Deep Brain Stimulation + Therapy for Stroke

Two Vercise™ Cartesia™ X Directional Leads (16-contact) - Model DB-2203 (P150031 - S065) will be surgically implanted bilaterally in the thalamus for the duration of Phases 2 and 3. The leads will be connected to a Vercise Genus R32 IPG (P150031 - S050), which will be surgically implanted in the chest and remain implanted for the duration of Phases 2 and 3. The IPG is rechargeable.

The Vercise Genus R32 IPG (P150031 - S050) is a rechargeable implantable pulse generator designed to deliver electrical stimulation to the thalamus via two surgically implanted Vercise™ Cartesia™ X Directional Leads (16-contact), Model DB-2203 (P150031 - S065). The system will be used for the duration of Phases 2 and 3.

The speech and swallowing training protocol (Rehab) is designed to engage with tailored exercises for speech and swallowing. For speech, the training exercises will be executed following the "Be Clear" program, which has been extensively validated in participants with non-progressive dysarthria and apraxia and has been recently shown to be effective also when administered through telemedicine. For swallowing, the training exercises will be based on the Intensive Dysphagia Rehabilitation protocol, developed for adults with neurogenic dysphagia.

Success Criteria: No serious adverse events related to the stimulation or intolerable adverse events reported.

The investigators will measure the change in the Penetration Aspiration Scale (PAS) from post-implant to the end of Phase 2 with stimulation off. The PAS is an 8-point medical rating system used to describe how deep food, liquid, or saliva goes into a person's airway during a swallow. Scores range from 1 to 8, with lower scores indicating better swallowing function and higher scores indicating worse swallowing function. Success criteria: Mean change in PAS score across Phase 2 is greater than zero, indicating an additional therapeutic benefit of DBS beyond speech and swallowing training executed in Phase 1.

The investigators will measure the change in the Penetration Aspiration Scale (PAS) from baseline to the end of Phase 2 with stimulation off. The PAS is an 8-point medical rating system used to describe how deep food, liquid, or saliva goes into a person's airway during a swallow. Scores range from 1 to 8, with lower scores indicating better swallowing function and higher scores indicating worse swallowing function. Success criteria: Mean change in PAS score across the study period is greater than zero.

The investigators will measure the change in intelligibility from the Speech Intelligibility Test (SIT) from post-implant to the end of Phase 2 with stimulation off. The SIT is a clinical tool used to measure how clearly a person speaks and how well an unfamiliar listener can understand them. The SIT score ranges from 0% to 100%, with higher scores indicating better speech intelligibility and lower scores indicating worse speech intelligibility. It is calculated by counting the number of correct words, dividing that by the total number of words in the target stimulus, and multiplying that by 100 to calculate the percent-correct intelligibility score. Success criteria: Mean change in intelligibility across Phase 2 is greater than zero, indicating an additional therapeutic benefit of DBS beyond speech and swallowing training executed in Phase 1.

The investigators will measure the change in intelligibility from the Speech Intelligibility Test (SIT) from baseline to the end of Phase 2 with stimulation off. The SIT is a clinical tool used to measure how clearly a person speaks and how well an unfamiliar listener can understand them. The SIT score ranges from 0% to 100%, with higher scores indicating better speech intelligibility and lower scores indicating worse speech intelligibility. It is calculated by counting the number of correct words, dividing that by the total number of words in the target stimulus, and multiplying that by 100 to calculate the percent-correct intelligibility score. Success criteria: Mean increase in intelligibility across the study period is equal or greater than 15 percentage points, indicating the average improvement surpasses the minimal clinically meaningful threshold.

The investigators will measure changes in the Modified Barium Swallow Impairment Profile (MBSImP) scores with stimulation on and stimulation off during the same session. The MBSImP evaluates 17 distinct physiological components of swallowing, grouped into three main operational domains. Each component is rated on an ordinal impairment scale, with scores ranging from 0 (normal swallowing function) to 3 to 5 points depending on the specific physiological measure. Lower scores indicate less swallowing impairment and better swallowing function, while higher scores indicate greater swallowing impairment. Success criteria: 75% of participants will have significantly lower MBSImP scores with DBS ON compared to DBS OFF. This will confirm that DBS can immediately improve swallowing function.

The investigators will measure changes in Frenchay Dysarthria Assessment-Second Edition (FDA-2) scores with stimulation on and stimulation off during the same session. The FDA-2 uses a 9-point rating scale, ranging from 1 (severe impairment) to 9 (normal function), with higher scores indicating better motor speech function. Participants will complete either of the motor speech function assessments depending on the nature of their motor speech impairments (i.e., dysarthria vs. apraxia) as identified by a speech-language pathologist prior to speech and swallowing training in Phase 1. Participants with both dysarthria and apraxia will complete both assessments. Success criteria: 75% of participants will have significantly improved scores on the FDA-2 (i.e., higher score) with DBS ON compared to DBS OFF. This will confirm that DBS can immediately improve motor speech function.

The investigators will measure changes in Apraxia Battery for Adults-Second Edition (ABA-2) scores with stimulation on and stimulation off during the same session. The ABA-2 assesses multiple aspects of motor speech and praxis, with subtest scores ranging from 0 to the maximum value specified for each subtest; higher or lower scores indicate better performance depending on the subtest. Participants will complete either of the motor speech function assessments depending on the nature of their motor speech impairments (i.e., dysarthria vs. apraxia) as identified by a speech-language pathologist prior to speech and swallowing training in Phase 1. Participants with both dysarthria and apraxia will complete both assessments. Success criteria: 75% of participants will have significantly improved scores on the ABA-2 (i.e., higher or lower score depending on the subsection) with DBS ON compared to DBS OFF. This will confirm that DBS can immediately improve motor speech function.