/or for whom botulinum-toxin treatment is planned during the study duration.
• Co-morbidities: The following conditions will exclude participation:

• Chronic Obstructive Pulmonary Disease (Stage IV).
• Cardiac insufficiency (NYHA Stage IV).
• Severe acute infections.
• Significant circulatory disturbances in the stimulated extremity.
• Sensory disorders that significantly impair the patient's ability to feel pain or react to unsuitable proprioceptive stimuli.
• Any other general medical conditions that, in the investigator's judgment, limit the safety or performance of study procedures (investigator's judgement).
• Electrical Stimulation Intolerance: Known inability to tolerate cutaneous electrical stimulation.